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1
Gomez-Puerta, Luis Antonio, Maria Teresa Lopez-Urbina, Hector Hugo Garcia, and Armando Emiliano Gonzalez. "Longevity and viability of Taenia solium eggs in the digestive system of the beetle Ammophorus rubripes." Revista Brasileira de Parasitologia Veterinária 23, no. 1 (March 2014): 94–97. http://dx.doi.org/10.1590/s1984-29612014014.
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The present study evaluated the capacity of Ammophorus rubripes beetles to carry Taenia solium eggs, in terms of duration and viability of eggs in their digestive system. One hundred beetles were distributed into five polyethylene boxes, and then they were infected with T. solium eggs. Gravid proglottids of T. solium were crushed and then mixed with cattle feces. One gram of this mixture was placed in each box for 24 hours, after which each group of beetles was transferred into a new clean box. Then, five beetles were dissected every three days. Time was strongly associated with viability (r=0.89; P<0.001) and the calculated time to cero viability is 36 days. The eggs in the intestinal system of each beetle were counted and tested for viability. Taenia solium eggs were present in the beetle's digestive system for up to 39 days (13th sampling day out of 20), gradually reducing in numbers and viability, which was 0 on day 36 post-infection. Egg viability was around 40% up to day 24 post-infection, with a median number of eggs of 11 per beetle at this time. Dung beetles may potentially contribute towards dispersing T. solium eggs in endemic areas.
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Bucher, Roman, Laura M. Japke, Ayse Gül Ünlü, and Florian Menzel. "Interactions of ants with native and invasive lady beetles and the role of chemical cues in intraguild interference." Chemoecology 31, no. 5 (May 24, 2021): 323–34. http://dx.doi.org/10.1007/s00049-021-00354-4.
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AbstractThe predator-predator naïveté hypothesis suggests that non-native predators benefit from being unknown to native predators, resulting in reduced intraguild interference with native predators. This novelty advantage should depend on the ability of native predators to recognize cues of non-native predators. Here, we compared ant aggression and lady beetle reaction in four native and the invasive lady beetle species Harmonia axyridis. In addition, we tested whether lady beetle cuticular hydrocarbons (CHCs) are involved in species recognition, which might explain naïveté if the invasive species has a specific CHC profile. To this end, we conducted behavioral assays confronting two native ant species with both living lady beetles and lady beetle elytra bearing or lacking CHCs of different lady beetle species. Finally, we characterized CHC profiles of the lady beetles using GC–MS. In general, the aggression of Lasius niger was more frequent than that of Myrmica rubra and L. niger aggression was more frequent towards most native lady beetle species compared to H. axyridis. The removal of CHCs from lady beetle elytra reduced aggression of both ant species. If CHCs of respective lady beetle species were added on cue-free elytra, natural strength of L. niger aggression could be restored. CHC analyses revealed a distinct cue composition for each lady beetle species. Our experiments demonstrate that the presence of chemical cues on the surface of lady beetles contribute to the strength of ant aggression against lady beetles. Reduced aggression of L. niger towards H. axyridis and reduced avoidance behavior in H. axyridis compared to the equally voracious C. septempunctata might improve the invasive lady beetle’s access to ant-tended aphids.
3
Jankowiak, Robert. "Fungi associated with the beetles of Ips typographus on Norway spruce in southern Poland." Acta Mycologica 39, no. 1 (August 20, 2014): 105–16. http://dx.doi.org/10.5586/am.2004.010.
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The mycobiota of the beetles of the phloem-feeding spruce bark beetle, <i>Ips typographus</i> was studied. The most important group of fungi were the ophiostomatoid fungi. Among them <i>O. penicillatum</i> was very frequent ophiostomatoid species. Other common fungi were <i>O. ainoae, O. bicolor, O. piceaperdum and O. piceae</i>. The ophiostomatoid fungi were often more frequent in beetles collected in galleries than in the beetles caught With a trap. Generally the ophiostomatoid fungi were more ofien isolated from the beetle.s bathed in sterile water for 30 seconds. However <i>C. polonica, O. ainoae</i>, and <i>O. minutum</i> occurred most abundantly in the beetles disinfected in 96% ethyl alcohol for 15 and 30 seconds.
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Pettey, Thomas M., and Charles Gardner Shaw. "Isolation of Fomitopsis pinicola from in-flight bark beetles (Coleoptera: Scolytidae)." Canadian Journal of Botany 64, no. 7 (July 1, 1986): 1507–9. http://dx.doi.org/10.1139/b86-204.
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Isolations of Hymenomycetes on a preferential medium were attempted from preflight pine engraver beetles, Ips pini, and the following in-flight bark beetles: pine engraver beetle, I. pini; western pine beetle, Dendroctonus brevicomis; mountain pine beetle, Dendroctonus ponderosae; and red turpentine beetle, Dendroctonus valens. Thirty pine engraver beetles removed from ponderosa pine slash (preflight) yielded no hymenomycete. However, Hymenomycetes were isolated from 50 of 114 beetles (all species) trapped in flight; Fomitopsis pinicola from 44, and other unidentified suspected Hymenomycetes, from 6. Cryptoporus volvatus was not isolated from any of the in-flight beetles. Since most of these isolates were without clamps (monokaryotic), the beetles may acquire basidiospores after emergence from beetle galleries in coniferous trees as hypothesized previously for the Douglas-fir beetle, Dendroctonus pseudotsugae. The isolation of F. pinicola from all species of in-flight bark beetles indicates that these beetles may be important in the dissemination of this hymenomycete.
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Cottrell, Ted E., and Eric W. Riddick. "Limited Transmission of the Ectoparasitic FungusHesperomyces virescensbetween Lady Beetles." Psyche: A Journal of Entomology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/814378.
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The ectoparasitic fungusHesperomyces virescensThaxter (Ascomycota: Laboulbeniales) commonly infects the invasive lady beetleHarmonia axyridis(Pallas) and several other aphidophagous lady beetles in North America and Europe. We tested the hypothesis that bodily contact between adults of different lady beetle species supports horizontal transmission ofH. virescens. We used laboratory assays to determine whetherH. axyridisorOlla v-nigrum(Mulsant) harboringH. virescens(i.e., source beetles) transmit the fungus to noninfected target beetlesH. axyridis,O. v-nigrum,Coccinella septempunctataL.,Coleomegilla maculata(De Geer), orHippodamia convergensGuerin-Meneville. Results indicate that intraspecific transmission (i.e., for the source beetlesH. axyridisandO. v-nigrum) was common but interspecific transmission (i.e., from sourceH. axyridisorO. v-nigrumto target species) was low. Interspecific transmission occurred at low rates fromH. axyridisto bothC. septempunctataandO. v-nigrumand fromO. v-nigrumto bothC. septempunctataandH. convergens. Based upon our laboratory assays of forced pairings/groupings of source and target beetles, we predict that horizontal transmission ofH. virescensbetween species of aphidophagous coccinellids is possible but likely rare.
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Forrest, T. G., H. E. Farris, and R. R. Hoy. "Ultrasound acoustic startle response in scarab beetles." Journal of Experimental Biology 198, no. 12 (December 1, 1995): 2593–98. http://dx.doi.org/10.1242/jeb.198.12.2593.
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We discovered an auditory sense in a night-flying scarab beetle, Euetheola humilis, the first scarab to be shown to hear airborne sounds. In the field, beetles were captured beneath speakers broadcasting ultrasound that simulated bat echolocation pulses. Apparently, the beetles took evasive action from a potential bat predator and flew into the traps. Using another behavioral assay in laboratory studies, the beetles were sensitive to frequencies ranging from 20 to 70 kHz at levels between 60 and 70 dB SPL. One component of the behavioral response, a head roll, was graded with stimulus intensity, and the number of potentials in electromyographic recordings from muscles involved in the roll increased as stimulus intensity increased. The response latency was about 40 ms at threshold, decreasing to about 30 ms at 20 dB above threshold. The beetle's short response latency is ideally suited for predator avoidance behavior and the frequency tuning of the response suggests that it could function in evasion from insectivorous bats. The beetle's acoustic sensitivity is remarkably similar to that of other night-flying insects showing ultrasound-induced startle and it should provide these scarab beetles with a similar advance warning of predation risk.
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Sugiura, Shinji. "Anti-predator defences of a bombardier beetle: is bombing essential for successful escape from frogs?" PeerJ 6 (November 30, 2018): e5942. http://dx.doi.org/10.7717/peerj.5942.
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Some animals, such as the bombardier beetles (Coleoptera: Carabidae: Brachinini), have evolved chemical defences against predators. When attacked, bombardier beetles can discharge noxious chemicals at temperatures of approximately 100 °C from the tip of their abdomens, “bombing” their attackers. Although many studies to date have investigated how bombardier beetles discharge defensive chemicals against predators, relatively little research has examined how predators modify their attacks on bombardier beetles to avoid being bombed. In this study, I observed the black-spotted pond frog Pelophylax nigromaculatus (Anura: Ranidae) attacking the bombardier beetle Pheropsophus jessoensis under laboratory conditions. In Japan, Pe. nigromaculatus is a generalist predator in grasslands where the bombardier beetle frequently occurs. Almost all the frogs (92.9%) observed rejected live bombardier beetles; 67.9% stopped their attacks once their tongues touched the beetles, and 25.0% spat out the beetles immediately after taking the beetles into their mouths. No beetle bombed a frog before being taken into a frog’s mouth. All beetles taken into mouths bombed the frogs. Only 7.1% of the frogs swallowed live bombardier beetles after being bombed in the mouth. When dead beetles were provided instead, 85.7% of the frogs rejected the dead beetles, 71.4% stopped their attacks after their tongues touched the beetles, and 14.3% spat out the beetles. Only 14.3% of the frogs swallowed the dead beetles. The results suggest that the frogs tended to stop their predatory attack before receiving a bombing response from the beetles. Therefore, bombing was not essential for the beetles to successfully defend against the frogs. Using its tongue, Pe. nigromaculatus may be able to rapidly detect a deterrent chemical or physical characteristics of its potential prey Ph. jessoensis and thus avoid injury by stopping its predatory attack before the beetle bombs it.
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Haselsteiner, Andreas F., Cole Gilbert, and Z. Jane Wang. "Tiger beetles pursue prey using a proportional control law with a delay of one half-stride." Journal of The Royal Society Interface 11, no. 95 (June 6, 2014): 20140216. http://dx.doi.org/10.1098/rsif.2014.0216.
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Tiger beetles are fast diurnal predators capable of chasing prey under closed-loop visual guidance. We investigated this control system using statistical analyses of high-speed digital recordings of beetles chasing a moving prey dummy in a laboratory arena. Correlation analyses reveal that the beetle uses a proportional control law in which the angular position of the prey relative to the beetle's body axis drives the beetle's angular velocity with a delay of about 28 ms. The proportionality coefficient or system gain, 12 s −1 , is just below critical damping. Pursuit simulations using the derived control law predict angular orientation during pursuits with a residual error of about 7°. This is of the same order of magnitude as the oscillation imposed by the beetle's alternating tripod gait, which was not factored into the control law. The system delay of 28 ms equals a half-stride period, i.e. the time between the touch down of alternating tripods. Based on these results, we propose a physical interpretation of the observed control law: to turn towards its prey, the beetle on average exerts a sideways force proportional to the angular position of the prey measured a half-stride earlier.
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Apigian, Kyle, and Nathaniel T. Wheelwright. "FOREST GROUND BEETLES (COLEOPTERA: CARABIDAE) ON A BOREAL ISLAND: HABITAT PREFERENCES AND THE EFFECT OF EXPERIMENTAL REMOVALS." Canadian Entomologist 132, no. 5 (October 2000): 627–34. http://dx.doi.org/10.4039/ent132627-5.
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AbstractWe used pitfall trapping to measure the species richness and relative abundance of ground beetles (Coleoptera: Carabidae) in four forest habitats on Kent Island, a 80-ha island in the Bay of Fundy, New Brunswick, Canada. Sixteen species of ground beetles representing 11 genera were identified in the forested habitats on Kent Island; the relative paucity of ground beetle species may be a result of the island’s harsh climate, dense colonies of breeding seabirds, and isolation from the mainland. Estimates of ground beetle population densities on Kent Island ranged from 50 000 to 250 000/ha. Most ground beetle species were trapped in all habitats and appeared to be habitat generalists. In a series of experiments in which we removed all ground beetles trapped daily over a 3-week period in two experimental plots, ground beetle densities remained as high as in a control plot; other ground beetles quickly moved into the experimental plots to replace beetles that had been removed. The density of ground beetles was highest in intact forest and large forest patches; in contrast, the density of invertebrates other than ground beetles (i.e., possible prey or competitors of ground beetles) was highest in open habitats and isolated forest patches, where ground beetles were less common. Removing ground beetles from experimental plots did not result in an increase in the density of other invertebrates.
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SINGH, GURJEET, RAVINDER SINGH, and AKANKSHA SINGLA. "Seasonal abundance of Blister Beetle, Mylabrispustulata Thunberg on Pigeonpea and Mungbean." MAUSAM 72, no. 3 (October 22, 2021): 645–48. http://dx.doi.org/10.54302/mausam.v72i3.1314.
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Seasonal abundance and activity period blister beetle (Mylabrispustulata) on pigeonpea and mungbean were recorded at Research Farms of Pulses Section, Department of Plant Breeding and Genetics, Punjab Agricultural University, Ludhiana. The results showed that the blister beetle started appearing in pigeonpea and mungbean in late August under Punjab conditions. During the crop season, its activity increased and reached at its peak in the end of September (13.90 beetles / 4 meter row length in pigeonpea and 5.48 beetles / 1 sq. meter quadrate in mungbean) coincided with the maximum flowering and afterwards it started declining due to the termination of flowers. The activity of blister beetle was more in the morning (20.23 beetles / 4 meter row length in pigeonpea and 8.04 beetles / 1 sq. meter quadrate in mungbean) and evening hours (21.04 beetles / 4 meter row length in pigeonpea and 8.06 beetles / 1 sq. meter quadrate in mungbean) as compared to the noon hours (0.43 beetles / 4 meter row length in pigeonpea and 0.33 beetles / 1 sq. meter quadrate in mungbean).
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Cameron, R. Scott. "Southern Pine Bark Beetles in the Urban Environment." Arboriculture & Urban Forestry 13, no. 6 (June 1, 1987): 145–51. http://dx.doi.org/10.48044/jauf.1987.031.
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Five species of bark beetles attack pine trees in the South. The southern pine beetle, Dendroctonus frontalis, is the most notorious because of the extensive destruction it periodically causes to commercial pine forests. However, the three species of Ips engraver beetles and the black turpentine beetle, Dendroctonus terebrans, collectively may be more destructive than the southern pine beetle in urban situations. Several insecticides are registered for the prevention and control of southern pine bark beetles, but insecticide treatments are expensive, and control is difficult. Most bark beetles kill pine trees very rapidly and symptoms of attack usually are not detected in time to save infested trees. The best way to prevent losses to bark beetles is to maintain healthy trees.
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Bentz, Barbara J. "Mountain pine beetle population sampling: inferences from Lindgren pheromone traps and tree emergence cages." Canadian Journal of Forest Research 36, no. 2 (February 1, 2006): 351–60. http://dx.doi.org/10.1139/x05-241.
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Lindgren pheromone traps baited with a mountain pine beetle (Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae, Scolytinae)) lure were deployed for three consecutive years in lodgepole pine stands in central Idaho. Mountain pine beetle emergence was also monitored each year using cages on infested trees. Distributions of beetles caught in pheromone traps and emergence cages were compared. Each year, mountain pine beetle emergence from infested trees occurred within a 30-d period, although beetles were caught in pheromone traps over a period as long as 130 d. A large proportion of the total number of beetles caught in pheromone traps occurred prior to and following peak emergence from infested trees. Beetles caught in pheromone traps during the main emergence period from infested trees had greater whole-body lipids compared to beetles caught early and late in the flight season. Low lipid content of beetles caught before and after the main emergence period could be the result of a long-distance flight caused by fewer sources of pheromone attraction on the landscape and (or) some proportion of reemerged parents in the sample. Results suggest that pheromone traps disproportionately sample mountain pine beetle populations and that natural pheromone sources may influence the number and timing of beetles caught in synthetically baited traps.
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Tiring, Gülsevim, Serdar Satar, and Okan Özkaya. "Orman Alanlarında Kabuk Böceklerinin (Coleoptera: Curculionidae, Scolytinae) Mücadelesinde Monoterpenlerin Kullanımı." Turkish Journal of Agriculture - Food Science and Technology 8, no. 7 (July 31, 2020): 1522–27. http://dx.doi.org/10.24925/turjaf.v8i7.1522-1527.3396.
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Bark beetles (Coleoptera: Curculionidae) are among the important pests of forest in the world and in Turkey. Pine-feeding bark beetles interact chemically with their host tree via the behavioral, physiological, and biochemical effects of one class of monoterpenes. The half of oleoresin producing by trees such as pines, spruces, firs in the forests is the monoterpene. The monoterpenes occur in the oleoresin and function as behaviorally active kairomones for pine bark beetles and their predators, presenting a classic example of tritrophic chemical communication. The monoterpenes are aggregation pheromones for pine bark beetle. In the control of bark beetles, monoterpenes are used in traps. For example, the monoterpenes are an attractant for bark beetles. Also, Myrcene is used for a synergistic effect in the trap. Monoterpenes can toxic to insects. Limonene is among the most toxic monoterpenes to bark beetles. Also, the interaction is found between monoterpenes and prey of bark beetle. Monoterpenes are enhanced to respond of predatory to the pheromone of bark beetle.
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DUDUMAN, Mihai-Leonard, and Nicolai OLENICI. "Non-target Bark Beetles in Ips duplicatus (Sahlberg) Pheromone Traps Baited with Host Volatiles." Notulae Botanicae Horti Agrobotanici Cluj-Napoca 43, no. 2 (December 2, 2015): 576–81. http://dx.doi.org/10.15835/nbha4329856.
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Response of several non-target bark beetles (Coleoptera: Curculionidae, Scolytinae) to different combinations of the northern spruce bark beetle’s synthetic pheromone with the monoterpenes (-)-alpha-pinene and (+)-limonene has been studied in choice experiments in the field with flight barrier traps. The experiments were organized in four Norway spruce stands (40-50 years old) outside its natural area, in the north-east of Romania, where Ips duplicatus (Sahlberg) populations had reached an epidemical level. Each experiment had five treatments randomly replicated in six blocks within each experimental plot. Four non-target bark beetle species were captured together with Ips duplicatus: I. typographus (L.) (2611 beetles), Pityogenes chalcographus (L.) (184 beetles), Hylastes cunicularius Erichson (107 beetles) and Dryocoetes autographus (Ratzeburg) (24 beetles), representing 1.77%, 0.13%, 0.07% and 0.02% respectively of total captures. Beetles of I. typographus were attracted by synthetic pheromone blend of I. duplicatus and have intensified their response in the presence of (-)-alpha-pinene or a combination between (-)-alpha-pinene and (+)-limonene, but the other species have been captured in the traps accidentally. The positive response of I. typographus to the present formulation of I. duplicatus pheromone suggests the possibility to use the pheromone dispensers for both species in the same traps when mass-trapping is the main goal, but new studies should clarify the real effects of putting together pheromone dispensers of I. typographus or P. chalcographus with those of I. duplicatus.
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Forrest, T. G., M. P. Read, H. E. Farris, and R. R. Hoy. "A tympanal hearing organ in scarab beetles." Journal of Experimental Biology 200, no. 3 (February 1, 1997): 601–6. http://dx.doi.org/10.1242/jeb.200.3.601.
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We describe the paired hearing organ of the scarab beetle Euetheola humilis. The auditory structures of the beetle are typical of other insect ears in that they have a thinned tympanic membrane backed by a tracheal airsac with associated chordotonal sensory structures. The tympanic membranes of the beetle are part of its cervical membrane and are located behind the head, where the cervix attaches dorsally and laterally to the pronotum. Each membrane is approximately 3 microns thick. The chordotonal sensory organ, which lies within the tracheal airsac, contains 3-8 scolopidia that attach by accessory cells directly to the tympanic membrane. Neurophysiological recordings from the neck connective of the beetle revealed that the auditory system is sensitive to frequencies between 20 and 80 kHz and has a minimum threshold of approximately 58 dB at 45 kHz. The neurophysiological audiogram is identical to the behavioral audiogram for a head roll, one behavioral component of the beetle's startle response elicited by ultrasound. Blocking experiments show that the membranous structures on the cervix are indeed the hearing organs. Neurophysiologically determined thresholds increased by more than 35 dB when drops of water covered the tympanic membranes and were essentially restored to the control level when the water was later removed. At least three other genera of Dynastinae scarabs have similar tympanum-like structures located in their cervical membranes. Behavioral and neurophysiological data show that the frequency tuning of species in two of these genera, Cyclocephala and Dyscinetus, is nearly identical to that of E. humilis. Our discovery represents only the second group of beetles known to respond to airborne sounds. However, the hearing organs of these scarab beetles differ in structure and placement from those of the tiger beetles, and thus they represent an independent evolution of auditory organs in the Coleoptera.
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Shore, Terry L., William G. Riel, Les Safranyik, and Julie Castonguay. "Survival of the Douglas-Fir Beetle in Peeled and Unpeeled Logs and in Stumps." Western Journal of Applied Forestry 20, no. 3 (July 1, 2005): 149–53. http://dx.doi.org/10.1093/wjaf/20.3.149.
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Abstract The Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) can cause significant mortality to mature Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco) during epidemics. Treatment methods are required to reduce local beetle populations to less-damaging levels. We conducted a study to compare the effect on beetle survival of peeling bark from infested logs at two times of year. By Aug., all beetles in bark from logs peeled in July were dead compared with 155.2 beetles/m2 bark in unpeeled logs. In bark from logs peeled at the end of Aug. and left over winter, there were 3.4 beetles/m2 of bark surface compared with 62.3/m2 in unpeeled logs. It was concluded that peeling logs reduces beetle populations, particularly if done early in the summer. We also examined beetle survival in stumps over winter and found that a mean of 70.4 beetles/stump, or 125.6/m2 of stump surface survived winter. It is estimated that it would take beetles emerging from 24 stumps to kill a tree. West. J. Appl. For. 20(3):149–153.
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Domek, John M., and Donn T. Johnson. "Effect of Food and Mating on Longevity and Egg Production in the Green June Beetle (Coleoptera: Scarabaeidae)." Journal of Entomological Science 26, no. 3 (July 1, 1991): 345–49. http://dx.doi.org/10.18474/0749-8004-26.3.345.
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A laboratory rearing experiment was conducted to determine the effect of food intake and mating on longevity and egg production of the female adult green June beetle, Cotinis nitida (L.). A positive relationship existed between the number of eggs laid per beetle and beetle longevity (r = 0.37; P < 0.0001), where apple-fed beetles laid 2.2 eggs per day during a lifespan of 23.0 days and the water-fed beetles laid 1.87 eggs per day during a significantly shorter lifespan of 14.8 days (P < 0.0001). After mean adjustments for the effects of beetle longevity (by the LSMEANS procedure), the apple-fed beetles laid an average of 50.8 eggs which was significantly higher than the 26.9 eggs laid by the water-fed beetles (P < 0.0002). The number of matings had no effect on the numbers of eggs produced nor on beetle longevity. The treatment effects on percentage egg hatch by mating and feeding were insignificant. However, the effect of mating on the percentage of egg hatch differed depending on feeding. These differences were presumed to be due to soil differences between egg rearing containers and not to the effects of mating or feeding. These results suggest that feeding beetles live longer and produce more offspring than beetles that do not feed.
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McKenna, Duane D., Seunggwan Shin, Dirk Ahrens, Michael Balke, Cristian Beza-Beza, Dave J. Clarke, Alexander Donath, et al. "The evolution and genomic basis of beetle diversity." Proceedings of the National Academy of Sciences 116, no. 49 (November 18, 2019): 24729–37. http://dx.doi.org/10.1073/pnas.1909655116.
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The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles—remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.
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Goldhammer, David S., Frederick M. Stephen, and Timothy D. Paine. "THE EFFECT OF THE FUNGI CERATOCYSTIS MINOR (HEDGECOCK) HUNT, CERATOCYSTIS MINOR (HEDGECOCK) HUNT VAR. BARRASII TAYLOR, AND SJB 122 ON REPRODUCTION OF THE SOUTHERN PINE BEETLE, DENDROCTONUS FRONTALIS ZIMMERMANN (COLEOPTERA: SCOLYTIDAE)." Canadian Entomologist 122, no. 3 (June 1990): 407–18. http://dx.doi.org/10.4039/ent122407-5.
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AbstractThe southern pine beetle, Dendroctonus frontalis Zimmermann, was studied in the laboratory to determine the influence of associated fungi on its reproduction. First-generation (P) surface-sterilized beetles associated with mycangial fungi (Ceratocystis minor [Hedgecock] Hunt var. barrasii Taylor or SJB 122) constructed more galleries and laid more eggs, at faster rates, than P beetles not associated with these mycangial fungi. No significant differences occurred among non-surface-sterilized P beetles associated with the phoretic blue staining fungus Ceratocystis minor (Hedgecock) Hunt and mycangial fungi or among progeny of P beetles (F1 generation) carrying mycangial fungi. P and F1 surface-sterilized beetles produced more eggs at a greater density than non-surface-sterilized beetles associated with blue stain, but gallery length and the rate of construction were not different. P and F1 surface-sterilized beetles laid more eggs and constructed galleries faster than surface-sterilized beetles that carried no mycangial fungi. The re-emergence rate of beetles was fastest for P beetles associated with C. minor and significantly slower for fungus-free P beetles, P beetles carrying only mycangial fungi, and F1 beetles, respectively. The F1 generation emerged fastest when associated with both mycangial fungi and slowest when associated with SJB 122, and C. minor var. barrasii or no fungus, respectively. This study employed a successful new rearing technique for isolating specific southern pine beetle/fungal associations.
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Boiteau, Gilles. "Role of vision throughout the flight initiation sequence of the Colorado potato beetle." Canadian Entomologist 137, no. 4 (August 2005): 420–27. http://dx.doi.org/10.4039/n04-111.
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AbstractThe role of vision in the flight initiation sequence of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was assessed by comparing the behavioral sequences and frequencies of takeoffs of untethered and tethered beetles with and without vision. Results showed that vision plays a critical role in the successful completion of the launch and the maintenance of lift for the adult Colorado potato beetle. The sequence was interrupted immediately before or during the lifting of the mesothoracic legs or before the launch for most blind beetles. Liftoffs of untethered beetles over a 1-h period in a flight chamber were reduced significantly, by 77%, in blind beetles compared with normal beetles. In addition, the preponderance of upward (dispersal) flights following successful liftoffs of normal beetles was replaced by a preponderance of downward (short) flights for blind beetles. Blind beetles that did not have to launch themselves because they were tethered initiated flight as frequently as tethered normal Colorado potato beetles. The duration and repeatability of flights initiated by tethered blind Colorado potato beetles were also similar to those of flights initiated by tethered normal Colorado potato beetles in a stationary environment. Together, the results of the tests with untethered and tethered beetles indicate that vision is a key factor during flight launching and for flight continuation.
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Barker, Philip S. "FIRST RECORDS OF PHORETIC BEHAVIOUR OF TARSONEMUS ASCITUS DELFINADO (ACARINA: TARSONEMIDAE) ON GRAIN-INHABITING BEETLES AND ITS SPATIAL DISTRIBUTION ON CARTODERE CONSTRICTA (GYLLENHAL) (COLEOPTERA: LATHRIDIIDAE)." Canadian Entomologist 123, no. 5 (October 1991): 1077–81. http://dx.doi.org/10.4039/ent1231077-5.
Full textAbstract:
AbstractAdult female Tarsonemus ascitus Delfinado mites are recorded for the first time as phoretic on the grain-inhabiting lathridiid beetles Cartodere constricta (Gyllenhal) and Enicmus fictus Fall, and the rhizophagid beetle Monotoma picipes Herbst. The mites preferred to attach to the lateral and undersides of the prothorax of the beetles. The spatial distribution of T. ascitus on C. constricta in suction traps was determined as a guide to the numbers of beetles that would have to be collected to obtain reliable estimates of numbers of mites found per beetle. The mean numbers of mites per beetle was always smaller than the variance, and the spatial distribution of the mites followed a negative binomial distribution. The numbers of beetles required to be collected to provide a predetermined measure of the precision of the numbers of mites per beetle were calculated.
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Bridges, J. Robert, and Thelma J. Perry. "EFFECTS OF MYCANGIAL FUNGI ON GALLERY CONSTRUCTION AND DISTRIBUTION OF BLUESTAIN IN SOUTHERN PINE BEETLE-INFESTED PINE BOLTS." Journal of Entomological Science 20, no. 2 (April 1, 1985): 271–75. http://dx.doi.org/10.18474/0749-8004-20.2.271.
Full textAbstract:
Southern pine beetles, Dentroctonus frontalis Zimmermann, treated to remove their mycangial fungi, were infected with Ceratocystis minor (Hedgcock) Hunt spores and placed in freshly-cut pine bolts. Galleries constructed by beetles without mycangial fungi were significantly shorter and contained significantly more bluestain than galleries constructed by beetles with mycangial fungi. It was concluded that southern pine beetle mycangial fungi limit the distribution of bluestain in southern pine beetle-infested trees. Inhibition of the spread of the bluestain fungus by mycangial fungi may be necessary for optimal beetle development.
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Goulet, H. "Biodiversity of ground beetles (Coleoptera: Carabidae) in Canadian agricultural soils." Canadian Journal of Soil Science 83, Special Issue (August 1, 2003): 259–64. http://dx.doi.org/10.4141/s01-061.
Full textAbstract:
In Canada, ground beetles (Carabidae) are abundant and diverse in agricultural ecosystems. Adults of all species are well characterized, but only 10% are known in the immature stages. In a typical agricultural site, one could find 40 to 60 species. While the ground beetle species composition consists mainly of native species in agriculture sites in the Prairie regions, a mixture of local and accidentally introduced species is the norm elsewhere. Although the diversity of introduced European species is not as great as that of native of ground beetles, the absolute number of European species may dominate an agricultural site. The basic biology and habitat requirements of almost all species occurring in agricultural habitats are known. Each species of beetle has special requirements based on soil type, moisture, pH, and light exposure. They are excellent indicators of habitat modification and of the quality of the environment. Although, most species of ground beetles are predators or scavengers, some are seed feeders. Because of their positive contribution to agricultural ecosystems, maintaining and developing their diversity by providing refuge habitats is recommended. Cropping sequence and type of crop influence ground beetle populations. More important, pesticides of all kinds reduce to various degrees the number of species and specimens. Female fecundity is a most sensitive test of sublethal pesticide effects on groun d beetles and should be considered in future studies of non-target insects. Key words: Ground beetles, carabidae, diversity, ground beetles and agriculture, ground beetles and pesticides, ground beetle extirpation
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Krut’, M. V. "Outstanding scientist-entomologist Z.S. Golovyanko." Ukrainian Entomological Journal 17, no. 2 (December 25, 2019): 68–72. http://dx.doi.org/10.15421/281915.
Full textAbstract:
Golovyanko Zinoviy Stepanovich is an outstanding entomologist well-known in Ukraine and abroad, specialist in insects, which are pests of forest. He is a Doctor of agricultural sciences, Professor. His scientific activity was generally devoted to working out of the measures on creating of pine plantations in the conditions of high number of the roots’ pests, which are largely grubs of May beetle (Melolontha melolontha L., M. hippocastani F.) and July beetle (Polyphillo fullo L.). He revealed that the density of May beetle’s grubs in the soil depends on temperature of this media. Не revealed the capacity of a pine to resist themselves against pests of their roots; this capacity was provided by oleoresin exudation from wounds, which were inflicted by the grubs on roots. He proposed recommendations on pine and deciduous tree species protection from May beetle’s grubs. He developed control measures against scarab beetles grubs for the first time. Z.S. Golovyanko brought the fundamental contribution into solution of the problem on revealing of the factors of population dynamics of bark beetles (Coleopera, Curculionidae: Scolytinae). He had worked out chemical method of forest pests’ control by use of aviation too. The scientific and practical heritage of Z.S. Golovyanko on ecological approach to forest protection from pest organisms is very actual in the present time.
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Toepfer, S., N. Levay, and J. Kiss. "Adult movements of newly introduced alien Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae) from non-host habitats." Bulletin of Entomological Research 96, no. 4 (August 2006): 327–35. http://dx.doi.org/10.1079/ber2006430.
Full textAbstract:
AbstractMark–release–recapture experiments were undertaken in order to investigate the movement of adult Diabrotica virgifera virgifera LeConte from accidental introduction points towards suitable habitats, such as its host plant, Zea mays L. In Hungary in 2003 and 2004, nine mark–release–recapture experiments were carried out in a grass steppe area and lucerne field, in which two small maize fields (10 × 10 m) had been planted 300 m distant from the central release point. After each release of 5500 to 6000 marked D. v. virgifera, beetle recaptures were recorded three times using non-baited yellow sticky traps placed on 30, 105, 205 and 305 m radii around the release point. In seven out of 15 recapture periods (47%), beetle populations showed no directional movements, and their movements towards any particular habitat cannot be predicted. During five recapture periods (33%), beetle populations showed a uni-directional movement, and in three cases (20%) a bi-directional movement was observed. In 10 out of 15 recapture periods (67%), the released populations moved in a direction that was comparable with the mean wind direction during these periods; thus, beetle movements were slightly correlated with wind direction. On average over sites and years, beetles were not preferentially moving towards the two small maize fields (located 300 m from the release point) compared to other directions. However, beetles moved significantly more frequently in the direction of naturally-occurring maize fields within a radius of 1500 m than towards other habitats. Beetles stayed more frequently within flowering lucerne fields out to a radius of 300 and 600 m than in non-flowering lucerne or other habitats. On average, 2.8% (SD 3.2) of all recaptured beetles arrived in one of the two small maize fields located 300 m from their release point indicating that there is a high risk of a founder population establishing. Habitat management cannot be suggested as a means of preventing the beetle's initial dispersal because movement was usually non-directional, and alternative food plants were used prior to reaching maize.
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Caldwell, John S., Sam Johnson, Michael LaChance, and Stephanie Stockton. "Threshold Monitoring, Trap Cropping, and Aluminum Mulch Repulsion for Management of Cucumber Beetles on Cucurbits." HortScience 33, no. 3 (June 1998): 475d—475. http://dx.doi.org/10.21273/hortsci.33.3.475d.
Full textAbstract:
Three approaches to cucumber beetle [striped, Acalymma vittata (Fabricius)]; spotted, Diabrotica undecimpunctata howardi Barber] management on cucurbits were tested on 11 farms in Virginia. Visual counts of striped cucumber beetles/five squash plants were similar in 1996 (2.6 ± 3.1, max 16) and 1997 (3.1 ± 3.8, max 18), but counts on adjacent yellow sticky traps were higher in 1996 (11.5 ± 14.5, max 66) than in 1997 (4.9 ± 4.1, max 16). Correlation between visual and card counts was stronger in 1996 (r = 0.66) than 1997 (r = 0.38). Regression indicated that a threshold of five beetles/five plants was equivalent to 16 beetles/trap in 1996, but only six beetles/trap in 1997. On two peak count dates in Aug. 1996, trap crop squash cultivar NK530 had 10 beetles/sticky card, significantly higher than the three to seven beetles/sticky card on `Seneca' and `Scallop'. Similar trends were seen in visual counts in these plots. In 1997, `NK530' also showed preferential beetle attraction over pumpkin cultivar Howden. On early squash in 1997, cucumber beetle counts on two June peak dates were higher on black plastic (40 and 23 beetles/trap) than on solid aluminum (eight and five beetles/trap) or black with aluminum strips (15 and 10 beetles/trap). Black plastic required 1.8 insecticidal applications compared to none for solid aluminum. There were no significant differences in cumulative yield, although yield at first picking was 38% less on aluminum. Premiums for lower pesticide use (25%) compare favorably with the $102/acre added expense for aluminum plastic.
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van Huis, Arnold. "Cultural Significance of Beetles in Sub-Saharan Africa." Insects 12, no. 4 (April 20, 2021): 368. http://dx.doi.org/10.3390/insects12040368.
Full textAbstract:
An overview is given of how beetles are utilised, perceived, and experienced in daily life across sub-Saharan Africa. More than 300 people from 27 countries were interviewed and the results were compared with literature findings. Both the adults and larvae of many beetle species are eaten, mainly from the families Curculionidae, Buprestidae, Cerambycidae, Dytiscidae and Scarabaeidae. Some beetle species are used for medicinal purposes. The use of breast-shaped water beetles by adolescent girls to stimulate breast growth could be due to superstition or the effect of the defensive secretion containing steroid hormones. Blister beetles contain cantharidin, which influences the urinary tract, and is therefore used as an aphrodisiac and for treating venereal disease. Throughout Africa children play with beetles by letting them fly on a string. In the Sahel, the hard work of dung beetles is an inspiration for stories. Fireflies are generally associated with ghosts and witches, likely because the glowing of the beetles is interpreted as magical. Many beetle groups are brightly and attractively coloured and are therefore used in ceremonies and commerce. This type of indigenous knowledge, revealed in stories provided by older people, is rapidly disappearing due to urbanisation.
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Rhodes, Douglas J., Jane Leslie Hayes, and Chris Steiner. "Retention of External and Internal Markers by Southern Pine Beetles (Coleoptera: Scolytidae) During Gallery Construction." Journal of Entomological Science 33, no. 2 (April 1, 1998): 221–32. http://dx.doi.org/10.18474/0749-8004-33.2.221.
Full textAbstract:
If retained, markers used in mark-release-recapture studies of bark beetle dispersal could provide valuable tools in the determination of post-dispersal fate. Retention of the internal marker rubidium (Rb) and of the external marker fluorescent powder during egg gallery construction, oviposition, and feeding were quantified at intervals from 0 to 96 h by allowing marked Southern pine beetles, Dendroctonus frontalis Zimmermann, to carry out these activities in untreated host material. Significant differences in Rb concentrations were found between fed and unfed Rb-marked beetles at all intervals after 12 h. Unfed Rb-marked beetles were detectable at all intervals, whereas reliable detection of fed Rb-marked beetles declined with time. Over 90% of fed southern pine beetle marked with fluorescent powder were detectably marked after 96 h, while less than 50% of the Rb-marked beetles were detectable after 72 h. Neither marking technique adversely affected the gallery length or number of eggs produced by marked beetles compared to unmarked beetles allowed to excavate for 96 h. Practical aspects of both techniques are considered.
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Hofstetter, Evan M., Wayne H. Knee, and Alexander A. Khaustov. "Phoretic mite assemblage of the pinyon pine beetle, Ips confusus (Curculionidae: Scolytinae), in Arizona." Acarologia 63, no. 2 (April 14, 2023): 480–90. http://dx.doi.org/10.24349/upy5-taez.
Full textAbstract:
Mites are among the most common associates of bark beetles and they can influence the ecology and microbial composition within bark beetle-colonized trees. The pinyon pine engraver, Ips confusus is a common beetle in pinyon trees in the southwestern United States, but the mite composition associated with this beetle has been little studied. In this study, we quantify the abundance, diversity, and attachment locations of phoretic mites on Ips confusus that emerge from naturally infested trees. In total, we observed 342 beetles for mites, 95% of which had at least one mite. We collected a total of 5842 mites, representing seven families and seven species: Cercoleipus coelonotus (Cercomegistidae) Dendrolaelaps quadrisetosimilis (Digamasellidae), Ereynetes propescutulis (Ereynetidae), Iponemus confusus confusus (Tarsonemidae), Mexecheles cf. virginiensis (Cheyletidae), Proctolaelaps subcorticalis (Melicharidae), and Trichouropoda californica (Trematuridae). We calculated the average number of mites per beetle to be 18, with a maximum of 147 mites on a single beetle. The vast majority of mites (98% of total abundance) was represented by three species (I. c. confusus, D. quadrisetosimilis, and T. californica). Attachment locations on the beetle varied across mite species, with mite species exhibiting a preference for specific locations. Mite abundances on emerging host beetles varied over time, with some species occurring mostly on early-emerging beetles, while others occurred on later emerging beetles.
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Miniyarov, Farit Talgatovich, Sergey Ivanovich Pavlov, and Andrey Stepanovich Yaitsky. "Nutrition of the seven-spotted beetles Coccinella septempunctata L. (Coleoptera, Coccinellidae) at different stages of the life cycle." Samara Journal of Science 8, no. 2 (April 1, 2019): 32–38. http://dx.doi.org/10.17816/snv201982106.
Full textAbstract:
The paper presents the results of studies of the seven-spotted beetle ( Coccinella septempunctata L.) life cycle, which has 2 generations in the climatic zone of southern Russia. The main stages of the life cycle are the emergence of imago from winter diapause, the first generation from egg to imago, the second generation from egg to imago, the care of adults for wintering. The eating behavior of coccinellid was studied at each stage of the life cycle, which showed the presence of a small herbivorous period (phytophagous beetles), most of the cycle of the beetles had a predatory lifestyle (entomophage beetles). Experiments in the natural and artificial conditions of studying the nutrition of a seven-point beetle showed that adult beetles were more effective in consuming aphids than the larvae. It was also established that in the natural environment, the degree of palatability, both in the larva and in the imago, was directly dependent on the density of the aphids: as the aphid decreased, the feeding intensity of the beetles decreased. To increase the efficiency of aphid consumption, the joint content of two predatory beetles in the imago stage was used: a seven-spotted beetle ( Coccinella septempunctata L.) and ground beetle ( Tomocarabus bessarabicus concretus Fischer von Waldheim). With such simultaneous use (polyculture), a synergistic effect was observed in their consumption of rosan aphid ( Macrosiphum rosae L.).
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Barchenkov, Alexey, Alexey Rubtsov, Inna Safronova, Sergey Astapenko, Kseniia Tabakova, Kristina Bogdanova, Eugene Anuev, and Alberto Arzac. "Features of Scots Pine Mortality Due to Incursion of Pine Bark Beetles in Symbiosis with Ophiostomatoid Fungi in the Forest-Steppe of Central Siberia." Forests 14, no. 7 (June 24, 2023): 1301. http://dx.doi.org/10.3390/f14071301.
Full textAbstract:
Forest decline is a significant issue affecting critical ecosystem processes worldwide. Here, we describe mortality in Pinus sylvestris L. monitored trees caused by the inhabitation of pine bark beetles (Tomicus minor Hart.) in symbiosis with ophiostomatoid fungi (Ophiostoma piceae (Munch) H. et P. Sydow) infection in the forest-steppe of central Siberia. Stem sap flow (Q) and stem diameter fluctuations (dRc) were monitored in eight pine trees during seven consecutive growing seasons (2015–2021). In addition, microcore sampling every ten days allowed the determination of stem wood formation in monitored trees in the 2021 growing season. During 2020 and 2021, two cases of Q termination were recorded among the monitored trees, with microcores revealing no cambium formation. Thus, the seasonal Q onset matches the beginning of the beetle dispersal period when they attack and inhabit tree stems. The decline of circumferential stem size began 10–12 days after Q onset, during the massive inhabitation of beetles into the stems. The disturbance of Q in trees occurred in 21–23 days, and total cessation of Q was observed 23–26 days after the Q onset at the beetle’s egg development phase. The timing of dRc disturbance and Q cessation observed directly coincides with the beetle life cycle. Thus, the phenology of pine trees and T. minor beetles is driven by seasonal weather conditions, particularly the cumulative air temperature (>0 °C).
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Hayslett, Maya, Jennifer Juzwik, and Bruce Moltzan. "Three Colopterus Beetle Species Carry the Oak Wilt Fungus to Fresh Wounds on Red Oak in Missouri." Plant Disease 92, no. 2 (February 2008): 270–75. http://dx.doi.org/10.1094/pdis-92-2-0270.
Full textAbstract:
Beetles in the family Nitidulidae can transmit the oak wilt fungus, Ceratocystis fagacearum, to fresh wounds on healthy oak trees, leading to infection and disease development. Historically, nitidulid beetles have not been considered important vectors of the pathogen in Missouri. Studies were conducted in the spring of 2005 and 2006 to determine frequencies of nitidulid beetle species contaminated with C. fagacearum visiting fresh wounds on red oak trees in central Missouri. Colopterus truncatus, C. niger, and C. semitectus were the most abundant species collected from fresh wounds and the only species found to be contaminated with Ceratocystis fagacearum. Of 230 beetles assayed for C. fagacearum, 23 yielded the fungus. Contamination frequencies were higher for beetles collected in April than May; no beetles collected in June were contaminated. We hypothesize that Colopterus truncatus, C. niger, and C. semitectus are principal nitidulid beetle vector species in Missouri during spring. The risk for pathogen transmission by these beetles appears to be greatest in April and least in June.
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Luzyanin, Sergey L., Alla A. Ditts, and Andrey S. Babenko. "Rove beetle communities (Coleoptera: Staphylinidae) in the rock dumps after coal mining." Ecologica Montenegrina 70 (December 15, 2023): 116–27. http://dx.doi.org/10.37828/em.2023.70.13.
Full textAbstract:
Rock dumps formed as a result of coal mining are unique model for studying the rove beetle communities. In total 60 species, 38 genera, 7 subfamilies of rove beetles were registered using soil traps. The greatest diversity of rove beetles was noted in forb-grass meadows (H` = 2.89) and pine plantations (H` = 2.39). The diversity of rove beetles was low (H` = 1.11) in birch and aspen-fir forests despite the greater number of revealed species. Only two eurytopic and mesophilic species (Drusilla canaliculata and Xantholinus linearis) were dominant in the rock dumps. Most of the rove beetles were eurytopic or forest species, zoophagous or mixophagous, mesophilous or hygrophilous. The number of eurytopic species and obligate predators increased, and the dynamic density of beetles decreased from older to younger dumps. The number of rove beetles depended on the soil temperature and humidity and the vegetation cover. Rove beetle communities are good indicators for monitoring the restoration of areas that have been technically degraded.
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Leung, Joyce P. S., Jenny S. Cory, J. Todd Kabaluk, and Alida F. Janmaat. "Effect of Collection Month, Visible Light, and Air Movement on the Attraction of Male Agriotes obscurus L. (Coleoptera: Elateridae) Click Beetles to Female Sex Pheromone." Insects 11, no. 11 (October 26, 2020): 729. http://dx.doi.org/10.3390/insects11110729.
Full textAbstract:
Elaterid female sex pheromone, while currently used for monitoring the adult life stage (click beetle), has only recently been explored as a potential management tool. Consequently, there is little understanding of how abiotic and biotic conditions influence the response of click beetles to the pheromone. We examined whether the response of male Agriotes obscurus L. (Coleoptera: Elateridae) beetles to a cellulose-based formulation of female sex pheromone (‘pheromone granules’) is influenced by air movement, presence of visible light, and month of beetle collection. In addition, we investigated the distance from which beetles were attracted to the pheromone granules. Click beetle response was determined by measuring movement parameters in free-walking arena experiments. The response to pheromone was not affected by the presence or absence of visible light. We found that beetles collected earlier in the season had increased activity and interaction with pheromone under moving air conditions, compared to beetles collected later. When controlling for storage time, we confirmed that individuals collected in May were less active than beetles collected in March and April. In the field, beetles were recaptured from up to 14 m away from a pheromone granule source, with over 50% being recovered within 4.4 h from a distance of 7 m or less. Understanding how abiotic and biotic factors affect pest response to pheromone can lead to more effective and novel uses of pheromone-based management strategies.
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Michael, Saluta, Joan A. Lasota, and James E. Roberts. "Yield Response and Efficacy of Penncap-M on Chinese Cabbage, 1984." Insecticide and Acaricide Tests 10, no. 1 (January 1, 1985): 84–85. http://dx.doi.org/10.1093/iat/10.1.84a.
Full textAbstract:
Abstract A randomized complete block design replicated 4 times was used. Plots were 7.5 ft by 3 ft and consisted of 10 plants per replicate. There was a 3-ft row spacing, 1.5 ft between plants and a 3-ft alley spacing between replicates. Prior to planting, 3 lb 10-10-10- fertilizer/100 sq ft and 10 lb lime/100 sq ft were incorporated into a tilled plot. The soil was fumigated with bromomethane (1 lb/100 sq ft). Seedlings were transplanted on 31 Jul. Insecticide was applied as a foliar broadcast spray over the row using a compressed air sprayer. A Teejet 8003 Fan type nozzle (25-30 psi, 20 gal/acre) was used for the first application, and 2 Teejet 8003 nozzles, with a boom spacing of 30 inches, were used for the second and third applications. Applications, which were made on 8 Aug, 15 Aug and 5 Sept, corresponded with the seedling, post-seedling and mature plant growth stages, respectively. Prior to these experimental treatments, an application of methomyl was delivered to all plants on 2 Aug. This was necessary to reduce a heavy flea beetle infestation which would have resulted in heavy seedling mortality if left untreated (Penncap-M was not vet available for use). The presence of flea beetle adults and their damage was assessed on 15 Aug. The following rating index was used to assess the quantity of adult flea beetles per plant; (0 = ((beetles, 1 = 1- 10 beetles, 2 = 11 - 20 beetles, 3 = 21 - 30 beetles, 4 = 31 - 40 beetles, 5 = 41-50 beetles, 6 = 50+ beetles). The number of flea beetle feeding scars in a 1 cm2 area at the center of 1 randomly chosen leaf per plant was used for rating flea beetle feeding damage. Yield data were collected on 20 Sep by weighing marketable heads.
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Marchioro, Matteo, Davide Rassati, Massimo Faccoli, Kate Van Rooyen, Chantelle Kostanowicz, Vincent Webster, Peter Mayo, and Jon Sweeney. "Maximizing Bark and Ambrosia Beetle (Coleoptera: Curculionidae) Catches in Trapping Surveys for Longhorn and Jewel Beetles." Journal of Economic Entomology 113, no. 6 (September 23, 2020): 2745–57. http://dx.doi.org/10.1093/jee/toaa181.
Full textAbstract:
Abstract Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.
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Khalid S. Alshallash, Khalid S. Alshallash. "Biological Control of the Weedy Plant (Rumex crispus) at the Seedling Growth Stage by the Green Dock Beetle (Gastrophysa viridula)." journal of King Abdulaziz University - Meteorology, Environment and Arid Land Agriculture Sciences 28, no. 1 (February 14, 2019): 21–31. http://dx.doi.org/10.4197/met.28-1.3.
Full textAbstract:
In four glasshouse experiments, the effectiveness of the adult green dock beetle Gastrophysa viridula (Coleoptera: Chrysomelidae), at the effective number of applied individuals, for use as a biological control agent of curled dock, Rumex crispus (Polygonaceae) were studied. The feeding of the beetle was investigated at four different numbers of beetle (0, 1, 2, 3) and at four seedling growth stages of the plant, defined by the average of leaf area per plant (1-1.22 , 2-4.45, 3-11.56, and 4-71.52 cm2/plant). Grazing by one, two or three dock beetles did not result in a significant reduction in dock dry weight or shoot numbers at the youngest growth stage. However, both at later seedling growth stages were significantly affected (P ? 0.0001), at any beetles number. The increase of beetle numbers caused nonsignificant increased effect, in some trials, confirming the impact of a single beetle. Three months after beetle grazing, dock seedlings of first, second and third growth stages were not able to regrow, however, some plants at the 4th growth stage, re-emerged. This suggested that the highest effect of beetle's feeding occurs on the early seedling stages. Statistical analysis showed a positive correlation (0.77) between dry weight and shoot number at all the four seedling growth stages, thus confirming the impact of the beetle on both the dry weight and shoot numbers. Combining beetle grazing with other control methods at older dock seedling stages could, therefore, provide better suppression
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Ma, Long, Nirodha Weeraratne, Saliya Gurusinghe, Jesmin Aktar, K. M. Shamsul Haque, Philip Eberbach, Geoff G. Gurr, and Leslie A. Weston. "Dung Beetle Activity Is Soil-Type-Dependent and Modulates Pasture Growth and Associated Soil Microbiome." Agronomy 13, no. 2 (January 21, 2023): 325. http://dx.doi.org/10.3390/agronomy13020325.
Full textAbstract:
The introduction of numerous exotic dung beetles across southern Australia in regions where native dung beetles are not generally efficient in processing livestock dung has resulted in significant reductions in the quantity of such dung on the soil surface in recent years. However, the direct impacts of such ecosystem services on pasture quality and soil nutrient mobility have not yet been investigated in detail in the Riverina region of New South Wales (NSW), an area recognised for prime cattle and sheep production in Australia. Utilising 48 soil columns for lysimetry, we quantified the impact of a common introduced dung beetle (Bubas bison) in this region on water quality after permeation through four different soil types sown to winter annual pastures. Dung beetle treatments included dung plus dung beetles, dung alone and no dung beetles, and no dung as a control. Dung beetles and soil type impacts on the performance of improved overseeded annual pastures as measured by biomass accumulation was assessed over a four-month growing season. The four soil types, namely, Chromosol, Kandosol, Rudosol, and Vertosol, differed considerably with respect to their water-holding capacity and nutrient profiles, as assessed by initial soil testing and soil leachate evaluation following rainfall plus simulated rainfall events. The concentration of Escherichia coli resulting from cattle dung, cattle dung plus beetles, and the control soils without dung or beetles was assessed in collected leachates over a three-month period. E. coli numbers were significantly increased following B. bison activity, when compared to the dung-only and control treatments. Evaluation of the soil microbiome, by assessing genomic DNA in soils sampled 10 cm below the soil surface where dung beetles remained active following tunnelling, revealed significant differences among soil types with respect to bacterial and fungal communities. Within each soil type, dung beetle activity impacted the fungal community structure, but not the bacterial community. Pasture performance as assessed by biomass accumulation was significantly improved following dung beetle activity in later stages of pasture growth, while E. coli numbers and total coliforms appeared unaffected by beetle presence.
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SAIMOVA, R. U., K. I. BATYROVA, N. A. BEKENOVA, E. KAUYNBAEVA, and B. K. ESIMOV. "GROUND BEETLES (COLEOPTERA: CARABIDAE) IN DIFFERENT AGROECOSYSTEMS OF SOUTHEAST KAZAKHSTAN." SABRAO Journal of Breeding and Genetics 54, no. 2 (June 30, 2022): 458–68. http://dx.doi.org/10.54910/sabrao2022.54.2.21.
Full textAbstract:
The recent study on ground beetles (Carabidae) was carried out in 2020 over five different agroecosystems, i.e., alfalfa, barley, corn, soybean, and triticale, at the Kaskelen Experimental Farm, Southeast Kazakhstan. Overall, 38 species of ground beetles related to 24 genera were identified. From these, the Harpаlus rufipes, Poecilus cupreus, and P. versicolor were the dominant ones in the different agroecosystems. Most of the ground beetles are general predators and useful as entomophages. These beetles and their larvae exterminate various agricultural pests. However, the presence of P. versicolorand P. cupreus suggests a threat to the crops. Those species have a mixed diet and are also known as economically significant pests, of which the most famous is the ground beetle Zabrus morio. Different agroecosystems have shown different distributions of ground beetle species, indicating the influence of cultivated crops on the formation of the ground beetle community. Findings from the study could provide the basis for designing crop management programs after promoting the presence of ground beetles that can contribute to the prevention and control of agricultural pests.
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Shirbhate, Milind, and Amrita Shirbhate. "Diversity and checklist of Beetles (Arthropoda: Coleoptera) from Forest areas and Agricultural areas of District Akola, (Maharashtra), India." Environment Conservation Journal 21, no. 1&2 (June 10, 2020): 89–94. http://dx.doi.org/10.36953/ecj.2020.211210.
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A survey was organised from August 2016 to February 2020 in the forest areas and agricultural areas of Akola district to know the diversity of Beetles for further research. A total of 68 genera and 90 species belonging to 13 different families of beetles viz. Buprestidae (Metallic Wood-boring Beetle), Carabidae (Ground Beetles), Cerambycidae, Chrysomelidae (Leaf beetles), Coccinellidae, Dytiscidae, Geotrupidae, Gyrinidae, Hydrophilidae, Hybosoridae, Meloidae (Blister Beetles), Scarabaeidae, Tenebrionidae (Darkling Beetles) were collected and identified from various habitats along with their valid scientific names, systematic position, and distribution within agricultural fields and forest areas of Akola district.
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Kandasamy, Dineshkumar, Rashaduz Zaman, Yoko Nakamura, Tao Zhao, Henrik Hartmann, Martin N. Andersson, Almuth Hammerbacher, and Jonathan Gershenzon. "Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes." PLOS Biology 21, no. 2 (February 21, 2023): e3001887. http://dx.doi.org/10.1371/journal.pbio.3001887.
Full textAbstract:
Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle’s host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.
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Raine, Elizabeth H., and Eleanor M. Slade. "Dung beetle–mammal associations: methods, research trends and future directions." Proceedings of the Royal Society B: Biological Sciences 286, no. 1897 (February 20, 2019): 20182002. http://dx.doi.org/10.1098/rspb.2018.2002.
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Dung beetles are increasingly used as a study taxon—both as bioindicators of environmental change, and as a model system for exploring ecosystem functioning. The advantages of this focal taxon approach are many; dung beetles are abundant in a wide range of terrestrial ecosystems, speciose, straightforward to sample, respond to environmental gradients and can be easily manipulated to explore species-functioning relationships. However, there remain large gaps in our understanding of the relationship between dung beetles and the mammals they rely on for dung. Here we review the literature, showing that despite an increase in the study of dung beetles linked to ecosystem functioning and to habitat and land use change, there has been little research into their associations with mammals. We summarize the methods and findings from dung beetle–mammal association studies to date, revealing that although empirical field studies of dung beetles rarely include mammal data, those that do, indicate mammal species presence and composition has a large impact on dung beetle species richness and abundance. We then review the methods used to carry out diet preference and ecosystem functioning studies, finding that despite the assumption that dung beetles are generalist feeders, there are few quantitative studies that directly address this. Together this suggests that conclusions about the effects of habitat change on dung beetles are based on incomplete knowledge. We provide recommendations for future work to identify the importance of considering mammal data for dung beetle distributions, composition and their contributions to ecosystem functioning; a critical step if dung beetles are to be used as a reliable bioindicator taxon.
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Santos-Heredia, Carolina, and Ellen Andresen. "Upward movement of buried seeds: another ecological role of dung beetles promoting seedling establishment." Journal of Tropical Ecology 30, no. 5 (August 1, 2014): 409–17. http://dx.doi.org/10.1017/s0266467414000376.
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Abstract:Dung beetles are known to perform important ecological functions, such as secondary seed dispersal of vertebrate-defecated seeds. We found that dung beetles also move buried seeds upwards, with positive consequences for seedling establishment. In the Lacandon rain forest of southern Mexico we conducted field experiments to address three questions: (1) What proportions of different-sized seeds buried by dung beetles are exhumed by them? (2) Does upward relocation of seeds caused by dung beetle activity promote seedling establishment? (3) Does recurrent beetle activity increase seedling establishment? Using 4-mm, 8-mm and 12-mm beads as seed mimics, embedded in howler-monkey dung, we found that 2–6% of buried beads were later exhumed by beetles, with smaller beads exhumed more often. In small plots (N = 100) where beetles were allowed to bury dung and seed rain was excluded, seedling establishment was over three times higher compared with plots without beetle activity. In plots (N = 8) where we placed dung on four occasions in 1 mo, seedling establishment was more than twice as high compared with plots with single-time dung placement. We believe that our findings open up interesting research opportunities to help further elucidate this newly discovered ecological function of dung beetles.
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Bracalini, Matteo, Guido Tellini Florenzano, and Tiziana Panzavolta. "Verbenone Affects the Behavior of Insect Predators and Other Saproxylic Beetles Differently: Trials Using Pheromone-Baited Bark Beetle Traps." Insects 15, no. 4 (April 9, 2024): 260. http://dx.doi.org/10.3390/insects15040260.
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In our study, we assessed the effects of verbenone, the most widely studied bark beetle aggregation inhibitor, on saproxylic beetles in a Mediterranean pine forest in Tuscany. Verbenone pouches were devised in the laboratory and then applied to Ips sexdentatus pheromone traps so that their catches could be compared to those of traps containing just the pheromone. The trial was carried out in spring–summer 2023, and insect catches were collected every two weeks. A total of 9440 beetles were collected that belonged to 32 different families and 57 species. About 80% of the captures were bark beetles, mainly Orthotomicus erosus. Beetle predators accounted for about 17% of the captures, with a total of 12 species. Some of these predator species had not yet been studied in relation to verbenone effects, like other saproxylic beetles recorded in this study. A significant reduction in captures was recorded for some beetles (e.g., I. sexdentatus and O. erosus), while for other species, no differences emerged, and in some cases, captures increased significantly when verbenone was present in the traps (i.e., Hylurgus ligniperda, Corticeus pini, and Aulonium ruficorne). The diversity of caught saproxylic beetles increased significantly in the verbenone traps, highlighting possible implications of the use of verbenone when managing bark beetle outbreaks.
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Conrad, Nils, Meike Brandes, Bernd Ulber, and Udo Heimbach. "Effect of immigration time and beetle density on development of the cabbage stem flea beetle, (Psylliodes chrysocephala L.) and damage potential in winter oilseed rape." Journal of Plant Diseases and Protection 128, no. 4 (June 2, 2021): 1081–90. http://dx.doi.org/10.1007/s41348-021-00474-7.
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AbstractIn a semi-field net cage experiment set up in three growing seasons (2015–2018) at Julius-Kühn Institute Braunschweig, Germany, the influence of different release times of adult cabbage stem flea beetles, Psylliodes chrysocephala (early September, mid-September, early October) and different beetle densities (6.7, 13.3 and 20 beetles/m2) on reproduction and damage potential in winter oil seed rape was investigated. In parallel to the cage trials, the number of deposited eggs was assessed in small boxes exposed in the field. Beetles released in early September laid significantly more eggs compared to beetles released early October, with a maximum of 270 eggs per female. The early release of beetles resulted in significantly higher numbers of larvae in autumn, but this differed significantly between the years. Warm autumn or winter conditions led to continued egg laying and development, whereas cold conditions stopped the reproduction. Significant yield losses (25%) and significant plant losses during winter were only found in 2016/17 in treatments with an early release of high numbers of beetles (20 beetles /m2). The German damage threshold of 3–5 larvae per plant was reached when 13 beetles/m2 were released before 20th September and 20 beetles per m2 after 20th September. Data of this study can be used for a better damage prediction and a more targeted beetle control.
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Noronha, Christine, and Conrad Cloutier. "GROUND AND AERIAL MOVEMENT OF ADULT COLORADO POTATO BEETLE (COLEOPTERA: CHRYSOMELIDAE) IN A UNIVOLTINE POPULATION." Canadian Entomologist 131, no. 4 (August 1999): 521–38. http://dx.doi.org/10.4039/ent131521-4.
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AbstractPitfall and screen traps were used around potato Solanum tuberosum L. (Solanaceae) plots to detect directional patterns of prediapause (two seasons) and postdiapause (one season) movement in a univoltine population of the Colorado potato beetle, Leptinotarsa decemlineata (Say), from Quebec. Prediapause beetles were sampled for diapause readiness using a feeding–digging test. In 1994, a plot left unprotected from the beetle (moderately defoliated) was monitored. In 1995, movement around a plot left unprotected from the beetle (severely defoliated) was compared to that from a plot protected (only lightly defoliated) by inundative release of the potato beetle predator Perillus bioculatus Say (Hemiptera: Pentatomidae). Movement frequency by postdiapause beetles in spring 1995 was low compared with 1994 prediapause movement, especially on the ground. Low-frequency flying persisted over several weeks of postdiapause beetle oviposition, with only a brief period of directionality. Flight movement by satiated prediapause beetles in August 1994 and 1995 was strongly directional, being oriented toward the closest forest border east of the plots, where sampling confirmed overwintering. In both years, satiated prediapause beetles also emigrated by walking, but mostly from densely populated and defoliated plots. Newly emerged (unsatiated) prediapause beetles emigrated en masse from severely defoliated plants, and did so exclusively by walking. Directional walking contrasted with directional flying in being predominantly oriented south-westward to northwestward, suggesting cueing on the sun position during warm hours of the day.
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Gavloski, J. E., U. Ekuere, A. Keddie, L. Dosdall, L. Kott, and A. G. Good. "Identification and evaluation of flea beetle (Phyllotreta cruciferae) resistance within Brassicaceae." Canadian Journal of Plant Science 80, no. 4 (October 1, 2000): 881–87. http://dx.doi.org/10.4141/p99-164.
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All currently registered varieties of canola/oilseed rape, Brassica napus and B. rapa, are susceptible to attack by flea beetles, although to varying degrees. The development of resistant cultivars would be an environmentally acceptable means to reduce the damage caused by flea beetles. Seedlings from 10 species of Brassicaceae were evaluated for levels of antixenosis resistance to flea beetles in the laboratory, along with 308 Sinapis alba/B. napus hybrids. Thlaspi arvense and 11 cultivars of S. alba were resistant to feeding by flea beetles. In addition, 34 S. alba/B. napus hybrids were resistant to feeding by flea beetle in at least one test, although many of these failed to demonstrate resistance with repeated testing. One hybrid line was resistant to feeding by flea beetles each of the four times it was tested, while another was resistant in three out of four tests. These data indicate that resistance to flea beetles within the Brassicaceae is a genetic trait and can be transferred by interspecific hybridization. This information is the first step towards introgression of genetic sources of flea beetle resistance from resistant relatives into canola varieties. Key words: Flea beetles, Phyllotreta cruciferae, Brassica, resistance, antixenosis, introgression
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von Hoermann, Christian, Sandra Weithmann, Markus Deißler, Manfred Ayasse, and Sandra Steiger. "Forest habitat parameters influence abundance and diversity of cadaver-visiting dung beetles in Central Europe." Royal Society Open Science 7, no. 3 (March 2020): 191722. http://dx.doi.org/10.1098/rsos.191722.
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Dung beetles provide crucial ecosystem services and serve as model organisms for various behavioural, ecological and evolutionary studies. However, dung beetles have received little attention as consumers of large cadavers. In this study, we trapped copronecrophagous dung beetles on above-ground exposed piglet cadavers in 61 forest plots distributed over three geographically distinct regions in Germany, Central Europe. We examined the effects of land use intensity, forest stand, soil characteristics, vascular plant diversity and climatic conditions on dung beetle abundance, species richness and diversity. In all three regions, dung beetles, represented mainly by the geotrupid species Anoplotrupes stercorosus and Trypocopris vernalis , were attracted to the cadavers. High beetle abundance was associated with higher mean ambient temperature. Furthermore, A. stercorosus and T. vernalis were more abundant in areas where soil contained higher proportions of fine sand. Additionally, an increased proportion of forest understorey vegetation and vascular plant diversity positively affected the species richness and diversity of dung beetles. Thus, even in warm dry monocultured forest stands exploited for timber, we found thriving dung beetle populations when a diverse understorey was present. Therefore, forestry practices that preserve the understorey can sustain stable dung beetle populations and ensure their important contribution to nutrient cycles.
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Boiteau, G., and P. C. McCarthy. "Is there a role for stripes of adults and colour of larvae in determining the avoidance of the Colorado potato beetle by the American toad?" Canadian Journal of Zoology 88, no. 5 (May 2010): 468–78. http://dx.doi.org/10.1139/z10-017.
Full textAbstract:
It has been suggested that the stripes on the elytra of the adult Colorado potato beetle ( Leptinotarsa decemlineata (Say, 1824); Coleoptera: Chrysomelidae) and the red colouration of the larvae are aposematic characters warning predators of their distastefulness as prey. The role of stripes and red colour in determining the avoidance behaviour of the American Toad ( Bufo americanus Holbrook, 1836 = Anaxyrus americanus (Holbrook, 1836); Anura: Bufonidae) for the Colorado potato beetle was investigated in a series of laboratory tests. The behaviour of toads exposed to wild Colorado potato beetles was compared with that of toads exposed to genetic mutant Colorado potato beetles without elytral stripes. Tests confirmed the distastefulness of adult and larval stages and demonstrated the development of prey avoidance (cessation of feeding in spite of hunger) combined or not to behavioural displays where the toad plants down, crouches, and turns away or shows wincing, prey dropping, and mouth gaping after snapping at the beetle. However, toads showed the same response to mutant adult beetles without stripes and to mutant larval beetles without the red colour as to wild adult beetles with stripes and to wild red larvae. Results indicate that the stripes and the red colouration of the Colorado potato beetle do not constitute aposematic characters for the toad.
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LAMB, R. J. "ASSESSING THE SUSCEPTIBILITY OF CRUCIFER SEEDLINGS TO FLEA BEETLE (Phyllotreta spp.) DAMAGE." Canadian Journal of Plant Science 68, no. 1 (January 1, 1988): 85–93. http://dx.doi.org/10.4141/cjps88-009.
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A 5-yr field study to develop a method for assessing the susceptibility of crucifer seedlings to damage by the flea beetles Phyllotreta cruciferae (Goeze) and Phyllotreta striolata (F.) is described. The recommended method consisted of five replicate 5-m rows per cultivar in a randomized complete-block design. Each test was sown three times at weekly intervals, to assure that at least one test received an appropriate level of flea beetle damage. Each test was assessed 4–5 wk after seeding by counting the number of surviving seedlings in each row and by weighing the dried aboveground portion of 10 randomly selected seedlings, although the latter discriminated fewer lines. The damage caused by flea beetles varied spatially, but this source of variation was minor and did not compromise the tests. This method proved adequate for discriminating among crucifer species and agronomically similar cultivars, some of which showed consistent, significant differences in their responses to flea beettle damage.Key words: Crucifer, rapeseed, flea beetle, pest resistance