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1
Sumah, Astrid Sri Wahyuni. "FUNCTIONAL RESPONSE OF PREDATOR Paederus sp. (COLEOPTERA: STAPHYLINIDAE)". Indonesian Journal of Applied Research (IJAR) 4, n. 1 (18 aprile 2023): 53–62. http://dx.doi.org/10.30997/ijar.v4i1.257.
Testo completoAbstract (sommario):
Research on predatory predation of Paederus sp. (Coleoptera: Staphylinidae) was carried out to study the functional response of the predator Paederus sp. Functional response is a form and size predictor of consumer impact on resource populations, determining the effectiveness of a predator as an agent in biological control. Predation time in hungry and not-hungry conditions influences predator-prey interactions, which are essential in functional response. The method used in predating Paederus sp. on the prey of aphids was Aphid spp. They are using four levels of prey density with two different predator treatments. The results show the functional response model of Paederus sp. predators. against the prey of Aphid spp. Described in a type II model. The level of predation of Paederus sp. showed different results for the two treatments and an increasing cystoid curve at a rising rate. The level of predation is still increasing, along with the increase in host density, and can be a starting point for controlling the Aphid spp and using predators Paederus sp. in the field.
2
Battisti, Corrado, Marisa Perchinelli, Luca Luiselli, Daniele Dendi e Sharon Vanadia. "Cages Mitigate Predation on Eggs of Threatened Shorebirds: A Manipulative-Control Study". Conservation 2, n. 3 (16 luglio 2022): 450–56. http://dx.doi.org/10.3390/conservation2030030.
Testo completoAbstract (sommario):
Beach-nesting birds (plovers; Aves; Charadridae) are impacted by many natural and human-induced threats (e.g., people trampling, dogs, and natural predators). In this regard, the use of anti-predator cages on their nests is effective in order to mitigate some of these pressures (i.e., predation). To evaluate the efficacy of anti-predator cages and the causes of nest failure in a breeding site of two species (Charadrius alexandrinus and C. dubius), we carried out a control-experimental design, comparing false nests (n = 69) in cages (experiment; n = 30) with false nests without cages (control; n = 39). We carried out the study in three seasonal periods (May, June, and July), controlling predations after three periods (three, six, and nine days) since positioning, recording the frequency of eggs still present and evidencing any predation event. The percentage of residual eggs was significantly higher in experimental nests when compared to control nests in all recording periods. Considering 59 predation events on false nests, the most important predators were: in experimental nests (n = 21) the fox, Vulpes vulpes (47.6%), and in control nests (n = 38), the hooded crow, Corvus cornix (50%). Our data suggest that the use of anti-predator cages significantly limits predation on eggs and therefore is likely to increase the hatching success in these ground-nesting birds independently in the seasonal period. However, also in the presence of a cage, the fox is a relevant egg predator.
3
Engeman, Richard M., R. Erik Martin, Henry T. Smith, John Woolard, Carrie K. Crady, Stephanie A. Shwiff, Bernice Constantin, Margo Stahl e John Griner. "Dramatic reduction in predation on marine turtle nests through improved predator monitoring and management". Oryx 39, n. 3 (luglio 2005): 318–26. http://dx.doi.org/10.1017/s0030605305000876.
Testo completoAbstract (sommario):
We describe improvements to monitoring/indexing methodology for predators of marine turtle nests on the east coast of Florida, and the resulting marine turtle conservation implications from integrating the methodology into predator management. A strip transect from dune line to the shore improved an already successful design for monitoring raccoons, and was also sensitive for armadillos. The data were integrated into predator management operations to effectively and efficiently remove the species responsible for turtle nest predation. Tracking plot data also served to validate predator patterns of behavior relative to turtle nesting and improve prospects for preventive predator management strategies. Perhaps the most important finding is that predation at a beach historically suffering nearly complete losses (95%) of marine turtle nests had nest predation reduced to nominal levels (9.4%). For 2002 this predation level represents an estimated 69,000 additional hatchling turtles produced over historical predation rates, and 16,700 additional hatchlings over the previous lowest predation rate.
4
Hodges, Karen E. "Differential predation by coyotes on snowshoe hares". Canadian Journal of Zoology 79, n. 10 (1 ottobre 2001): 1878–84. http://dx.doi.org/10.1139/z01-153.
Testo completoAbstract (sommario):
Differential predation on particular sex or age classes of a population can arise as a result of predator preferences or prey attributes. I examined the impacts of age, size, and body mass of snowshoe hares, Lepus americanus, on their susceptibility to predation by coyotes, Canis latrans. I observed coyote predation on naïve radio-collared hares during a fortuitous natural experiment: a coyote entered a predator exclosure fence in which hares of all ages had no previous experience with terrestrial predators, thus separating age from experience with this predator. I contrasted this manipulation with populations in which hares grew up in the presence of coyotes. Prey naiveté per se did not influence coyote predation, but older hares appeared to be more susceptible to coyote predation than younger ones. There were no obvious effects of body mass or size on coyote predation during the winter.
5
Albecker, Molly, e Heather D. Vance-Chalcraft. "Mismatched anti-predator behavioral responses in predator-naïve larval anurans". PeerJ 3 (7 dicembre 2015): e1472. http://dx.doi.org/10.7717/peerj.1472.
Testo completoAbstract (sommario):
Organisms are adept at altering behaviors to balance the tradeoff between foraging and predation risk in spatially and temporally shifting predator environments. In order to optimize this tradeoff, prey need to be able to display an appropriate response based on degree of predation risk. To be most beneficial in the earliest life stages in which many prey are vulnerable to predation, innate anti-predator responses should scale to match the risk imposed by predators until learned anti-predator responses can occur. We conducted an experiment that examined whether tadpoles with no previous exposure to predators (i.e., predator-naive) exhibit innate antipredator behavioral responses (e.g., via refuge use and spatial avoidance) that match the actual risk posed by each predator. Using 7 treatments (6 free-roaming, lethal predators plus no-predator control), we determined the predation rates of each predator onLithobates sphenocephalustadpoles. We recorded behavioral observations on an additional 7 nonlethal treatments (6 caged predators plus no-predator control). Tadpoles exhibited innate responses to fish predators, but not non-fish predators, even though two non-fish predators (newt and crayfish) consumed the most tadpoles. Due to a mismatch between innate response and predator consumption, tadpoles may be vulnerable to greater rates of predation at the earliest life stages before learning can occur. Thus, naïve tadpoles in nature may be at a high risk to predation in the presence of a novel predator until learned anti-predator responses provide additional defenses to the surviving tadpoles.
6
Agostinho, Angelo Antonio, Carlos Sergio Agostinho, Fernando Mayer Pelicice e Elineide Eugênio Marques. "Fish ladders: safe fish passage or hotspot for predation?" Neotropical Ichthyology 10, n. 4 (ottobre 2012): 687–96. http://dx.doi.org/10.1590/s1679-62252012000400001.
Testo completoAbstract (sommario):
Fish ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent) of large predatory fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir) using gillnets, cast nets and counts or visual observations. The captured fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-fish vertebrates. The main predatory fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the fish corridor into a hotspot for predation.
7
Lerch, Brian A., e Maria R. Servedio. "Predation drives complex eco-evolutionary dynamics in sexually selected traits". PLOS Biology 21, n. 4 (3 aprile 2023): e3002059. http://dx.doi.org/10.1371/journal.pbio.3002059.
Testo completoAbstract (sommario):
Predation plays a role in preventing the evolution of ever more complicated sexual displays, because such displays often increase an individual’s predation risk. Sexual selection theory, however, omits a key feature of predation in modeling costs to sexually selected traits: Predation is density dependent. As a result of this density dependence, predator–prey dynamics should feed back into the evolution of sexual displays, which, in turn, feeds back into predator–prey dynamics. Here, we develop both population and quantitative genetic models of sexual selection that explicitly link the evolution of sexual displays with predator–prey dynamics. Our primary result is that predation can drive eco-evolutionary cycles in sexually selected traits. We also show that mechanistically modeling the cost to sexual displays as predation leads to novel outcomes such as the maintenance of polymorphism in sexual displays and alters ecological dynamics by muting prey cycles. These results suggest predation as a potential mechanism to maintain variation in sexual displays and underscore that short-term studies of sexual display evolution may not accurately predict long-run dynamics. Further, they demonstrate that a common verbal model (that predation limits sexual displays) with widespread empirical support can result in unappreciated, complex dynamics due to the density-dependent nature of predation.
8
Bennett, A. M., e D. L. Murray. "Carryover effects of phenotypic plasticity: embryonic environment and larval response to predation risk in Wood Frogs (Lithobates sylvaticus) and Northern Leopard Frogs (Lithobates pipiens)". Canadian Journal of Zoology 93, n. 11 (novembre 2015): 867–77. http://dx.doi.org/10.1139/cjz-2015-0129.
Testo completoAbstract (sommario):
Limitations of phenotypic plasticity affect the success of individuals and populations in changing environments. We assessed the plasticity-history limitation on predator-induced defenses in anurans (Wood Frogs, Lithobates sylvaticus (LeConte, 1825), and Northern Leopard Frogs, Lithobates pipiens (Schreber, 1782)), predicting that plastic responses to predation risk by dragonfly larvae (family Aeshnidae) in the embryonic environment would limit the defensive response to predators in the larval environment. Predator-conditioned Wood Frog embryos increased relative tail depth in response to those same cues as larvae, whereas predator-naive tadpoles did not. However, no carryover effect was noted in the behavioural response of Wood Frog tadpoles to predation risk. Predator-naive Northern Leopard Frog tadpoles increased relative tail depth in response to predation risk in the larval environment. Predator-conditioned Northern Leopard Frog embryos hatched with, and maintained, a marginal increase in tail depth as larvae in the absence of predation risk. Predator-conditioned Northern Leopard Frog embryos exposed to predation risk as larvae showed no morphological response. While we find no strong support for the plasticity-history limitation per se, carryover effects across embryonic and larval life-history stages were noted in both Wood Frog and Northern Leopard Frog, suggesting that predation risk early in ontogeny can influence the outcome of future interactions with predators.
9
Beauchamp, Guy. "Susceptibility to Predation Varies with Body Mass, Foraging Niche, and Anti-Predator Responses among Bird Species". Birds 4, n. 1 (5 febbraio 2023): 73–84. http://dx.doi.org/10.3390/birds4010006.
Testo completoAbstract (sommario):
Predation is a major source of mortality for many avian species. Species that face more predators, and those with less effective anti-predator responses, are presumably more likely to die from predation over time. Predation rate, as a measure of susceptibility to predation, is difficult to measure in the field. Radio-tracking studies, however, allow researchers to determine the time and cause of death of marked individuals, making it possible to estimate predation rate. I used estimates of predation rates from a large number of published radio-tracking studies in birds to assess in a phylogenetic framework the effect of several potential determinants. I obtained 393 estimates of predation rates from 129 species. Predation rates were lower in areas with fewer predators, such as islands and aquatic habitats, and for species with fewer potential predators, such as larger species. The predation rate was also lower for prey species with effective anti-predator responses, such as those that forage in flocks. Radio-tracking studies provide a unique opportunity to estimate overall predation rate in the field. Broadening the range of species and the range of habitats involved in such studies will help to further elucidate the factors that affect susceptibility to predation.
10
Berry, Lainie. "Predation rates of artificial nests in the edge and interior of a southern Victorian forest". Wildlife Research 29, n. 4 (2002): 341. http://dx.doi.org/10.1071/wr01022.
Testo completoAbstract (sommario):
Predation rates of nests at human-induced habitat edges may be greater than in forest interior due to differences in predator assemblages and predator activity. I compared the predation rates on 192 artificial nests containing plasticine eggs placed in forest edge and interior sites at Bunyip State Park, Victoria. The nest-predation rates at the forest edge sites were significantly greater (mean = 52–58%) than that at the forest interior sites (mean = 30–39%). The relative rates of predation by birds compared with mammals were significantly greater at forest edge sites (mean = 78–94%) than at forest interior sites (mean = 36–67%). Higher rates of nest predation at forest edges appeared to be due to greater densities of avian predators such as the grey shrike-thrush (Colluricincla harmonica), and/or lower abundances of small mammals. However, biases towards certain predator types may mask real, or create false, patterns in predation rates of artificial nests. A better understanding of how predators respond to artificial nests compared with natural nests is required. Until then, results of predation studies that use artificial nests should be interpreted with caution.
11
Leighton, Lindsey R. "Inferring predation intensity in the marine fossil record". Paleobiology 28, n. 3 (2002): 328–42. http://dx.doi.org/10.1666/0094-8373(2002)028<0328:ipiitm>2.0.co;2.
Testo completoAbstract (sommario):
Accurate estimates of predation intensity, the frequency of mortality from predation, are critical to studies of the evolution of species in response to predation, and to studies of predator-prey systems in general. Most commonly used indirect proxies for predation intensity in the fossil record have logistical or theoretical problems. Direct proxies, using actual traces of predatory activity, such as drilling and repair scars, may hold more promise. However, these direct proxies often have been used in conjunction with optimal foraging models, and in this context, the underlying assumptions and predictions of optimal foraging are examined.Results from theoretical models using optimal foraging suggest that (1) the ratio of internal shell volume to shell thickness of prey (benefit/cost ratio) may be a questionable measurement of prey “value” to the predator, as it fails to account adequately for energetic cost to the predator during pursuit and grappling; (2) drilling and repair frequency are invalid measures of prey preference, because optimal foraging predicts that specific prey types are either always taken or always ignored; (3) pooled drilling frequency will not be a useful metric of predation intensity in systems in which the predator need not always drill; and (4) an increase in repair frequency can be a consequence of either an increase or a decrease in predation intensity.Although drilling frequency may not indicate prey preference, it is a valid proxy for selection due to predation. An approach using size classes, in which the minimum size at which a predation refuge is achieved, is suggested for use with repair frequency.
12
Schenk, Amber R., Thomas K. Stevens e Amanda M. Hale. "Predator-Prey Dynamics Are Decoupled in the Raptor Community in a Large Urban Forest". Diversity 14, n. 3 (28 febbraio 2022): 177. http://dx.doi.org/10.3390/d14030177.
Testo completoAbstract (sommario):
Predator-prey dynamics are fundamental in shaping and regulating wildlife communities; however, these relationships are often altered by urbanization. An urban predation paradox, where predation rates are lower in urban areas despite an increase in predator abundance, has been observed in some predator communities. We looked for evidence of an urban predation paradox in a raptor community in a large urban forest fragment in north Texas, USA. From May–August 2019, we conducted weekly raptor surveys and deployed prey mimics along an urban-to-rural gradient within the forest fragment. We examined relationships between predation rates on mimics, predator abundance, and urbanization intensity using a variety of statistical tests. We detected 161 raptors representing eight species and found that raptor activity was significantly higher in our low urbanization sites. Of the 732 prey mimics deployed, 61 were attacked, and we found no relationship between predation rates and urbanization. Furthermore, we found no relationship between raptor activity and depredation events. Although we failed to find evidence for an urban predation paradox, our results showed a decoupling of the relationship between the abundance of predators and prey in this urban setting. The use of prey mimics is a useful tool for assessing predator-prey dynamics, and more research is necessary to fully understand the impacts of urbanization on this important ecological process.
13
Tanis, Brian P., Bradley Bott e Brian J. Gaston. "Sex-based differences in anti-predator response of crickets to chemical cues of a mammalian predator". PeerJ 6 (11 giugno 2018): e4923. http://dx.doi.org/10.7717/peerj.4923.
Testo completoAbstract (sommario):
Anti-predator behaviors like vigilance or hiding come at the expense of other fitness increasing behaviors such as foraging. To compensate for this trade-off, prey assess predation risk and modify the frequency of anti-predator behaviors according to the likelihood of the threat. In this study, we tested the ability of house crickets (Acheta domesticus) to indirectly assess predation risk via odors from a mammalian predator, Elliot’s short-tailed shrew (Blarina hylophaga). As natural differences in encounter rates and predation risk differs between sexes, we tested if male and female crickets perceive similar rates of predation risk from the presence of shrew odor measured via anti-predator behavioral response. Crickets were placed in enclosed, cardboard-lined chambers either treated with shrew odor or control, along with a food source. Time until foraging was measured for each individual and compared across treatment and sex. We found that in the presence of shrew odor, female crickets delayed foraging while males showed no response. These results suggest adult crickets can use chemical cues to detect mammalian predators. Furthermore, we demonstrate that female crickets associate greater predation risk from shrew predators than do male crickets, which are more stationary yet acoustically conspicuous. As predation risk potentially differs drastically for each sex, changes to the operational sex ratios of wild cricket populations could be influenced by the identity of the predator community.
14
Gunzburger, M. S., e J. Travis. "Effects of multiple predator species on green treefrog (Hyla cinerea) tadpoles". Canadian Journal of Zoology 83, n. 7 (1 luglio 2005): 996–1002. http://dx.doi.org/10.1139/z05-093.
Testo completoAbstract (sommario):
Prey species that occur across a range of habitats may be exposed to variable communities of multiple predator species across habitats. Predicting the combined effects of multiple predators can be complex. Many experiments evaluating the effects of multiple predators on prey confound either variation in predator density with predator identity or variation in relative predator frequency with overall predation rates. We develop a new experimental design of factorial predator combinations that maintains a constant expected predation rate, under the null hypothesis of additive predator effects. We implement this design to evaluate the combined effects of three predator species (bass, aeshnid and libellulid odonate naiads) on mortality rate of a prey species, Hyla cinerea (Schneider, 1799) tadpoles, that occurs across a range of aquatic habitats. Two predator treatments (libellulid and aeshnid + libellulid) resulted in lower tadpole mortality than any of the other predator treatments. Variation in tadpole mortality across treatments was not related to coarse variation in microhabitat use, but was likely due to intraguild predation, which occurred in all predator treatments. Hyla cinerea tadpoles have constant, low survival values when exposed to many different combinations of predator species, and predation rate probably increases linearly with predator density.
15
Laurila, Anssi, Pierre-André Crochet e Juha Merilä. "Predation-induced effects on hatchling morphology in the common frog (Rana temporaria)". Canadian Journal of Zoology 79, n. 5 (1 maggio 2001): 926–30. http://dx.doi.org/10.1139/z01-045.
Testo completoAbstract (sommario):
As mortality due to predation is often high at early independent life stages in many animals, it can be expected that predation-induced modifications of early life history and morphology will be common when predation risk varies spatially or temporally. However, studies of such effects are still rare. Predation-induced changes in life history and morphology have often been described in amphibian larvae, but the focus has been on older larvae and little is known about responses of hatchlings or very young larvae. We examined whether predator presence influenced timing of hatching and hatchling morphology in the common frog, Rana temporaria. In a paired design, eggs from 10 clutches were allowed to develop from fertilization to hatching, with or without the nonlethal presence of a larva of the large diving beetle Dytiscus marginalis. We found no evidence that predator presence affected timing of hatching. However, hatchlings raised in the presence of the predator had relatively shorter bodies and deeper tail fins than their full-sibs raised in the absence of the predator, indicating that predation induces morphological responses in R. temporaria hatchlings. This is one of the very few studies showing that predators, or chemical cues released during a predation event, can induce a plastic morphological changes in vertebrates at very early life stages.
16
ALAM, SHARIFUL. "RISK OF DISEASE-SELECTIVE PREDATION IN AN INFECTED PREY-PREDATOR SYSTEM". Journal of Biological Systems 17, n. 01 (marzo 2009): 111–24. http://dx.doi.org/10.1142/s0218339009002703.
Testo completoAbstract (sommario):
In this paper the mathematical model of disease-selective predation as proposed by Roy and Chattopadhyay10 is considered to identify the true risk of selective predation where the predator can recognize the infected prey and avoids those during predation. Furthermore, the model is modified by adding a discrete time delay in the term involving the gestation of prey by the predator and analyzed both numerically and analytically to review the risk factors.
17
Fraser, Fiona J., e Peter J. Whitehead. "Predation of artificial ground nests in Australian tropical savannas: inverse edge effects". Wildlife Research 32, n. 4 (2005): 313. http://dx.doi.org/10.1071/wr04021.
Testo completoAbstract (sommario):
Depredation of artificial ground nests was examined in tropical savanna in northern Australia to assess potential predation pressures on nests of the partridge pigeon (Geophaps smithii), a declining tropical granivore. Predation rates were examined at two sites, Kakadu National Park (which supported a relatively high density of partridge pigeons) and Berry Springs (which had greater habitat fragmentation and comparatively low partridge pigeon density). The effects of distance from road, understorey structure, topography and nest-microsite concealment on nest predation rates were examined. Artificial-nest predation rates were greater at 150 m from roads than <1 m from the roadside. Predation rates did not vary with understorey structure, topography, or level of nest concealment. There was marked variation between sites, with predation levels at Kakadu more than double those recorded for Berry Springs. Discerning predator identity, or even the size of a predator, from marks left in clay eggs proved difficult and was possible for ~35% of predation events. Of these, 42% of predation events involved predators of a size we considered too small to take a natural partridge pigeon nest. We suggest that extrapolation from artificial to natural ground-nest predation rates be undertaken with caution for landscapes such as Australia’s tropical savanna, which supports a high diversity and abundance of small potential predators of artificial nests. There was no evidence of predation by birds, and the methodology proved inadequate for identifying predation by feral cats (Felis catus).
18
Mihalitsis, Michalis, Renato A. Morais e David R. Bellwood. "Small predators dominate fish predation in coral reef communities". PLOS Biology 20, n. 11 (29 novembre 2022): e3001898. http://dx.doi.org/10.1371/journal.pbio.3001898.
Testo completoAbstract (sommario):
Ecosystem processes are challenging to quantify at a community level, particularly within complex ecosystems (e.g., rainforests, coral reefs). Predation is one of the most important types of species interactions, determining several ecosystem processes. However, while it is widely recognised, it is rarely quantified, especially in aquatic systems. To address these issues, we model predation on fish by fish, in a hyperdiverse coral reef community. We show that body sizes previously examined in fish–fish predation studies (based on a metanalysis), only represent about 5% of likely predation events. The average fish predator on coral reefs is just 3.65 cm; the average fish prey just 1.5 cm. These results call for a shift in the way we view fish predation and its ability to shape the species or functional composition of coral reef fish communities. Considered from a functional group approach, we found general agreement in the distribution of simulated and observed predation events, among both predator and prey functional groups. Predation on coral reefs is a process driven by small fish, most of which are neither seen nor quantified.
19
Luo, Yantao, Long Zhang, Zhidong Teng e Tingting Zheng. "Coexistence for an Almost Periodic Predator-Prey Model with Intermittent Predation Driven by Discontinuous Prey Dispersal". Discrete Dynamics in Nature and Society 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/7037245.
Testo completoAbstract (sommario):
An almost periodic predator-prey model with intermittent predation and prey discontinuous dispersal is studied in this paper, which differs from the classical continuous and impulsive dispersal predator-prey models. The intermittent predation behavior of the predator species only happens in the channels between two patches where the discontinuous migration movement of the prey species occurs. Using analytic approaches and comparison theorems of the impulsive differential equations, sufficient criteria on the boundedness, permanence, and coexistence for this system are established. Finally, numerical simulations demonstrate that, for an intermittent predator-prey model, both the intermittent predation and intrinsic growth rates of the prey and predator species can greatly impact the permanence, extinction, and coexistence of the population.
20
Elvidge, Chris K., Indar Ramnarine e Grant E. Brown. "Compensatory foraging in Trinidadian guppies: Effects of acute and chronic predation threats". Current Zoology 60, n. 3 (1 giugno 2014): 323–32. http://dx.doi.org/10.1093/czoolo/60.3.323.
Testo completoAbstract (sommario):
Abstract In response to acute predation threats, prey may sacrifice foraging opportunities in favour of increased predator avoidance. Under conditions of high or frequent predation risk, such trade-offs may lead to reduced fitness. Here, we test the prediction that prey reduce the costs associated with lost opportunities following acute predation threats by exhibiting short-term compensatory foraging responses. Under semi-natural conditions, we exposed female guppies Poecilia reticulate from high and low predation risk sites to one of three levels of acute predation threat (high, intermediate or low concentrations of conspecific alarm cues). Our results confirm previous reports, demonstrating that guppies from a high predation site were consistently ‘bolder’ (shorter escape latencies) and exhibited graded threat-sensitive responses to different simulated threat levels while those from the low predation site were ‘shyer’ and exhibited non-graded responses. Most importantly, we found that when guppies from low predation sites resumed foraging, they did so at rates significantly lower than baseline rates. However, guppies from high predation sites resumed foraging either at rates equal to baseline (in response to low or intermediate risk stimuli) or significantly increased relative to baseline rates (in response to high risk stimuli). Together, these results highlight a complex compensatory behavioral mechanism that may allow prey to reduce the long-term costs associated with predator avoidance.
21
Engeman, Richard, R. Erik Martin, John Woolard, Margo Stahl, Charles Pelizza, Anthony Duffiney e Bernice Constantin. "An ideal combination for marine turtle conservation: exceptional nesting season, with low nest predation resulting from effective low-cost predator management". Oryx 46, n. 2 (1 novembre 2011): 229–35. http://dx.doi.org/10.1017/s0030605311000020.
Testo completoAbstract (sommario):
AbstractWe examined impacts from effective predator management on nesting success of marine turtles in an exceptional nesting year at Hobe Sound National Wildlife Refuge, Florida, USA, a beach with a high density of nesting marine turtles that has a history of severe nest predation. Historically up to 95% of nests were predated, primarily by raccoons Procyon lotor and, more recently, armadillos Dasypus novemcinctus. Predator control was identified as the most important conservation tool for marine turtle reproduction. Predator management by refuge staff as ancillary duties typically only held predation levels to c. 50%. However, when experts in predator control were employed predation was substantially reduced. An extraordinary opportunity to evaluate the biological and economic benefits of this management approach occurred in 2008, a year with exceptionally heavy nesting. Loggerhead turtle Caretta caretta nesting resurged, green Chelonia mydas and leatherback Dermochelys coriacea turtles nested in record numbers, producing twice or more than their median number of nests, and the first Kemp’s ridley Lepidochelys kempii nest was observed. Overall predation was 14.7%, resulting in an estimated > 128,000 additional hatchlings emerging compared to estimates had no predator management been in place and historical predation rates occurred, and > 56,000 hatchlings more than expected had predator management been conducted as ancillary duties rather than by experts. The USD 12,000 investment for expert predator management equated to only USD 0.09 spent for each additional hatchling produced compared to the scenario of no predator control and only USD 0.21 compared to the scenario of predator control as ancillary duties.
22
Gabor, Caitlin, Julia Coyle e Andrea Aspbury. "Effect of predation on male mating behaviour in a unisexual-bisexual mating system". Behaviour 147, n. 1 (2010): 53–63. http://dx.doi.org/10.1163/000579509x12483520922160.
Testo completoAbstract (sommario):
AbstractMate choice for conspecifics is beneficial when closely related species live in sympatry, but mate choice can be costly in the presence of predators. Male sailfin mollies are sexually parasitized by gynogenetic Amazon mollies. Amazon mollies must mate with male sailfin mollies to initiate embryogenesis, but inheritance is maternal. We tested if male sailfin molly mate choice for conspecific females is affected by predation risk. Male mate choice was tested in one of four treatments: (1) predation/no refuge, (2) predation/refuge, (3) no predation/refuge and (4) no predation/no refuge. Predation consisted of dipping the beak of a great blue heron decoy in the aquarium prior to a mating trial. Refuge was provided by java-moss. For each trial the number of mating attempts toward each female was recorded. There was a significant interaction between predation and refuge on strength of preference (SOP) for conspecific females. The highest SOP was in the no predator/no refuge treatment, and the lowest SOP was in the predator/no refuge treatment. These results suggest that the cost of predation is higher than the cost of mating with heterospecifics, and that the presence of a refuge may reduce this cost. This could explain the continued maintenance of Amazon mollies.
23
Maier, Thomas J., e Richard M. DeGraaf. "Predation on Japanese Quail vs. House Sparrow Eggs in Artificial Nests: Small Eggs Reveal Small Predators". Condor 102, n. 2 (1 maggio 2000): 325–32. http://dx.doi.org/10.1093/condor/102.2.325.
Testo completoAbstract (sommario):
Abstract Nest predation studies frequently use eggs such as Japanese Quail (Coturnix japonica) to identify potential predators of Neotropical migrants' eggs, but such eggs may be too large or thick-shelled to identify the full complement of potential predators. We compared predation events and predators of Japanese Quail and smaller House Sparrow (Passer domesticus) eggs in paired, camera-monitored ground nests within edges and interiors of 40 mixed-hardwood forest stands in central Massachusetts. House Sparrow eggs were depredated significantly more than Japanese Quail eggs at both forest edges and interiors. Eleven potential predator species disturbed nests, six of which were confirmed as predators. Our use of House Sparrow eggs revealed predation by eastern chipmunks (Tamias striatus) and Black-capped Chickadee (Poecile atricapillus), but not by white-footed mice (Peromyscus leucopus), the most abundant small mammal species in all 40 stands. Neither predator species composition (as detected by camera) nor the frequency of nest predation differed between forest edge and interior. We conclude that the egg type used in artificial nest studies affects both the predation rates and the predator species detected.
24
Engeman, Richard M., R. Erik Martin, Henry T. Smith, John Woolard, Carrie K. Crady, Bernice Constantin, Margo Stahl e N. Paige Groninger. "Impact on predation of sea turtle nests when predator control was removed midway through the nesting season". Wildlife Research 33, n. 3 (2006): 187. http://dx.doi.org/10.1071/wr05049.
Testo completoAbstract (sommario):
The beach at Hobe Sound National Wildlife Refuge (HSNWR) is a high-density nesting beach serving three species of threatened and endangered sea turtles. Historically, up to 95% of turtle nests at HSNWR were lost to predation by raccoons and armadillos. Consequently, predator control was identified as the most important conservation tool at HSNWR, and predator control optimised by predator monitoring led to highly successful results whereby predation had been reduced to low levels (7–13.5% of monitored nests) in 2002 and 2003. In 2004, funding shortfalls caused predator control to be curtailed with ~1.5–2 months remaining in the nesting/hatching season. We analysed the resulting effects on turtle nest predation levels compared with the results from 2002 and 2003. The predation rate in 2004 compared favourably with that of 2002 and 2003 until the end of June, after which control was curtailed. Thereafter, predation rapidly accelerated, with the 2004 predation rate increasing to 1.5–3 times the rates from 2002 and 2003 by the end of August. The discrepancy in all likelihood would have grown further, except Hurricane Frances destroyed all remaining nests with 1.5–2 months left in the nesting/hatching season. Product-limit survival analyses demonstrated substantial differences in turtle nest survival between 2004 versus 2002 and 2003, but not between 2002 and 2003. When analysed as cohorts based on month of nest deposition, no differences were found among 2002, 2003, 2004 for nests deposited in May. These nests received full protection from predation in each of the three years. However, the survival analyses for nests deposited in June, and those deposited in July showed inferior survival for 2004 when predator control was removed for the last half of nesting/hatching.
25
Kurz, David J., Katherine M. Straley e Brett A. DeGregorio. "Out-foxing the red fox: how best to protect the nests of the Endangered loggerhead marine turtle Caretta caretta from mammalian predation?" Oryx 46, n. 2 (2 dicembre 2011): 223–28. http://dx.doi.org/10.1017/s0030605311000147.
Testo completoAbstract (sommario):
AbstractRecovery plans for the Endangered loggerhead marine turtle Caretta caretta cite mammalian predation as a major threat, and recommend nest protection efforts, already present at many rookery beaches, to protect eggs and hatchlings. Nest protection techniques vary but wire box cages and plastic mesh screens are two common tools used to deter predation by a host of beach-foraging, opportunistic mammalian predators. We empirically tested the efficacy of wire cages and plastic mesh screens in preventing red fox Vulpes vulpes predation on artificial nests. Both techniques averted fox predation (0%), whereas unprotected control nests suffered 33% predation under conditions of normal predator motivation, or a level of motivation stimulated by loggerhead turtle egg scent. However, in side-by-side comparisons under conditions of presumed high predator motivation, 25% of mesh screens were breached whereas no cage-protected nests were successfully predated. In addition to effectiveness at preventing predation, factors such as cost, ease of use, deployment time, and magnetic disturbance were evaluated. Our study suggests that the efficacy of plastic screens and the potential disadvantages associated with galvanized wire should influence selection of mechanical barriers on beaches where fox predation threatens loggerhead nests.
26
Fonseca, Aldeiza M., e Bruno S. Sant'Anna. "Predation on eggs of the apple snail Pomacea dolioides (Reeve, 1856) in rural and urban areas of the Amazon". Marine and Freshwater Research 71, n. 6 (2020): 662. http://dx.doi.org/10.1071/mf19095.
Testo completoAbstract (sommario):
This study investigated the predation of eggs of the apple snail Pomacea dolioides in Itacoatiara, Amazonas, Brazil. Predation was compared between rural and urban areas, period of day, shaded and unshaded clutches. In addition, we evaluated clutch height and the behaviour of predators. Between April 2017 and July 2018, 962 egg clutches were observed at different times of the day: 492 in rural areas with predation of 68 egg clutches and 470 in urban areas with predation of only 9 egg clutches. Significant differences were recorded for predation rate and differences were recorded for egg clutch height in the areas. In the rural areas, the most frequent predators during the day were ants Solenopsis invicta, Crematogaster cf. carinata and the most abundant were S. invicta, Wasmannia aff. iheringi and C. cf. carinata. During the night, S. invicta was the most frequent and abundant predator. In urban areas, the frequency of predation and abundance of S. invicta were higher during the day and night than those of other predators. Populations of P. dolioides in rural areas are more affected by egg predation, mostly by S. invicta and C. cf. carinata, and predatory behaviour depended on the species of the predator.
27
Groenewoud, Frank, Sjouke A. Kingma, Kat Bebbington, David S. Richardson e Jan Komdeur. "Experimentally induced antipredator responses are mediated by social and environmental factors". Behavioral Ecology 30, n. 4 (12 aprile 2019): 986–92. http://dx.doi.org/10.1093/beheco/arz039.
Testo completoAbstract (sommario):
AbstractNest predation is a common cause of reproductive failure for many bird species, and various antipredator defense behaviors have evolved to reduce the risk of nest predation. However, trade-offs between current reproductive duties and future reproduction often limit the parent’s ability to respond to nest predation risk. Individual responses to experimentally increased nest predation risk can give insights into these trade-offs. Here, we investigate whether social and ecological factors affect individual responses to predation risk by experimentally manipulating the risk of nest predation using taxidermic mounts in the cooperative breeding Seychelles warbler (Acrocephalus sechellensis). Our results show that dominant females, but not males, alarm called more often when they confront a nest predator model alone than when they do so with a partner, and that individuals that confront a predator together attacked more than those that did so alone. Dominant males increased their antipredator defense by spending more time nest guarding after a presentation with a nest predator, compared with a nonpredator control, but no such effect was found for females, who did not increase the time spent incubating. In contrast to incubation by females, nest guarding responses by dominant males depended on the presence of other group members and food availability. These results suggest that while female investment in incubation is always high and not dependent on social and ecological conditions, males have a lower initial investment, which allows them to respond to sudden changes in nest predation risk.
28
Miller, C. W., e S. D. Hollander. "Predation on heliconia bugs, Leptoscelis tricolor: examining the influences of crypsis and predator color preferences". Canadian Journal of Zoology 88, n. 1 (gennaio 2010): 122–28. http://dx.doi.org/10.1139/z09-128.
Testo completoAbstract (sommario):
Individuals in natural populations commonly vary in color, and such color variation can be important for survival under predation pressure. Potential prey may be more likely to survive when they are cryptic against their backgrounds. Alternatively, individual coloration, regardless of background, may itself best predict predation events. Few studies have simultaneously tested the importance of crypsis and predator color preferences in explaining predation events. In this study we used objective measures of coloration to examine whether heliconia bugs, Leptoscelis tricolor Westwood, 1842 (Hemiptera: Coreidae), resembling their background were less likely to be eaten by avian predators (crypsis hypothesis). Next, we evaluated whether insect color, irrespective of background, best explains predation events (color preference hypothesis). We found the strongest evidence for the crypsis hypothesis; predators chose prey that differed most from their background in color saturation. Some evidence was also found for the color preference hypothesis; predators avoided brightly colored prey. These results suggest that crypsis can be effective in detouring predation. However, when potential prey are detected, predator color preferences may best explain predation events.
29
Duplisea, Daniel E. "Running the gauntlet: the predation environment of small fish in the northern Gulf of St Lawrence, Canada". ICES Journal of Marine Science 62, n. 3 (1 gennaio 2005): 412–16. http://dx.doi.org/10.1016/j.icesjms.2004.11.005.
Testo completoAbstract (sommario):
Abstract Predation size spectra were constructed for the northern Gulf of St Lawrence, covering prey size ranges that include pre-recruit cod. Predation by fish and harp seals was modelled with a log-normally distributed predator–prey size ratio along with a relationship between predator body size and the energy required. Fish concentrate predation on prey of weight 0.5–2 g, whereas harp seals prefer prey of 60–125 g. It is speculated that predation caused by harp seals on pre-recruits could be a major factor limiting cod recruitment in the system. The northern Gulf of St Lawrence is a cold boreal system with a large predatory seal population, and cod recruit older than elsewhere. Therefore, cod recruitment may be more strongly affected by predation in the northern Gulf of St Lawrence than in warmer systems such as the North Sea, where recruitment is strongly influenced by temperature.
30
P. Brown, Kerry. "Predation at nests of two New Zealand endemic passerines; implications for bird community restoration". Pacific Conservation Biology 3, n. 2 (1997): 91. http://dx.doi.org/10.1071/pc970091.
Testo completoAbstract (sommario):
Predation at North Island Robin Petroica australis longipes and North Island Tomtit Petroica macrocephala toitoi nests was studied in New Zealand over the 1993/94 breeding season to determine impacts of predators. Infra-red, time-lapse video photography and sign left after predation were used to identify predators at nests. Accurate estimates of predation rates depended on early detection of nests. Previous studies of predation may have greatly under-estimated predation rates and therefore predation impacts. Predation was patchy and intense, resulting in failure to produce young in some territories despite up to ten nesting attempts. A maximum of 82% of nests were preyed on (n = 65; 95% confidence interval 72.4%?90%) and Ship Rats Rattus rattus were probably responsible for at least 72% (95% confidence interval 57.4%?84.4%) of predations. Nine of 24 territories lost breeding females, mainly to Ship Rats, which significantly impacted on population productivity. Ship Rat predation was equally intense at exposed and concealed nests (at the site and patch levels). Predation attributed to avian predators was strongly correlated with exposed nests (at the patch level). Restoration of New Zealand's threatened forest bird communities is dependent on a commitment to further research into the significance of different predators and predation impacts on bird populations.
31
Fonner, Christopher W., e Sarah K. Woodley. "Testing the predation stress hypothesis: behavioural and hormonal responses to predator cues in Allegheny Mountain dusky salamanders". Behaviour 152, n. 6 (2015): 797–819. http://dx.doi.org/10.1163/1568539x-00003254.
Testo completoAbstract (sommario):
The predation stress hypothesis posits that exposure to predators and/or predator cues causes release of glucocorticoid hormones which coordinate behavioural responses that facilitate predator avoidance. We measured responses to short-term and repeated exposure to predator-derived kairomones in Allegheny Mountain dusky salamanders (Desmognathus ochrophaeus). Salamanders expressed predator avoidance behaviours (reduced locomotion, reduced mating behaviour) in the presence of predator kairomones. However, plasma glucocorticoids after short-term exposure to predator kairomones were similar to levels after exposure to controls. After repeated exposure to predator-derived kairomones, locomotory activity and plasma glucocorticoids were similar compared to controls. There was no evidence of habituation to predator kairomones. Overall, results did not support the predation stress hypothesis in Allegheny Mountain dusky salamanders in either an acute or chronic context. Use of glucocorticoids to mediate antipredator responses may occur when predation pressure is unpredictable, and when energetic and opportunity costs of linking glucocorticoids to anti-predator responses are low.
32
Kinoshita, Hikari, Yasuhiro Kamimura, Ken-Ichiro Mizuno e Jun Shoji. "Night-time predation on post-settlement Japanese black rockfish Sebastes cheni in a macroalgal bed: effect of body length on the predation rate". ICES Journal of Marine Science 71, n. 4 (19 luglio 2013): 1022–29. http://dx.doi.org/10.1093/icesjms/fst033.
Testo completoAbstract (sommario):
Abstract Recent field studies have pointed out that the vulnerability of juvenile fish to predation is higher than anticipated during night-time in vegetated habitats. Effects of abundance, body length, and growth rate on predation were examined in juvenile Japanese black rockfish in 2009–2011 in a macroalgal bed. Juvenile rockfish abundance ranged between 2.5 and 49.0 ind. 100 m–2 and the biomass of potential predators (piscivorous fish >82.5 mm) between 140.0 and 601.3 g 100 m−2. Sebastes inermis was the most dominant predator, compromising more than 50% by wet weight on all sampling days. Comparison of the total length of juveniles surviving (as original population, OP) and that of juveniles ingested (IG) by predators provided the evidence of the size-selective predation on juvenile rockfish on three of seven sampling days. The juvenile predation rate estimated as abundance of IG (N 100 m−2)/(abundance of IG + OP (N 100 m−2)) × 100100 varied between 0.4 and 12.5%. Neither juvenile rockfish abundance nor predator biomass had a significant effect on the juvenile predation rate, whereas the juvenile body length had a significant effect, smaller individuals being more vulnerable to predation. The growth-selective predation was not detected. Macroalgal habitats, although functioning as nurseries during the day, may contribute as feeding grounds for piscivorous fish predators at night leading to enhanced nocturnal predation rates.
33
Costa, Claylton Abreu, Lucas Rafael Uchôa, Sâmia Caroline Melo Araújo, Mariane Silva Oliveira e Etielle Barroso Andrade. "Predator-prey: predation strategies of Leptodactylus macrosternum and defensive behavior of Leptodactylus fuscus". Acta Brasiliensis 6, n. 2 (30 maggio 2022): 61. http://dx.doi.org/10.22571/2526-4338586.
Testo completoAbstract (sommario):
Congeneric predation between two Leptodactylus species was recorded and information was collected on the predation strategy of L. macrosternum and the defensive behavior and distress call of L. fuscus. The entire predation event lasted about 90 min and ended when predator tore integument of the prey's ventral region, facilitating swallowing. The distress call description was based on a record of 40 s containing seven calls, consisting of a pulsatile and harmonically complex structure composed of two notes. Although the batrachophagy is well-documented in the genus Leptodactylus, descriptions of predatory and defensive behaviors are not fully described. Thus, the defensive behaviors observed here made predation a physiologically taxing event, while we look at how the predator can use various mechanisms to overcome prey defensive behaviors.
34
Moseby, Katherine E., Melissa A. Jensen e Jack Tatler. "Dietary flexibility and high predator efficacy facilitate coexistence in a novel predator interaction". Journal of Mammalogy 103, n. 1 (26 novembre 2021): 124–35. http://dx.doi.org/10.1093/jmammal/gyab120.
Testo completoAbstract (sommario):
Abstract Predator diet can be influenced by competition and intraguild predation, leading to resource partitioning and/or avoidance. For sympatric, endemic predators, these processes form as predator species coevolve, facilitating coexistence. However, when novel predator interactions occur, significant dietary overlap could create acute levels of competition leading to intraguild predation and population extinction, or accelerated changes in diet and/or spatial and temporal avoidance. We measured diet, intraguild predation, and spatial and temporal overlap in two predator species in a novel predator interaction: the western quoll (Dasyurus geoffroii), a small, native carnivore reintroduced to semi-arid Australia, and the domestic cat (Felis catus), a larger introduced carnivore already resident at the release site. Both species exhibited high dietary overlap and fed on mammals, reptiles, birds, and invertebrates. Cats included quolls in their diet. Quoll diet was broader (including carrion, bats, and plant material) and flexible, changing significantly with age, sex, and season. Introduced rabbit was the most common prey item recorded for both species (frequency of occurrence = 40–50%). However, quolls consumed rabbits in relation to their availability while rabbit consumption in cats was unrelated to availability suggesting a stronger dependence on rabbit prey. Quoll diet did not change over time since release and they did not spatially or temporally avoid cats. However, cats were significantly spatially associated with rabbits while quolls were not, suggesting higher predation efficacy in quolls possibly due to their smaller body size enabling them to catch rabbits inside warrens. Despite high dietary overlap and intraguild predation, the quoll’s broad and flexible diet and high predation efficacy appeared to assist in facilitating coexistence and reducing competition in this novel predator interaction. This dietary flexibility may be harnessed to improve conservation outcomes: reducing introduced rabbits in our study area could naturally reduce feral cat populations while having less impact on native quolls.
35
Essington, Timothy E., e Sture Hansson. "Predator-dependent functional responses and interaction strengths in a natural food web". Canadian Journal of Fisheries and Aquatic Sciences 61, n. 11 (1 novembre 2004): 2215–26. http://dx.doi.org/10.1139/f04-146.
Testo completoAbstract (sommario):
Predator-dependent functional responses decouple predation mortality from fluctuations in predator abundance and therefore can prevent strong "top-down" interaction strengths in food webs. We evaluated whether contrasts in the functional response of Baltic Sea cod (Gadus morhua) were consistent with the contrasting population dynamics of two prey species, herring (Clupea harengus) and sprat (Sprattus sprattus): sprat abundance increased nearly threefold following a sharp decline in the cod population (a strong interaction), whereas herring abundance failed to increase (a weak interaction). We found striking differences in the functional response of cod on alternative prey, and these were consistent with the observed patterns in interaction strengths. Cod predation was the dominant source of mortality for age-1 and age-2 sprat but was only important for age-1 herring. Moreover, the magnitude of predation mortality on age-1 and age-2 sprat was highly sensitive to cod biomass, whereas predation mortality on herring was only moderately sensitive to cod biomass. These analyses suggest the possibility that food webs are comprised of linkages that vary with respect to the magnitude and importance of predation mortality and how this mortality varies with changes in predator abundance.
36
Torgersen, Thomas. "Aggregated predators and vulnerability-independent mortality of prey". Canadian Journal of Fisheries and Aquatic Sciences 64, n. 7 (1 luglio 2007): 941–55. http://dx.doi.org/10.1139/f07-066.
Testo completoAbstract (sommario):
I present a mechanistic predation model with explicit representation of predator aggregation for analysing the relationship between mortality rate of prey and their vulnerability (e.g., conspicuousness, escape ability). The model is developed for an aquatic setting with plankton as prey and planktivores as predators, but the principle is general. When predators are aggregated, encounters between prey and predators are not independent events. This means that a prey that runs into one predator is more likely to run into more predators, and any prey that runs into a high number of predators will eventually be perceived and captured, almost irrespective of how cryptic it is or how well it escapes attacks. A prey that has not run into a predator yet is more likely to continue to not run into predators and may therefore avoid predation even if it displays no crypsis or anti predation behaviour. Therefore, the predation risk from aggregated predators is less dependent on prey vulnerability than the intuitive proportionality relationship that applies to predation risk from solitary predators. This has important implications for patterns of mortality within prey communities (e.g., size dependency of plankton mortality).
37
Septriani, Utari, My Syahrawati e Arneti Arneti. "Does competition between Pardosa pseudoannulata and Menochilus sexmaculatus reduce the predation rate on brown planthopper?" CROPSAVER - Journal of Plant Protection 6, n. 2 (31 dicembre 2023): 130. http://dx.doi.org/10.24198/cropsaver.v6i2.51131.
Testo completoAbstract (sommario):
Pardosa pseudoannulata and Menochilus sexmaculatus are classified as natural enemies of the brown planthopper or BPH (Nilaparvata lugens). This study aimed to determine the effect of differences in density on mortality and their predation rate in suppressing the BPH population. This study used a completely randomized design of 15 treatments and 3 replications. The treatments consisted of different densities of two predators (1, 2, and 3 individuals). The variables observed were predator mortality, predation rate, competition between predators, and competition behavior. The results showed that competition between predators at different densities was not directly related to predator mortality and the predation rate of joint predators. Predator density tended to increase the predation rate, especially on M. sexmaculatus (R=0.894), while the density of P. pseudoannulata and joint predators was moderate (Rpardosa=0.587, Rjoint=0.522). M. sexmaculatus won the competition when its population increased. Equal competition occurred in the composition of 1 P. pseudoannulata and 3 M. sexmaculatus (P1M3); in this composition, no deaths were found due to competition, with the predation rate reaching 86.7%. Cannibalism dominates intraspecific competition between individuals of P. pseudoannulata, while interspecific competition occurs between the two species, causing sub-lethal effects.
38
Yang, Yuan-Gang, Guo-Zhen Shang, Xue-Qin Wu, Hui-Qing Chen, Yan Wu, Yi-Fan Cao e Jiang-Hui Bian. "Effects of parasites and predators on nociception: decreases analgesia reduces overwinter survival in root voles (Rodentia: Cricetidae)". Zoologia 38 (7 luglio 2021): 1–9. http://dx.doi.org/10.3897/zoologia.38.e67845.
Testo completoAbstract (sommario):
Growing evidence suggests that parasite-infected prey is more vulnerable to predation. However, the mechanism underlying this phenomenon is obscure. In small mammals, analgesia induced by environmental stressors is a fundamental component of the defensive repertoire, promoting defensive responses. Thus, the reduced analgesia may impair the defensive ability of prey and increase their predation risk. This study aimed to determine whether coccidia infection increases the vulnerability to predation in root voles, Microtus oeconomus (Pallas, 1776), by decreased analgesia. Herein, a predator stimulus and parasitic infection were simulated in the laboratory via a two-level factorial experiment, then, the vole nociceptive responses to an aversive thermal stimulus were evaluated. Further, a field experiment was performed to determine the overwinter survival of voles with different nociceptive responses via repeated live trapping. The coccidia-infected voles demonstrated reduced predator-induced analgesia following exposure to predator odor. Meanwhile, pain-sensitive voles had lower overwinter survival than pain-inhibited voles in enclosed populations throughout the duration of the experiment. Our findings suggest that coccidia infection attenuates predator-induced analgesia, resulting in an increased vulnerability to predation.
39
Neumann, Viola, Matthias Schaber, Margit Eero, Uwe Böttcher e Friedrich W. Köster. "Quantifying predation on Baltic cod early life stages". Canadian Journal of Fisheries and Aquatic Sciences 74, n. 6 (giugno 2017): 833–42. http://dx.doi.org/10.1139/cjfas-2016-0215.
Testo completoAbstract (sommario):
Predation on cod (Gadus morhua) eggs by sprat (Sprattus sprattus) and herring (Clupea harengus) is known to be one of the processes influencing reproductive success of the eastern Baltic cod and has been reported to have contributed to lack of recovery of the stock in the 1990s. This study quantifies the predation on cod eggs in the Bornholm Basin, the major spawning area of cod in the central Baltic Sea, in the 1990s in comparison with the second half of the 2000s. The analyses involve estimating daily consumption rates of predator populations, which are then compared with corresponding daily egg production rates. As a methodological advancement compared with earlier studies, spatially resolved information on predator distribution and abundance is utilized in quantifying predator stock size. This resulted in more realistic consumption estimates in relation to overall egg production compared with earlier studies that consistently overestimated predation pressure by clupeids. Our results suggest a generally lower predation pressure on cod eggs in the mid- to late 2000s, due to a combination of reduced predator abundance and lower daily rations by individual predators.
40
Lucatero, Azucena, Shalene Jha e Stacy M. Philpott. "Local Habitat Complexity and Its Effects on Herbivores and Predators in Urban Agroecosystems". Insects 15, n. 1 (7 gennaio 2024): 41. http://dx.doi.org/10.3390/insects15010041.
Testo completoAbstract (sommario):
In urban community gardens, cultivated vegetation provides variable levels of habitat complexity, which can suppress pests by promoting predator diversity and improving pest control. In this study, we examine three components of the structural complexity of garden vegetation (cover, diversity, and connectivity) to investigate whether higher garden vegetation complexity leads to fewer herbivores, more predators, and higher predation. We worked in eight community gardens where we quantified vegetation complexity, sampled the arthropod community, and measured predation on corn earworm eggs. We found that plots with high vegetation cover supported higher species richness and greater abundance of predatory insects. High vegetation cover also supported a greater abundance and species richness of spiders. In contrast, high vegetation diversity was negatively associated with predator abundance. While high predator abundance was positively associated with egg predation, greater predator species richness had a negative impact on egg predation, suggesting that antagonism between predators may limit biological control. Community gardeners may thus manipulate vegetation cover and diversity to promote higher predator abundance and diversity in their plots. However, the species composition of predators and the prevalence of interspecific antagonism may ultimately determine subsequent impacts on biological pest control.
41
Tamba, Tua A. "Modeling and bifurcation analysis of an intraguild predation system". International Journal of Advances in Applied Sciences 12, n. 2 (1 giugno 2023): 103. http://dx.doi.org/10.11591/ijaas.v12.i2.pp103-110.
Testo completoAbstract (sommario):
This paper proposes a mathematical model of an asymmetric intraguild (IG) predation system with an exclusive alternative resource. In particular, this paper analyzes the effects that the exclusive alternative resource has on the consumption/predation behaviors of both the IG predator and IG prey species in the system. The results presented on this paper show that, if the IG predator is less competitive in consumption and less efficient in conversion of the shared resource than that of the IG prey, then there exists a lower bound on the value of the predation rate parameter that should be maintained by IG predator species to ensure its survival and co-existence in the system.
42
Hulthén, Kaj, Ben B. Chapman, P. Anders Nilsson, Jerker Vinterstare, Lars-Anders Hansson, Christian Skov, Jakob Brodersen, Henrik Baktoft e Christer Brönmark. "Escaping peril: perceived predation risk affects migratory propensity". Biology Letters 11, n. 8 (agosto 2015): 20150466. http://dx.doi.org/10.1098/rsbl.2015.0466.
Testo completoAbstract (sommario):
Although migratory plasticity is increasingly documented, the ecological drivers of plasticity are not well understood. Predation risk can influence migratory dynamics, but whether seasonal migrants can adjust their migratory behaviour according to perceived risk is unknown. We used electronic tags to record the migration of individual roach ( Rutilus rutilus ), a partially migratory fish, in the wild following exposure to manipulation of direct (predator presence/absence) and indirect (high/low roach density) perceived predation risk in experimental mesocosms. Following exposure, we released fish in their lake summer habitat and monitored individual migration to connected streams over an entire season. Individuals exposed to increased perceived direct predation risk (i.e. a live predator) showed a higher migratory propensity but no change in migratory timing, while indirect risk (i.e. roach density) affected timing but not propensity showing that elevated risk carried over to alter migratory behaviour in the wild. Our key finding demonstrates predator-driven migratory plasticity, highlighting the powerful role of predation risk for migratory decision-making and dynamics.
43
Kroth, Nádia, Gilberto Dinis Cozzer, Sonia Lemes da Silva, Renan de Souza Rezende, Jacir Dal Magro e Daniel Albeny-Simões. "Female oviposition preferences and larval behavior of the Aedes aegypti mosquito (Linnaeus, 1762) exposed to predator cues (Odonata: Libellulidae)". Limnetica 44, n. 1 (25 giugno 2024): 1. http://dx.doi.org/10.23818/limn.44.06.
Testo completoAbstract (sommario):
The reproductive success of mosquitoes is heavily influenced by females' ability to select suitable oviposition sites for the proper development of their offspring. Many of these potential habitats may harbor predators, and the detection of these predators is crucial for assessing the risk of predation, which can, in turn, influence the behavior of the prey. However, there are often trade-offs to consider, which can impact the life history of these organisms. In our study, we investigated the oviposition preferences and larval behavioral responses of the Aedes aegypti mosquito when exposed to cues from predators and the actual presence of predation by Libellulidae (Odonata) larvae. We observed the mosquito's choices regarding oviposition with and without predation cues for a duration of ten weeks, following 48 hours of exposure. Additionally, we measured larval behavior across various treatments, including those with predation cues, predator cues, the presence of larvae, and controls with only water. Our findings revealed that the highest preference for oviposition occurred in containers with high organic matter content, regardless the presence of both predator cues and actual predators. Furthermore, we noted significant changes in larval behavior in response to predation cues, including evasive behaviors. When facing the risk of predation, larvae spent more time near the container's edges and exhibited discrete feeding behaviors or avoidance of the risk of predation. Conversely, in the absence of predation risk, larvae explored the entire container, swimming vigorously. These results highlight the significance of anti-predatory behaviors triggered by the recognition of predation cues in the context of Ae. aegypti's reproductive success.
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Kotler, BP, JS Brown e WA Mitchell. "The Role of Predation in Shaping the Behavior, Morphology and Community Organization of Desert Rodents". Australian Journal of Zoology 42, n. 4 (1994): 449. http://dx.doi.org/10.1071/zo9940449.
Testo completoAbstract (sommario):
Predation greatly influences many aspects of the ecology of desert rodents, from foraging behaviour to mechanisms of species coexistence to the evolution of specialised morphologies. Using a foraging-theory approach, we examine consequences of predation for assemblages of desert rodents from North America and the Middle East. In particular, we review experimental evidence that examines the influence of predation on foraging costs and foraging behaviour, explore how predation can act to structure communities, and discuss the role that predation may have played in the evolution of bipedal locomotion. Finally, we compare the importance of predation for the evolution of anti-predator behaviours and morphology, for population dynamics, and for community processes, with its magnitude and heterogeneity. In regard to foraging behaviour, desert rodents treat the risk of predation as a cost of foraging. They combine assessments of food and safety to arrive at foraging decisions, exploiting resource patches less intensively in response to increased predatory risk. The cost of predation can be up to 91% of the foraging costs of desert rodents, but the proportion is greater for Middle Eastern rodents than for North American rodents. In regard to community structure, predation can provide the niche axis as well as the necessary tradeoff for species coexistence. Despite the importance of predation in shaping the foraging behaviour of desert rodents, predation may not always influence species coexistence. Predation contributes to species coexistence at sites in the Sonoran and Great Basin deserts. But in the Negev Desert, where predation costs are the greatest, predation does not provide a mechanism of species coexistence. In regard to bipedal locomotion, predation most likely confers superior ability to avoid predators by improving sprint speed and ability to take evasive action, but at the expense of foraging ability in safe microhabitats. The evolution of bipedality will be favoured by situations where the risk of predation is great: the open microhabitat is riskier than the bush, the richest patches are found in the riskiest places, and rich patches are far apart. The magnitude of predatory risk will affect the evolution of anti-predator behaviour and morphologies. However, the importance of predation in community processes is not determined by its magnitude, but by its heterogeneity in time and space relative to the abilities of potentially coexisting species.
45
Liu, Xin, Jian Wen, Xingyu Geng, Lu Xiao, Yan Zou, Zhe Shan, Xianli Lu, Ying Fu, Yu Fu e Fengqin Cao. "The Impact of Predation Risks on the Development and Fecundity of Bactrocera dorsalis Hendel". Insects 15, n. 5 (1 maggio 2024): 322. http://dx.doi.org/10.3390/insects15050322.
Testo completoAbstract (sommario):
Predators are dependent on the capture of prey to meet their energetic and nutritive requirements, which brings the risk of predation to prey. The predation risk is divided into consumptive and non-consumptive effects. Non-consumptive effects may manifest through altered growth and ontogenetic trajectories in prey species, a dynamic modulated by olfactory or other sensory cues from predators. Bactrocera dorsalis Hendel represents a major invasive threat to global horticulture. While earlier research was primarily centered on the consumptive interactions between B. dorsalis and its natural enemies, the potential consequences of non-consumptive interactions on the development of B. dorsalis have been overlooked. In this study, we investigated the impact of predation risk effects, induced by both visual exposure to the predatory mantis Hierodula patellifera Serville and its associated odor, on the life history traits of B. dorsalis. Female B. dorsalis demonstrated a reduced developmental time in the presence of a caged predator (H. patellifera) or predator odors, but showed significantly increased fecundity. Conversely, males displayed no significant change in developmental time. Additionally, neither the female nor male body weight at death was significantly influenced by the predation risk from the caged predator or predator odors. This study investigated the effects of predation risk on the development and reproduction of B. dorsalis, emphasizing the potential importance of odor risk in biological and pest control.
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Gong, Anson. "The Effects of Predator Exposure On the Female Choice of Guppies (Poecilia Reticulata) From a High-Predation Population". Behaviour 134, n. 5-6 (1997): 373–89. http://dx.doi.org/10.1163/156853997x00593.
Testo completoAbstract (sommario):
AbstractStudies have shown that, under intense predation, guppy (Poecilia reticulata) populations have evolved duller male colouration and weaker female preference for brightly coloured males. Gong & Gibson (1996) found that females descended from a low-predation population responded to the presence of a fish predator by becoming less receptive and reversing their typical sexual preference for the brighter and more active of a pair of males. Here, I investigated whether this response is more strongly developed in guppies descended from a captive population exposed to predation from a natural predator. I measured the social and sexual preferences of virgin females for a pair of males both before and after visual exposure to a predatory cichlid in an adjacent tank. Females initially preferred the more actively displaying male. Exposure to the cichlid caused some females to become unreceptive and the remainder avoided the previously preferred male. These effects did not differ in magnitude from the responses of females descended from a low-predation population (Gong & Gibson, 1996). The avoidance of conspicuous males by females seems to be a generalized response to predation risk that is independent of current predation pressure on a population.
47
Kiran, R., e Melally G. Venkatesha. "Record of Coranus siva Kirkaldy (Hemiptera: Reduviidae) on coffee berry borer, Hypothenemus hampei Ferrari (Coleoptera: Curculionidae) in India". ENTOMON 47, n. 2 (30 giugno 2022): 179–82. http://dx.doi.org/10.33307/entomon.v47i2.720.
Testo completoAbstract (sommario):
The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae) is a serious pest affecting coffee worldwide. The present study provides the first report of the natural predation of Coranus siva Kirkaldy on H. hampei. As of now, there is no report on the genus Coranus or other reduviid predation on coffee pests from India or form other coffee growing countries. The predator captured the adult and sucked the body fluid. The predator found to paralyze many adults of H. hampei whenever more prey adults were provided. Predation of C. siva and its sequence of behavioural events are reported.
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O’Neil, Robert J. "A MODEL OF PREDATION BY PODISUS MACULIVENTRIS (SAY) ON MEXICAN BEAN BEETLE, EPILACHNA VARIVESTIS MULSANT, IN SOYBEANS". Canadian Entomologist 120, n. 7 (luglio 1988): 601–8. http://dx.doi.org/10.4039/ent120601-7.
Testo completoAbstract (sommario):
AbstractA model of predation by Podisus maculiventris (Say) on Mexican bean beetle, Epilachna varivestis Mulsant, larvae in soybeans is presented. The attack equation described the number of prey attacked as a function of the number of prey, soybean leaf area, and the search behavior of the predator. The area searched by P. maculiventris was related to the amount of leaf area and the number of prey. Predictions of the number of Mexican bean beetles attacked per predator were compared with an independent field data set. The relevance of the predation model to studies of predation in other agricultural systems is discussed.
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Mather, Martha E. "The role of context-specific predation in understanding patterns exhibited by anadromous salmon". Canadian Journal of Fisheries and Aquatic Sciences 55, S1 (1 gennaio 1998): 232–46. http://dx.doi.org/10.1139/d98-002.
Testo completoAbstract (sommario):
Predation is frequently studied in aquatic systems that contain salmon. Because these systems are difficult to manipulate and replicate, rigorous across-system comparisons are essential. Herein I review the literature on factors that may influence predation across systems. Specifically, I evaluated how often predation on salmonids was important across prey taxa, life stage, habitat, predator taxa, methodology, and spatial scale. Further, I examined what factors were influential in systems where predation was important. In nine journals from 1959-1996, 45 field studies explicitly tested the importance of direct effects of predation on anadromous salmonid prey. Authors of 36 (80%) studies concluded that predation was important. More studies in which predation was deemed important focused on smolts subjected to fish predation in the transitional river and estuary habitats. Furthermore, field surveys at larger spatial scales were most often used. Finally, most studies reported little information on confounding factors that complicate predation. If we are to learn from these complex systems, we need to collect, analyze, and report similar types of information that are collected across systems and years using rigorous and systematic methods.
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Stewart, Heather C., e Sandra J. Walde. "THE DYNAMICS OF APHIS POMI DE GEER (HOMOPTERA: APHIDIDAE) AND ITS PREDATOR, APHIDOLETES APHIDIMYZA (RONDANI) (DIPTERA: CECIDOMYIIDAE), ON APPLE IN NOVA SCOTIA". Canadian Entomologist 129, n. 4 (agosto 1997): 627–36. http://dx.doi.org/10.4039/ent129627-4.
Testo completoAbstract (sommario):
AbstractThe dynamics of Aphis pomi De Geer (Homoptera: Aphididae) and its predator, Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae), were studied over two seasons in a commercial apple orchard in Nova Scotia. Aphid and predator population dynamics were very different in the two seasons. The most numerous predator in both years was A. aphidimyza. This predator was found in the earliest colonies sampled each season and was present throughout the growing season. In the year with relatively high aphid densities a single peak in aphid and predator density was seen in mid-July, just prior to maximum predation rate. The predator’s numerical response resulted in delayed density dependence in predation rate. In the year of low aphid densities, predator and prey dynamics appeared uncoupled, and a higher rate of colony turnover may have been caused by other predators such as mirids. Aphidoletes aphidimyza tended to aggregate oviposition in high-density aphid colonies, but this aggregation resulted in predation that was only very weakly spatially density dependent.