Articoli di riviste: "Parasitoids Immunology"

1

Henry, Lee M., Bernard D. Roitberg e David R. Gillespie. "Covariance of phenotypically plastic traits induces an adaptive shift in host selection behaviour". Proceedings of the Royal Society B: Biological Sciences 273, n. 1603 (15 agosto 2006): 2893–99. http://dx.doi.org/10.1098/rspb.2006.3672.

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Abstract (sommario):

Flexibility in adult body size allows generalist parasitoids to use many host species at a cost of producing a range of adult sizes. Consequently, host selection behaviour must also maintain a level of flexibility as adult size is related to capture efficiency. In the present study, we investigated covariance of two plastic traits—size at pupation and host size selection behaviour—using Aphidius ervi reared on either Acyrthosiphon pisum or Aulacorthum solani , generating females of disparate sizes. Natal host was shown to change the ranking of perceived host quality with relation to host size. Parasitoids preferentially attacked hosts that corresponded to the size of the second instar of their natal host species. This resulted in optimal host selection behaviour when parasitoids were exposed to the same host species from which they emerged. Parasitoid size was positively correlated with host size preference, indicating that females use relative measurements when selecting suitable hosts. These coadapted gene complexes allow generalist parasitoids to effectively use multiple host species over several generations. However, the fixed nature of the behavioural response, within a parasitoid's lifetime, suggests that these traits may have evolved in a patchy host species environment.

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Özbek, Rabia, Krishnendu Mukherjee, Fevzi Uçkan e Andreas Vilcinskas. "Reprograming of epigenetic mechanisms controlling host insect immunity and development in response to egg-laying by a parasitoid wasp". Proceedings of the Royal Society B: Biological Sciences 287, n. 1928 (10 giugno 2020): 20200704. http://dx.doi.org/10.1098/rspb.2020.0704.

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Abstract (sommario):

Parasitoids are insects that use other insects as hosts. They sabotage host cellular and humoral defences to promote the survival of their offspring by injecting viruses and venoms along with their eggs. Many pathogens and parasites disrupt host epigenetic mechanisms to overcome immune system defences, and we hypothesized that parasitoids may use the same strategy. We used the ichneumon wasp Pimpla turionellae as a model idiobiont parasitoid to test this hypothesis, with pupae of the greater wax moth Galleria mellonella as the host. We found that parasitoid infestation involves the suppression of host immunity-related effector genes and the modulation of host genes involved in developmental hormone signalling. The transcriptional reprogramming of host genes following the injection of parasitoid eggs was associated with changes in host epigenetic mechanisms. The introduction of parasitoids resulted in a transient decrease in host global DNA methylation and the modulation of acetylation ratios for specific histones. Genes encoding regulators of histone acetylation and deacetylation were mostly downregulated in the parasitized pupae, suggesting that parasitoids can suppress host transcription. We also detected a strong parasitoid-specific effect on host microRNAs regulating gene expression at the post-transcriptional level. Our data therefore support the hypothesis that parasitoids may favour the survival of their offspring by interfering with host epigenetic mechanisms to suppress the immune system and disrupt development.

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3

Potter, Kristen A., e H. Arthur Woods. "Trichogramma parasitoids alter the metabolic physiology of Manduca eggs". Proceedings of the Royal Society B: Biological Sciences 279, n. 1742 (20 giugno 2012): 3572–76. http://dx.doi.org/10.1098/rspb.2012.1050.

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Egg parasitoids face unique developmental constraints. First, they have exceptionally limited resources to support themselves and their siblings through three life stages. Second, they develop within the physiological system of another species, which they modify to their own ends. We examined how these constraints affect the metabolic physiology of egg parasitism, and whether parasitoids retool their host eggshell to account for their different metabolic demands. Higher-conductance eggshells allow more oxygen to reach the developing parasitoids, but also allow more water to leave the egg. We used Manduca sexta (Lepidoptera: Sphingidae) eggs and Trichogramma (Hymenoptera: Trichogrammatidae) parasitoids from southeastern AZ, USA. Compared with unparasitized Manduca eggs, eggs parasitized by Trichogramma had lower peak metabolic rates and approximately 50 per cent lower metabolic efficiency. However, developing Trichogramma were far more efficient than typical transfer efficiencies between tropic levels (approx. 10%). Even within a few hours of parasitization, eggs containing more Trichogramma had lower per-parasitoid metabolic rates, suggesting that parasitoid larvae have mechanisms for rapidly adjusting their metabolic rates based on number of siblings. Parasitoids also appear to control the conductance of their host eggshell: their different metabolic demands were mirrored by shifts in rates of water loss.

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4

Staab, Michael, Helge Bruelheide, Walter Durka, Stefan Michalski, Oliver Purschke, Chao-Dong Zhu e Alexandra-Maria Klein. "Tree phylogenetic diversity promotes host–parasitoid interactions". Proceedings of the Royal Society B: Biological Sciences 283, n. 1834 (13 luglio 2016): 20160275. http://dx.doi.org/10.1098/rspb.2016.0275.

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Evidence from grassland experiments suggests that a plant community's phylogenetic diversity (PD) is a strong predictor of ecosystem processes, even stronger than species richness per se . This has, however, never been extended to species-rich forests and host–parasitoid interactions. We used cavity-nesting Hymenoptera and their parasitoids collected in a subtropical forest as a model system to test whether hosts, parasitoids, and their interactions are influenced by tree PD and a comprehensive set of environmental variables, including tree species richness. Parasitism rate and parasitoid abundance were positively correlated with tree PD. All variables describing parasitoids decreased with elevation, and were, except parasitism rate, dependent on host abundance. Quantitative descriptors of host–parasitoid networks were independent of the environment. Our study indicates that host–parasitoid interactions in species-rich forests are related to the PD of the tree community, which influences parasitism rates through parasitoid abundance. We show that effects of tree community PD are much stronger than effects of tree species richness, can cascade to high trophic levels, and promote trophic interactions. As during habitat modification phylogenetic information is usually lost non-randomly, even species-rich habitats may not be able to continuously provide the ecosystem process parasitism if the evolutionarily most distinct plant lineages vanish.

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Härri, Simone A., Jochen Krauss e Christine B. Müller. "Fungal endosymbionts of plants reduce lifespan of an aphid secondary parasitoid and influence host selection". Proceedings of the Royal Society B: Biological Sciences 275, n. 1651 (5 agosto 2008): 2627–32. http://dx.doi.org/10.1098/rspb.2008.0594.

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Abstract (sommario):

Complex biotic interactions shape ecological communities of plants, herbivores and their natural enemies. In studies of multi-trophic interactions, the presence of small, invisible micro-organisms associated with plants and those of a fourth above-ground trophic level have often been neglected. Incorporating these neglected factors improves our understanding of the processes within a multi-trophic network. Here, we ask whether the presence of a fungal endosymbiont, which alters plant quality by producing herbivore-toxic substances, trickles up the food chain and affects the performance and host-selection behaviour of aphid secondary parasitoids. We simultaneously offered hosts from endophyte-free and endophyte-infected environments to secondary parasitoids. Older and more experienced parasitoid females discriminated against hosts from the endophyte-infected environment. Developing in lower quality hosts from the endophyte-infected environment reduced the lifespan of secondary parasitoids. This indicates that aphid secondary parasitoids can perceive the disadvantage for their developing offspring in parasitoids from the endophyte environment and can learn to discriminate against them. In the field, this discrimination ability may shift the success of primary parasitoids to endophyte-infected plants, which co-occur with endophyte-free plants. Ultimately, the control of aphids depends on complex interactions between primary and secondary parasitoids and their relative sensitivity to endophytic fungi.

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6

Castelo, Marcela K., e José E. Crespo. "Microorganismal Cues Involved in Host-Location in Asilidae Parasitoids". Biology 11, n. 1 (13 gennaio 2022): 129. http://dx.doi.org/10.3390/biology11010129.

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Abstract (sommario):

Parasitoids are organisms that kill their host before completing their development. Typical parasitoids belong to Hymenoptera, whose females search for the hosts. But some atypical Diptera parasitoids also have searching larvae that must orientate toward, encounter, and accept hosts, through cues with different levels of detectability. In this work, the chemical cues involved in the detection of the host by parasitoid larvae of the genus Mallophora are shown with a behavioral approach. Through olfactometry assays, we show that two species of Mallophora orient to different host species and that chemical cues are produced by microorganisms. We also show that treating potential hosts with antibiotics reduces attractiveness on M. ruficauda but not to M. bigoti suggesting that endosymbiotic bacteria responsible for the host cues production should be located in different parts of the host. In fact, we were able to show that M. bigoti is attracted to frass from the most common host. Additionally, we evaluated host orientation under a context of interspecific competence and found that both parasitoid species orient to Cyclocephaala signaticollis showing that host competition could occur in the field. Our work shows how microorganisms mediate orientation to hosts but differences in their activity or location in the host result in differences in the attractiveness of different cues. We show for the first time that M. bigoti behaves similar to M. ruficauda extending and reinforcing that all Mallophora species have adopted a parasitoid lifestyle.

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7

Fatouros, N. E., A. Cusumano, F. Bin, A. Polaszek e J. C. van Lenteren. "How to escape from insect egg parasitoids: a review of potential factors explaining parasitoid absence across the Insecta". Proceedings of the Royal Society B: Biological Sciences 287, n. 1931 (22 luglio 2020): 20200344. http://dx.doi.org/10.1098/rspb.2020.0344.

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Abstract (sommario):

The egg is the first life stage directly exposed to the environment in oviparous animals, including many vertebrates and most arthropods. Eggs are vulnerable and prone to mortality risks. In arthropods, one of the most common egg mortality factors is attack from parasitoids. Yet, parasitoids that attack the egg stage are absent in more than half of all insect (sub)orders. In this review, we explore possible causes explaining why eggs of some insect taxa are not parasitized. Many insect (sub)orders that are not attacked by egg parasitoids lack herbivorous species, with some notable exceptions. Factors we consider to have led to escape from egg parasitism are parental egg care, rapid egg development, small egg size, hiding eggs, by e.g. placing them into the soil, applying egg coatings or having thick chorions preventing egg penetration, eusociality, and egg cannibalism. A quantitative network analysis of host–parasitoid associations shows that the five most-speciose genera of egg parasitoids display patterns of specificity with respect to certain insect orders, especially Lepidoptera and Hemiptera, largely including herbivorous species that deposit their eggs on plants. Finally, we discuss the many counteradaptations that particularly herbivorous species have developed to lower the risk of attack by egg parasitoids.

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8

Girling, Robbie D., Alex Stewart-Jones, Julie Dherbecourt, Joanna T. Staley, Denis J. Wright e Guy M. Poppy. "Parasitoids select plants more heavily infested with their caterpillar hosts: a new approach to aid interpretation of plant headspace volatiles". Proceedings of the Royal Society B: Biological Sciences 278, n. 1718 (26 gennaio 2011): 2646–53. http://dx.doi.org/10.1098/rspb.2010.2725.

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Plants produce volatile organic compounds (VOCs) in response to herbivore attack, and these VOCs can be used by parasitoids of the herbivore as host location cues. We investigated the behavioural responses of the parasitoid Cotesia vestalis to VOCs from a plant–herbivore complex consisting of cabbage plants ( Brassica oleracea ) and the parasitoids host caterpillar, Plutella xylostella . A Y-tube olfactometer was used to compare the parasitoids' responses to VOCs produced as a result of different levels of attack by the caterpillar and equivalent levels of mechanical damage. Headspace VOC production by these plant treatments was examined using gas chromatography–mass spectrometry. Cotesia vestalis were able to exploit quantitative and qualitative differences in volatile emissions, from the plant–herbivore complex, produced as a result of different numbers of herbivores feeding. Cotesia vestalis showed a preference for plants with more herbivores and herbivore damage, but did not distinguish between different levels of mechanical damage. Volatile profiles of plants with different levels of herbivores/herbivore damage could also be separated by canonical discriminant analyses. Analyses revealed a number of compounds whose emission increased significantly with herbivore load, and these VOCs may be particularly good indicators of herbivore number, as the parasitoid processes cues from its external environment.

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9

McLean, Ailsa H. C., e H. Charles J. Godfray. "Evidence for specificity in symbiont-conferred protection against parasitoids". Proceedings of the Royal Society B: Biological Sciences 282, n. 1811 (22 luglio 2015): 20150977. http://dx.doi.org/10.1098/rspb.2015.0977.

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Many insects harbour facultative symbiotic bacteria, some of which have been shown to provide resistance against natural enemies. One of the best-known protective symbionts is Hamiltonella defensa , which in pea aphid ( Acyrthosiphon pisum ) confers resistance against attack by parasitoid wasps in the genus Aphidius (Braconidae). We asked (i) whether this symbiont also confers protection against a phylogenetically distant group of parasitoids (Aphelinidae) and (ii) whether there are consistent differences in the effects of bacteria found in pea aphid biotypes adapted to different host plants. We found that some H. defensa strains do provide protection against an aphelinid parasitoid Aphelinus abdominalis. Hamiltonella defensa from the Lotus biotype provided high resistance to A. abdominalis and moderate to low resistance to Aphidius ervi , while the reverse was seen from Medicago biotype isolates. Aphids from Ononis showed no evidence of symbiont-mediated protection against either wasp species and were relatively vulnerable to both. Our results may reflect the different selection pressures exerted by the parasitoid community on aphids feeding on different host plants, and could help explain the maintenance of genetic diversity in bacterial symbionts.

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10

Quicke, Donald L. J., e Buntika A. Butcher. "Review of Venoms of Non-Polydnavirus Carrying Ichneumonoid Wasps". Biology 10, n. 1 (12 gennaio 2021): 50. http://dx.doi.org/10.3390/biology10010050.

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Abstract (sommario):

Parasitoids are predominantly insects that develop as larvae on or inside their host, also usually another insect, ultimately killing it after various periods of parasitism when both parasitoid larva and host are alive. The very large wasp superfamily Ichneumonoidea is composed of parasitoids of other insects and comprises a minimum of 100,000 species. The superfamily is dominated by two similarly sized families, Braconidae and Ichneumonidae, which are collectively divided into approximately 80 subfamilies. Of these, six have been shown to release DNA-containing virus-like particles, encoded within the wasp genome, classified in the virus family Polydnaviridae. Polydnaviruses infect and have profound effects on host physiology in conjunction with various venom and ovarial secretions, and have attracted an immense amount of research interest. Physiological interactions between the remaining ichneumonoids and their hosts result from adult venom gland secretions and in some cases, ovarian or larval secretions. Here we review the literature on the relatively few studies on the effects and chemistry of these ichneumonoid venoms and make suggestions for interesting future research areas. In particular, we highlight relatively or potentially easily culturable systems with features largely lacking in currently studied systems and whose study may lead to new insights into the roles of venom chemistry in host-parasitoid relationships as well as their evolution.

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11

Trainor, Jordann E., Pooja KR e Nathan T. Mortimer. "Immune Cell Production Is Targeted by Parasitoid Wasp Virulence in a Drosophila–Parasitoid Wasp Interaction". Pathogens 10, n. 1 (8 gennaio 2021): 49. http://dx.doi.org/10.3390/pathogens10010049.

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Abstract (sommario):

The interactions between Drosophila melanogaster and the parasitoid wasps that infect Drosophila species provide an important model for understanding host–parasite relationships. Following parasitoid infection, D. melanogaster larvae mount a response in which immune cells (hemocytes) form a capsule around the wasp egg, which then melanizes, leading to death of the parasitoid. Previous studies have found that host hemocyte load; the number of hemocytes available for the encapsulation response; and the production of lamellocytes, an infection induced hemocyte type, are major determinants of host resistance. Parasitoids have evolved various virulence mechanisms to overcome the immune response of the D. melanogaster host, including both active immune suppression by venom proteins and passive immune evasive mechanisms. We identified a previously undescribed parasitoid species, Asobara sp. AsDen, which utilizes an active virulence mechanism to infect D. melanogaster hosts. Asobara sp. AsDen infection inhibits host hemocyte expression of msn, a member of the JNK signaling pathway, which plays a role in lamellocyte production. Asobara sp. AsDen infection restricts the production of lamellocytes as assayed by hemocyte cell morphology and altered msn expression. Our findings suggest that Asobara sp. AsDen infection alters host signaling to suppress immunity.

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12

von Burg, Simone, Julia Ferrari, Christine B. Müller e Christoph Vorburger. "Genetic variation and covariation of susceptibility to parasitoids in the aphid Myzus persicae : no evidence for trade-offs". Proceedings of the Royal Society B: Biological Sciences 275, n. 1638 (12 febbraio 2008): 1089–94. http://dx.doi.org/10.1098/rspb.2008.0018.

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Abstract (sommario):

Parasitoids are an important mortality factor for insects. Susceptibility to parasitoids should thus be under strong negative selection. Nevertheless, ample genetic variation for susceptibility to parasitoids is commonly observed in natural populations, suggesting that trade-offs may constrain the evolution of reduced susceptibility. This can be studied by assessing genetic variation for susceptibility and its covariation with other components of fitness. In a set of 17 clones of the peach potato aphid, Myzus persicae , for which good estimates of heritable variation for life-history traits were available, we found significant clonal variation for susceptibility to two of their common parasitoids: Aphidius colemani and Diaeretiella rapae . One clone, the only one harbouring a facultative endosymbiotic bacterium, Regiella insecticola , was entirely resistant to both parasitoids. Susceptibilities to the two parasitoids exhibited a positive genetic correlation close to unity, implying a general mechanism of defence. However, the susceptibility to parasitoids was uncorrelated to the clones' fecundity or rate of increase, providing no evidence for costs of the ability to resist parasitoids.

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Macfadyen, Sarina, Paul G. Craze, Andrew Polaszek, Kees van Achterberg e Jane Memmott. "Parasitoid diversity reduces the variability in pest control services across time on farms". Proceedings of the Royal Society B: Biological Sciences 278, n. 1723 (30 marzo 2011): 3387–94. http://dx.doi.org/10.1098/rspb.2010.2673.

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Abstract (sommario):

Recent declines in biodiversity have increased interest in the link between biodiversity and the provision and sustainability of ecosystem services across space and time. We mapped the complex network of interactions between herbivores and parasitoids to examine the relationship between parasitoid species richness, functional group diversity and the provision of natural pest control services. Quantitative food webs were constructed for 10 organic and 10 conventional farms. Parasitoid species richness varied from 26 to 58 species and we found a significant positive relationship between parasitoid species richness and temporal stability in parasitism rates. Higher species richness was associated with lower variation in parasitism rate. A functional group analysis showed significantly greater parasitoid species complementarity on organic farms, with on average more species in each functional group. We simulated parasitoid removal to predict whether organic farms experienced greater robustness of parasitism in the face of local extinctions. This analysis showed no consistent differences between the organic and conventional farm pairs in terms of loss of pest control service. Finally, it was found that the different habitats that make up each farm do not contribute equally to parasitoid species diversity, and that hedgerows produced more parasitoid species, significantly more so on organic farms.

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Hajek, Ann E., e Saskya van Nouhuys. "Fatal diseases and parasitoids: from competition to facilitation in a shared host". Proceedings of the Royal Society B: Biological Sciences 283, n. 1828 (13 aprile 2016): 20160154. http://dx.doi.org/10.1098/rspb.2016.0154.

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Abstract (sommario):

Diverse parasite taxa share hosts both at the population level and within individual hosts, and their interactions, ranging from competitive exclusion to facilitation, can drive community structure and dynamics. Emergent pathogens have the potential to greatly alter community interactions. We found that an emergent fungal entomopathogen dominated pre-existing lethal parasites in populations of the forest defoliating gypsy moth, Lymantria dispar . The parasite community was composed of the fungus and four parasitoid species that only develop successfully after they kill the host, and a virus that produces viable propagules before the host has died. A low-density site was sampled over 17 years and compared with 66 sites across a range of host densities, including outbreaks. The emergent fungal pathogen and competing parasitoids rarely co-infected host individuals because each taxa must kill its host. The virus was not present at low host densities, but successfully co-infected with all other parasite species. In fact, there was facilitation between the virus and one parasitoid species hosting a polydnavirus. This newly formed parasite community, altered by an emergent pathogen, is shaped both by parasite response to host density and relative abilities of parasites to co-inhabit the same host individuals.

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Ruther, Joachim, Lorena Prager e Tamara Pokorny. "Parasitic wasps do not lack lipogenesis". Proceedings of the Royal Society B: Biological Sciences 288, n. 1951 (26 maggio 2021): 20210548. http://dx.doi.org/10.1098/rspb.2021.0548.

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Abstract (sommario):

Fatty acids are crucial primary metabolites for virtually all creatures on earth. Most organisms thus do not rely exclusively on a nutritional supply containing fatty acids, but have the ability to synthesize fatty acids and triacylglycerides de novo from carbohydrates in a process called lipogenesis. The ubiquity of lipogenesis has been questioned by a series of studies reporting that many parasitic wasps (parasitoids) do not accumulate lipid mass despite having unlimited access to sugar. This has been interpreted as an evolutionary metabolic trait loss in parasitoids. Here, we demonstrate de novo biosynthesis of fatty acids from 13 C-labelled α- d -glucose in 13 species of parasitoids from seven families. We furthermore show in the model organism Nasonia vitripennis that lipogenesis occurs even when lipid reserves are still intact, but relative 13 C-incorporation rates increase in females with widely depleted fat reserves. We therefore conclude that the presumed ‘lack of lipogenesis' in parasitoids needs to be re-evaluated.

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Cayetano, Luis, Lukas Rothacher, Jean-Christophe Simon e Christoph Vorburger. "Cheaper is not always worse: strongly protective isolates of a defensive symbiont are less costly to the aphid host". Proceedings of the Royal Society B: Biological Sciences 282, n. 1799 (22 gennaio 2015): 20142333. http://dx.doi.org/10.1098/rspb.2014.2333.

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Abstract (sommario):

Defences against parasites are typically associated with costs to the host that contribute to the maintenance of variation in resistance. This also applies to the defence provided by the facultative bacterial endosymbiont Hamiltonella defensa, which protects its aphid hosts against parasitoid wasps while imposing life-history costs. To investigate the cost–benefit relationship within protected hosts, we introduced multiple isolates of H. defensa to the same genetic backgrounds of black bean aphids, Aphis fabae , and we quantified the protection against their parasitoid Lysiphlebus fabarum as well as the costs to the host (reduced lifespan and reproduction) in the absence of parasitoids. Surprisingly, we observed the opposite of a trade-off. Strongly protective isolates of H. defensa reduced lifespan and lifetime reproduction of unparasitized aphids to a lesser extent than weakly protective isolates. This finding has important implications for the evolution of defensive symbiosis and highlights the need for a better understanding of how strain variation in protective symbionts is maintained.

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Nair, Abhilash, Etsuko Nonaka e Saskya van Nouhuys. "Increased fluctuation in a butterfly metapopulation leads to diploid males and decline of a hyperparasitoid". Proceedings of the Royal Society B: Biological Sciences 285, n. 1885 (22 agosto 2018): 20180372. http://dx.doi.org/10.1098/rspb.2018.0372.

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Abstract (sommario):

Climate change can increase spatial synchrony of population dynamics, leading to large-scale fluctuation that destabilizes communities. High trophic level species such as parasitoids are disproportionally affected because they depend on unstable resources. Most parasitoid wasps have complementary sex determination, producing sterile males when inbred, which can theoretically lead to population extinction via the diploid male vortex (DMV). We examined this process empirically using a hyperparasitoid population inhabiting a spatially structured host population in a large fragmented landscape. Over four years of high host butterfly metapopulation fluctuation, diploid male production by the wasp increased, and effective population size declined precipitously. Our multitrophic spatially structured model shows that host population fluctuation can cause local extinctions of the hyperparasitoid because of the DMV. However, regionally it persists because spatial structure allows for efficient local genetic rescue via balancing selection for rare alleles carried by immigrants. This is, to our knowledge, the first empirically based study of the possibility of the DMV in a natural host–parasitoid system.

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Nair, Abhilash, Toby Fountain, Suvi Ikonen, Sami P. Ojanen e Saskya van Nouhuys. "Spatial and temporal genetic structure at the fourth trophic level in a fragmented landscape". Proceedings of the Royal Society B: Biological Sciences 283, n. 1831 (25 maggio 2016): 20160668. http://dx.doi.org/10.1098/rspb.2016.0668.

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Abstract (sommario):

A fragmented habitat becomes increasingly fragmented for species at higher trophic levels, such as parasitoids. To persist, these species are expected to possess life-history traits, such as high dispersal, that facilitate their ability to use resources that become scarce in fragmented landscapes. If a specialized parasitoid disperses widely to take advantage of a sparse host, then the parasitoid population should have lower genetic structure than the host. We investigated the temporal and spatial genetic structure of a hyperparasitoid (fourth trophic level) in a fragmented landscape over 50 × 70 km, using microsatellite markers, and compared it with the known structures of its host parasitoid, and the butterfly host which lives as a classic metapopulation. We found that population genetic structure decreases with increasing trophic level. The hyperparasitoid has fewer genetic clusters ( K = 4), than its host parasitoid ( K = 15), which in turn is less structured than the host butterfly ( K = 27). The genetic structure of the hyperparasitoid also shows temporal variation, with genetic differentiation increasing due to reduction of the population size, which reduces the effective population size. Overall, our study confirms the idea that specialized species must be dispersive to use a fragmented host resource, but that this adaptation has limits.

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Pulido, Hannier, Kerry E. Mauck, Consuelo M. De Moraes e Mark C. Mescher. "Combined effects of mutualistic rhizobacteria counteract virus-induced suppression of indirect plant defences in soya bean". Proceedings of the Royal Society B: Biological Sciences 286, n. 1903 (22 maggio 2019): 20190211. http://dx.doi.org/10.1098/rspb.2019.0211.

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Abstract (sommario):

It is increasingly clear that microbial plant symbionts can influence interactions between their plant hosts and other organisms. However, such effects remain poorly understood, particularly under ecologically realistic conditions where plants simultaneously interact with diverse mutualists and antagonists. Here, we examine how the effects of a plant virus on indirect plant defences against its insect vector are influenced by co-occurrence of other microbial plant symbionts. Using a multi-factorial design, we manipulated colonization of soya bean using three different microbes: a pathogenic plant virus (bean pod mottle virus (BPMV)), a nodule-forming beneficial rhizobacterium ( Bradyrhizobium japonicum ) and a plant growth-promoting rhizobacterium ( Delftia acidovorans ). We then assessed recruitment of parasitoids ( Pediobious foveolatus (Eulophidae)) and parasitism rates following feeding by the BPMV vector Epilachna varivestis (Coccinellidae). BPMV infection suppressed parasitoid recruitment, prolonged parasitoid foraging time and reduced parasitism rates in semi-natural foraging assays. However, simultaneous colonization of BPMV-infected hosts by both rhizobacteria restored parasitoid recruitment and rates of parasitism to levels similar to uninfected controls. Co-colonization by the two rhizobacteria also enhanced parasitoid recruitment in the absence of BPMV infection. These results illustrate the potential of plant-associated microbes to influence indirect plant defences, with implications for disease transmission and herbivory, but also highlight the potential complexity of such interactions.

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Ismail, Ismail, Rusli Anwar e Wartomo. "PEMANFAATAN BUNGA PUKUL DELAPAN (Turnera subulata) SEBAGAI TANAMAN INANG BAGI PREDATOR DAN PARASITOID ULAT API (Studi Kasus PT. Tritunggal Sentra Buana)". JURNAL AGRIMENT 6, n. 2 (3 dicembre 2021): 120–26. http://dx.doi.org/10.51967/jurnalagriment.v6i2.588.

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Abstract (sommario):

This research is motivated by the importance of knowledge about alternative pest control that is safe but still supports the achievement of maximum oil palm production so that the balance of the oil palm plantation ecosystem can occur. The purpose of this study is to determine the technical cultivation and benefits of the Turnera subulata flower as a host plant for predators and parasitoids that function as biological agents for caterpillars and can be a reference for controlling caterpillar pests that are safe and still support the achievement of maximum oil palm production. The method used in this research is field observation and documentation from the company. The scope of this research covers the technical aspects of the biological control of caterpillars. This research data uses primary data and secondary data obtained from field observations and literature studies in the form of company reports in the form of percentages. The realization of Turnera subulata planting reached 21,659 m on CR road and 19,914 m on MR road. The planned planting of Turnera subulata is 57,200 m on the CR road and 45,823 m on the MR road. For the realization of the planting of Turnera subulata itself using seeds that are ready for planting. To obtain the seedling, the company conducts its nurseries. The seedling technique was done using the stem cutting technique. The stems for the cutting technique were taken from the Turnera subulata plant stems that have grown large. The type of stem taken is the old Turnera subulata plant stem. For seed care, the seeds are always watered every morning and evening like other flower plants. For the natural enemy insects, been proven that there are 6 natural enemy insects associated with Turnera subulata plants, 3 predators, and 3 parasitoids, each with a large enough number of insects. The types are Eocanthecona furcellata, Cosmolestes sp., Sycannus dichotomus, Spinaria spinator, Fornicia sp., and Chaetexorista javana. The development and the implementation of a control system are by optimizing the conservation and utilization of these biological control agents is a wise step to obtain an effective, efficient and environmentally friendly technique for controlling caterpillars. The presence of Turnera subulata plants can be used to suppress the development of pests in oil palm plantations by increasing the potential for natural enemies, both predators, and parasitoids. The diversity of wild plants with flowers can increase the variety of insects so that the balance of the ecosystem occurs.

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21

Nappi, Anthony J., e Yves Carton. "Immunogenetic aspects of the cellular immune response of Drosophila against parasitoids". Immunogenetics 52, n. 3-4 (24 gennaio 2001): 157–64. http://dx.doi.org/10.1007/s002510000272.

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22

Arguelles, Joseph, Jenny Lee, Lady V. Cardenas, Shubha Govind e Shaneen Singh. "In Silico Analysis of a Drosophila Parasitoid Venom Peptide Reveals Prevalence of the Cation–Polar–Cation Clip Motif in Knottin Proteins". Pathogens 12, n. 1 (14 gennaio 2023): 143. http://dx.doi.org/10.3390/pathogens12010143.

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As generalist parasitoid wasps, Leptopilina heterotoma are highly successful on many species of fruit flies of the genus Drosophila. The parasitoids produce specialized multi-strategy extracellular vesicle (EV)-like structures in their venom. Proteomic analysis identified several immunity-associated proteins, including the knottin peptide, LhKNOT, containing the structurally conserved inhibitor cysteine knot (ICK) fold, which is present in proteins from diverse taxa. Our structural and docking analysis of LhKNOT’s 36-residue core knottin fold revealed that in addition to the knottin motif itself, it also possesses a Cation–Polar–Cation (CPC) clip. The CPC clip motif is thought to facilitate antimicrobial activity in heparin-binding proteins. Surprisingly, a majority of ICKs tested also possess the CPC clip motif, including 75 bona fide plant and arthropod knottin proteins that share high sequence and/or structural similarity with LhKNOT. Like LhKNOT and these other 75 knottin proteins, even the Drosophila Drosomycin antifungal peptide, a canonical target gene of the fly’s Toll-NF-kappa B immune pathway, contains this CPC clip motif. Together, our results suggest a possible defensive function for the parasitoid LhKNOT. The prevalence of the CPC clip motif, intrinsic to the cysteine knot within the knottin proteins examined here, suggests that the resultant 3D topology is important for their biochemical functions. The CPC clip is likely a highly conserved structural motif found in many diverse proteins with reported heparin binding capacity, including amyloid proteins. Knottins are targets for therapeutic drug development, and insights into their structure–function relationships will advance novel drug design.

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23

Mathis, Kaitlyn A., e Neil D. Tsutsui. "Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants". Proceedings of the Royal Society B: Biological Sciences 283, n. 1836 (17 agosto 2016): 20161281. http://dx.doi.org/10.1098/rspb.2016.1281.

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Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe , which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant's alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant–myrmecophile interactions beyond just their pairwise context.

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24

Gagic, Vesna, Teja Tscharntke, Carsten F. Dormann, Bernd Gruber, Anne Wilstermann e Carsten Thies. "Food web structure and biocontrol in a four-trophic level system across a landscape complexity gradient". Proceedings of the Royal Society B: Biological Sciences 278, n. 1720 (16 febbraio 2011): 2946–53. http://dx.doi.org/10.1098/rspb.2010.2645.

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Abstract (sommario):

Decline in landscape complexity owing to agricultural intensification may affect biodiversity, food web complexity and associated ecological processes such as biological control, but such relationships are poorly understood. Here, we analysed food webs of cereal aphids, their primary parasitoids and hyperparasitoids in 18 agricultural landscapes differing in structural complexity (42–93% arable land). Despite little variation in the richness of each trophic group, we found considerable changes in trophic link properties across the landscape complexity gradient. Unexpectedly, aphid–parasitoid food webs exhibited a lower complexity (lower linkage density, interaction diversity and generality) in structurally complex landscapes, which was related to the dominance of one aphid species in complex landscapes. Nevertheless, primary parasitism, as well as hyperparasitism, was higher in complex landscapes, with primary parasitism reaching levels for potentially successful biological control. In conclusion, landscape complexity appeared to foster higher parasitism rates, but simpler food webs, thereby casting doubt on the general importance of food web complexity for ecosystem functioning.

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25

Kraaijeveld, Alex R., Naji P. Elrayes, Hansjürgen Schuppe e Philip L. Newland. "l-Arginine enhances immunity to parasitoids in Drosophila melanogaster and increases NO production in lamellocytes". Developmental & Comparative Immunology 35, n. 8 (agosto 2011): 857–64. http://dx.doi.org/10.1016/j.dci.2011.03.019.

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26

Schlenke, Todd A., Jorge Morales, Shubha Govind e Andrew G. Clark. "Contrasting Infection Strategies in Generalist and Specialist Wasp Parasitoids of Drosophila melanogaster". PLoS Pathogens 3, n. 10 (26 ottobre 2007): e158. http://dx.doi.org/10.1371/journal.ppat.0030158.

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27

McLean, A. H. C., J. Hrček, B. J. Parker, H. Mathé-Hubert, H. Kaech, C. Paine e H. C. J. Godfray. "Multiple phenotypes conferred by a single insect symbiont are independent". Proceedings of the Royal Society B: Biological Sciences 287, n. 1929 (17 giugno 2020): 20200562. http://dx.doi.org/10.1098/rspb.2020.0562.

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Abstract (sommario):

Many microbial symbionts have multiple phenotypic consequences for their animal hosts. However, the ways in which different symbiont-mediated phenotypes combine to affect fitness are not well understood. We investigated whether there are correlations between different symbiont-mediated phenotypes. We used the symbiont Spiroplasma , a striking example of a bacterial symbiont conferring diverse phenotypes on insect hosts. We took 11 strains of Spiroplasma infecting pea aphids ( Acyrthosiphon pisum ) and assessed their ability to provide protection against the fungal pathogen Pandora neoaphidis and the parasitoids Aphidius ervi and Praon volucre . We also assessed effects on male offspring production for five of the Spiroplasma strains. All but one of the Spiroplasma strains provided very strong protection against the parasitoid P. volucre . As previously reported, variable protection against P. neoaphidis and A. ervi was also present; male-killing was likewise a variable phenotype. We find no evidence of any correlation, positive or negative, between the different phenotypes, nor was there any evidence of an effect of symbiont phylogeny on protective phenotype. We conclude that multiple symbiont-mediated phenotypes can evolve independently from one another without trade-offs between them.

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28

Le Ralec, Anne, Caroline Anselme, Yannick Outreman, Marylène Poirié, Joan van Baaren, Cécile Le Lann e Jacques J. M. van Alphen. "Evolutionary ecology of the interactions between aphids and their parasitoids". Comptes Rendus Biologies 333, n. 6-7 (giugno 2010): 554–65. http://dx.doi.org/10.1016/j.crvi.2010.03.010.

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29

Farris, Sarah M., e Susanne Schulmeister. "Parasitoidism, not sociality, is associated with the evolution of elaborate mushroom bodies in the brains of hymenopteran insects". Proceedings of the Royal Society B: Biological Sciences 278, n. 1707 (10 novembre 2010): 940–51. http://dx.doi.org/10.1098/rspb.2010.2161.

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Abstract (sommario):

The social brain hypothesis posits that the cognitive demands of social behaviour have driven evolutionary expansions in brain size in some vertebrate lineages. In insects, higher brain centres called mushroom bodies are enlarged and morphologically elaborate (having doubled, invaginated and subcompartmentalized calyces that receive visual input) in social species such as the ants, bees and wasps of the aculeate Hymenoptera, suggesting that the social brain hypothesis may also apply to invertebrate animals. In a quantitative and qualitative survey of mushroom body morphology across the Hymenoptera, we demonstrate that large, elaborate mushroom bodies arose concurrent with the acquisition of a parasitoid mode of life at the base of the Euhymenopteran (Orussioidea + Apocrita) lineage, approximately 90 Myr before the evolution of sociality in the Aculeata. Thus, sociality could not have driven mushroom body elaboration in the Hymenoptera. Rather, we propose that the cognitive demands of host-finding behaviour in parasitoids, particularly the capacity for associative and spatial learning, drove the acquisition of this evolutionarily novel mushroom body architecture. These neurobehavioural modifications may have served as pre-adaptations for central place foraging, a spatial learning-intensive behaviour that is widespread across the Aculeata and may have contributed to the multiple acquisitions of sociality in this taxon.

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30

Stireman, John O., John D. Nason, Stephen B. Heard e Julie M. Seehawer. "Cascading host-associated genetic differentiation in parasitoids of phytophagous insects". Proceedings of the Royal Society B: Biological Sciences 273, n. 1586 (6 dicembre 2005): 523–30. http://dx.doi.org/10.1098/rspb.2005.3363.

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31

Wang, Rong, Xiao-Yong Chen, Yan Chen, Gang Wang, Derek W. Dunn, Rupert J. Quinnell e Stephen G. Compton. "Loss of top-down biotic interactions changes the relative benefits for obligate mutualists". Proceedings of the Royal Society B: Biological Sciences 286, n. 1897 (20 febbraio 2019): 20182501. http://dx.doi.org/10.1098/rspb.2018.2501.

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Abstract (sommario):

The collapse of mutualisms owing to anthropogenic changes is contributing to losses of biodiversity. Top predators can regulate biotic interactions between species at lower trophic levels and may contribute to the stability of such mutualisms, but they are particularly likely to be lost after disturbance of communities. We focused on the mutualism between the fig tree Ficus microcarpa and its host-specific pollinator fig wasp and compared the benefits accrued by the mutualists in natural and translocated areas of distribution. Parasitoids of the pollinator were rare or absent outside the natural range of the mutualists, where the relative benefits the mutualists gained from their interaction were changed significantly away from the plant's natural range owing to reduced seed production rather than increased numbers of pollinator offspring. Furthermore, in the absence of the negative effects of its parasitoids, we detected an oviposition range expansion by the pollinator, with the use of a wider range of ovules that could otherwise have generated seeds. Loss of top-down control has therefore resulted in a change in the balance of reciprocal benefits that underpins this obligate mutualism, emphasizing the value of maintaining food web complexity in the Anthropocene.

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32

Amo, Luisa, Anna Mrazova, Irene Saavedra e Katerina Sam. "Exogenous Application of Methyl Jasmonate Increases Emissions of Volatile Organic Compounds in Pyrenean Oak Trees, Quercus pyrenaica". Biology 11, n. 1 (6 gennaio 2022): 84. http://dx.doi.org/10.3390/biology11010084.

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Abstract (sommario):

The tri-trophic interactions between plants, insects, and insect predators and parasitoids are often mediated by chemical cues. The attraction to herbivore-induced Plant Volatiles (HIPVs) has been well documented for arthropod predators and parasitoids, and more recently for insectivorous birds. The attraction to plant volatiles induced by the exogenous application of methyl jasmonate (MeJA), a phytohormone typically produced in response to an attack of chewing herbivores, has provided controversial results both in arthropod and avian predators. In this study, we examined whether potential differences in the composition of bouquets of volatiles produced by herbivore-induced and MeJA-treated Pyrenean oak trees (Quercus pyrenaica) were related to differential avian attraction, as results from a previous study suggested. Results showed that the overall emission of volatiles produced by MeJA-treated and herbivore-induced trees did not differ, and were higher than emissions of Control trees, although MeJA treatment showed a more significant reaction and released several specific compounds in contrast to herbivore-induced trees. These slight yet significant differences in the volatile composition may explain why avian predators were not so attracted to MeJA-treated trees, as observed in a previous study in this plant-herbivore system. Unfortunately, the lack of avian visits to the experimental trees in the current study did not allow us to confirm this result and points out the need to perform more robust predator studies.

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33

Giovannini, Lucrezia, Giuseppino Sabbatini-Peverieri, Patricia Glynn Tillman, Kim Alan Hoelmer e Pio Federico Roversi. "Reproductive and Developmental Biology of Acroclisoides sinicus, a Hyperparasitoid of Scelionid Parasitoids". Biology 10, n. 3 (16 marzo 2021): 229. http://dx.doi.org/10.3390/biology10030229.

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Abstract (sommario):

Acroclisoides sinicus (Hymenoptera: Pteromalidae) was described in 1988 from China, but recent findings in Europe and North America within the framework of Halyomorpha halys (Hemiptera: Pentatomidae) biological control indicate a Holarctic distribution. The few records and fragmented information on A. sinicus are derived from generic observations of other species belonging to the same genus, and its biological and ethological traits are still completely unexplored. It was suspected to be a facultative or obligate hyperparasitoid of many egg parasitoid species (e.g., Scelionidae and Eupelmidae), especially those parasitizing Pentatomidae eggs. Laboratory colonies of A. sinicus were established from specimens collected in the field in Europe and the USA, which allowed us to investigate for the first time the life traits of this somewhat enigmatic species. Our studies confirmed the obligate hyperparasitoid hypothesis for species of Scelionidae but not of Eupelmidae. Laboratory studies revealed that A. sinicus is extremely selective in its host recognition as only the pupal stage of its host species is exploited for parasitization. Taking into consideration its hyperparasitoid habit, the adventive A. sinicus populations in Europe and North America may potentially be severe threats to pentatomid natural control as new components in the trophic chain of pentatomids and their parasitoid guilds.

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34

Daversa, D. R., R. F. Hechinger, E. Madin, A. Fenton, A. I. Dell, E. G. Ritchie, J. Rohr, V. H. W. Rudolf e K. D. Lafferty. "Broadening the ecology of fear: non-lethal effects arise from diverse responses to predation and parasitism". Proceedings of the Royal Society B: Biological Sciences 288, n. 1945 (24 febbraio 2021): 20202966. http://dx.doi.org/10.1098/rspb.2020.2966.

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Abstract (sommario):

Research on the ‘ecology of fear’ posits that defensive prey responses to avoid predation can cause non-lethal effects across ecological scales. Parasites also elicit defensive responses in hosts with associated non-lethal effects, which raises the longstanding, yet unresolved question of how non-lethal effects of parasites compare with those of predators. We developed a framework for systematically answering this question for all types of predator–prey and host–parasite systems. Our framework reveals likely differences in non-lethal effects not only between predators and parasites, but also between different types of predators and parasites. Trait responses should be strongest towards predators, parasitoids and parasitic castrators, but more numerous and perhaps more frequent for parasites than for predators. In a case study of larval amphibians, whose trait responses to both predators and parasites have been relatively well studied, existing data indicate that individuals generally respond more strongly and proactively to short-term predation risks than to parasitism. Apart from studies using amphibians, there have been few direct comparisons of responses to predation and parasitism, and none have incorporated responses to micropredators, parasitoids or parasitic castrators, or examined their long-term consequences. Addressing these and other data gaps highlighted by our framework can advance the field towards understanding how non-lethal effects impact prey/host population dynamics and shape food webs that contain multiple predator and parasite species.

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35

Leitão, Alexandre B., Xueni Bian, Jonathan P. Day, Simone Pitton, Eşref Demir e Francis M. Jiggins. "Independent effects on cellular and humoral immune responses underlie genotype-by-genotype interactions between Drosophila and parasitoids". PLOS Pathogens 15, n. 10 (7 ottobre 2019): e1008084. http://dx.doi.org/10.1371/journal.ppat.1008084.

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36

HOUSTON, A., J. MCNAMARA e H. GODFRAY. "The effect of variability on host feeding and reproductive success in parasitoids". Bulletin of Mathematical Biology 54, n. 2-3 (1992): 465–76. http://dx.doi.org/10.1016/s0092-8240(05)80037-0.

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37

Houston, A. I., J. M. McNamara e H. C. J. Godfray. "The effect of variability on host feeding and reproductive success in parasitoids". Bulletin of Mathematical Biology 54, n. 2-3 (marzo 1992): 465–76. http://dx.doi.org/10.1007/bf02464844.

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38

CHATTOPADHAYAY, JOYDEV, RAMRUP SARKAR, MARIA ELENA FRITZSCHE-HOBALLAH, TED C. J. TURLINGS e LOUIS-FÉLIX BERSIER. "Parasitoids may Determine Plant Fitness—A Mathematical Model Based on Experimental Data". Journal of Theoretical Biology 212, n. 3 (ottobre 2001): 295–302. http://dx.doi.org/10.1006/jtbi.2001.2374.

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39

Murray, Elizabeth A., Andrew E. Carmichael e John M. Heraty. "Ancient host shifts followed by host conservatism in a group of ant parasitoids". Proceedings of the Royal Society B: Biological Sciences 280, n. 1759 (22 maggio 2013): 20130495. http://dx.doi.org/10.1098/rspb.2013.0495.

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40

Laxmanappa Hoti, Suggerappa, e Veena Tandon. "Ocular Parasitoses and Their Immunology". Ocular Immunology and Inflammation 19, n. 6 (22 novembre 2011): 385–96. http://dx.doi.org/10.3109/09273948.2011.626141.

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41

Brandt, Jayce W., Germain Chevignon, Kerry M. Oliver e Michael R. Strand. "Culture of an aphid heritable symbiont demonstrates its direct role in defence against parasitoids". Proceedings of the Royal Society B: Biological Sciences 284, n. 1866 (novembre 2017): 20171925. http://dx.doi.org/10.1098/rspb.2017.1925.

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Abstract (sommario):

Heritable symbionts are common in insects with many contributing to host defence. Hamiltonella defensa is a facultative, bacterial symbiont of the pea aphid, Acyrthosiphon pisum that provides protection against the endoparasitoid wasp Aphidius ervi . Protection levels vary among strains of H. defensa that are differentially infected by bacteriophages named APSEs. By contrast, little is known about mechanism(s) of resistance owing to the intractability of host-restricted microbes for functional study. Here, we developed methods for culturing strains of H. defensa that varied in the presence and type of APSE. Most H. defensa strains proliferated at 27°C in co-cultures with the TN5 cell line or as pure cultures with no insect cells. The strain infected by APSE3, which provides high levels of protection in vivo , produced a soluble factor(s) that disabled development of A. ervi embryos independent of any aphid factors. Experimental transfer of APSE3 also conferred the ability to disable A. ervi development to a phage-free strain of H. defensa . Altogether, these results provide a critical foundation for characterizing symbiont-derived factor(s) involved in host protection and other functions. Our results also demonstrate that phage-mediated transfer of traits provides a mechanism for innovation in host restricted symbionts.

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42

Myers, Judith H. "Population cycles: generalities, exceptions and remaining mysteries". Proceedings of the Royal Society B: Biological Sciences 285, n. 1875 (21 marzo 2018): 20172841. http://dx.doi.org/10.1098/rspb.2017.2841.

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Abstract (sommario):

Population cycles are one of nature's great mysteries. For almost a hundred years, innumerable studies have probed the causes of cyclic dynamics in snowshoe hares, voles and lemmings, forest Lepidoptera and grouse. Even though cyclic species have very different life histories, similarities in mechanisms related to their dynamics are apparent. In addition to high reproductive rates and density-related mortality from predators, pathogens or parasitoids, other characteristics include transgenerational reduced reproduction and dispersal with increasing-peak densities, and genetic similarity among populations. Experiments to stop cyclic dynamics and comparisons of cyclic and noncyclic populations provide some understanding but both reproduction and mortality must be considered. What determines variation in amplitude and periodicity of population outbreaks remains a mystery.

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43

Nieuwenhuizen, Natalie E. "Anisakis- immunology of a foodborne parasitosis". Parasite Immunology 38, n. 9 (settembre 2016): 548–57. http://dx.doi.org/10.1111/pim.12349.

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44

Germinara, Giacinto Salvatore, Antonio De Cristofaro e Giuseppe Rotundo. "Electrophysiological and Behavioral Responses ofTheocolax elegans(Westwood) (Hymenoptera: Pteromalidae) to Cereal Grain Volatiles". BioMed Research International 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/5460819.

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Abstract (sommario):

Volatiles emitted by the host’s food would be the first signals used by parasitoids in the host location process and are thought to play an important role in host habitat location. In this study, the olfactory responses ofTheocolax elegans(Westwood), a Pteromalid wasp that parasitizes immature stages of stored-product insect pests developing inside cereal or leguminous grains, to volatiles emitted by healthy wheat grains, their hexane extracts, and different doses of three individual compounds previously identified in cereal grain odors were investigated in Y-tube olfactometer and Petri dish arena behavioral bioassays and electroantennogram recordings. In Y-tube olfactometer bioassays, odors from healthy wheat grains and their hexane extracts were attractive to both sexes ofT. elegans. Moreover, hexane extracts elicited arresting effects in Petri dish arena. The three synthetic compounds valeraldehyde, maltol, and vanillin elicited dose-dependent responses in both male and female adult wasps confirming the capability of the peripheral olfactory systems to perceive cereal volatiles. In behavioral bioassays, different doses of vanillin were significantly attractive to both sexes.

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45

Deas, Joseph B., e Martha S. Hunter. "Mothers modify eggs into shields to protect offspring from parasitism". Proceedings of the Royal Society B: Biological Sciences 279, n. 1730 (14 settembre 2011): 847–53. http://dx.doi.org/10.1098/rspb.2011.1585.

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Abstract (sommario):

Eggs are an immobile, vulnerable stage of development and their success often depends on the oviposition decisions of the mother. Studies show that female animals, and sometimes males, may invest parental resources in order to increase the survival of their offspring. Here, we describe a unique form of parental investment in offspring survival. The seed beetle Mimosestes amicus may lay eggs singly, or may cover eggs with additional egg(s). This egg stacking serves to significantly reduce the mortality of the protected egg from parasitism by the parasitic wasp, Uscana semifumipennis . The smaller top eggs serve only as protective shields; they are inviable, and wasps that develop in them suffer negative fitness consequences. Further, we found egg stacking to be inducible; M. amicus increase the number of stacks they lay when parasitoids are present. However, stacking invokes a cost. When wasps are absent, beetles lay more single eggs, and produce more offspring, highlighting the adaptive value of this extraordinary example of behavioural plasticity in parental investment.

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46

Forsman, Anders, Per-Eric Betzholtz e Markus Franzén. "Variable coloration is associated with dampened population fluctuations in noctuid moths". Proceedings of the Royal Society B: Biological Sciences 282, n. 1808 (7 giugno 2015): 20142922. http://dx.doi.org/10.1098/rspb.2014.2922.

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Abstract (sommario):

Theory and recent reviews state that greater genetic and phenotypic variation should be beneficial for population abundance and stability. Experimental evaluations of this prediction are rare, of short duration and conducted under controlled environmental settings. The question whether greater diversity in functionally important traits stabilizes populations under more complex ecological conditions in the wild has not been systematically evaluated. Moths are mainly nocturnal, with a large variation in colour patterns among species, and constitute an important food source for many types of organisms. Here, we report the results of a long-term (2003–2013) monitoring study of 115 100 noctuid moths from 246 species. Analysis of time-series data provide rare evidence that species with higher levels of inter-individual variation in colour pattern have higher average abundances and undergo smaller between-year fluctuations compared with species having less variable colour patterns. The signature of interspecific temporal synchronization of abundance fluctuations was weak, suggesting that the dynamics were driven by species-specific biotic interactions rather than by some common, density-independent factor(s). We conclude that individual variation in colour patterns dampens population abundance fluctuations, and suggest that this may partly reflect that colour pattern polymorphism provides protection from visually oriented predators and parasitoids.

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Mesterton-Gibbons, Mike, Antonino Cusumano e Ian C. W. Hardy. "Escaping the evolutionary trap: Can size-related contest advantage compensate for juvenile mortality disadvantage when parasitoids develop in unnatural invasive hosts?" Journal of Theoretical Biology 527 (ottobre 2021): 110821. http://dx.doi.org/10.1016/j.jtbi.2021.110821.

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48

Vorburger, Christoph, Alexandre Gouskov e Simone von Burg. "Genetic covariation between effectiveness and cost of defence in aphids". Biology Letters 4, n. 6 (2 settembre 2008): 674–76. http://dx.doi.org/10.1098/rsbl.2008.0382.

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Abstract (sommario):

Ecological immunology distinguishes between the long-term evolutionary costs of possessing defences against parasites and the short-term costs of using them. Evolutionary biologists have typically focused on the former in the search for constraints on the evolution of resistance. Here, we show in the peach-potato aphid, Myzus persicae , that short-term costs may be of equal evolutionary importance. Survivors of more resistant aphid clones suffered a higher reduction of fecundity upon parasitoid attack than survivors of more susceptible clones. This genetically based trade-off between benefits and costs of defence may limit the evolution of increased resistance and explain the maintenance of genetic variation for resistance under environmental variation in parasitism risk.

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49

Simon, L., F. Peyron e M. Wallon. "Parasitosis digestivas". EMC - Pediatría 57, n. 3 (agosto 2022): 1–15. http://dx.doi.org/10.1016/s1245-1789(22)46767-9.

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50

Solomons, Noel W. "MALNUTRITION AND INFECTION: AN UPDATE". British Journal of Nutrition 98, S1 (ottobre 2007): S5—S10. http://dx.doi.org/10.1017/s0007114507832879.

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Abstract (sommario):

The original Scrimshaw, Taylor and Gordon conceptual framework for the interaction of nutrition and infection has well served the scientific community for almost half a century. At its core is the notion of synergistic (mutually reinforcing) and antagonistic (mutually nullifying) influences of the malnourished state on infectious conditions and vice versa. Research on a series of advancing fronts, however, has allowed the incorporation of both relevant public health issues (parasitosis, emerging infectious diseases, obesity and overweight, etc.) and advancing science (molecular immunology, oxidation biology, multiple micronutrient deficiencies, etc.). The present review is an interpretative update on close to 50 years of demographic and epidemiological evolution in the field of human nutrition and the implications for the interaction in the context of microbiological and immunological developments on the infectious side of the dialectic.

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