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1.
Habitat selection, including oviposition site choice, is an important driver of community assembly in freshwater systems. Factors determining patch quality are assessed by many colonising organisms and affect colonisation rates, spatial distribution and community structure. For many species, the presence/absence of predators is the most important factor affecting female oviposition decisions. However, individual habitat patches exist in complex landscapes linked by processes of dispersal and colonisation, and spatial distribution of factors such as predators has potential effects beyond individual patches. Perceived patch quality and resulting colonisation rates depend both on risk conditions within a given patch and on spatial context. Here we experimentally confirm the role of one context‐dependent processes, spatial contagion, functioning at the local scale, and provide the first example of another context‐dependent process, habitat compression, functioning at the regional scale. Both processes affect colonisation rates and patterns of spatial distribution in naturally colonised experimental metacommunities. 相似文献
2.
1. Theory predicts that natural selection should favour females that are able to correctly assess the risk of predation and then use that information to avoid high‐risk oviposition sites to reduce the risk of offspring predation. Despite the potential significance of such behaviour on individual fitness, population dynamics and community structure, relatively few studies of oviposition behaviour connected to the risk of predation have been carried out. 2. However, some recent studies suggest that oviposition site selection in response to risk of predation may be a common phenomenon, at least among amphibians and mosquitoes. A vast majority of previous studies have, however, neglected to investigate how the offspring are affected, in terms of fitness related parameters, by the maternal oviposition site choice. 3. In an outdoor artificial pond experiment we tested the oviposition site selection of female aquatic beetles (Hydroporus spp.) in relation to the presence or absence of a predatory fish (Perca fluviatilis). In addition, we monitored how the oviposition site selection affected the behaviour, growth and food resource of the progeny. 4. We show that free‐flying females of the aquatic beetles Hydroporus incognitus and H. nigrita prefer to oviposit in waters without fish compared with waters with fish. Larval activity of Hydroporus spp. was unaffected by fish presence. Our results indicate that beetle larvae from females that do lay eggs in waters with fish show increased growth compared with larvae in waters without fish. We explain this difference in growth by a higher per‐capita food supply in the presence of a fish predator. This finding may have important implications for our understanding of how the variance of oviposition site selection in a population is sustained. 相似文献
3.
Manon Bonneau Beniamino Caputo Aude Ligier Rudy Caparros Sandra Unal Marco Perriat‐Sanguinet Daniele Arnoldi Mathieu Sicard Mylne Weill 《Molecular ecology》2019,28(21):4725-4736
Endosymbiotic Wolbachia bacteria are, to date, considered the most widespread symbionts in arthropods and are the cornerstone of major biological control strategies. Such a high prevalence is based on the ability of Wolbachia to manipulate their hosts' reproduction. One manipulation called cytoplasmic incompatibility (CI) is based on the death of the embryos generated by crosses between infected males and uninfected females or between individuals infected with incompatible Wolbachia strains. CI can be seen as a modification‐rescue system (or mod‐resc) in which paternal Wolbachia produce mod factors, inducing embryonic defects, unless the maternal Wolbachia produce compatible resc factors. Transgenic experiments in Drosophila melanogaster and Saccharomyces cerevisiae converged towards a model where the cidB Wolbachia gene is involved in the mod function while cidA is involved in the resc function. However, as cidA expression in Drosophila males was required to observe CI, it has been proposed that cidA could be involved in both resc and mod functions. A recent correlative study in natural Culex pipiens mosquito populations has revealed an association between specific cidA and cidB variations and changes in mod phenotype, also suggesting a role for both these genes in mod diversity. Here, by studying cidA and cidB genomic repertoires of individuals from newly sampled natural C. pipiens populations harbouring wPipIV strains from North Italy, we reinforce the link between cidB variation and mod phenotype variation fostering the involvement of cidB in the mod phenotype diversity. However, no association between any cidA variants or combination of cidA variants and mod phenotype variation was observed. Taken together our results in natural C. pipiens populations do not support the involvement of cidA in mod phenotype variation. 相似文献
4.
Pascal Milesi Benoît S. Assogba Célestine M. Atyame Nicolas Pocquet Arnaud Berthomieu Sandra Unal Patrick Makoundou Mylène Weill Pierrick Labbé 《Molecular ecology》2018,27(2):493-507
Gene duplications occur at a high rate. Although most appear detrimental, some homogeneous duplications (identical gene copies) can be selected for beneficial increase in produced proteins. Heterogeneous duplications, which combine divergent alleles of a single locus, are seldom studied due to the paucity of empirical data. We investigated their role in an ongoing adaptive process at the ace‐1 locus in Culex pipiens mosquitoes. We assessed the worldwide diversity of the ace‐1 alleles (single‐copy, susceptible S and insecticide‐resistant R, and duplicated D that pair one S and one R copy), analysed their phylogeography and measured their fitness to understand their early dynamics using population genetics models. It provides a coherent and comprehensive evolutionary scenario. We show that D alleles are present in most resistant populations and display a higher diversity than R alleles (27 vs. 4). Most appear to result from independent unequal crossing‐overs between local single‐copy alleles, suggesting a recurrent process. Most duplicated alleles have a limited geographic distribution, probably resulting from their homozygous sublethality (HS phenotype). In addition, heterozygotes carrying different HS D alleles showed complementation, indicating different recessive lethal mutations. Due to mosaic insecticide control practices, balancing selection (overdominance) plays a key role in the early dynamics of heterogeneous duplicated alleles; it also favours a high local polymorphism of HS D alleles in natural populations (overdominance reinforced by complementation). Overall, our study shows that the evolutionary fate of heterogeneous duplications (and their long‐term role) depends on finely balanced selective pressures due to the environment and to their genomic structure. 相似文献
5.
One of the most important defenses for the eggs of ovipositing female organisms is to avoid being laid in the same habitat as their predators. However, for most organisms, completely avoiding an offspring's predators is not possible. One mechanism that has been largely overlooked is for females to partition an oviposition site into microhabitats that differ in quality for offspring survival. We conducted a series of experiments to examine whether female newts avoid microhabitats utilized by their offspring's primary predator, caddisfly larvae. Female newts avoided laying eggs near predatory caddisflies and shifted egg laying upward in the water column when provided with a vertical dimension. Caddisflies were attracted to chemical stimuli from female newts and their eggs, yet primarily used benthic areas in experimental chambers. Finally, results from a field experiment indicate that the behavioral strategy employed by female newts increases offspring survival. This subset of non‐genetic maternal effects, micro‐oviposition avoidance, is likely an important yet underexplored mechanism by which females increase offspring survival. 相似文献
6.
7.
Experimental evidence for predation risk sensitive oviposition by a mosquito, Culiseta longiareolata 总被引：1，自引：0，他引：1
1. Females should choose to oviposit in habitats where risk of predation and competition are low. The ovipositional responses of a mosquito, Culiseta longiareolata, to a predator and to species sharing the same trophic level as this mosquito (controphic species) were assessed experimentally in outdoor artificial pools. 2. The predator, larval Anax imperator, which strongly reduced larval C. longiareolata survival, resulted in a 52% reduction of C. longiareolata egg rafts. The controphic species (primarily Daphnia magna), which had a small but statistically significant negative effect on the survival of C. longiareolata larvae, did not have a statistically significant influence on the number of egg rafts. 3. Laboratory trials indicated that only a small fraction of the reduced number of egg rafts seen in predator pools may be due to consumption of the egg rafts by A. imperator. 4. The experimental evidence indicates that the reduced number of C. longiareolata egg rafts found in the presence of A. imperator is due largely to oviposition habitat selection, i.e. C. longiareolata females choose pools with low risk of predation for their offspring. 相似文献
8.
Yali Si Yanjie Xu Fei Xu Xueyan Li Wenyuan Zhang Ben Wielstra Jie Wei Guanhua Liu Hao Luo John Takekawa Sivananintha Balachandran Tao Zhang Willem F. de Boer Herbert H. T. Prins Peng Gong 《Ecology and evolution》2018,8(12):6280-6289
East Asian migratory waterfowl have greatly declined since the 1950s, especially the populations that winter in China. Conservation is severely hampered by the lack of primary information about migration patterns and stopover sites. This study utilizes satellite tracking techniques and advanced spatial analyses to investigate spring migration of the greater white‐fronted goose (Anser albifrons) and tundra bean goose (Anser serrirostris) wintering along the Yangtze River Floodplain. Based on 24 tracks obtained from 21 individuals during the spring of 2015 and 2016, we found that the Northeast China Plain is far‐out the most intensively used stopover site during migration, with geese staying for over 1 month. This region has also been intensely developed for agriculture, suggesting a causal link to the decline in East Asian waterfowl wintering in China. The protection of waterbodies used as roosting area, especially those surrounded by intensive foraging land, is critical for waterfowl survival. Over 90% of the core area used during spring migration is not protected. We suggest that future ground surveys should target these areas to confirm their relevance for migratory waterfowl at the population level, and core roosting area at critical spring‐staging sites should be integrated in the network of protected areas along the flyway. Moreover, the potential bird–human conflict in core stopover area needs to be further studied. Our study illustrates how satellite tracking combined with spatial analyses can provide crucial insights necessary to improve the conservation of declining Migratory species. 相似文献
9.
The number of prey killed by diverse predator communities is determined by complementarity and interference among predators, and by traits of particular predator species. However, it is less clear how predators' nonconsumptive effects (NCEs) scale with increasing predator biodiversity. We examined NCEs exerted on Culex mosquitoes by a diverse community of aquatic predators. In the field, mosquito larvae co‐occurred with differing densities and species compositions of mesopredator insects; top predator dragonfly naiads were present in roughly half of surveyed water bodies. We reproduced these predator community features in artificial ponds, exposing mosquito larvae to predator cues and measuring resulting effects on mosquito traits throughout development. Nonconsumptive effects of various combinations of mesopredator species reduced the survival of mosquito larvae to pupation, and reduced the size and longevity of adult mosquitoes that later emerged from the water. Intriguingly, adding single dragonfly naiads to ponds restored survivorship of larval mosquitoes to levels seen in the absence of predators, and further decreased adult mosquito longevity compared with mosquitoes emerging from mesopredator treatments. Behavioral observations revealed that mosquito larvae regularly deployed “diving” escape behavior in the presence of the mesopredators, but not when a dragonfly naiad was also present. This suggests that dragonflies may have relaxed NCEs of the mesopredators by causing mosquitoes to abandon energetically costly diving. Our study demonstrates that adding one individual of a functionally unique species can substantially alter community‐wide NCEs of predators on prey. For pathogen vectors like mosquitoes, this could in turn influence disease dynamics. 相似文献
10.
Abstract. Some species of mosquitoes can detect the presence of predatory notonectid bugs and avoid oviposition in predator pools. The oviposition response of two mosquito species, Culiseta longiareolata Macquart and Culex laticinctus Edwards (Diptera: Culicidae), to a range of densities of the predator, Notonecta maculata Fabricius (Heteroptera: Notonectidae), was tested here. Densities of 0, 1, 2 or 4 Notonecta were established in 30-L artificial pools. Both mosquito species oviposited less in predator pools, but the response was unrelated to predator density, whereas vulnerability of Culiseta immatures to predation was density-dependent. Thus, although mosquitoes can detect Notonecta at any density within the range tested, they may be unable to discriminate among predator densities. The avoidance of predator pools by Culiseta , as well as its vulnerability to predation, occurred to a lesser degree than in earlier studies. This may have been due to the mitigating effects of components of the biotic community. 相似文献
11.
Although we often focus on the causes of geographic variation, understanding processes that act to reduce geographic variation is also important. Here, we consider a process whereby adaptive foraging across the landscape and directional selection exerted by a conifer seed predator, the common crossbill (Loxia curvirostra), potentially act to homogenize geographic variation in the defensive traits of its prey. We measured seed predation and phenotypic selection exerted by crossbills on black pine (Pinus nigra) at two sites in the Pindos Mountains, Greece. Seed predation by crossbills was over an order of magnitude higher at the site where cone scale thickness was significantly thinner, which was also the cone trait that was the target of selection at the high predation site. Additional comparisons of selection differentials demonstrate that crossbills exert selection on black pine that is consistent in form across space and time, and increases in strength with increasing seed predation. If predators distribute themselves in relation to the defensive traits of their prey and the strength of selection predators exert is proportional to the amount of predation, then predators may act to homogenize trait variation among populations of their prey in a process analogous to coevolutionary alternation with escalation. 相似文献
12.
Alon Silberbush Shai Markman Efraim Lewinsohn Einat Bar Joel E. Cohen Leon Blaustein 《Ecology letters》2010,13(9):1129-1138
13.
Matthew A. Mumma Michael P. Gillingham Chris J. Johnson Katherine L. Parker 《Ecology and evolution》2017,7(23):10266-10277
Predation risk is a driver of species’ distributions. Animals can increase risk avoidance in response to fluctuations in predation risk, but questions remain regarding individual variability and the capacity to respond to changes in spatial risk across human‐altered landscapes. In northeast British Columbia, Canada, boreal caribou populations declined as roads and seismic lines have increased, which are theorized to increase gray wolf predation. Our goal was to model risk and to evaluate individual variability and the development of risk perception by examining individual risk avoidance in response to reproductive status and age. We used locations from collared caribou and wolves to identify landscape features associated with the risk of a potential wolf‐caribou encounter and risk of being killed given an encounter. We built resource selection functions to estimate individual responses to risk. We used general linear regressions to evaluate individual risk and linear feature avoidance as a function of age and reproductive status (calf or no calf). Linear features increased the risk of encounter. Older caribou and caribou with calves demonstrated stronger avoidance of the risk of encounter and roads, but weaker avoidance in late summer to the risk of being killed relative to younger and calf‐less individuals. Mechanisms explaining the inverse relationships between the risk of encounter and risk of being killed are uncertain, but it is conceivable that caribou learn to avoid the risk of encounter and roads. Responses by females with vulnerable calves to the risk of encounter and risk of being killed might be explained by a trade‐off between these two risk types and a prioritization on the risk of encounter. Despite the capacity to alter their responses to risk, the global decline in Rangifer populations (caribou and wild reindeer) suggests these behaviors are insufficient to mitigate the impacts of anthropogenic disturbances. 相似文献
14.
Marisa K. Lipsey David E. Naugle Joshua Nowak Paul M. Lukacs 《Diversity & distributions》2017,23(7):783-793
15.
Dispersal is the movement of organisms across space, which has important implications for ecological and evolutionary processes, including community composition and gene flow. Previous studies have demonstrated that dispersal is influenced by body condition; however, few studies have been able to separate the effects of body condition from correlated variables such as body size. Moreover, the results of these studies have been inconsistent with respect to the direction of the relationship between condition and dispersal. We examined whether body condition influences dispersal in backswimmers (Notonecta undulata). We also tested whether an interaction between body condition and predation risk (another proximate factor that influences dispersal) could contribute to the previously observed inconsistent relationship between condition and dispersal. We imposed diet treatments on backswimmers in the laboratory, and measured the effects of food availability on body condition and dispersal in the field. We found that dispersal was a positive function of body condition, which may have important consequences for population characteristics such as the rate of gene flow and population growth. However, the effects of body condition and predation risk were additive, not interactive, and therefore, our data do not support the hypothesis that the interaction between condition and predation risk contributes to the inconsistency in the results of previous condition‐dependent dispersal studies. 相似文献
16.
Hiroyuki Hirayama Takayuki So Eiiti Kasuya 《Entomologia Experimentalis et Applicata》2015,154(3):222-227
Parasitoids and predators compete for host or prey species. The efficiency of obtaining prey or host items is reduced by intraspecific competition. As the optimal search behavior depends on the intensity of competition, it is important for the parasitoid or predator to obtain information on this intensity. Previous studies have shown that parasitoids can obtain information regarding competition from encounters with already parasitized hosts. They then change their host searching behavior accordingly. However, whether parasitoids obtain the information directly from observing the presence of conspecifics remains unclear. We used Tiphodytes gerriphagus (Marchal) (Hymenoptera: Scelionidae), the solitary egg parasitoid of water striders, for testing the effect of density of conspecifics on host searching behavior. Females of T. gerriphagus dive into the water to search for hosts and sometimes they dive without hosts present. Thus, we investigated whether T. gerriphagus changed underwater activities in response to the density of conspecifics in the absence of hosts. Four densities (1, 2, 4, and 8 female T. gerriphagus) were investigated. Females in competitive situations (groups of 2, 4, and 8 females) displayed host searching behavior, but the solitary females did not. This indicates that the presence of conspecifics triggers host searching behavior and that T. gerriphagus females obtain information on competition directly from conspecifics and use it for modifying their behavior. 相似文献
17.
Kyla Ercit 《Ecology and evolution》2016,6(15):5118-5128
Understanding temporal variation in selection in natural populations is necessary to accurately estimate rates of divergence and macroevolutionary processes. Temporal variation in the strength and direction of selection on sex‐specific traits can also explain stasis in male and female phenotype and sexual dimorphism. I investigated changes in strength and form of viability selection (via predation by wasps) in a natural population of male and female tree crickets over 4 years. I found that although the source of viability stayed the same, viability selection affected males and females differently, and the strength, direction and form of selection varied considerably from year to year. In general, males experienced significant linear selection and significant selection differentials more frequently than females, and different male traits experienced significant linear selection each year. This yearly variation resulted in overall weak but significant convex selection on a composite male trait that mostly represented leg size and wing width. Significant selection on female phenotype was uncommon, but when it was detected, it was invariably nonlinear. Significant concave selection on traits representing female body size was observed in some years, as the largest and smallest females were preyed on less (the largest may have been too heavy for flying wasps to carry). Viability selection was significantly different between males and females in 2 of 4 years. Although viability selection via predation has the potential to drive phenotypic change and sexual dimorphism, temporal variation in selection may maintain stasis. 相似文献
18.
P. A. Trillo K. A. Athanas D. H. Goldhill K. L. Hoke W. C. Funk 《Journal of evolutionary biology》2013,26(1):216-222
Sexual selection plays an important role in mating signal divergence, but geographic variation in ecological factors can also contribute to divergent signal evolution. We tested the hypothesis that geographic heterogeneity in predation causes divergent selection on advertisement call complexity within the Engystomops petersi (previously Physalaemus petersi) frog species complex. We conducted predator phonotaxis experiments at two sites where female choice is consistent with call trait divergence. Engystomops at one site produces complex calls, whereas the closely related species at the other site produces simple calls. Bats approached complex calls more than simple calls at both sites, suggesting selection against complex calls. Moreover, bat predation pressure was greater at the site with simple calls, suggesting stronger selection against complex calls and potentially precluding evolution of complex calls at this site. Our results show that geographic variation in predation may play an important role in the evolution and maintenance of mating signal divergence. 相似文献
19.
Arnout Francis Grégoir Eli Samuel Joachim Thoré Charlotte Philippe Tom Pinceel Luc Brendonck Bram Vanschoenwinkel 《Ecology and evolution》2018,8(13):6390-6398
Both constitutive and inducible antipredator strategies are ubiquitous in nature and serve to maximize fitness under a predation threat. Inducible strategies may be favored over constitutive defenses depending on their relative cost and benefit and temporal variability in predator presence. In African temporary ponds, annual killifish of the genus Nothobranchius are variably exposed to predators, depending on whether larger fish invade their habitat from nearby rivers during floods. Nonetheless, potential plastic responses to predation risk are poorly known. Here, we studied whether Nothobranchius furzeri individuals adjust their life history in response to a predation threat. For this, we monitored key life history traits in response to cues that signal the presence of predatory pumpkinseed sunfish (Lepomis gibbosus). While growth rate, adult body size, age at maturation, and initial fecundity were not affected, peak and total fecundity were higher in the predation risk treatment. This contrasts with known life history strategies of killifish from permanent waters, which tend to reduce reproduction in the presence of predators. Although our results show that N. furzeri individuals are able to detect predators and respond to their presence by modulating their reproductive output, these responses only become evident after a few clutches have been deposited. Overall our findings suggest that, in the presence of a predation risk, it can be beneficial to increase the production of life stages that can persist until the predation risk has faded. 相似文献
20.
Maegwin Bonar Micheline Manseau Justin Geisheimer Travis Bannatyne Susan Lingle 《Ecology and evolution》2016,6(13):4387-4402
Juvenile survival is a highly variable life‐history trait that is critical to population growth. Antipredator tactics, including an animal's use of its physical and social environment, are critical to juvenile survival. Here, we tested the hypothesis that habitat and social characteristics influence coyote (Canis latrans) predation on white‐tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) fawns in similar ways during the neonatal period. This would contrast to winter when the habitat and social characteristics that provide the most safety for each species differ. We monitored seven cohorts of white‐tailed deer and mule deer fawns at a grassland study site in Alberta, Canada. We used logistic regression and a model selection procedure to determine how habitat characteristics, climatic conditions, and female density influenced fawn survival during the first 8 weeks of life. Fawn survival improved after springs with productive vegetation (high integrated Normalized Difference Vegetation Index values). Fawns that used steeper terrain were more likely to survive. Fawns of both species had improved survival in years with higher densities of mule deer females, but not with higher densities of white‐tailed deer females, as predicted if they benefit from protection by mule deer. Our results suggest that topographical variation is a critical resource for neonates of many ungulate species, even species like white‐tailed deer that use more gentle terrain when older. Further, our results raise the possibility that neonatal white‐tailed fawns may benefit from associating with mule deer females, which may contribute to the expansion of white‐tailed deer into areas occupied by mule deer. 相似文献