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Fig. S1. Typical anal pads of female (a) and male (b) small Indian mongooses (Urva 4 auropunctata), demonstrating sexual dimorphism. A: anus, AP: anal pad (photo MAO, 2012, 5 Hawaii). 6
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Sexual selection theory provides a framework for investigating the evolution of traits involved in attracting and competing for mates. Given the sexual function of such traits, studies generally focus on individual interactions (i.e., displays and contests) in explaining trait origin and persistence. We show that ecological factors can strongly inf...
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There is no satisfactory explanation for why peacock possesses a tail, presence and especially courtship display of which makes the organism vulnerable to predation. Here, I present a model according to which in a polygynous mating system a mechanism which increases vulnerability to predation, a Zahavian handicap, evolves when other two mechanisms...
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... Sexual selection is widely recognized as one of the main evolutionary forces driving the development and refinement of traits that influence mating success (9,10), and sexual selection can drive differences in sexual traits within and between native and invasive populations of the same species (11,12). Mate choice is a multi-phase process that can occur before, during and after mating (13,14). ...
Biological invasions of freshwater habitats are of increasing biological and economical concern, and both, salinity and parasites are considered to be key contributors to invasion success. Salinity, for example, influences the distribution of invasive mosquitofish ( Gambusia holbrooki ) and native killifish ( Aphanius fasciatus ) in Europe, with the latter now predominantly confined to high-salinity habitats. Here, we examined how salinity might affect female activity and preference for large and non-parasitized males in multiple populations of mosquitofish and killifish in Sardinia, Italy. We predicted that (1) females of both species would associate preferentially with larger and uninfected males, and that (2) female behavior in both species would be significantly influenced by salinity. We used dichotomous choice tests, in which we presented focal females with video animations of photos of the same male but differing in body size and presence/absence of an ectoparasite ( Lernaea cyprinacea ). We calculated female preference based on association time and quantified female inactivity as time spent in the central neutral zone during trials. Contrary to prediction 1, females did not prefer the large or uninfected male stimuli over their counterparts in any of the populations. However, while salinity did not significantly affect female preferences, it did significantly affect their activity, with mosquitofish becoming more inactive at higher salinities and killifish exhibiting the opposite pattern, matching prediction 2. These results suggest that salinity limits mosquitofish invasiveness by reducing their activity and thus provides a refuge for the Mediterranean killifish.
... However, the findings from these island studies are not necessarily transferable to native populations, as the ecological conditions in island environments are often very different from native environments. For example, density estimates for small Indian mongoose average 51-64 times higher in introduced ranges, and reproductive features are significantly different (Owen & Lahti, 2020). ...
Southeast Asia is rich in small carnivore species, but baseline information on these species is frequently lacking. Many of the region's remaining forests are degraded, which can drastically change ecosystem function and structure. The Javan mongoose is a small generalist carnivore with a wide distribution across Southeast Asia, whose population, home-range size, and micro-habitat selection are poorly known. We investigated each within a degraded forest fragment in Northeast Thailand using a multimethod approach involving camera trap and radio telemetry data. We found mongoose abundance was positively associated with dry dipterocarp forest (DDF) and has a negative relationship with basal area of small trees (diameter at breast height < 10 cm). Across our entire study site, we found a mean abundance of 1.10 animals per sampling station (SE 0.30 95% CI 0.65-1.92) and within the DDF we found 3.04 animals per station (SE 0.75 95% CI 1.87-4.96). The mean home-range size for two males was 1.86 km 2 and for one female was 0.27 km 2. Availability of termite mounds with entry holes was our top model for den site selection. Prey availability did not affect micro-habitat selection by mongoose, presumably due to an even distribution of small mammals across the DDF. Mongoose selected for areas with low numbers of small trees, indicating an avoidance of closed forest environments. Our findings indicate that Javan mongoose select for open dry forest and can tolerate moderate forest degradation.
Competition for mates can play a critical role in determining reproductive success, shaping phenotypic variation within populations, and influencing divergence. Yet, studies of the role of sexual selection in divergence and speciation have focused disproportionately on mate choice. Here, we synthesize the literature on how mate competition may contribute to speciation and integrate concepts from work on sexual selection within populations – mating systems, ecology, and mate choice. Using this synthesis, we generate testable predictions for how mate competition may contribute to divergence. Then, we identify the extent of existing support for these predictions in the literature with a systematic review of the consequences of mate competition for population divergence across a range of evolutionary, ecological, and geographic contexts. We broadly evaluate current evidence, identify gaps in available data and hypotheses that need testing, and outline promising directions for future work. A major finding is that mate competition may commonly facilitate further divergence after initial divergence has occurred, e.g., upon secondary contact and between allopatric populations. Importantly, current hypotheses for how mate competition contributes to divergence do not fully explain observed patterns. While results from many studies fit predictions of negative frequency dependent selection, agonistic character displacement, and ecological selection, results from ~30% studies did not fit existing conceptual models. This review identifies future research aims for scenarios in which mate competition is likely important but has been understudied, including how ecological context and interactions between mate choice and mate competition can facilitate or hinder divergence and speciation.
Functional trait–based mediation of animal invasions is only now developing, yet it is already showing as much promise as the approach has for plant invasion biology. Here, we provide a theory-founded examination of functional trait-based ecology with respect to animal invasions, together with a review of the empirical research. Recent developments in the scaling of traits to ecosystems, along with the frameworks for invasion ecology, provide a powerful foundation for investigations. Despite growing empirical research in this field, interspecific comparisons incorporating comparative phylogenetic approaches remain uncommon, and those examining assemblages are even more so. Despite the importance of time since introduction, it is rarely included in studies. Broad environmental tolerances, life history traits associated with fast growth or greater reproduction, and in some cases, greater phenotypic plasticity of traits, mediate the success of animal alien species at various stages of invasion, although introduction effort remains one of the most important factors affecting success.
Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 54 is November 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
This chapter reviews the mechanisms underlying, and dynamics of, rapid evolution in invasive species. By synthesising recent research, the relative roles of adaptive (abiotic and biotic) and non-adaptive (founder events, bottlenecks, drift, spatial sorting) processes in causing rapid evolution in invasive species are discussed. Traits that often undergo rapid evolution in invasive species, such as clinal variation in phenology, increased competitive ability, changes in reproductive biology, etc., are examined in detail. The need to account for geographic structure in traits, as well as stochastic processes associated with the introduction history and spread of exotic species, when studying rapid evolution, is discussed. The chapter concludes by suggesting future avenues for the study of rapid evolution in invasive species.
Although most invasive species engage in mutualism, we know little about how mutualism evolves as partners colonize novel environments. Selection on cooperation and standing genetic variation for mutualism traits may differ between a mutualism's invaded and native ranges, which could alter cooperation and coevolutionary dynamics. To test for such differences, we compare mutualism traits between invaded‐ and native‐range host‐symbiont genotype combinations of the weedy legume, Medicago polymorpha, and its nitrogen‐fixing rhizobium symbiont, Ensifer medicae, which have co‐invaded North America. We find that mutualism benefits for plants are indistinguishable between invaded‐ and native‐range symbioses. However, rhizobia gain greater fitness from invaded‐range mutualisms than from native‐range mutualisms, and this enhancement of symbiont fecundity could increase the mutualism's spread by increasing symbiont availability during plant colonization. Furthermore, mutualism traits in invaded‐range symbioses show lower genetic variance and a simpler partitioning of genetic variance between host and symbiont sources, compared to native‐range symbioses. This suggests that biological invasion has reduced mutualists’ potential to respond to coevolutionary selection. Additionally, rhizobia bearing a locus (hrrP) that can enhance symbiotic fitness have more exploitative phenotypes in invaded‐range than in native‐range symbioses. These findings highlight the impacts of biological invasion on the evolution of mutualistic interactions.
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