摘要: There are many short-lived animals, but those displaying a lifecycle with more than one generation per year (multivoltine lifecycle) are rare among terrestrial vertebrates. The multivoltine lifecycle requires rapid growth and maturation and a long active season. Thus, small lizards in humid tropical or subtropical areas are candidates for multivoltine lifecycles. To test this prediction, we conducted a capture-mark-recapture study of a subtropical grass lizard, Takydromus toyamai, endemic to Miyako Islands, Japan. Juveniles grew very quickly, averaging 0.3 mm/day in the warm season, and attained sexual maturity at 2.5 months post-hatching. The breeding season was very long, and hatchlings emerged from May to November. The prolonged breeding season and rapid growth to maturity allowed some individuals to produce a second generation in their first year. Estimates of hatching date from growth rates indicated that many females that hatched in May-June became gravid 76-120 days after hatching and 122-165 days after oviposition of the eggs from which they hatched. Analyses of juvenile survivorship and month of hatching suggest that nearly half of breeding adults were members of multivoltine generations, although the 2 generations were not discrete. The species is short-lived, with only 16% of individuals surviving beyond 12 months, and few individuals reproduced in a second year. We refer to this condition as a semi-multivoltine lifecycle. Individuals that hatch late in the season defer reproduction until the following year and become founders of the next season's cohort. This putative advantage of late-hatching individuals may have driven the evolution of this lifecycle.

摘要: Niche theory predicts that closely related and ecologically similar species with overlapping distribution ranges can coexist through resource partitioning that limits interspecific competition. However, studies examining the mechanisms promoting coexistence of top predators at a large geographical scale are still scant. Here, we describe the foraging ecology of 3 sympatric owl species (Northern long-eared owl [Asio otus], Tawny owl [Strix aluco], Eurasian eagle owl [Bubo bubo]) in the Mediterranean Basin. We review 160 studies reporting diet information (212,236 vertebrate preys) and investigate among-species differences in diet metrics (diversity, evenness, prey size, and proportion of mammals) and their variation along geographical and environmental gradients. Moreover, we test whether diet metrics differ in presence or absence of the other predators. All the 3 species mainly rely on small mammals, but they significantly differ in diet metrics. The smallest predator (i.e., long-eared owl) shows a higher level of specialism on small mammals (highest proportion but lowest diversity of mammals in the diet) compared to the larger ones. In addition, mean prey size significantly increases with predator body size (long-eared owl < tawny owl < eagle owl). Finally, interspecific competition results in an increase of diet diversity and evenness in the long-eared owl, and species' diet also varies in response to environmental factors. The 3 species thus segregate along several dietary niche axes over a large spatial scale and according to both morphological characteristics (i.e., body size) and environmental variables. Such dietary niche segregation may adaptively buffer interspecific competition costs, ultimately allowing coexistence.

摘要: Many prey species rely on publicly available personal and social information regarding local predation threats to assess risks and make context-appropriate behavioral decisions. However, in sexually dimorphic species, males and females are expected to differ in the perceived costs and/or benefits associated with predator avoidance decisions. Recent studies suggest that male Trinidadian guppies (Poecilia reticulata) show reduced or absent responses to acute personal information cues, placing them at greater risk of predation relative to females. Our goal here was to test the hypothesis that adult (reproductively active) male guppies rely on social information to limit potential costs associated with their lack of response to risky personal cues. Adult male guppies were exposed to personal chemosensory cues (either conspecific alarm cues (AC), a novel odor, or a water control) in the presence of a shoal of three females inside a holding container that allowed the transmission of visual but not chemical cues. At the same time, we exposed females to either risk from AC or no risk, resulting in the display of a range of female behavior, from calm to alarmed, available as social information for males. Alarmed females caused male fright activity to increase and male interest in females to decrease, regardless of the personal cue treatment. These results indicate that male guppies rely more on female information regarding predation risk than their own personal information, probably to balance trade-offs between reproduction and predator avoidance.

摘要: Natal dispersal is a critical trait for individual fitness and the viability, structure, and genetic identity of populations. However, there is a pronounced information gap for large and long-lived species due to the difficulty of monitoring individuals at appropriate spatio-temporal scales. Here we study how individual traits and social and environmental characteristics influence natal dispersal decisions of griffon vultures (Gyps fulvus) using long-term (30 years) monitoring of a large number of individuals marked as nestlings in Spain. Our results show a strong philopatry in both sexes, with some individuals recruiting as breeders on the same cliffs, and even the same nests, where they were born. This philopatric tendency was modulated by the effect of conspecific density on individual parameters and emphasized the importance of conspecific attraction and changes in food availability that may have influenced the increment in colony size and the colonization of new areas. Although further research is needed considering smaller colonies and more isolated population nuclei, our results highlight the importance of long-term studies on long-lived species to understand the factors that determine their population dynamics and their relationship with anthropogenic activities, whose effects should be predicted and managed using conservation criteria.

摘要: Noise pollution has been shown to affect wild animals in various ways, but little is known about its consequences at the community level. Investigating animals' overall vocal responses to noise across multiple sympatric species can reveal the complex nature of noise impacts but is challenging. In this study, we employed social network analysis (SNA) to evaluate how anuran communities and populations vary their calling behaviors in response to aircraft noise. SNA of anuran communities revealed that conspecific individuals increase the aggregation of their spectral (i.e., minimum frequency, maximum frequency, and dominant frequency), temporal (call duration, call rate, and call effort), and overall spectral-temporal features as an airplane passes through. SNA of populations also revealed that anurans could increase the interindividual similarity of multiple call characteristics in response to airplane noise. Furthermore, our network analysis of multiple species and multiple call traits revealed an effect of noise in species whose calling behavior did not change in previous separate analyses of each species and single traits. This study suggests that noise pollution may change the pattern of combined acoustic properties at the community level. Our findings highlight the importance of integrated methods and theories for understanding the ecological consequences of noise pollution in future studies.

摘要: Inbreeding and loss of genetic diversity increase the extinction risk of small isolated populations. Genetic rescue by augmenting gene flow is a powerful means for the restoration of lost genetic variation. In this study, we used multigenerational pedigrees and neutral genetic markers to assess the consequences of outbreeding management in the Chinese and Vietnamese populations of the endangered crocodile lizard, Shinisaurus crocodilurus. Compared with the purebred Chinese population, the outbreeding population exhibited greater molecular genetic variation and a 3-fold larger population size. Moreover, the first-generation hybrids had a longer lifespan than purebreds, suggesting that outbreeding depression did not occur, but the long-term fitness effect of outbreeding needs to be further evaluated. Our study provides valuable insights into the potential for genetic rescue in the endangered crocodile lizard, emphasizing the importance of an evidence-based genetic management approach to address the risks of inbreeding and outbreeding depression in threatened populations.

摘要: European mountain systems have played a crucial role in shaping the distribution of species and of their genetic diversity during the Quaternary climatic changes, with the establishment of allopatric patterns across main mountain ranges. Here we investigated the evolutionary history of flea beetles of the Longitarsus candidulus species-group showing an uncommon disjunct biogeographic pattern across the Apennine and the Pyrenees. We applied a multilocus molecular approach and multispecies coalescent models to establish a phylogenetic and systematic framework for this morphologically homogeneous species-group and to estimate the time of main cladogenetic events underlying the origin of the Apennine-Pyrenees pattern. We found strong support for the monophyly of the candidulus group with a sister relationship between Longitarsus laureolae and L. leonardii endemic to the Apennine and the Pyrenees mountains respectively. The timing of speciation events in the candidulus species-group coincides with 2 major climatic transitions during the Early and Middle Pleistocene which resulted in significant environmental changes in Europe and suggest a scenario of allopatric isolation and divergence on distinct mountain ranges. The split between the thermophilic species L. candidulus and the ancestor of the temperate species L. laureolae and L. leonardii is estimated at similar to 3 Ma during the transition from Pliocene to Pleistocene and was probably triggered by their segregation in xerophilous and temperate habitats. The speciation between L. laureolae and L. leonardii, estimated at similar to 1 Ma during the Mid-Pleistocene Transition, can be explained by the establishment of unfavorable conditions in West Alps and Central Massif underlying the onset of the Apennine-Pyrenees disjunct pattern. Finally, the strict association between members of the candidulus group and distinct Thymelaeaceae plants suggests further studies to address the hypothesis that speciation in these flea beetles might have been also associated with Pleistocene range changes of their host plants.

摘要: Mounting evidence suggests that male sperm may be gradually depleted after consecutive matings, resulting in the decline of female reproductive output in insect species. It is predicted that females may employ adaptive strategies to avoid the sperm-depleted males, such as mating multiply with different males and/or discriminating against previously mated males (MMs). Similarly, males may exhibit adaptive behaviors toward females varying in mating status. However, in spiders with males lacking primary copulatory organs and their pedipalps modified to transfer sperm, there are few studies on male mating potential and previous mating experience on their subsequent mate choice. In this study, we used a polyandrous crab spider, Ebrechtella tricuspidata, a sit-and-wait predator with female-biased sex ratio as a model system to ascertain whether 1) male mating experiences influence female reproductive fitness; 2) females respond differently to males varying in mating status; and 3) males respond differently to females varying in mating status. Our results showed that female fecundity was independent of male mating experiences, but female fertility markedly declined with the increase of male previous mating experiences in the first eggsac. Counter to our predictions, females preferred to choose and mate with the larger males, regardless of their mating status. In contrast, male mating status influenced their mating preference toward females. Virgin males did not show any preference between virgin and mated females; however, MMs were more likely to prefer the virgin females over the mated ones. Overall, our results indicated that female choice depended primarily on male relative size rather than male mating status, whereas male choice depended on female mating status. Depending on the investigation of reproductive dynamics and mate choice in E. tricuspidata, the study will provide valuable insights into the adaptive behaviors of both males and females exhibiting toward mates varying in mating status.

摘要: Shrimps of the genus Synalpheus (Caridea) are commonly found in subtropical and tropical marine habitats around the world. The present work aims to provide the first description of the reproductive system of this genus using histological, histochemical, and morphological perspectives to elucidate the gonochoric or hermaphrodite sexual system in this genus. Males have a slender and very translucent reproductive system that is challenging to observe. The entire cephalothorax was histologically sectioned to ensure that all regions of the reproductive system could be identified. This non-gambarelloides group shows a gonochoric condition. The caridean pattern of the reproductive system was observed where the male has a pair of testes and a pair of very thin vasa deferentia, ending at the opening of the gonopore. Spermatophore structure is absent, without any layers surrounding the spermatozoa that are aggregated in a sperm mass. In females, the reproductive system consists of a pair of ovaries that extend to the end of the pleon. The extension of the ovary has a particular pattern compared to other caridean shrimps. Here, we hypothesize that males invest energy on somatic morphological structures to protect the host and female, using the larger pistol-like cheliped, while females invest energy in reproduction since all the members of this group are typical pair-bond examples. The observed pattern of the reproductive male morphology could also be evidence of a possible synapomorphy for this genus within the infraorder.

摘要: Understanding the molecular relevance of metabolic rate (MR) is crucial for unveiling the mechanisms driving the evolution of animals. In this study, we investigated the association between mitochondrial DNA characteristics and both resting and maximal MRs in conjunction with life-history traits among 139 species of teleost fish. We gathered fish MR data from various sources and procured sequences of 13 mitochondrial protein-encoding genes. We calculated the absolute substitution rate for entire nucleotide sequences and 4-fold degenerate sites of each gene, along with encoding amino acid sequences. Using the phylogenetic comparative method, we then explored the associations between MR and mitochondrial DNA absolute substitution rate. Additionally, we screened MR-associated single nucleotide variants in mitochondrial DNA. The findings indicate no positive correlation between MRs and any substitution rate values of both combined sequences and individual mitochondrial protein-coding genes, refuting the MR hypothesis. Instead, both maximum body size and longevity correlated negatively with molecular substitution rates, suggesting their influences on both mutation and fixation within mitochondrial genes in fish. Results also revealed significant correlations between base variation at ATP6_169 and both resting MR and maximum MR, identifying the unique ATP6_169G in Scombridae fish, which results in an extremely low isoelectric point (pI) value of the ATP6 protein. Considering its functional significance, the ATP6_169G in Scombridae fish might link to their lifestyle characterized by fast locomotion and high metabolic demands alongside a slower molecular evolutionary rate.