Integrative zoology最新文献

Deep-sea shrimps from the family Alvinocarididae are prominent inhabitants of chemosynthesis-based habitats worldwide. However, their genetic diversity and population connectivity remain poorly understood due to limited sampling. To fill these knowledge gaps, we compared the population genetics of two vent- and seep-dwelling alvinocaridid species with overlapped geographic ranges between the South China Sea and the Manus Basin. Alvinocaris longirostris has a wider distribution, ranging from 35°N to 3°S and at depths of 930 to 1736 m, while Alvinocaris kexueae is more restricted, found between 16°N and 3°S at depths of 1300 to 1910 m. Our analysis, based on the mitochondrial cytochrome c oxidase subunit 1 gene, revealed that A. longirostris had lower genetic diversity and minimal genetic differentiation across eight disjoint vent and seep populations. In contrast, the narrower-distributed A. kexueae exhibited higher genetic diversity and significant genetic differentiation, with stronger gene flow observed from its Haima seep population to the Manus Basin vent population. In addition, both species appear to have experienced population expansion in their recent evolutionary history. These results suggest that A. longirostris and A. kexueae may possess distinct life-history traits that contribute to their differing distribution ranges in the Western Pacific.

This paper addresses the population genetic structure of the forest-dwelling gonyleptid Geraeocormobius sylvarum (Arachnida, Opiliones). Phylogeographic analyses using cytochrome oxidase subunit I (COI) were conducted on 186 individuals from 43 localities in Argentina and Paraguay, arranged into nine operational sectors and defined upon geographic and vegetation features. Given the current environmental uniformity, it was aimed to assess whether molecular fingerprints of G. sylvarum correlate with Pleistocene fragmentation events, inferred through forest contraction/expansion cycles. The network of 87 haplotypes displayed an unstructured pattern; 75 were found in unique localities (54 on single individuals), with most haplotypes restricted to a single operational sector. The calibrated phylogenetic tree revealed significant admixture, with each clade mainly related to one operational sector. Results suggest multiple fragmentation events; most COI diversity arose in the Late Pleistocene/Early Holocene; recent and relict lineages coexist at a few sites. Banks of major rivers (Paraná and Uruguay) in Misiones Province may have served as main refuge areas, with dispersal within each basin being frequent but sporadic across the watershed divide, keeping basins separated for long periods. The split of the Misiones opiliogeographical area into two sectors corresponding to the major basins is proposed.

Animal signals are complex, comprising multiple components influenced by ecological factors and viewing perspectives that together impact their overall effectiveness. Our study explores how these factors affect the efficacy of multi-component signals in the Qinghai toad-headed agama, Phrynocephalus vlangalii. Using 3D animations, we simulated natural environments to evaluate how tail coiling and tail lashing-two primary tail displays-vary in effectiveness from both conspecific and predator perspectives under different ecological conditions. Baseline comparisons showed no significant difference in effectiveness between tail coiling and tail lashing without environmental constraints, though side-on tail coiling was consistently more effective than front-on displays. When noise proximity was introduced, tail lashing was more effective when the noise source was nearby, but this advantage diminished with distance. Conversely, tail coiling maintained consistent effectiveness across varying noise proximities, especially from a side-on view. In complex habitats with diverse plant species and varying wind conditions, tail lashing proved more effective, particularly from a front-on perspective, while tail coiling excelled from a side-on view. From a predator's perspective, tail lashing was slightly more effective under low wind conditions at close distances, though its visibility decreased with higher wind speeds. These findings highlight the adaptive significance of multi-component signals and the critical role of signal orientation in enhancing communication. This research offers insights into the evolutionary pressures shaping animal communication strategies.

Selection on body size tends to favor larger males that outcompete smaller males to mate with females, and larger, more fecund females. For many web-building spiders in the Nephilidae family, reproductive success increases with body size, which in turn, is related to diet. The diet of female spiders may overlap with males who share her web, but diet patterns could depend on size if certain males have better access to prey ensnared in the web. Therefore, we tested the hypothesis that Joro spider (Trichonephila clavata) dietary patterns are sex-specific and related to body size and condition. We combined morphometric size analysis with molecular gut content analysis via DNA metabarcoding and high-throughput sequencing to characterize male and female Joro spider diets from 60 webs at 25 locations. Female Joro spiders were larger than males and their diets were more diverse. While male Joro spiders consumed the same prey taxa as females, more than 50 additional taxa were detected in female diets, which led to significant dissimilarity in prey composition between sexes. As male body size increased, diet diversity and body condition decreased, suggesting a potential trade-off between time spent foraging versus active defense of their position on the web. Female and male spiders captured from the same web shared prey taxa. However, the proportion of prey overlap was not related to male size. Combined, Joro spiders show sex-specific dietary patterns, and males appear to have less access to the diverse food captured in female webs.

Over the past few decades, ocean hypoxia has been increasing due to human activities. Hypoxic stress, characterized by a reduced level of dissolved oxygen, is an escalating threat to marine ecosystems, with potentially devastating effects on the viability of endangered species such as the tri-spine horseshoe crab Tachypleus tridentatus. Even though this species is remarkably resilient to low oxygen levels, persistent hypoxia can negatively impact its population's survivability. The objective of this research was to examine the impact of short-term hypoxia on the behavior, gut microbiota, and metabolomics of juvenile T. tridentatus. First instar juvenile horseshoe crabs were subjected to hypoxic stress (2 mg O₂/L) for 14 days and then recovered for 7 days in an environment with normal dissolved oxygen. The findings demonstrated that short-term hypoxia reduced the rates of swimming and burrowing of horseshoe crabs, and induced the change of tissue metabolites and intestinal flora malfunction. Additionally, in the hypoxia groups on day 14, 86 distinct metabolites showed a trend of downregulation, while 29 metabolites showed an upregulation trend. Arginine biosynthesis; histidine metabolism; vitamin B6 metabolism; aminoacyl-tRNA biosynthesis; and alanine, aspartate, and glutamate metabolism were the top five metabolic KEGG pathways (p < 0.05) enriched with 8 metabolites. In conclusion, our results provided new insights related to the behaviors, microbiota, and metabolites involved in juvenile T. tridentatus exposed to short-term hypoxic conditions and confirmed that hypoxia impairs their behavioral and physiological status.

The genus Hylomys now comprises seven species instead of two; the Hylomys species in China should be classified as Hylomys peguensis.

Plague, a zoonotic disease caused by Yersinia pestis, remains a major public health threat in several parts of the world, including Madagascar. Factors underlying long-term persistence and emergence of the pathogen remain poorly understood. We implemented a longitudinal survey to provide insights into plague reservoir ecology within an endemic focus. Six trapping sessions (TS) were conducted in six different localities of the Ankazobe district from 2018 to 2020 in order to monitor small mammal communities. A total of 2762 individuals composed of six species (Rattus rattus, Rattus norvegicus, Mus musculus, Setifer setosus, Suncus murinus and Tenrec ecaudatus) were caught over the six successive TS. R. rattus represented 88% of all captures, with the highest relative abundances observed during the dry season (June to August 2019). None of the micromammals tested positive for the presence of Y. pestis, neither with qPCR nor bacterial culture. However, 11 seropositive individuals (6 R. rattus, 2 M. musculus and 3 S. murinus) were retrieved following ELISA, thus leading to a global seroprevalence of 0.4%. Our study highlighted the significant influence of climatic data on the seasonal variations of R. rattus abundance and suggest that black rat control should be conducted before the dry season, that is, during high reproduction period of rats, in order to reduce the number of reproducing animals and prevent subsequent increase in abundance. As three S. murinus and two M. musculus plague seropositive were identified in the present study, their potential role in plague eco-epidemiology in Madagascar should be explored further.

The burrow microhabitats created by burrowing mammals, as a hotspot for biodiversity distribution in ecosystems, provide multiple critical resources for many other sympatric species. However, the cascading effects of burrow resources on sympatric animal community assemblages and interspecific interactions are largely unknown. During 2020-2023, we monitored 184 Chinese pangolin (Manis pentadactyla) burrows using camera traps to reveal the burrow utilization patterns of commensal species. We totally recorded up to 57 species, with 19 mammal species, 32 bird species, and 1 reptile species recorded in the burrows revisited by Chinese pangolin, with 19 mammal species and 25 bird species in the non-revisited burrows. Among them, most bird species as peripheral species primarily utilize soil mounds while most mammal species as burrow-used species utilize burrow tunnels. The structure of animal communities in the burrows revisited by Chinese pangolins is more complex than that in the burrows not revisited. Furthermore, the positive correlation between community species in pangolin-revisited burrows is also stronger. Our results demonstrate that the presence and repeated visitation by Chinese pangolins could enhance positive interactions (i.e., the emergence of one species promotes the emergence of another) among species that utilize the burrow resources (particularly, burrow-used species). Our study provides the first evidence that the ecological role of the Chinese pangolin and its associated burrow microhabitats in promoting the coexistence of burrowing commensals and the restoration of Chinese pangolin populations may potentially contribute to the restoration of local biodiversity and ecological processes.

Pomacea canaliculata is recognized as a globally invasive aquatic species. Analyses of intestinal microbiota, dietary composition, and metabolism of invasive species can enhance our understanding of their feeding strategies and physiological adaptation strategies to the environment. Intestinal content samples were collected from P. canaliculata inhabiting three distinct environments including a pond, a river, and a ditch. These samples were subjected to 16S rRNA gene sequencing analysis and multiple metabarcoding analyses, including eukaryotic 18S rRNA, mitochondrial cytochrome c oxidase I (COI), and chloroplast rbcL genes. In addition, metabolomics analysis was conducted on the intestinal content samples to investigate metabolic change. The highest dietary diversity in P. canaliculata was observed in the ditch, and females exhibited a higher dietary diversity than males in the pond. The 18S rRNA gene has a high potential for identifying the dietary components of omnivorous species. The intestinal microbiota of P. canaliculata from different habitats displayed significant variations, attributed to differences in food resources and other environmental factors. Bacteria in the aquatic environment had minimal impact on the intestinal microbiota of P. canaliculata. Overall, P. canaliculata exhibited adaptive changes in physiological characteristics across different habitats, including alterations in diet, which, in turn, influence microbiota and metabolic pathways such as amino acid biosynthesis in the intestine. The present study investigated the physiological mechanisms that enable P. canaliculata to adapt to diverse habitats, considering various factors including diet, which is important for comprehending its invasive potential and the subsequent threats it poses to aquatic ecosystems.