Specific Life History Research Articles

Key bacterial taxa with specific metabolisms and life history strategies sustain soil microbial network stability exposed to carbendazim and deoxynivalenol

Co-contamination of carbendazim (CBD) and deoxynivalenol (DON) is common in agricultural soils, yet their ecological impact on soil microbiome remains poorly assessed. Here, we investigated the influence of CBD and DON on the structure, function, and co-occurrence networks of soil microbiome. The combined treatment of CBD and DON significantly exacerbated the negative impacts on soil microbial diversity, functional diversity, and microbial network stability compared to individual treatments. Specifically, Lysobacter, Gemmatimonas, Nitrospira, Massilia, and Bacillus were identified as indicator species for CBD and DON. Simultaneously, the abundance of genes involved in key ecological functions, such as nitrification (amoA) and organic phosphorus mineralization (phoAD), was significantly reduced. Notably, key bacterial taxa Nitrospira and Gemmatimonas, with K-life history strategy and capabilities for nitrification and organic nitrogen mineralization, played crucial roles in promoting positive interactions in networks. Furthermore, variance partitioning analysis (VPA) and structural equation modeling (SEM) demonstrated that the abundance and niche breadth of key bacterial taxa were the primary drivers of microbial network stability. In conclusion, our study provides new insights into how soil microbiomes and networks respond to pesticides and mycotoxins, aiding in a more comprehensive assessment of exposure risks.

Non-senescent species are not immortal: Stress and decline in two planaria species.

Potential immortality is observed in several species (e.g. prickly pear cactus, hydra and flatworms) and is indicative of their negligible or even negative senescence rates. Unlike in senescent species, which experience reduced individual performance with age due to physiological degradation, species with negligible or negative senescence display mortality rates that remain constant or decline with age, respectively. These rates vary across taxa and are correlated with life history traits. Yet, the extent to which variable resource availability, a key driver of variation in life history traits, impacts species that show negligible or negative senescence is currently unknown. Here, we examine whether and how variation in the quantity, quality and feeding interval of resources impact population structure, population performance and life history trait trade-offs in two long-lived planaria that do not senesce: Schmidtea mediterranea and Dugesia tahitiensis. In a full factorial design, different combinations of resource quantity (reduced intake, standard intake and high intake) and quality (high and low quality) were provided in two different feeding intervals (7-day and 14-day intervals) for 19 weeks. We show that variability in resource availability, via decreases in quantity, quality and frequency of resources, does not diminish population viability in either species but does result in suboptimal conditions of stress in S. mediterranea. The high population viability we report can be attributed to two different mechanisms: increased reproduction or increased investment into maintenance at the expense of reproduction. Moreover, which mechanism was responsible for said high population viability was context-dependent and modulated by the specific life history strategy of the two planaria species. We show that suboptimal conditions can cause stress responses that have significant impacts on non-senescent species. The context-dependent response we observe suggests that species that do not senesce but are subject to suboptimal conditions of stress may ultimately exhibit declines in performance and ultimately die. A clearer understanding of the impact of suboptimal conditions of resource availability on non-senescent species is needed to determine the extent of stress experienced and ultimately whether a species can truly be immortal.

Patterns of Ecological Specialisation Among Multiple Piscivorous Morphs of a Diverse Assemblage of Salvelinus Fishes

ABSTRACTAdaptive radiation is considered to be a major source of biodiversity in charrs of the genus Salvelinus. These fishes demonstrate numerous examples of diversification in postglacial lakes and rivers resulting in the emergence of different ecomorphs, including piscivorous. Usually, the number of fish feeders does not exceed two, suggesting the existence of ecological and/or internal factors that prevent further diversification. Under these circumstances, rare instances of increases in the number of piscivorous morphs are of particular interest. Here, we present a comprehensive study of the piscivorous charr assemblage in Lake Kronotskoe, residence of the most diverse species flock of Salvelinus fishes. To unravel the diversity and ecological relationships of piscivorous charrs, we analysed their morphology and microsatellite DNA polymorphism, distribution within the lake, trophic preferences and parasite load, as well as trace element accumulation, stable isotope and free fatty acid ratios. We revealed that, apart from a few strictly benthivorous morphs, the lake is inhabited by four closely related but morphologically and genetically distinct morphs that exhibit a range of piscivorous specialisation: from opportunistic secondary predation to ultra‐specialised primary piscivory. They effectively exploit the spatiotemporal structure of the ecosystem and experience diversifying selection due to niche discordance. Each piscivorous morph develops specific phenotypic, ecological and life history traits that allow it to terminate weakly overlapping branches of the trophic chain and share the energy flows of the lake ecosystem. Our data suggest that Lake Kronotskoe facilitates high level of ecological opportunity that favours niche expansion and allows the piscivorous lineage to simultaneously realise the archetypical modes of ecological diversification available to fishes in cold‐water freshwaters.

Daphnia stress response to environmental concentrations of chloramphenicol—multi-omics approach

Commonly used medicines, when discarded or improperly disposed of, are known to contaminate freshwater ecosystems. Pharmaceuticals can be toxic and mutagenic, and can modify freshwater organisms, even at environmentally relevant concentrations. Chloramphenicol (CAP) is an antibiotic banned in Europe. However, it is still found in surface waters around the world. The aim of this study was to evaluate the impact of chloramphenicol contamination in freshwater on the model organism Daphnia magna. Specific life history parameters, proteome, and host-associated microbiome of four D. magna clones were analyzed during a three-generation exposure to CAP at environmental concentrations (32 ng L−1). In the first generation, no statistically significant CAP effect at the individual level was detected. After three generations, exposed animals were smaller at first reproduction and on average produced fewer offspring. The differences in D. magna’s life history after CAP treatment were in accordance with proteome changes. D. magna’s response to CAP presence indicates the high stress that the tested organisms are under, e.g., male production, upregulation of ubiquitin-conjugating enzyme E2 and calcium-binding protein, and downregulation of glutathione transferase. The CAP-exposed D. magna proteome profile confirms that CAP, being reactive oxygen species (ROS)-inducing compounds, contributes to structural changes in mitochondria. Microbiome analysis showed a significant difference in the Shannon index between control and CAP-exposed animals, the latter having a more diverse microbiome. Multilevel analyses, together with long exposure in the laboratory imitating conditions in a polluted environment, allow us to obtain a more complete picture of the impact of CAP on D. magna.

Single housing of juveniles accelerates early-stage growth but extends adult lifespan in African turquoise killifish.

Within the same species, individuals exhibiting faster growth tend to have shorter lifespans, even if their fast growth arises from early-life pharmacological interventions. However, in vertebrates, the impact of the early-life environment on the growth rate and lifespan has not been fully elucidated. In this study, by utilizing the short-lived African turquoise killifish, which is suitable for a comprehensive life-stage analysis in a brief timeframe, we explored the effects of housing density during the juvenile stage on holistic life traits. As a result, we found that lower housing densities resulted in faster growth, but led to longer adult lifespan, which was contrary to the common notion. Furthermore, the single-housed adult fish displayed a longer egg-laying period than did their group-housed counterparts. Our transcriptome analysis also demonstrated that, in terms of internal transcriptional programs, the life stage progression and aging process of single-housed fish were slower than those of group-housed fish. Collectively, our results suggest that sharing housing with others in early life might influence whole-life attributes, potentially leading to specific life history traits beyond the typical relationship between the growth rate and lifespan.

Quantification of heritable variation in multiple lodgepole pine chemical and physical traits that contribute to defense against mountain pine beetle (Dendroctonus ponderosae)

Bark beetles are major causes of conifer mortality worldwide. We quantified genetic contributions to key chemical and physical traits in lodgepole pine that contribute to defense against mountain pine beetle, a native tree-killing herbivore. Assays were conducted with mature trees in replicated provenance trials. Among chemical defenses, monoterpene composition (relative proportions of various compounds) had higher genetic variability than monoterpene concentration (absolute quantities). Additionally, constitutive concentrations had higher genetic variabilities than induced concentrations elicited by simulated attack. Resin flow elicited by mechanical wounding likewise showed very low genetic variability. In previous studies with this and related systems, induced monoterpene concentration and resin flow are the two best predictors respectively of which trees will survive outbreaks under natural conditions. This means that expression of the most efficacious defense traits is strongly influenced by environmental factors. These low heritabilities despite their survival values likely arise from specific life history and ecological aspects of this system, such as the lengthy period between when lodgepole pines begin cone production and become large enough for brood development, the extended viability of serotinous cones post-mortem, the high heterogeneity of both resources and stressors that trees experience across landscapes, and a strong proximate-neighbor effect on tree mortality arising from beetle aggregation pheromones. However, low heritability values do not preclude long-term evolvability and coadaptation of defenses, for which there is extensive mechanistic and associational evidence in this system. Among other traits we evaluated, sesquiterpenes had higher genetic variability than monoterpenes. Sesquiterpenes are not known to influence conifer-bark beetle interactions but have anti-herbivore properties in some other plant-insect systems. The lengths of lesions formed in response to simulated attack showed no heritable component and likewise do not predict tree survival in nature. Bark texture was highly heritable and is known to influence beetle post-landing orientation and colonization patterns, but whether it influences survival patterns at the whole-tree level is unknown. Relationships between tree defenses and growth were generally positive, suggesting that environmental heterogeneity in resource quality among trees supersedes potential underlying substrate allocation processes within trees. Similarly, relationships between various defense traits were generally positive rather than showing trade-offs, suggesting conifer resistance to native bark beetles entails coordinated defense syndromes. Implications to tree breeding, forest management, and coevolution between long-lived plants and rapidly reproducing herbivores are discussed. The extent to which these trends may apply to other bark beetle systems is evaluated, along with specific priorities for future research.

Importance of life history traits for vulnerability to climate change: implications for macroalgal restoration

Fucalean algae are dominant canopy-forming species that create extensive and highly productive ecosystems in the intertidal and subtidal rocky shores of temperate seas. Regrettably, these marine forests are in decline due to various human drivers, with the Mediterranean Sea one of the most threatened areas. To design appropriate restoration strategies adapted to cope with the unavoidable change in future climate conditions, the response to climate change of the candidate species must be considered. It is important to assess how the specific life history traits of the foundational species may determine environmental requirements, and thus responses to future climate change. This knowledge will allow us to predict the potential winners and losers among the species potentially inhabiting the same areas in a future context of global climate change, providing important information to fine-tune future restoration interventions. The aim of this study was to evaluate the response of two canopy-forming species inhabiting similar upper subtidal zones but with different life history traits to a combination of anomalous high temperatures and increased UV radiation. One of the species (Ericaria crinita) was perennial, slightly exposed rocky shores and dwelling in areas where extreme temperatures can be frequent; while the other (Ericaria mediterranea) a semi-perennial species that dwells in wave-exposed zones, with seawater temperatures buffered by the high hydrodynamism. Our results show that the effects of temperature and radiation are species- (mediated by the species life history traits) and life-stage specific. High temperatures strongly affected the adults of both species, especially E. mediterranea. The germlings in addition to being very susceptible to high temperatures, were also vulnerable to UV radiation, exacerbating the impacts of temperature, especially on E. crinita recruits. Interestingly, vulnerability to climate-driven impacts was determined by the specific life history traits, with i) the species dwelling in open areas the most sensitive to warming and, ii) the perennial species the most vulnerable to UV radiation. Last, we discuss how these species-specific responses to climate-driven impacts may be key in terms of species that could foster the resistance and resilience of marine ecosystems to future climate impacts.

Prediction of suitable habitat shifts and assessment of ecological niche overlaps for three Tridentiger species with intertidal and subtidal characteristics under future climate changes

To show how dramatic global climate change affects marine ecosystem species in different habitats. We used a joint species distribution model (SDM) and an ecological niche model (ENM) to investigate the suitable habitat shifts and ecological niche overlaps of the Tridentiger fishes. In the present study, the SDM results showed that 5 hotspots were identified for T. trigonocephalus and T. barbatus, and 4 hotspots for T. bifasciatus. The study on center-of-mass transfer revealed notable reductions in the habitual range of the three Tridentiger species with future climate change and no significant bipolar shifts in the center of mass. The ENM results indicated that T. trigonocephalus and T. barbatus exhibited the greatest ecological niche overlap with Schoener's D (D) and Hellinger-based I (I) values of 0.4719 and 0.7690, respectively. Both SDM and ENM results have suggested that T. trigonocephalus occupied a wider distribution and greater adaptability to future climate change. This study sought to measure the variations in the effects of global climate change on marine species in different habitats. Our study first found that intertidal species with specific life histories may be more resilient to environmental change.

Assessing five decades of garden bee studies

Urban garden spaces are potentially important habitats for bee conservation. Gardens can host diverse flora, which provide floral resources across foraging seasons for bee species. Recent reviews have focused on the impacts of cityscapes on urban bee assemblages in different green spaces. Urban gardens are distinct from other urban green spaces, and bee communities in urban spaces have been an increasing topic of study over the past few decades. We reviewed 28 urban garden bee studies spanning five decades and 14 countries to compile an original metadataset of bee species' functional traits to understand the conservation value of gardens, identify gaps in bee sampling efforts, and summarize the calls to action included by their authors. Studies of urban garden bees have documented between 674 (conservative count, excluding morphospecies) and 830 (liberal count, including morphospecies) bee species. Urban garden bee communities were taxonomically and functionally diverse, although bee species that were non-eusocial, ground-nesting, generalist foragers, and native were most common in garden habitats. The proportion of parasitic bee species and specialist foragers found in urban gardens was comparable to proportions for global bee taxa. This suggests that gardens contain the hosts and forage needed to support bees with specialized life history requirements, and thus represent high quality habitat for a subset of bee communities. Garden bee research was strongly biased toward the northern hemisphere, which signifies a large gap in our understanding of garden bee communities in other regions. The variety of, and non-standard sampling methods in garden bee research makes it difficult to directly compare results between studies. In addition, both intentional low taxonomic resolution and a lack of collaboration with taxonomists constrains our understanding of bee diversity. Our analyses highlight both successes of past urban garden bee studies, and areas of opportunity for future research as we move into a sixth decade of garden bee research.

奎章閣 書吏 金德亨의 삶과 문예 고찰

This paper examines the life, literature and art of Kim Deok-hyeong(金德亨) from Gyeongajeon in the late 18th century and early 19th century. In the meantime, there has been mention of his existence, which is excellent in flower painting, but his specific life history or literature such as poetry and calligraphy were not dealt with. Accordingly, in this paper, I tried to comprehensively examine his life and literature by examining various documents that mentioned him, such as 『Naegag-illyeog(내각일력)』, 『Jinhuisokgo(震彙續攷)』, 『Ihyanggyeonmunrok(里鄕見聞錄)』, etc.
 Kim Deok-hyeong’s name received upon reaching adulthood is Kangjung, his pen name is Samyangjae and Hwasanja, and is from the Gimhae Kim family. Kim Deok-hyeong performed the duties of Gakri(閣吏), the secretary of Kyujanggak, among Gyeongajeon, and the duties were passed on to his son Kim Shin-won(renamed Kim Ye-won) and his grandson Kim Geon-shik(金健植). In September 1780, he served as Byeongjo Seori(書吏), and in December 1781, he became Gakri(閣吏), a secretary at Kyujanggak, and served until 1795. He served as secretary at Kyujanggak for a total of 15 years, but as he has been associated with Kang Se-hwang(姜世晃), Shim Sa-jeong(沈師正), Heo Pil(許佖), Choi Buk(崔北), and Kim Hong-do(金弘道) since childhood, he had a chance to sharpen his eyesight. Thanks for this, even after becoming a Gakri, he displayed his special abilities in the field of literature and art. Through his poems such as 『Pungyosamseon』, we were able to get a glimpse of Kim Deok-hyeong's elegant spiritual world and poetic world, and through the records of Ma Seong-rin, who was the same Yeohangin, we confirmed his excellent calligraphy. Through the reviews of Yu Deuk-gong, Park Je-ga, and Yoon Haeng-im, he showed his painting skills, and he showed his special skills in painting rather than writing, and in painting flowers. The fact that he had no choice but to excel in flower painting was also due to his love for and exploration of real flowers. As a result, his teacher, Kang Se-hwang, regarded his flower paintings as treasures and kept them. Through the above research, the existence of Kim Deok-hyung as Yeohangin and the fact that he was a non-professional artist from Suri, apart from being a professional painter of painted books, have given us a glimpse into a part of Yeohang’s culture that promoted late Joseon Dynasty literature.

Stage-mediated priority effects and season lengths shape long-term competition dynamics.

The relative arrival time of species can affect their interactions and thus determine which species persist in a community. Although this phenomenon, called priority effect, is widespread in natural communities, it is unclear how it depends on the length of growing season. Using a seasonal stage-structured model, we show that differences in stages of interacting species could generate priority effects by altering the strength of stabilizing and equalizing coexistence mechanisms, changing outcomes between exclusion, coexistence and positive frequency dependence. However, these priority effects are strongest in systems with just one or a few generations per season and diminish in systems where many overlapping generations per season dilute the importance of stage-specific interactions. Our model reveals a novel link between the number of generations in a season and the consequences of priority effects, suggesting that consequences of phenological shifts driven by climate change should depend on specific life histories of organisms.

How do landscape and life history traits contribute to the threat context of Brazilian primates?

AbstractBrazilian primates differ regarding landscape characteristics within their ranges (e.g. habitat availability) and life‐history traits (e.g. body size). These landscape and life history attributes may be related to extinction risk. Here, we verified how such attributes correlate with primate threat categories. We considered 124 Brazilian primates based on the 2014 Brazilian list of threatened (Critically Endangered, Endangered and Vulnerable) and non‐threatened (Least Concern and Near Threatened) species. We then characterized their landscape (i.e. habitat availability, habitat loss and fragmentation, indigenous lands, roads, urban areas, deforestation arch) and life‐history attributes (i.e. body weight, gestation length and generation time), which together make up the threat context for each threat category. We compared threat categories to identify differences in such attributes, considering biome (Atlantic Forest, Amazon, Caatinga and Cerrado) as a factor and testing for phylogenetic effect. We investigated the attributes responsible for group characterization for specific threats and binary threatened/non‐threatened categories. We show that life history and landscape attributes differ in the biomes. However, only landscape features varied across biomes. In the Amazon, the threatened categories reached the highest level of habitat loss in the last 30 years, while in the Atlantic Forest, the landscape of threatened species had the highest proportions of roads and urban areas. Most threatened species landscapes in the Caatinga and Cerrado were highly fragmented. We found a positive link between human impacts and extinction risk in the Amazon. In the other biomes, anthropogenic landscape characteristics were associated with threatened and non‐threatened species. Threatened species tended to have large bodies and a slow life history, regardless of the biome. The more closely related the species, the more similar the traits. We suggest considering biomes and threat categories together with specific landscape and life history attributes to distinguish primate threat context for species conservation priority‐setting.

Metabarcoding analysis identifies high diversity of harmful algal bloom species in the coastal waters of the Beibu Gulf.

Harmful algal blooms (HABs) have occurred more frequently in recent years. In this study, to investigate their potential impact in the Beibu Gulf, short-read and long-read metabarcoding analyses were combined for annual marine phytoplankton community and HAB species identification. Short-read metabarcoding showed a high level of phytoplankton biodiversity in this area, with Dinophyceae dominating, especially Gymnodiniales. Multiple small phytoplankton, including Prymnesiophyceae and Prasinophyceae, were also identified, which complements the previous lack of identifying small phytoplankton and those unstable after fixation. Of the top 20 phytoplankton genera identified, 15 were HAB-forming genera, which accounted for 47.3%-71.5% of the relative abundance of phytoplankton. Based on long-read metabarcoding, a total of 147 OTUs (PID > 97%) belonging to phytoplankton were identified at the species level, including 118 species. Among them, 37 species belonged to HAB-forming species, and 98 species were reported for the first time in the Beibu Gulf. Contrasting the two metabarcoding approaches at the class level, they both showed a predominance of Dinophyceae, and both included high abundances of Bacillariophyceae, Prasinophyceae, and Prymnesiophyceae, but the relative contents of the classes varied. Notably, the results of the two metabarcoding approaches were quite different below the genus level. The high abundance and diversity of HAB species were probably due to their special life history and multiple nutritional modes. Annual HAB species variation revealed in this study provided a basis for evaluating their potential impact on aquaculture and even nuclear power plant safety in the Beibu Gulf.

Demographic history and genomic consequences of 10,000 generations of isolation in a wild mammal

Increased human activities caused the isolation of populations in many species-often associated with genetic depletion and negative fitness effects. The effects of isolation are predicted by theory, but long-term data from natural populations are scarce. We show, with full genome sequences, that common voles (Microtus arvalis) in the Orkney archipelago have remained genetically isolated from conspecifics in continental Europe since their introduction by humans over 5,000 years ago. Modern Orkney vole populations are genetically highly differentiated from continental conspecifics as a result of genetic drift processes. Colonization likely started on the biggest Orkney island and vole populations on smaller islands were gradually split off, without signs of secondary admixture. Despite having large modern population sizes, Orkney voles are genetically depauperate and successive introductions to smaller islands resulted in further reduction of genetic diversity. We detected high levels of fixation of predicted deleterious variation compared with continental populations, particularly on smaller islands, yet the fitness effects realized in nature are unknown. Simulations showed that predominantly mildly deleterious mutations were fixed in populations, while highly deleterious mutations were purged early in the history of the Orkney population. Relaxation of selection overall due to benign environmental conditions on the islands and the effects of soft selection may have contributed to the repeated, successful establishment of Orkney voles despite potential fitness loss. Furthermore, the specific life history of these small mammals, resulting in relatively large population sizes, has probably been important for their long-term persistence in full isolation.

Contrasts in riverscape patterns of intraspecific genetic variation in a diverse Neotropical fish community of high conservation value.

Spatial patterns of genetic variation compared across species provide information about the predictability of genetic diversity in natural populations, and areas requiring conservation measures. Due to their remarkable fish diversity, rivers in Neotropical regions are ideal systems to confront theory with observations and would benefit greatly from such approaches given their increasing vulnerability to anthropogenic pressures. We used SNP data from 18 fish species with contrasting life-history traits, co-sampled across 12 sites in the Maroni- a major river system from the Guiana Shield -, to compare patterns of intraspecific genetic variation and identify their underlying drivers. Analyses of covariance revealed a decrease in genetic diversity as distance from the river outlet increased for 5 of the 18 species, illustrating a pattern commonly observed in riverscapes for species with low-to-medium dispersal abilities. However, the mean within-site genetic diversity was lowest in the two easternmost tributaries of the Upper Maroni and around an urbanized location downstream, indicating the need to address the potential influence of local pressures in these areas, such as gold mining or fishing. Finally, the relative influence of isolation by stream distance, isolation by discontinuous river flow, and isolation by spatial heterogeneity in effective size on pairwise genetic differentiation varied across species. Species with similar dispersal and reproductive guilds did not necessarily display shared patterns of population structure. Increasing the knowledge of specific life history traits and ecological requirements of fish species in these remote areas should help further understand factors that influence their current patterns of genetic variation.

Evolution of relative brain size in dogs-no effects of selection for breed function, litter size, or longevity.

Domestication is a well-known example of the relaxation of environmentally based cognitive selection that leads to reductions in brain size. However, little is known about how brain size evolves after domestication and whether subsequent directional/artificial selection can compensate for domestication effects. The first animal to be domesticated was the dog, and recent directional breeding generated the extensive phenotypic variation among breeds we observe today. Here we use a novel endocranial dataset based on high-resolution CT scans to estimate brain size in 159 dog breeds and analyze how relative brain size varies across breeds in relation to functional selection, longevity, and litter size. In our analyses, we controlled for potential confounding factors such as common descent, gene flow, body size, and skull shape. We found that dogs have consistently smaller relative brain size than wolves supporting the domestication effect, but breeds that are more distantly related to wolves have relatively larger brains than breeds that are more closely related to wolves. Neither functional category, skull shape, longevity, nor litter size was associated with relative brain size, which implies that selection for performing specific tasks, morphology, and life history does not necessarily influence brain size evolution in domesticated species.

Diet composition, niche overlap and partitioning of five sympatric rhinolophid bats in Southwestern China during summer

Understanding trophic niche differentiation is critical for exploring interspecific competition and stable coexistence among morphologically similar sympatric species. Bats are an ideal model for studying trophic niche differentiation among species because of their high taxonomic and ecological diversities, as well as their special life history traits. Although many factors can affect bat trophic niches, few studies have combined multiple factors to investigate the influences on bat trophic niches. In this study, we analyzed the summer diet and potential influencing factors of five sympatric rhinolophid bats in southwestern China: Rhinolophus macrotis, Rhinolophus osgoodi, Rhinolophus ferrumequinum, Rhinolophus affinis, and Rhinolophus pusillus. All five species mainly fed on Lepidopteran and Dipteran insects, with a large trophic niche breadth for each species and a low degree of dietary overlap. With the exception of R. affinis and R. pusillus, significant differences in diet composition were detected among species, which indicated relatively low interspecific competition. Canonical correspondence analysis showed that both echolocation calls and body size significantly affected interspecific diet differentiation, while wing morphology and bite force had relatively weak effects. This study suggests that the combined effects of multiple factors may drive trophic niche differentiation among five rhinolophid bat species in the study area.

Assessing interspecific variation in life-history traits of three sympatric tropical mullets using age, growth and otolith allometry

Life history theory predicts that organisms optimize their life-history traits according to evolutionary context and environmental constraints. Sympatric estuarine-dependent fish are intriguing subjects for studying life-history variation, as their traits are molded by their complex habitat use and co-occurrence with ecologically similar species. In this study, we investigated life-history traits of three tropical mullet species (Mugil curema, M. liza and M. rubrioculus) using age, growth, and otolith allometry. Our results indicate that otolith allometric patterns are useful predictors of specific life history traits: the faster-growing species M. rubrioculus (K = 0.31) was characterized by earlier stanza changing points (SCPs), with 0.8 years of life. In contrast, the slower-growing species, M. liza (K = 0.21) was characterized by later changing points, 1.3 years of life. M. curema is intermediate (K = 0.25), with 0.95 years of life. The first SCP may register juvenile movements between estuarine and coastal habitats before the first year of life, and the second SCPs appear to reflect the migration to the sea and age at maturation. More generally, our study species exhibit fine-scale temporal differences in life cycle events that may be related to growth rates and body size that can be predicted by otolith allometry, as well as a gradient of interspecific divergences in life-history traits. These are likely to be driven by differences in their migratory behavior and habitat use that permit coexistence.

Impacts of river fragmentation on limiting individual dietary specialization of Amazonian predatory fish.

Individual dietary specialization is one of the factors that promotes variation in resource use at the individual level. Here we used stable isotope analysis of multiple tissues with different turnover rates to examine the degree of individual specialization in two sub-populations of the predator Cichla temensis inhabiting both fragmented and undammed rivers within the Uatumã River basin of the Amazon. Our results showed that the undammed river provides better conditions to promote individual dietary specialization than the fragmented river. This study contributes to the understanding of how specific life history characteristics of populations of generalist predators are impacted by fragmentation within megadiverse environments such as the Amazon basin.

Global biogeography of ant social parasites: Exploring patterns and mechanisms of an inverse latitudinal diversity gradient

AbstractAimOne of the most consistent global biogeographic patterns is the latitudinal diversity gradient where species richness peaks within the equatorial tropics and decreases towards the poles. Here, we explore the global biogeography of socially parasitic ant species, which comprises the most diverse group of social parasites in the Hymenoptera. We test the biogeographic hypothesis that ant social parasites are distributed along an inverse latitudinal diversity gradient (iLDG) by peaking in diversity outside of the equatorial tropics, which would contrast with the biogeographic pattern observed in free‐living, non‐parasitic ant species.LocationGlobal.TaxonAnts (Hymenoptera: Formicidae).MethodsWe assembled a comprehensive biogeographic dataset consisting of 6001 geographic distribution records for all 371 taxonomically described socially parasitic ant species. We used phylogenetic and taxonomic studies to estimate the number of independent evolutionary origins of ant social parasitism to directly compare species richness with the number of species representing independent evolutionary origins of social parasitism across a latitudinal gradient. In addition, we compared ant social parasite diversity across biogeographic regions using rarefaction to account for different sampling efforts. Finally, we tested for a correlation between latitude and the proportion of ant social parasite species within regional ant faunae.ResultsThe geographic distribution records and the inferred 91 independent evolutionary origins of socially parasitic life histories in ants show that both species richness and the number of species representing independent evolutionary origins of social parasitism peak in the northern hemisphere outside of the equatorial tropics. Based on rarefaction curves, northern latitude regions harbour the most ant social parasite species, but the diversity of independent evolutionary origins is not significantly different between northern and southern hemispheres. The proportion of ant social parasite species within regional faunae is tightly correlated with latitude only in the northern hemisphere.Main conclusionsThe iLDG of ant social parasites contrasts with the biogeographic pattern observed in free‐living, non‐parasitic ant species and appears to be driven by large species radiations as well as by the presence of specialized life histories exclusive to the northern hemisphere.