摘要: In social groups, competition for individual advantage is balanced with cooperation, for the collective benefit. Selection against aggression has favored cooperation and non-aggressive competitive strategies. Because social play is a behavioral system that fluctuates between cooperation and competition, selection against aggression might have especially influenced this behavior. African savannah elephants (Loxodonta africana) are a low aggressive species, therefore suitable to investigate this aspect. We collected all occurrences observational audio-video data on social play, aggression/threats, and affiliation on an African elephant colony housed in a 25-ha open space at Parque de la Naturaleza de Cabarceno (Cantabria, Spain) and composed of 4 family groups (3 immature males, 3 immature females, and 7 adult females) and 2 adult males. Anticipating the influence of reduced aggression, we found that social play decreased with age, persisting in adults, and that it was highest in males. Social play was associated with affiliation (informing cooperation). Indeed, individuals that were central in the social play network were also central in the affiliation network. For immature subjects, we found a correlation between social play and affiliation sociomatrices. However, such correlation was absent in adults and social play mostly occurred between families. Despite the limitations related to dealing with a small captive group, this study largely supports the idea that the features of social play in African savannah elephants may be related to low aggression. This investigation hints toward a non-purely cooperative use of play, possibly as a non-aggressive interaction that accommodates different levels of cooperation and competition.

摘要: Group living may engender conflict over food, reproduction, or other resources and individuals must be able to manage conflict for social groups to persist. Submission signals are an adaptation for establishing and maintaining social hierarchy position, allowing a subordinate individual to avoid protracted and costly aggressive interactions with dominant individuals. In the daffodil cichlid fish (Neolamprologus pulcher), subordinates may use submission signals to resolve conflicts with dominant individuals and maintain their social status within the group. The complexity of the physical environment may affect the value of submission signals compared with fleeing or avoidance, which may require certain physical features such as shelters to be effective. We investigated how the ecological context affected the expression of submission in subordinate daffodil cichlids by examining their behavior under different arrangements of the physical environment within their territories. We altered the number of shelters provided to daffodil cichlid groups and compared the interactions between dominant and subordinate individuals under each shelter condition by scoring the social and cooperative behaviors of the group members. We found that behaviors of group members were modulated by the environment: subordinates displayed fewer submission and fleeing behaviors in more structurally complex environments and dominants were more aggressive to subordinates when more shelters were present. Our results help to elucidate the role of the physical environment in the modulation of social interactions in group-living animals and may have implications for the welfare of captively housed social cichlid groups.

摘要: The present review provides a compilation of the published data on the ecology and social behavior of tamarisk gerbils. Both field studies and direct observations under semi-natural conditions provide evidence that the tamarisk gerbil is a nocturnal herbivorous rodent that lives in highly seasonal habitats and displays seasonal fluctuations in reproduction and spatial organization. A typical feature of the tamarisk gerbils' spatial organization is higher mobility of males during the breeding season (as compared with the nonbreeding period) and formation of temporary aggregations of males competing for access to receptive females; the composition of these aggregations was variable and depended on the reproductive condition of the females. Females tend to occupy exclusive home ranges irrespective of their reproductive condition. The mating system of the species can be defined as scramble competition polygyny with some features of polygynandry and promiscuity. The tamarisk gerbil has distinct features of a solitary species and its social structure is primarily based on aggressive interactions or mutual avoidance of conspecifics resulting in a dominance hierarchy among males and site-dependent dominance among females during the breeding season. By the end of the breeding season, males become less mobile and occupy nearly exclusive home ranges, consistent with solitary living. The main features of the spatial and social organization of this species, which distinguish it from other solitary rodents, are the higher mobility of males and the formation of temporary multimale-multifemale aggregations during the breeding season. Overall, the data presented expand our understanding of socioecology of gerbils.

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摘要: Epidermal growth factor receptor (EGFR) is one of the most important tyrosine kinase receptor families, which plays a pivotal role in cell signaling transduction and physiological processes. Studies on the EGFR gene in humans and other species have demonstrated its pivotal role in regulating the sodium ion balance and mediating sodium and water reabsorption in the kidney's proximal tubules. However, the impact of EGFR gene in how the Yarkand hare (Lepus yarkandensis) adapts to extreme environmental habitat remains unclear. The Yarkand hare is a desert-dwelling animal with multiple adaptations to cope with drought. Given the important physiological function of EGFR gene, we strived to understand its role in arid environment and explore the molecular mechanism of drought tolerance in the Yarkand hare. We first performed segmental cloning of the CDS of the Yarkand hare EGFR gene. Then, we constructed the phylogenetic tree of the Yarkand hare's EGFR gene and compared it with that of other species. The results showed that the Yarkand hare was most closely related to the Tolai hare (Lepus tolai). Through quantitative reverse transcription polymerase chain reaction (RT-qPCR), we discovered that EGFR expression in the kidneys of the Yarkand hare was higher than in the allopatric Tolai hare from non-arid areas. Therefore, we hypothesized that EGFR gene overexpression in the kidney of the Yarkand hare may play a crucial role in drought adaptability. Subsequently, we inserted CDS of EGFR gene into a pcDNA3.1-EGFP expression vector to construct recombinant plasmid, which was transfected into HeLa cells and overexpressed. RT-qPCR demonstrated a notable and statistically significant increase in EGFR mRNA expression and western blot proved stable expression of this protein in HeLa cells. Through cell experiments, EGFR gene overexpression markedly enhanced the survival of Hela cells subjected to NaCl, H2O2, and heat stresses, increased superoxide dismutase activity, and decreased malondialdehyde content. In conclusion, these findings preliminarily suggest that EGFR might help the Yarkand hare adapt to extreme environmental conditions. EGFR manipulation in vivo could be a promising strategy to enhance the resilience of animals to extreme conditions.

摘要: Sexual selection is thought to play a major role in the evolution of color due to the correlation between a signaler's physiological state and the displayed color. As such, researchers often investigate how color correlates to the quality of the signaler. However, research on the relationship between color and individual quality is often taxonomically limited and researchers typically investigate how color phenotypes relate to one index of quality, such as a linear measure of body size. Here, we investigated the relationship among body size, claw size, claw muscle mass, lipid content, and the color of the claw in male fiddler crabs (Leptuca uruguayensis) which wield an exaggerated claw that varies in color from brown to red. We hypothesized that if the color was correlated to one or more indices of male quality, the color displayed on the claws of male L. uruguayensis could be under sexual selection. We found L. uruguayensis claw color varies substantially among the individuals we photographed. However, we did not find a correlation between claw color and indices of quality; neither brightness nor hue correlated to the indices of quality we measured. Our findings suggest that claw color in L. uruguayensis is unlikely to have evolved to signal quality, but may instead function as a species identity or as a non-indicator sexual signal.

摘要: We are far from knowing all species living on the planet. Understanding biodiversity is demanding and requires time and expertise. Most groups are understudied given problems of identifying and delimiting species. DNA barcoding emerged to overcome some of the difficulties in identifying species. Its limitations derive from incomplete taxonomic knowledge and the lack of comprehensive DNA barcode libraries for so many taxonomic groups. Here, we evaluate how useful barcoding is for identifying arthropods from highly diverse leaf litter communities in the southern Appalachian Mountains (USA). We used 3 reference databases and several automated classification methods on a data set including several arthropod groups. Acari, Araneae, Collembola, Coleoptera, Diptera, and Hymenoptera were well represented, showing different performances across methods and databases. Spiders performed the best, with correct identification rates to species and genus levels of similar to 50% across databases. Springtails performed poorly, no barcodes were identified to species or genus. Other groups showed poor to mediocre performance, from around 3% (mites) to 20% (beetles) correctly identified barcodes to species, but also with some false identifications. In general, BOLD-based identification offered the best identification results but, in all cases except spiders, performance is poor, with less than a fifth of specimens correctly identified to genus or species. Our results indicate that the soil arthropod fauna is still insufficiently documented, with many species unrepresented in DNA barcode libraries. More effort toward integrative taxonomic characterization is needed to complete our reference libraries before we can rely on DNA barcoding as a universally applicable identification method.

摘要: The study of temperament and behavioral syndromes in insects is still in its early stage, and research conducted to date has mainly focused on locomotor activity and thanatosis. Dung beetles have been the subject of extensive behavioral studies; however, very few studies have addressed the expression of temperament. Those doing so only looked at subsocial and sexual horn dimorphic species, suggesting subsociality and/or sexual horn-dimorphism as possible facilitators of temperament expression. To test this assumption, we conducted a temperament study in a hornless, non-subsocial species, namely Geotrupes mutator (Marsham, 1802). We set up laboratory tests to evaluate 3 behaviors (activity, thanatosis, and distress calls) through the measurement of 7 distinct behavioral traits (3 activity-, 1 thanatosis-, and 3 call-related traits). We found high levels of individual repeatability in all activity- and thanatosis-related traits. We also identified behavioral differences between individuals, which may reflect differences in temperament. Statistical analyses revealed a negative correlation between activity and thanatosis. These results show that the temperament and behavioral syndromes related to activity and thanatosis may also be expressed in dung beetle species that are neither subsocial nor sexual horn dimorphic. By contrast, we only found one of 3 sound-related traits tested (frequency) to be clearly repeatable. Males and females presented a different structure of the stridulatory apparatus, suggesting that morphology may affect the frequency of sounds emitted.These results indicate that certain sound traits might not be good descriptors of individual temperament revealing the need for future research addressing the role of bioacoustics.

摘要: In the current research, we investigated the impact of gradually increasing inbreeding on the life span and reproductive rate of yellow steppe lemmings, Eolagurus luteus, that reproduced in the Moscow Zoo. The focal captive colony existed from 2017 to 2021. The studied animals belonged to the second to tenth generations. The founders of the colony were 5 females and 5 males originating from 3 females and 4 males livetrapped in the Zaisan basin (Kazakhstan). The degree of their descendant relatedness progressively increased. The animals intended to be used for reproduction were distributed to pairs with unfamiliar partners. We constructed the pedigree of 177 individuals and calculated their inbreeding coefficients. This parameter varied from 0 to 0.29, and the maximum values were registered in the lemmings of the seventh to tenth generations. We measured the life span of 61 individuals and used information about the reproduction or its absence in 45 pairs. A substantial decline in individual life span and reproductive parameters in the breeding pairs, along with a progressive increase in the inbreeding coefficients, was registered. The number of delivered litters, born pups, and young lived up to the age of puberty significantly depended on the level of mother inbreeding. The noticeable traits of inbreeding depression in the colony appeared in 2019-2020 when the offspring inbreeding coefficients reached approximately 0.2. Therefore, we assume that if the E. luteus population originates from a relatively small number of noninbred and unfamiliar individuals, then successful reproduction without significant inbreeding depression will continue for several generations of offspring.

摘要: Biological invasions are a major driver of global biodiversity loss, impacting endemic species, ecosystems, and economies. Although the influence of life history traits on invasive success is well-established, the role of behavior in the invasive potential of animals is less studied. The common coqu & iacute; frog, Eleutherodactylus coqui, is a highly successful invader in Hawai'i. We build on previous research characterizing changes in physiology and morphology to explore behavioral variation across the invasive range of coqu & iacute; in Hawai'i. Coqu & iacute; have expanded both outward and upward from their initial introduction site, and-by comparing frogs from different densities and elevations-we specifically asked how the physiological challenges of high-elevation living interact with the competitive challenge of high-densities at population centers. To investigate whether differences in the field represent local adaptation or behavioral plasticity, we additionally evaluated behavior following acclimation to a shared laboratory environment. Although we identified only subtle behavioral variation among populations in the field, we found that individuals from all populations became less bold, active, and exploratory in the laboratory, converging on a similar behavioral phenotype. Alongside previous work, our results suggest that coqu & iacute; adjust their behavior to local environmental conditions across their invasive range and that behavioral flexibility may contribute to invasive success.