Integrative zoology最新文献

Social hierarchy is a fundamental aspect of social behavior in animals, influencing individual health and well-being. This study investigated the role of serotonin (5-HT) neurons in the dorsal raphe (DR) nucleus and their projections to the central amygdala (CeA) in regulating social dominance in male mice. We first observed elevated c-Fos expression in 5-HT neurons of subordinate mice, indicating heightened neuronal activity during social competition. Using chemogenetic approaches, we found that activation of DR 5-HT neurons and DR^5-HT-CeA projections significantly reduced the social rank of dominant individuals, while inhibition had negligible effects on the subordinates. Additionally, activation of the DR^5-HT-CeA circuit induced anxiety-like behaviors in dominant mice, as evidenced by reduced exploration in the open-field test. Pharmacological blockade of 5-HT1A receptors in the CeA reversed the effects of chemogenetic activation, highlighting the involvement of 5-HT1A receptors in this process. These findings underscore the critical role of the DR^5-HT-CeA circuit in modulating social dominance and suggest that 5-HT1A receptors in the CeA play a pivotal regulatory role. Overall, the current study provides new insights into the neural mechanisms underlying social hierarchy, which is closely related to our health and welfare.

Bird parasites belonging to the genus Plasmodium (Haemosporida: Plasmodiidae) are found worldwide, with over 50 described species categorized into five subgenera. The subgenus Novyella comprises 22 morphologically identified species, of which 59% are genetically associated with at least one haplotype. In the Americas, only three morphospecies have their microscopic characteristics linked to a molecular signature. In this study, we described a new species of Plasmodium (Novyella) infecting a white-shouldered fire-eye (Pyriglena leucoptera) in Brazil. Molecular analysis reveals that the new species, associated with the lineage PYLEU01, is closely genetically related to Plasmodium (Novyella) homopolare, exhibiting a genetic divergence of 4.18%. However, it differs from P. homopolare due to the presence of many mature amoeboid trophozoites and some young meronts located laterally in relation to the erythrocyte nuclei and the smaller average number of merozoites in mature erythrocytic meronts. Morphology of blood stages of new species is most similar to Plasmodium vaughani and Plasmodium rouxi, but is different from these parasites due to the presence of predominantly 4 merozoites in mature erythrocytic meronts (not characteristic of P. vaughani) and the presence of 5–6 merozoites in some mature erythrocytic meronts (not characteristic of P. rouxi). Our integrative analyses reveal that the newly described species represents a distinct Plasmodium parasite from other Novyella morphospecies.

The greater horseshoe bat is a widely distributed cave-dwelling Palaearctic species that forms large colonies in its core distribution areas. Thanks to its size and diverse diet, it plays a crucial role as an insectivorous predator, of utmost importance in maintaining the balance of the ecosystem. Despite being extensively studied in the 20th century, its trophic ecology remains incomplete, as most studies have primarily focused on the species' northern distribution and have relied solely on morphological analyses of fecal remains. Thus, using metabarcoding methods, we analyzed the seasonal dietary changes of three maternity colonies in the Northern Iberian Peninsula, a core area of the bat's distribution range, across various landscapes, levels of urbanization, and climates. We identified significant spatial and temporal differences in diet, particularly noting a stronger reliance on riparian habitats in Mediterranean areas. The species exhibits great ecological adaptability with strong plasticity in prey source habitats, shifting preferences among forests, riparian habitats, shrubs, and grasslands. Our results emphasize the importance of preserving these habitats for conservation management purposes.

Environmental factors, including climatic and habitat conditions, not only critically sustain ecosystem functioning and community stability but also serve as key determinants of species distributions. Research on the instant effects of environmental factors impacts remains limited. Although traditional methods, such as species distribution model, are commonly applied to assess environmental effects, they frequently overlook interspecific interactions that may determine distribution patterns. In this study, we employed a joint species distribution model and a generalized additive model to analyze the lagged responses of 2022-2023 geographic distribution patterns to historical habitat conditions (2001-2019) in four widespread high-elevation ungulates (Equus kiang, Pantholops hodgsonii, Procapra picticaudata, and Bos mutus) on the Tibetan Plateau, defining this delayed response of animal distributions to environmental changes as the distribution lag effect (DLE). Our analysis revealed that while climate strongly influenced species distributions, habitat change drove most observed delays in distribution responses. In terms of community ecology, dispersed communities exhibited shorter time lags than concentrated groups. Analyses of lag duration revealed a 5-6-year DLE in high-altitude ungulate distributions. Our results provide valuable insights into sustainable alpine steppe management by highlighting the importance of maintaining habitat quality and mitigating resource competition over time. Furthermore, it offers guidance for the long-term conservation of high-altitude ungulate species.

The evolution of ZP (zona pellucida) genes in fish involves both gene expansion and expression organ transition. However, it is unclear when the expansion and transition occurred. Furthermore, it is also unclear whether there is a correlation between ZP gene expansion and expression organ transition. In this study, we identified all ZPs from 15 representative species in Cyclostomata and Neopterygii, and analyzed their expression in available transcriptome data in 8 species. The results showed that the expansion of ZP genes restricted to ZPB1 and ZPC1 first appeared in lamprey and was retained in bowfin and basal teleosts. The expanded ZP genes were highly expressed in teleosts, with ZPB1(a) (7-17 duplicates) and ZPC1(a) (8-32 duplicates), accounting for 82%-92% of the total ZP gene FPKM. The expression organ transition of highly expressed ZP genes occurred in the ancestor of Euteleostei, between Denticipitoidei and Clupeoidei in Clupeiformes. After the transition, only a few copies of ZPB1 and ZPC1 were retained (verified in another 20 species of the Euteleostei), and only ZPB1a and ZPC1aa were expressed in the liver (accounting for 64%-95% of the total ZP gene FPKM) in advanced teleosts. The N-terminus of expanded ZPB1(a) or ZPC1(a) and liver-expressed ZPB1a contains repeated units or low-complexity regions to form helical structures to ensure more elastic egg membranes for better protection of embryos. Taken together, our results demonstrate that teleosts evolved two different strategies to ensure sufficient ZP synthesis: genome expansion of ZPB1(a) and ZPC1(a) in basal species or liver-expression of ZPB1a and ZPC1aa in advanced species.

Sexual cannibalism, a behavioral syndrome where one mating partner consumes the other before, during, or after copulation, is particularly widespread among spiders and often exemplifies sexual conflict. Female sexual cannibalism has driven the evolution of numerous male counter-adaptations. Here we review sexual cannibalism in spiders, evaluate five broad hypotheses explaining its evolution, and provide possible explanations for numerous male reproductive strategies associated with this behavior. These male strategies include mating with immature females, opportunistic mating with molting or feeding females, coercive mating, nuptial gifts, inducing female quiescence, thanatosis, mate binding, sperm transfer adjustments, catapulting, and remote copulation. We emphasize the importance of clearly defining these behaviors and advocate for greater experimental repeatability in future experimental and comparative research. The evolutionary dynamics of these strategies are discussed within the frameworks of sexual conflict, sexually antagonistic coevolution, sperm competition, and cryptic female choice. We call for future research to expand taxonomic sampling, standardize methodologies, integrate field-based observations/experiments, and quantify the costs and benefits for each sex. Such efforts are essential to contextualize sexual cannibalism within broader ecological and evolutionary paradigms.

Avian chronic hemoparasite infections occur commonly in wild birds, causing adverse effects on host fitness and breeding success. However, the potential impact of such infections on the incubation behavior has been scarcely experimentally studied. We reduced the infection of hemoparasites in wild-breeding female pied flycatchers (Ficedula hypoleuca) through medication with primaquine to test the possible effects on incubation patterns compared with non-medicated control females. As predicted, medicated females significantly reduced their parasite infection compared to control females. This had a direct significant effect on the female behavior, as medicated females were able to have longer incubation sessions, while control females reduced the time devoted to each incubation session. In addition, females from both treatment groups spent less time incubating as incubation progressed, with control females showing a greater reduction. In contrast, the average length of recess sessions did not vary across treatment groups. Moreover, incubation sessions were more frequently interrupted when clutches were smaller. However, these changes had no apparent effects on immediate fitness. To our knowledge, this is the first study showing changes in individual incubation patterns in response to parasites in a wild-bird population, adding to previous studies showing that blood parasites have detrimental effects on bird reproductive success.

Food sharing is very common in the animal kingdom. Despite extensive research, the mechanisms underlying food sharing remain debated. Moreover, the majority of studies on food sharing in non-human animals have been conducted under controlled environments. The natural behavioral characteristics and ecological factors influencing the natural selection of food sharing are still not well understood. In this study, we introduce a method to examine food-sharing behaviors in wild birds within their natural habitat. Using two types of feeders-one permitting food sharing with conspecifics and the other providing exclusive access to food-along with infrared cameras to record feeder-triggering events, we found that azure-winged magpies did not exhibit proactive food-sharing behaviors. However, they did exhibit passive food-sharing behaviors under conditions of low food availability. Consistent with the harassment-avoidance hypothesis, the birds prioritized the sharing feeders to decrease harassment from food snatching when food was limited. These findings suggest that food sharing is likely shaped into a passive behavioral pattern under limited resources conditions, which induce conflicts within social groups. This context-dependent strategy may effectively reduce harassment costs, optimize individual access to resources to maximize individual benefits, and potentially enhance the survival of other group members.

Amphibians are the vertebrates most sensitive to environmental change, in part due to their relatively thin skin. As such, research seeks to better understand variation in amphibian skin traits. One source of variation that is poorly understood is seasonal variation in amphibian skin thickness that has been reported in two anurans and one caudatan. It is currently unknown how widespread this trait is among amphibians, or the pattern it follows throughout the year, because existing studies have only sampled specimens at two or three times of the year. We use museum specimens of three sympatric anurans from the northern United States to test for the presence of seasonal changes in skin thickness and which functional hypothesis best explains the pattern: either an environmental function/response or an intrinsic life history-related pattern. Seasonal changes in skin thickness were detected in all skin regions and layers measured in the American bullfrog (Lithobates catesbeianus), in some of the skin layers of the northern leopard frog (L. pipiens), but such changes were not detected in spring peepers (Pseudacris crucifer). The results favored the life history functional hypothesis, where skin is thinnest after brumation, increasing in thickness throughout the year ahead of hibernation. The differences between skin thickness variables between early- and late-year specimens of L. catesbeianus were as high as 40%, indicating that this source of variation has the potential to skew the results of morphological studies of amphibian skin thickness if not controlled for.