Current Zoology最新文献

Urban wetlands are considered as "habitat islands" within the urban matrix that contribute to species conservation. Waterbirds are sensitive pollution indicators in terrestrial and aquatic ecosystems, and their diversity in urban wetlands reflects the response of wildlife to urbanization. However, very few studies have investigated seasonal differences in the multidimensional diversity of waterbirds in urbanized landscapes. In this study, we analyzed various wetland parameters that could potentially affect the seasonal variations in multidimensional diversity of waterbirds in Nanjing, China. We surveyed waterbirds in 29 urban wetlands using the point count method during breeding and non-breeding seasons from November 2022 to June 2023. We then employed multiple linear regressions and information-theoretic approaches to investigate the impact of wetland characteristics on waterbird diversity. We found that water body area and buffer zone connectivity consistently emerged as positive factors affecting waterbird taxonomic and phylogenetic diversity across seasons. Conversely, the urbanization synthetic index was negatively correlated with waterbird diversity only during the breeding season. Regarding functional diversity, we found that the positive correlation between buffer zone connectivity and waterbird diversity was specific to the breeding season. Therefore, for effective conservation of waterbird diversity in our system, wetland planning should prioritize expanding wetland water body areas, enhancing wetland connectivity, minimizing human disturbance during the breeding season, and implementing ecological restoration measures in urbanized wetlands to mitigate adverse effects of urbanization.

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.

Global climate change has caused range shifts and population declines in various species. However, causal evidence from manipulative studies, particularly for vertebrates, remains scarce. Prolonged temperature increases, a direct consequence of climate change, pose significant challenges to species adaptation and survival. We examined the effects of prolonged temperature increases on reproduction, physiology, and behavior adaption in the greater long-tailed hamster using semi-natural enclosures where temperature was manipulated via plastic roofs and windows, creating a greenhouse effect without affecting rainfall. We analyzed data using grouped enclosures (low temperature, LT; high temperature, HT), which showed that prolonged temperature increases led to reduced reproductivity per capita during the breeding season. In addition, prolonged temperature increases reduced night-time activity in founder hamsters during overwintering, increased burrow depth during the breeding season, and raised testicular weights in founder males during the overwintering season. Our study provides experimental evidence that prolonged temperature increases negatively impact population growth of greater long-tailed hamsters by inducing temperature stress and impairing reproductive performance, highlighting the need to address heat stress in wildlife management under climate warming.

[This corrects the article DOI: 10.1093/cz/zoae053.].

Avian malaria, caused by parasites of the genus Plasmodium, is prevalent among wild bird populations worldwide and can have significant impact on avian health and populations. With the rise in global temperatures due to climate change, concerns have arisen about the spread of southern malaria species, that potentially can affect previously unexposed bird populations. We studied juvenile siskins infected with two distinct malaria parasites: Plasmodium relictum (SGS1 lineage) and P. ashfordi (GRW2 lineage). While the former is common in the Northern Palearctic, the latter is primarily found in Central and Southern Africa. We assessed the impact of these infections on siskins' physiological well-being using resting metabolic rate (RMR) and interleukin-6 (IL-6) levels. Changes in RMR reflect the energetic cost of disease, while IL-6 serves as a one of the inflammatory cytokines in the innate immune system's response to infection. Our experimental findings reveal distinct outcomes during the acute phase of SGS1 and GRW2 infections. Infection with SGS1 was marked by reduced RMR and IL-6 levels in siskins. A similar IL-6 pattern was observed in the GRW2 group initially, though it was not sustained. Additionally, GRW2-infected siskins showed distinct RMR dynamics compared to SGS1-infected birds. Our study did not conclusively demonstrate that tropical malaria has more severe effects on siskins. However, similarities with previous studies with SGS1 infected birds and variations in disease progression between the two experimental groups underscore the complexity of host-parasite interactions in avian malaria infections.

Sounds, like screams, which contain acoustic nonlinearities can elicit fearful, emotional responses in animals. In humans, screams activate the amygdala and are perceived as less positive than spoken words. We conducted a playback experiment to see if two skink species (one of which is known to negatively respond to nonlinearities) responded differently to human spoken words and screams. We broadcast short phrases of humans screaming, humans speaking, or a control, a novel bird song. We studied the immediate response by quantifying the change in rates of vigilance and locomotion. We also studied a slightly delayed response in risk assessments by measuring skink flight initiation distance after the playback. Furthermore, we conducted experiments in nonresidential and residential areas to understand how human exposure may influence human discrimination and potentially valence perception (i.e., how sound is emotionally perceived). Blue-tailed skinks (Emoia impar) altered both immediate behavior and their delayed risk assessment when human screaming was broadcast, but only in residential areas. By contrast, white-bellied copper-striped skinks (Emoia cyanura) only altered their delayed risk assessment when human stimuli were broadcast in residential areas. These results indicate that skinks respond differently to human vocalizations depending on their exposure to humans and based on species-specific behaviors. Our results suggest the importance of considering many variables when studying cognition in nature. The amount of human exposure and the acoustic cues contained in auditory stimuli may affect an individual's risk assessment and behavioral responses.