Royal Society Open Science最新文献

Snake venom is an ecologically relevant functional trait directly linked with a snake's fitness and survival, facilitating predation and defence. Snake venom variation occurs at all taxonomic levels, but the study at the intraspecific level is still in its early stages. The common adder (Vipera berus) exhibits considerable variation in colour phenotypes across its distribution range. Melanistic (fully black) individuals are the subject of myths and fairytales, and in German folklore such 'hell adders' are considered more toxic than their normally coloured conspecifics despite any formal investigation. Here, we provide the first comparative analysis of venoms from melanistic and normally coloured common adders. Specifically, we compared the venom profiles by sodium dodecylsulfate polyacrylamide gel electrophoresis and reversed-phase high-performance liquid chromatography and tested the venoms' protease, phospholipase A₂ and cytotoxic activities. Phospholipase A₂ activity was similar in both phenotypes, whereas general protease activity was higher in the melanistic venom, which was also more cytotoxic at two concentrations (6.25 and 12.5 µg ml^-1). These minor differences between the venoms of melanistic and normally coloured adders are unlikely to be of clinical relevance in the context of human envenomation. In light of our results, the claim that melanistic adders produce more toxic venom than their normally coloured conspecifics appears rooted entirely in folklore.

Density-dependent competition for food influences the foraging behaviour and demography of colonial animals, but how this influence varies across a species' latitudinal range is poorly understood. Here we used satellite tracking from 21 Northern Gannet Morus bassanus colonies (39% of colonies worldwide, supporting 73% of the global population) during chick-rearing to test how foraging trip characteristics (distance and duration) covary with colony size (138-60 953 breeding pairs) and latitude across 89% of their latitudinal range (46.81-71.23° N). Tracking data for 1118 individuals showed that foraging trip duration and maximum distance both increased with square-root colony size. Foraging effort also varied between years for the same colony, consistent with a link to environmental variability. Trip duration and maximum distance also decreased with latitude, after controlling for colony size. Our results are consistent with density-dependent reduction in prey availability influencing colony size and reveal reduced competition at the poleward range margin. This provides a mechanism for rapid population growth at northern colonies and, therefore, a poleward shift in response to environmental change. Further work is required to understand when and how colonial animals deplete nearby prey, along with the positive and negative effects of social foraging behaviour.

Gender bias has been documented in many aspects of Science, Technology, Engineering and Mathematics (STEM) careers, yet efforts to identify the underlying causes have been inconclusive. To what extent do cognitive biases, including unequal receptiveness in women and men to evidence of gender bias, contribute to gender bias in STEM? We investigated receptiveness in a STEM context among members of the general public, by undertaking a high-powered (total N = 1171) replication, including three experiments (2 pre-registered) of the prominent study by Handley et al. [22]. It was hypothesized that men would evaluate a research summary reporting evidence of gender bias less favourably than women but that there would be no difference between men and women's evaluations of research summaries unrelated to gender bias. The results revealed no effect of the assessor's gender on receptiveness to scientific evidence of gender bias. The different results compared to those of Handley et al. [22] suggest either that the gender bias they detected has diminished in the past decade or that their findings are a false positive. The present research adds to a growing body of evidence suggesting that some influential studies on cognitive 'markers' of gender bias warrant re-examination.

We investigate the collective dynamics of multi-agent systems in two- and three-dimensional environments generated by minimizing discrete Ricci curvature with local and non-local interaction neighbourhoods. We find that even a single effective topological neighbour suffices for significant order in a system with non-local topological interactions. We also explore topological information flow patterns and clustering dynamics using Hodge spectral entropy and mean Forman-Ricci curvature.

The global decline of shark populations, largely driven by overfishing to supply the shark fin trade, poses a significant threat to marine ecosystems. Southeast Asia, and particularly Singapore, is a key hub for the transit and trade of shark fins that contribute to the exploitation of these apex predators. Through the use of DNA barcoding techniques, this study aimed to determine what species of shark are involved in the Singapore shark fin trade. Fins were collected from markets, dried goods shops and traditional Chinese medicine halls throughout Singapore. In total, DNA was extracted from 684 fins collected in January 2024 and PCR amplification targeted a fragment of the mitochondrial COI gene for species identification. Results revealed fins from 24 species across 16 genera, with 19 species listed on CITES Appendices II, and 16 listed as threatened on the IUCN Red List (critically endangered = 2, endangered = 4, vulnerable = 10). The top five most frequently identified species were Carcharhinus falciformis, Galeorhinus galeus, Rhizoprionodon oligolinx, Sphyrna lewini and Rhizoprionodon acutus. Of these, four are listed on CITES Appendix II and four are listed as threatened on the IUCN Red List.

Stigmergy, the indirect communication between agents of a swarm through dynamic environmental modifications, is a fundamental self-organization mechanism of animal swarms. Engineers have drawn inspiration from stigmergy to establish strategies for the coordination of swarms of robots and of mixed societies of robots and animals. Currently, all models of stigmergy are algorithmic, in the form of behavioural rules implemented at an individual level. A critical challenge for the understanding of stigmergic behaviour and translation of stigmergy to engineering is the lack of a holistic approach to determine which modifications of the environment are necessary to achieve desired behaviours for the swarm. Here, we propose a mathematical framework that rigorously describes the relationship between environmental modifications and swarm behaviour. Building on recent strides in continuification techniques, we model the swarm and environmental modifications as continua. This approach allows us to design the environmental modifications required for the swarm to behave as desired. Through analytical derivations and numerical simulations of one- and two-dimensional examples, we show that our framework yields the distribution of traces required to achieve a desired formation. Such an approach provides an adaptable framework for different implementation platforms, from robotic swarms to mixed societies of robots and animals.

Paranormal beliefs encompass a wide variety of phenomena, including the existence of supernatural entities such as ghosts and witches, as well as extraordinary human abilities such as telepathy and clairvoyance. In the current study, we used a nationally representative sample ( $N=2534$ ) to investigate the presence and correlates of paranormal beliefs among the secular Dutch population. The results indicated that most single paranormal phenomena (e.g. belief in clairvoyance) are endorsed by 10-20% of Dutch respondents; however, 55.6% of respondents qualify as paranormal believers based on the preregistered criterion that they believe in at least one phenomenon with considerable certainty. In addition, we invited four analysis teams with different methodological expertise to assess the structure of paranormal beliefs using traditional factor analysis, network analysis, Bayesian network analysis and latent class analysis (LCA). The teams' analyses indicated adequate fit of a four-factor structure reported in a 1985 study, but also emphasized different conclusions across techniques; network analyses showed evidence against strong connectedness within most clusters, and suggested a five-cluster structure. The application of various analytic techniques painted a nuanced picture of paranormal beliefs and believers in The Netherlands and suggests that despite increased secularization, subgroups of the general population still believe in paranormal phenomena.

Temperature seasonality plays a pivotal role in shaping the thermal biology of ectotherms. However, we still have a limited understanding of how ectotherms maintain thermal balance in the face of varying temperatures, especially in fossorial species. Due to thermal buffering underground, thermal ecology theory predicts relaxed selection pressure over thermoregulation in fossorial ectotherms. As a result, fossorial ectotherms typically show low thermoregulatory precision and low evidence of thermotactic behaviours in laboratory thermal gradients. Here, we evaluated how temperature selection (T _sel) and associated behaviours differed between seasons in a fossorial amphibian, the spotted salamander (Ambystoma maculatum). By comparing thermoregulatory parameters between the active and overwintering seasons, we show that A. maculatum engages in active behavioural thermoregulation despite being fossorial. In both seasons, T _sel was consistently offset higher than acclimatization temperatures. Thermoregulation differed between seasons, with salamanders having higher T _sel and showing greater evidence of thermophilic behaviours in the active compared with the overwintering season. Additionally, our work lends support to experimental assumptions commonly made but seldom tested in thermal biology studies. Ultimately, our study demonstrates that the combination of careful behavioural and thermal biology measurements is a necessary step to better understand the mechanisms that underlie body temperature control in amphibians.