Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions

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  Distinct pathophysiological mechanisms of Heterometrus laoticus and Lychas mucronatus scorpion venoms on cardiovascular and renal functions Abstract Background:    Heterometrus laoticus and Lychas mucronatus are widely distributed in Southeast Asia, yet their pathophysiological effects of both venoms remain poorly characterized due to low human fatality rates. This study compared their venom compositions and acute cardiovascular and renal effects. Methods:   Anesthetized male New Zealand White rabbits were monitored for blood pressure (BP), heart rate (HR), and renal clearance following intravenous administration of crude venom (0.5 mg/kg). Venom components were identified via LC-MS/MS, and hematological/biochemical parameters were assessed. Results:    H. laoticus venom induced a rapid, transient hypotension ( p < 0.05), followed by a mild, prolonged hypotensive phase (up to 120 min). Conversely, L. mucronatus venom elicited a biphasic response: ...

Behavioural variation in the invasive cellar spider Pholcus manueli (Araneae: Pholcidae)

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Behavioural variation in the invasive cellar spider Pholcus manueli (Araneae: Pholcidae)

Abstract

Behaviours such as boldness and exploration are highly plastic and as such, we expect differences between populations, especially for invasive species. In particular, populations at the leading edge of an invasion front may display differences in these behaviours relative to long established core populations as they are often key to their dispersal and invasion success. Likewise, in species with sexual dimorphism, the importance of these behaviours to invasion success may differ for males and females. Here we report on an invasive cellar spider, Pholcus manueli (Araneae: Pholcidae), that is expanding westward across the United States. We investigated whether boldness in response to simulated predator cues (physical and airborne disturbances) and exploration of a novel environment varied across P. manueli’s invasive range and between males and females. We found significant differences in the reaction to the simulated predator cues, but not in exploration. Although there was variation between the leading edge and core, the greatest differences lay between males and females from core populations when exposed to a puff of air. We additionally investigated whether females would be less selective of a potential mate at the leading edge. We found marginal support for this and uncovered interesting details regarding P. manueli’s mating system, wherein smaller females were more likely to mate than large ones. Overall, we found boldness and mating behaviour differences between the leading edge and core, but our data suggests greater differences lay between the sexes.
Salazar, A. R., & Rypstra, A. L. (2025). Behavioural variation in the invasive cellar spider Pholcus manueli (Araneae: Pholcidae). Behavioural Processes, 105259. https://doi.org/10.1016/j.beproc.2025.105259