Venom Variation as a Window into the Ecology and Evolution of Snakes

Posted by
  Venom Variation as a Window into the Ecology and Evolution of Snakes Abstract Snake venoms are complex biochemical systems that function primarily in prey subjugation and defense, yet their composition varies extensively across individuals, populations, species, and environments. This variation provides a powerful framework for investigating ecological and evolutionary processes. Here, we offer a forward-looking synthesis of snake venom diversity that proposes new research directions and highlights how venom variation can illuminate eco-evolutionary dynamics across biological scales. We review evidence for ten key contexts in which venom variation arises, including within-population differences, sexual dimorphism, geographic structuring, ontogenetic shifts, seasonal changes, interspecific divergence, hybridization, convergent evolution, prey specificity, and venom resistance. Together, these processes demonstrate that venom phenotypes are shaped by interacting selective pressures...

Weathering the storm for love: Mate searching behaviour of wild males of the Sydney funnel-web spider (Atrax robustus)

Posted by

 

Weathering the storm for love: Mate searching behaviour of wild males of the Sydney funnel-web spider (Atrax robustus)

    Abstract

The risky business of mate-searching often leaves the actively searching sex facing threats and rapidly changing conditions. Yet, active mate-searching behaviour is rarely studied in invertebrates, and we have limited understanding of how mate-searching strategies have evolved to cope with risks posed by harsh weather. We investigated how mate-searching males move through their habitat and how their movement is affected by weather conditions in the Sydney funnel-web spider (Atrax robustus), one of the world's most venomous spiders. As is common in mygalomorphs spiders, females are functionally sessile, and are thought to spend their whole lives in a single burrow, whereas males must permanently abandon their burrows to mate during the breeding season. Nineteen male spiders were fitted with micro-radio transmitters and tracked during their mating seasons in 2020 (n = 2), 2021 (n = 8) and 2022 (n = 9) in Lane Cove National Park, in Sydney, Australia. Males moved at night, typically in a zig-zag pattern, and were found in new locations on approximately 50% of daily resighting's. Males often spent several days in a female's burrow, and some female burrows were visited by multiple males. When outside a female's burrow, males constructed and occupied temporary shelters ('temporacula'). Males were most likely to move and/or moved furthest when there was no rain, and on warm nights after cool days. Our findings suggest that mate-searching A. robustus males prefer to search for females in less risky conditions, revealing novel risk-minimizing strategies, especially in response to rainfall and temperature.


Weathering the storm for love: Mate searching behaviour of wild males of the Sydney funnel-web spider (Atrax robustus) Caitlin Nicole Creak, Hugo Muirhead, Russell Bonduriansky, Michael Kasumovic, Bruno Buzatto 

bioRxiv 2024.07.23.604707; doi: https://doi.org/10.1101/2024.07.23.604707