Mate-seeking behaviour of wild male Sydney funnel-web spiders (Atrax robustus)

The risky act of mate-hunting often exposes the actively mate-seeking sex to threats and rapidly changing conditions. However, active mate-hunting behavior in invertebrates has been rarely studied, and there is limited understanding of how mate-hunting strategies have evolved to cope with the risks posed by severe weather. We investigated how mate-hunting males move within their habitat and how their movements are influenced by weather conditions in the Sydney funnel-web spider (Atrax robustus), one of the world’s most venomous spiders. As is common in mygalomorph spiders, females are thought to be functionally sessile, spending their entire lives in a single burrow, whereas males must permanently abandon their burrow to mate during the breeding season. Nineteen male spiders were fitted with miniature radio transmitters and tracked in Lane Cove National Park, Sydney, Australia, during the mating seasons of 2020 (n = 2), 2021 (n = 8), and 2022 (n = 9). Males migrated at night, typically in a zigzag pattern, and were found in new locations in approximately 50% of daily resightings. Males often spent several days in female burrows, and some female burrows were visited by multiple males. Outside female burrows, males constructed and occupied temporary shelters (“temporacula”). Males were most likely to migrate, and traveled the farthest, when it was not raining and on warm nights after cool days. Our findings suggest that mate-seeking A. robustus males prefer to search for females in less risky situations, revealing a novel risk-minimization strategy, particularly in response to rainfall and temperature.

Weathering the storm for love: mate-seeking behavior of wild male Sydney funnel-web spiders (Atrax robustus) Caitlin Nicole Creek, Hugo Muirhead, Russell Bondurianski, Michael Kasumovich, Bruno Buzzatto

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