We are investigating how active hunting and web-building spiders will respond to climate change

It is likely that the thermal tolerance of an organism reflects the range of temperatures it is exposed to during normal behaviour. Testing this ‘exposure hypothesis’ is difficult, because often behaviours are confounded with taxonomy, geography, habitat or trophic level. Spiders represent a unique model organism because they exhibit two very distinct behaviours in the same locations within one taxonomic and trophic grouping – web building versus active foraging. By testing this exposure hypothesis, we can better predict winners and losers following climate change. By measuring upper thermal maximum (CTmax) of over 2000 spiders from over 100 species, collected at 40 sites across Hong Kong we revealed: 1) higher critical thermal maximum (CTmax) of day-feeding than night-feeding spiders, 2) higher CTmax of active hunters than web-builders in all habitat types 3) Higher CTmax in sun-exposed habitats than canopy-covered habitats. Our findings reveal how species behavioural traits translate to climate change vulnerability in spiders across the habitats they occupy, allowing us to develop generalisable predictions of how the characteristics determining ectotherms’ exposure to larger ranges and higher temperatures reflect in higher thermal tolerance. 

Funded by the Robert Whyte Memorial Research Grant