Dr. Brittany Barker, a post doctoral researcher at the University of Arizona, recently photographed another example of an invertebrate tackling and eating a vertebrate, this one from Sabino Canyon in the Santa Catalina mountains:
“The spider apparently attacked the baby gecko – they appear to be sit and wait predators. Gecko was still partially alive – I could see his/her eyelids moving – but not moving. The stuff I see here in Tucson is crazy!”
Interestingly, sit-and-wait predators that ambush their prey tend to have larger effects on prey behavior, according to experiments with spiders and grasshoppers that appeared in the journal Ecology. Prey are much more cautious and avoid areas from which predators might ambush them. I know I avoid large rocky outcroppings where a mountain lion could be lying in wait when I hike alone at dusk. This avoidance behavior, though, can change the way they forage on the landscape either by where they forage or how much they eat, and that has effects on their resources in turn. Cool to think about, right? I wonder if geckos are instinctively avoiding places that look like spider ambush points, and if so, did this one just get unlucky? Or is it something they have to learn, and this individual was too young and naive?
[Update: Brittany writes that after some research, she believes the spider is a funnel-web wolf spider in the genus Sosippus. Can you find evidence to confirm that or to determine what species it is?]