Research by Professor Robert Jackson and Dr Fiona Cross has been published in the Royal Society (Interface Focus) journal as part of a special issue called ‘Convergent minds: the evolution of cognitive complexity in nature’.
Dr Cross was additionally pleased as her spider photo was selected for the cover. See here>
Intercom asked Dr Cross a few questions about the research.
In layman’s terms, what does your latest paper focus on?
Previous work had shown that Portia, a species of jumping spider, takes detours to reach a vantage point for capturing its prey. This strategy is very important because Portia’s preferred prey are other spiders, which are often fully capable of eating Portia. Knowing that Portia is predisposed to carrying out these detours, we investigated whether this spider would become disinclined to complete a detour path if it encountered a particular number of prey spiders that it did not expect to see. At the start of each trial, Portia could view prey ranging in number between 1 and 6, and then we either changed this number during the trial or kept this number the same. Using this design, we found evidence of Portia discriminating between different numbers.
Are these new findings?
Very little has been done to investigate numerical cognition using spiders. Results from earlier Canterbury research had shown that Portia prefers to ambush its prey when in the presence of one other conspecific individual, instead of zero, two or three conspecific individuals. The new research is different because it pertains to prey number instead of conspecific number. It also differs because it is based on Portia taking detours to reach its prey.
Did you submit your photo for cover consideration or was its selection a surprise?
I did submit the photo for consideration for the journal cover, and it was a very nice surprise to discover it had been chosen! I had taken that photo while I was in Kenya last year, in the hope it could be used to help communicate our new findings.
What are you working on now?
Next on the agenda is determining whether Portia pays attention to more than prey number while it takes detours – does it also pay attention to conspecific number, for instance?