Dr Fiona Cross
Animal Behaviour Postdoctoral Fellow
PhD (2009) University of Canterbury, New Zealand
Phone: +64 3 3642987 ext 7044
Fax: +64 3 364 2590
Postal address: School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
I work with a jumping spider (Evarcha culicivora) that comes from the Lake Victoria region of East Africa. This species is small – on average, only about 5 mm in body length – and so perhaps it doesn’t look very impressive. However, don’t let that fool you.
There is much more to this spider than meets the eye. In fact, jumping spiders are renowned for having good eyesight and so their vision-based behaviour is often very impressive, in spite of their miniscule appearance. E. culicivora is no exception, but it makes a lot of use of olfaction as well. This includes being remarkably good at identifying its preferred prey by both vision and olfaction.
What is even more remarkable is E. culicivora’s prey preference. This spider shows an active preference for mosquitoes that have recently fed on vertebrate blood and, unusually, this means that it feeds indirectly on vertebrate blood. No other predator is known to express an active preference for mosquitoes as prey or to choose prey on the basis of what the prey has eaten.
Yet E. culicivora’s prey preference is all the more remarkable because of a second level of preference. Its preferred mosquitoes for obtaining blood meals come from the genus Anopheles and this is of particular interest because all human malaria vectors belong to this genus.
In East Africa, the most notorious human-malaria vector is An. gambiae and we know that human odour is an important cue by which An. gambiae finds people for blood meals. A term for this is ‘anthropophily’. Intriguingly, we have discovered that human odour is salient to E. culicivora as well. This is evidence of something unprecedented: an anthropophilic predator that preys on anthropophilic mosquitoes.
Feeding on blood has an important role in this predator’s mating strategy as well because, by feeding on blood-carrying mosquitoes, both sexes E. culicivora become more attractive to the opposite sex. This means that E. culicivora kills mosquitoes not only for food but also for ‘perfume’.
My undergraduate background is in Psychology and I’m interested in how we perceive and pay attention to the world around us. This, in turn, has made me interested in how E. culicivora makes use of selective attention in the context of finding prey and in the context of finding potential mates. It’s not as easy as it sounds. E. culicivora has to do this with a tiny nervous system. But time and again we are defied by what this tiny nervous system can really do.
Examples of research publicity