Evarcha culicivora jumping spiders, also known as vampire spiders, are picky eaters by any standards. Explaining that the arachnid's environment is swamped with insects, Ximena Nelson from the University of Canterbury, New Zealand, says, 'You can see from the diet when you find them in the field that there is a high number of mosquitoes in what they eat'. And when Robert Jackson investigated their diet further, he found that the spiders were even more selective. The delicacy that E. culicivora prize above all others is female blood-fed Anopheles mosquitoes, which puzzled Nelson. How could these picky spiders pick out blood-engorged Anopheles mosquitoes from the swarms of similarly sized insects infesting the area? Nelson and Jackson decided to do some jumping spider psychology to find out how the arachnids pick out blood-fed female Anopheles mosquitoes from the crowd and they publish their discovery that the spiders identify the females by their antennae in The Journal of Experimental Biology at http://jeb.biologists.org.
According to Nelson, identifying Anopheles mosquitoes (males and females) is quite straightforward. 'The bodies of Anopheles mosquitoes rest on a 45deg angle from the substrate but most others rest parallel', she explains. But what other distinguishing features could the famished spiders use when selecting the females specifically? 'Obviously, blood-fed females have an engorged red abdomen and the other difference that comes to mind between males and females is the antennae', says Nelson. Explaining that male Anopheles have luxuriant fluffy antennae, while the female's are less elaborate, Nelson decided to see which mosquito features E. culicivora fixate on.
Collecting male and female Anopheles and Culex mosquitoes at the International Centre for Insect Physiology and Ecology in Kenya, Ne
|Contact: Kathryn Knight|
The Company of Biologists