For a creature that — legs and all — might be no bigger than a pencil eraser, spiders continue to amaze researchers with their cognitive abilities.
Lisa Taylor, an entomologist at the University of Florida, has spent her career studying arachnids. She says understanding how spiders think is just one of the unknowns driving her research.
“They’re such small animals, with even smaller brains and a sensory system that we don’t quite understand,” she said.
This curiosity led Taylor and two international collaborators – Fiona Cross from the University of Canterbury in New Zealand and Robert Jackson from the International Center for Insect Physiology and Ecology in Kenya – to examine the food preferences of a jumping spider from East Africa known scientifically as Evarcha culicivora. . Their findings have just been published in the journal “Animal Behaviour”.
“My collaborators have spent years observing these spiders in the field and noticed that they feed almost exclusively on mosquitoes,” said Taylor, a research assistant in the UF/IFAS Department of Entomology and Nematology. “It’s not something that’s typical of all spiders – specializing in one type of prey.”
As they watched the spiders’ behavior, another pattern emerged: spiders seemed to follow mosquitoes and target those with bright red abdomens, a telltale sign (at least to humans) of a recently fed mosquito.
For the experiment, carried out in Kenya, the researchers provided the mosquitoes with either red-tinted sugar water – which caused their abdomens to mimic a recent blood meal – or gray-tinted sugar water, to represent mosquitoes without blood. They strongly preferred the red-bellied mosquitoes.
“They also didn’t have a whiff of blood to base their decisions on,” Taylor pointed out. “The use of sugar water meant that odor was not a factor in the spiders choosing their prey.”
In the long term, Taylor said, such research can help shed light on issues such as mosquito control. But in the short term, she adds, this is just another piece of the puzzle for spider research.
“It’s a localized example, but it’s a good study system to help us understand how animals can make decisions with really tiny brains and a completely different sensory system than ours,” Taylor said. “It reveals broader patterns in the natural world.”
Read the full study, “Blood-red color as an index of prey choice for specialist mosquito predators,” at sciencedirect.com/science/article/pii/S0003347222000951.
Source: UF/IFAS Entomology and Nematology Service
