Today’s Solutions: June 28, 2022

The enemy of my enemy is my friend, so the saying goes. As it turns out, this applies to humans and the natural world as well. Mosquitoes are the prime movers of malaria around the world, and scientists have worked hard to eliminate mosquitoes’ spread of this deadly disease. Yet, another species is also attacking mosquitoes and seems to have some success. 

A recent study from the University of Florida proved that a species of jumping spiders from Kenya much preferred preying on mosquitoes who recently fed on blood. 

Helpful hunters 

Lisa Taylor, an entomologist at the University of Florida and lead author of the study published in ScienceDirect, and her collaborators studied the peculiar hunting habits of an East African jumping spider called Evarcha culicivora. They noticed that these jumping spiders seemed to be tracking mosquitoes. 

“They’re such tiny animals, with an even tinier brain, and a sensory system that we don’t quite understand,” says Taylor. “My collaborators spent years watching these spiders in the field and noticed that they were feeding almost exclusively on mosquitoes. This isn’t something that’s typical of all spiders—to specialize in one type of prey.”

Not only that, but they also seemed to be targeting mosquitoes with red-colored bellies, an indication that the mosquito had recently fed and had a stomach full of blood. It seemed like the jumping spiders were leaping after these mosquitoes in particular. 

They tested this observation in Kenya, marking mosquitoes by feeding them red-dyed glucose water, which would still look like they had fed on blood, and other mosquitoes with gray-dyed water. The spiders still went after the red-dye-fed mosquitoes, eliminating the possibility that they were hunting by smelling the blood in mosquitoes. 

How might this influence future mosquito management?

According to Taylor, these findings could certainly have a longer-term influence on how to eradicate or manage disease-carrying mosquitoes in problem areas. In the short term, however, it is just another small but important find in spider research. 

“This is 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 says. “It reveals broader patterns in the natural world.”

Source Study: ScienceDirectBlood-red color as a prey choice cue for mosquito specialist predators – ScienceDirect

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