Do Spiders Like Blood?
WouterSpiders do not eat blood. They suck juices from insects and other animals. However, many scientists think they are miniature vampires. They like to kill mosquitoes that carry malaria.
To test this theory, researchers conducted an experiment. They glued together the body parts of mosquitoes that had never fed on blood and those that had. Then, the researchers dangled the mix-and-match mosquitoes in front of a test spider. After 30 minutes, the grill was removed. The researchers found that the mosquitoes that had never fed on blood were highly reflective in the red portion of the spectrum.
Researchers also used a Y-shaped olfactometer to study the spider’s response to odors. They set the airflow to 1,500 ml/min. The olfactometer was then washed with 80% EtOH and allowed to dry.
They also examined the colour of the mosquitoes’ abdomens after feeding. The females showed a change in colour from a greyish blue to a bright red. Then, they compared the color of the abdomens to those of a female mosquito that had just eaten a meal of blood.
The research revealed that Evarcha culicivora, a jumping spider, is attracted to blood-carrying mosquitoes. It prefers the smaller female mosquitoes and can detect the prey by its smell alone.
The research also concluded that the test spider’s preference changed over time. It started to select the red-dyed mosquitoes as its preferred prey, but its choice switched to blood-free mosquitoes after a few days. Despite its preference for blood-carrying mosquitoes, it was not aggressive towards humans.
