Discover Which Spiders Have Brains
WouterSpiders are no strangers to cognitive behaviors. These creatures weave complex webs, hunt prey, detect carbon dioxide, and even engage in mating behaviors.
Previously, it was assumed that spiders didn’t have the intelligence to process information. However, researchers are beginning to understand the brains of spiders. In particular, the jumping spider has garnered attention for its impressive visual capabilities.
In order to better understand the jumping spider’s brain, scientists have conducted a number of experiments. They have measured the amount of electrical activity in the spider’s central nervous system. They have also discovered a minimally invasive way to access the spider’s mind.
Using a microelectrode inserted into the spider’s brain, researchers recorded the individual neurons’ response to visual stimuli. Specifically, they monitored the neuron’s response to video images of flies moving back and forth. They also tested the ability of these neurons to pick up ecologically relevant signals.
In order to make this work, researchers had to be careful about what they recorded. For instance, they had to be careful about the type of electrodes they used. Glass electrodes are too fragile and would not survive penetration through the spider’s exoskeleton. For that reason, they decided to use tungsten electrodes.
Similarly, it’s not the size of the brain that matters as much as how it functions. Most spiders have a relatively small central nervous system. This is due to their relatively large body sizes.
The largest spiders, such as the rainforest giant Nephila clavipes, weigh 400,000 times more than the smallest. This means that they probably convert a great deal of their food into brain power.
