What Does Marijuana Do to Spiders?

Jason mentioned the other day that he and his wife were watching the new series Orange is the New Black, wherein one of the characters talks about how deer were eating her marijuana plants. The factoid checked out. Deer really are a problem for pot growers because fresh growth on the plants makes an excellent snack. 

According to forest rangers who were led to a hilltop grow site by under-the-influence animals in Italy, deer who’ve consumed marijuana plants are “unusually frisky” and “abnormally high-spirited.” This got us wondering what kind of effect marijuana had on other animals. 

Cannabinoid receptors have been found in non-human mammals, birds, reptiles, fish and even some invertebrates, so there are plenty of animals that react to marijuana. Most of those reactions aren’t that surprising, or all that interesting, though. Dogs and cats act kind of funny and groggy after eating weed (please don’t feed them your stash, no matter how YouTube famous you want to be, though—the stuff can be toxic to them, especially dogs), and monkeys exposed to THC keep wanting more.

Spiders, though, are infinitely interesting when they get stoned because the effects of the drug are clear in the odd-looking webs they build afterwards.

Getting spiders high for science started in 1948, when German zoologist H.M. Peters got fed up with trying to study web-building behavior in spiders who wouldn't do him the courtesy of working on his schedule. His garden spiders tended to build their webs between two and five a.m., and he asked his pharmacologist friend P.N. Witt if there might be some chemical stimulant that would coax the spiders into building their webs at a more reasonable time.

Witt tried giving the spiders some amphetamine and, while they kept building at their usual hour (to Peters' dismay), the two scientists did notice that those webs were more haphazard than normal. Over the next few decades, Witt continued to dose spiders with a smorgasbord of psychoactive substances, including marijuana, LSD, caffeine and mescaline, to see how they reacted. Since spiders can’t use tiny bongs or drink from little mugs, Witt and his team either dissolved the drugs in sugar water or injected them into flies and then fed the spiders with them.

The drugs affected the size and shape of the spiders’ webs, the number of radii and spirals, the regularity of thread placement and other characteristics. By comparing photographs and measurements of normal and “drug webs,” Witt and other researchers could see how the different substances affected different aspects of the web and, by extension, the spiders’ motor skills and behavior.

The line of study didn’t have many practical applications at the time and was eventually discontinued. In 1995, though, NASA repeated some of Witt’s experiments and analyzed the webs with modern statistical tools and image processors. This allowed them to quantify the differences between webs, and they suggested that comparisons like this could be used to test the toxicity of different chemicals on spiders instead of “higher” animals like mice, saving time and money. 

What a web they weave

NASA says the spiders that were given marijuana were easily sidetracked while building and left their webs unfinished.

The spiders on benzedrine, a stimulant also known as “bennies,” weaved their webs energetically, even frantically, but without planning or attention to detail. Their webs were characterized by large gaps.

Caffeinated spiders made smaller, but wider webs, characterized by threads meeting at wide angles, disorganized cells and a lack of the normal “hub and spoke” pattern.

Spiders given the sedative chloral hydrate gave up on their webs even faster than the ones who’d had a little pot.

Finally, spiders given low doses of LSD actually maintained more geometric regularity than they did when they were stone sober.

For a funny take on this experiment, see this video.