Spiders are clever in various ways; depending on their lifestyle

Spiders who sit in their webs and collect prey have different skills than spiders who actively hunt

Having gone down a black hole of reading about social vs nonsocial spiders, I saw there was limited evidence for significant intelligence in social spiders, based on the articles I perused. But there was interesting information about African velvet spider (Stegodyphus dumicola) social order that seemed to show a higher level in cognition in leaders, and not always in a good way.

Badly behaved leaders

While small, less than 1 inch, African velvet spiders who lead use bold aggression to help their fellow spiders capture more prey, they also often spread misinformation when dealing with the presence of an enemy, and those leaders were often small and not necessarily in good body condition. Perhaps the fact that leadership does not seem to be based on specific characteristics of the bold spider but rather than the willingness of most of the other spiders in the group to follow that leader explains this. Finally, boldness was not necessarily a permanent trait. Bold spiders don’t always stay bold.

So much for African velvet spiders as consistent leaders in arachnid intelligence.

Unnamed species of spider Photo by PIERRE LEMON on Unsplash

Using non-brain neurons and the environment

Digging further, I found information on extended, as opposed to central, cognition needs to be considered in spiders. They show diverse ways of learning which may involve this extended learning. That is, rather than leaving everything to the central nervous system (brain) they also use neurons in other parts of their bodies, as well as tapping into their environment. Think of bees dancing to convey information and, as the authors note, humans using computers, as forms of extended cognition. And for smaller creatures, like spiders, a large energy intensive brain in such a small body is limiting, so why not spread the neurons, and the work, around?

Araneophagic (spider eating) spiders such as the (Portia fimbriata), which is about 1/4 inch long, hunt orb weaving spiders, watching their prey from a distance then taking a roundabout route to get near the top of the orb weaver’s nest. They lose sight of the orb weaver as they make this journey, needing to use working memory to re-find their prey. Once in position on the orb weaver’s nest, the Portia spiders dangle on a line and grab the prey spider from the center of its web. This shows advance route planning and the ability to adjust to altered situations.

Those orb weaving spiders (Araneae family), which range in size from 0.02 to 3.5 inches, sit and wait, often at the edge of their web and don’t show as much web building innovation as their predators do. Still, let’s not write them off completely as they illustrate something about the lack of negative connection between small size and competence. In fact, the tiniest orb spiders made the fastest changes to their webs when compared to the larger orb spiders. Whether that’s related to brain capacity or just neural capacity is still being studied, but I find the concept intriguing.

A complex spider web Photo by Wyxina Tresse on Unsplash

The orb shaped webs these spiders construct are complex and different types of silks, or fibrins, a type of protein produced in their silk glands, each of which is used for a specific task: the framing areas of the web are the strongest, the stretchiest silk is found further in, and the capture spiral is made with ‘gluey’ silk..

The glands connect to spinnerets, a mysterious development whose origin is still being debated. Suffice it to say, the silk goes from the spinnerets through a tiny spigot which then extrudes it outside the body for the spider to use in creating its web.

Given that these spiders design their orb web using multiple legs, I have to wonder whether there is some hard-wired pattern that orb spiders are born with or if there is intention in their designs-do they ‘create’ in the artistic or artisan sense. Each spider web, after all, is unique. Some day we may know.

Can some spiders count, plan or change tactics?

Getting back to the Portia spiders, they also appear to have some ability to numerate (the word scientists use when they don’t want to say that a species can count) at least up to three, when evaluating the number of prey in their webs. In test situations, these spiders were shown a web with a specific number of trapped prey and the web was then concealed while the spider made its way toward it. Once the web came back in view, the spiders would hesitate if the number of prey had changed. The study authors, being good skeptical scientists, ‘suggest’ that the spiders can detect when there is a change, not just in the way the target web looks, but rather how many prey are now in the web, versus how many were in the web previously. That level of actual ‘numerating’ stops at three, yet they seem to understand the concepts of more and less as well. And counting to three is equal to the level of a one-year-old child. Not bad.

Most interesting, they also appear to study their access to orb spider webs before moving toward them, suggesting they look at the situation before deciding how to proceed, in other words, they plan. They change the way they make the orb spiders’ webs move when imitating prey, using several of their ten legs independently. And in different environments, they change tactics, changing from place specific behaviors to a more generalized problem-solving ways of hunting.

I’d have to give the Portia spiders the nod for having quite a bit of intelligence for their size, and think there’s a strong possibility, given the precision of their work and the ability to coordinate multiple appendages in doing that work, that the orb weaving spiders will eventually be recognized for some level of intelligence. Sorry, African velvet spiders, you appear to have some work to do to catch up.