Ten facts about wolf spiders
I'm going to start a semi-regular series of blog posts called "Ten facts". In this series (and will the help of other experts), I'll highlight interesting facts about particular groups of organisms; facts that are hopefully new to many and hopefully open people's imagination and curiosity about biodiversity. Since I know some things about wolf spiders, I'll start with these marvellous spiders:
- Wolf spiders are in the Order Araneae (spiders) and in the family Lycosidae; there are about close to 2400 species within this family, worldwide.
- Wolf spiders have eight eyes. In fact, most spider species have eight eyes.
- Wolf spider females carry their egg sacs attached to their abdomens, as photograph at the end of this post illustrates. These egg sacs often appear "blueish" in colour (I do not know why this is the case…). Many, many eggs are contained within these egg sacs. For example, some of my own research has found between well over 40 eggs in the sacs of some relatively small-bodied species in the genus Pardosa. Many, many more eggs can be found in the egg sacs of larger species.
- After the young wolf spiders (called 'spiderlings') hatch, the crawl upon their mother's abdomen, and she carries them around for a while before they disperse off their mother's abdomen.
- Sometimes parasitic wasps will lay their eggs in the wolf spider egg sacs, and these wasps end up consuming the contents of the egg sac. So, instead of spiderlings, wasps will emerge.
- Wolf spiders are really nothing like wolves: they aren't mammals, they don't hunt in packs, and they don't howl at the moon. They are sort-of hairy, though, and are largely carnivorous, but that's about the limit of the similarities
- Many wolf spiders are commonly associated with wet/boggy areas, especially those in the genus Pirata. Sometimes wolf spiders are confused with spiders in family Pisauridae; a family which includes many species also commonly associated with bodies of water (e.g., in the genus Dolomedes). Interestingly, Pisaurid females also carry around egg sacs, but instead of attaching to their spinnerets (back end) they carry them around with their chelicerae ('mouth')
- Wolf spiders are pretty quick, and run around a great deal, especially in open-habitats, when the sun in shining. There is some evidence to suggest females speed up development of their young by 'sunning' their egg sacs on warm days.
- Wolf spiders use multi-modal means to communicate, from visual to vibratory cues, as this review paper discusses. You can see (& hear) some evidence of this in a video showing courtship behaviour by males. Overall, wolf spiders have been a model taxon for studies of behaviour and communication.
- Wolf spiders are among the most abundant arthropods in northern regions, especially in open boreal forest habitats, and in the Arctic. There densities can be extraordinary (estimated at about 0.5 individuals per square meter). Although their diversity is not really high in these regions, their biomass is. They are important food for many vertebrates (e.g., birds)