Spiders More Omnivorous Than Believed
They have a notorious reputation for being fierce carnivores, but new research reveals that spiders may not be the pure predators we think they are.
New research reveals that some spiders make up a quarter of their diet by eating pollen. Scientists found that some of these arachnids, like the orb web spider, choose to eat pollen even when insects are available.
Using stable isotope analysis, lead researcher Dr, Dirk Sanders of the University of Exeter looked at whether juvenile spiders incorporated plant resources into their diet.
The findings revealed that 25 percent of spiders' food intake was made up of pollen, with the remaining 75 percent consisting of flying insects.
Researchers explained that spiders that incorporated both pollen and flies into their diet gained optimal nourishment, with all essential nutrients delivered by the combination.
"Most people and researchers think of spiders as pure carnivores, but in this family of orb web spiders that is not the case. We have demonstrated that the spiders feed on pollen caught in their webs, even if they have additional food, and that it forms an important part of their nourishment," Sanders said in a news release.
"The proportion of pollen in the spiders' diet in the wild was high, so we need to classify them as omnivores rather than carnivores," he added.
Previously, researchers suggested that orb web spiders "accidentally" consume pollen when they eat their webs to recycle silk proteins. Besides catching insects, researchers explain that spider webs can also trap aerial plankton like pollen and fungal spores. However, the latest study suggests that spiders are actively consuming pollen. Researchers explain that it would be impossible for spiders to accidentally consume pollen because of the size of the grains ingested.