Researchers found that pollen grains make for a quarter of some spider species' diet, which choose to eat these grains even when other insects are available, according to a press statement.
Generally spiders use their web to catch their prey. While studying oral web spiders, University of Exeter researchers made yet another interesting discovery of this spider species. They found that oral web spiders use their webs not just to catch insects but also aerial plankton like pollen and fungal spores, which account for a quarter of their diet. Spiders usually take down and eat their webs to recycle the silk protein. It was previously believed that oral web spiders indirectly consumed these pollens while eating the web. However, the new study found that this was not true. The size of the pollen grains suggested that the spiders were actively eating them.
To confirm their findings, Dr Dirk Sanders of the University of Exeter and his team carried out an experiment to see whether juvenile spiders included plant resources in their diet. They found that while only 75 per cent of their diet consisted of flying insects, the rest comprised of pollen grains. A mixture of these plant resources and insects gave spiders maximum nourishment.
"Most people and researchers think of spiders as pure carnivores, but in this family of orb web spiders that is not the case," Dr. Sanders said. "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. The proportion of pollen in the spiders' diet in the wild was high, so we need to classify them as omnivores rather than carnivores."
Findings of the study were published in the online journal PLOS One.
