35 research outputs found
Herbivory in spiders: The importance of pollen for orb-weavers
This is the final version. Available from the publisher via the DOI in this record.Orb-weaving spiders (Araneidae) are commonly regarded as generalist insect predators but resources provided by
plants such as pollen may be an important dietary supplementation. Their webs snare insect prey, but can also trap
aerial plankton like pollen and fungal spores. When recycling their orb webs, the spiders may therefore also feed on
adhering pollen grains or fungal spores via extraoral digestion. In this study we measured stable isotope ratios in the
bodies of two araneid species (Aculepeira ceropegia and Araneus diadematus), their potential prey and pollen to
determine the relative contribution of pollen to their diet. We found that about 25% of juvenile orb-weaving spidersâ
diet consisted of pollen, the other 75% of flying insects, mainly small dipterans and hymenopterans. The pollen grains
in our study were too large to be taken up accidentally by the spiders and had first to be digested extraorally by
enzymes in an active act of consumption. Therefore, pollen can be seen as a substantial component of the spidersâ
diet. This finding suggests that these spiders need to be classified as omnivores rather than pure carnivores.University of Ber