Non-predatory feeding
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Although spiders are generally regarded as predatory, the jumping spider Bagheera kiplingi gets over 90% of its food from Beltian bodies, a solid plant material produced by acacias as part of a mutualistic relationship with a species of ant.[1]
Juveniles of some spiders in the families Anyphaenidae, Corinnidae, Clubionidae, Thomisidae and Salticidae feed on plant nectar. Laboratory studies show that they do so deliberately and over extended periods, and periodically clean themselves while feeding. These spiders also prefer sugar solutions to plain water, which indicates that they are seeking nutrients. Since many spiders are nocturnal, the extent of nectar consumption by spiders may have been underestimated. Nectar contains amino acids, lipids, vitamins and minerals in addition to sugars, and studies have shown that other spider species live longer when nectar is available. Feeding on nectar avoids the risks of struggles with prey, and the costs of producing venom and digestive enzymes.[2]
Various species are known to feed on dead arthropods (scavenging), web silk, and their own shed exoskeletons. Pollen caught in webs may also be eaten, and studies have shown that young spiders have a better chance of survival if they have the opportunity to eat pollen. In captivity, several spider species are also known to feed on bananas, marmalade, milk, egg yolk and sausages.[2] Airborne fungal spores caught on the webs of orb-weavers may be ingested along with the old web before construction of a new web. The enzyme chitinase present in their digestive fluid allows for the digestion of these spores.[3]
Spiders have been observed to consume plant material belonging to a large variety of taxa and type. Conversely, cursorial spiders comprise the vast majority (over 80%) of reported incidents of plant-eating.[4]
- ^ Meehan, C.J.; Olson, E.J.; Curry, R.L. (21 August 2008). Exploitation of the Pseudomyrmex–Acacia mutualism by a predominantly vegetarian jumping spider (Bagheera kiplingi). 93rd ESA Annual Meeting. Retrieved 2008-10-10.
- ^ a b Jackson, R.R.; Pollard, Simon D.; Nelson, Ximena J.; Edwards, G.B.; Barrion, Alberto T. (2001). "Jumping spiders (Araneae: Salticidae) that feed on nectar" (PDF). J. Zool. Lond. 255: 25–29. doi:10.1017/S095283690100108X. Archived from the original (PDF) on 18 March 2009. Retrieved 11 August 2007.
- ^ Nyffeler, Martin; Machado, Glauco; Hartmann, Arik; Keiser, Carl N. (14 March 2023). "Fungus and fruit consumption by harvestmen and spiders (Opiliones, Araneae): the vegetarian side of two predominantly predaceous arachnid groups". The Journal of Arachnology. 51 (1): 1–18. doi:10.1636/JoA-S-22-015. ISSN 0161-8202. Retrieved 1 September 2024.
- ^ Nyffeler, Martin; Olson, Eric J.; Symondson, William O.C. (April 2016). "Plant-eating by spiders". Journal of Arachnology. 44 (1): 15–27. doi:10.1636/P15-45.1. ISSN 0161-8202. Retrieved 1 September 2024.