The book, The Lives of Spiders: A Natural History of the World's Spiders, looks at three spiders and their unusual feeding habits. (Image credit: Wirestock, Inc./Alamy Stock Photo; blickwinkel/Alamy Stock Photo; Josiah O. Kuja, Robert R. Jackson, Godfrey O. Sune, Rebecca N. H. Karanja, Zipporah O. Lagat, Georgina E. Carvell, CC BY 4.0, via Wikimedia Commons)
There are about 50,000 species of spiders on our planet, from giant huntsmen and tarantulas to tiny pygmy orb-weavers and patu diguas. In this excerpt from The Lives of Spiders: A Natural History of the World’s Spiders (Princeton University Press, 2024), author Ximena Nelson explores three species with exotic diets—plants, blood, and woodlice.
Vegetarian spider
Bagheera kiplingi's diet consists almost exclusively of vegetation.
Scientific name: Bagheera kiplingi
Family: Salticidae
Length: 1∕5–¼ inch (5–6 mm)
Distinguishing anatomy: Males have iridescent green markings on the cephalothorax and abdomen.
Distinguishing feature: mostly vegetarian.
A vegetarian among spiders seems unlikely, but Bagheera kiplingi almost fits the bill. In addition to nectar, ant larvae, and nectar-eating flies, this jumping spider feeds almost exclusively on Beltian bodies—the separable fatty, proteinaceous tips of the Vachellia acacia leaves.
Bagheera is so dependent on Beltian bodies that it becomes an obligate resident of Vachellia plants, living in areas where Pseudomyrmex ants do not actively patrol. This plant has such a degree of host specificity that the spider's geographic distribution is limited by the presence of Vachellia.
Plant mutualisms
Ants can be helpful to plants because they tend to be aggressive and repel herbivorous insects. Thus, many plants seek to attract ants as guards, supporting them by producing nectar through extrafloral nectaries. This constant food source is irresistible to ants, but is often also used by spiders, especially wandering spiders, which wander in search of prey.
Many jumping spider species may use nectar feeding as a common foraging strategy that involves less risk of injury than hunting. Nectar may increase the spiders' lifespan and reproductive success. Importantly, for tiny spiders, nectar provides the energy they need to hunt prey that is typically larger than themselves.
Sourse: www.livescience.com
