by Piter Kehoma Boll
Jumping spiders are the most diverse and one of the most fascinating groups of spiders. A long time ago I presented one species here, a vegetarian jumping spider. Now it is time for the second jumping spider and, if a vegetarian spider was not odd enough, what about a spider that feeds on human blood?
Evarcha culicivora is a lovely jumping spider found in Africa only around Lake Victoria. Its common name, vampire spider, comes from the fact that it loves blood, although it does not feed on it directly. The prey of the vampire spider are mosquitoes and similar dipterans, and it can feed on a variety of species. It shows, however, a marked preference for blood-fed female mosquitos, especially Anopheles gambiae, the most common species to suck blood from humans in this region of Africa.
Species of Anopheles seem to be their preferred prey even when other blood-sucking mosquitoes, such as those of the genus Culex are present. The vampire spider is able to recognize Anopheles by the mosquito’s posture at rest and tries to move to a position from which it can capture the prey from behind. Attempts to capture other species are not that refined.
While female spiders eating their male partner is a widespread and well-known practice, in vampire spiders the opposite is more common. Larger males often kill and eat females, so chosing an adequate mate is very important for female vampire spiders. An experiment has shown that virgin males and females prefer larger individuals of the opposite sex to mate, probably because larger individuals have more resources to invest in the offspring. However, while non-virgin males still prefer larger females, non-virgin females prefer smaller males, probably because they realized the danger that a large male represent to them. They survived the first but are not willing to risk their lives again.
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References:
Cross FR, Jackson RR, Pollard SD (2007) Male and Female Mate‐Choice Decisions by Evarcha culicivora, An East African Jumping Spider. Ethology 113(9):901–908. https://doi.org/10.1111/j.1439-0310.2007.01394.x
Jackson RR, Nelson XJ (2011) Evarcha culicivora chooses blood‐fed Anopheles mosquitoes but other East African jumping spiders do not. Medicinal and Veterinary Entomology 26(2):233–235. https://doi.org/10.1111/j.1365-2915.2011.00986.x
Nelson XJ, Jackson RR, Sune G (2005) Use of Anopheles-specific prey-capture behavior by the small juveniles of Evarcha culicivora, a mosquito-eating jumping spider. Journal of Arachnology 33(2):541–548. https://doi.org/10.1636/05-3.1
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