Evarcha culicivora is a species of jumping spider (family Salticidae) found only around Lake Victoria in Kenya and Uganda. At maturity, E. culicivora spiders have an average size of 5 mm for both males and females. The range in size for either sex is quite small, with females being only slightly larger on average (4–7 mm compared to 3–6 mm).
It is commonly known as the vampire spider because it indirectly desires the blood of vertebrates. It does this by predating on blood-sucking female mosquitoes in the genus Anopheles, the mosquito responsible for transmitting malaria in the region, as well as other vector-borne diseases in humans. Experimentally, these spiders are considered Anopheles specialists. E. culicivora has an association with the native plants Lantana camara and Ricinus communis. They consume the nectar for food and preferentially use these plants as a location for courtship.
The mating interactions of E. culicivora is species-specific. Their mating interactions follow mutual mate choice in which both males and females have preferences for partners and perform displays. These preferences vary with gender and age. This behavioral characteristic differs from other jumping spiders, where the majority of males show preference and pursue females.
Description
As juveniles, all E. culicivora are grey-brown in color, both on their bodies and face. Adult males have blood-red faces and white-hair patches above the principal eyes and at the side of the clypeus and on palp tibia. Juveniles and adult females have grey-brown faces, but adult females have a faint red tint. It is rare for adult females and juveniles to have white patches. Body lengths of males range from 3 mm to 6 mm, whereas females range from 4 mm to 7 mm.
Taxonomy
E. culicivora belongs to the jumping spider genus Evarcha, a relatively large genus comprising 89 nominal species. Evarcha is widespread, ranging from the Palaearctic, Africa and Southern Asia to the middle Pacific area, with a few species from America and Australia. Within the genus, species are polyphyletic as the species have very different morphology of genital organs. For example, the embolus ranges from short, strong and compact to long and filamentous.
Habitat and distribution
Evarcha culicivora is found only around Lake Victoria in Kenya and Uganda. This area is full of a variety of insect life and has a large number of Chaoboridae midges. These lake flies are similar in size and appearance to Anopheles mosquitos, common prey of E. culicivora, but E. culicivora disregards their presence as well as the majority of all other insects present. E. culicivora builds nests, where it primarily resides. Nests are built within closed spaces such as tree trunks or walls of buildings and are often made of dead foliage such as leaves. It hides in the grass or other plants close to the ground when it is quiescent. When it is hunting, it will go to more exposed locations such as the walls inside some mosquito-infested houses.
Home range and territoriality
Nest structure
Around E. culicivora common habitats, such as tree trunks or walls of buildings, individuals build nests on dead leafs inside their webs. Their webs are silk tubes. The length of an individual's web equates to four-times the resident spider's body length, while the width of the web is six-times the resident spider's body width. Typically, there are one or more elastic openings. The nests are built from dead, rolled-up leaves and some grass, which form an enclosed space in the spider webs. Nests located at the narrow end of the conical leaf typically contain only one door, opening at the wider end. For nests that have more space, there are two openings. It is rare to have three openings in a nest.
Interactions at the nest
In female-female and male-male interactions, the intruder encroaches when the resident is quiescent in the nest. The intruder usually probes first and then pushes its face into the silk, chewing and tugging the silk. The resident pulls on the silk as a response. For male-female interaction at the nest, see the mating section. Observations have been made of males cohabiting with females. In cases of cohabitation, the two silk tubes are woven together and the two doors of the two chambers are aligned together. See the Courtship section for more information on how cohabitation plays a role in courtship.