Predation of Two Common House Spiders upon Medically Significant Pests

Abstract

Two common house spiders prey upon medically significant pests. The remains of 15 brown recluse spiders were discovered in the webs of Steatoda triangulosa. Achaearanea tepidariorum was observed preying upon the lone star tick. Although spiders are generally considered unwelcome inhabitants of homes, two species of common house spiders in Kansas prey upon medically important pests. This note records the predation of Achaearanea tepidariorum (C. L. Koch) (Araneae: Theridiidae) upon the lone star tick, Amblyomma americanum (Linnaeus) (Acarina: Ixodidae), and the predation of Steatoda triangulosa (Walckenaer) (Araneae: Theridiidae) upon the venomous brown recluse spider, Loxosceles reclusa Gertsch and Mulaik (Araneae: Loxoscelidae). Rocky Mountain spotted fever and tularemia are transmitted to the human population by the three active stages of the lone star tick (Waddington, 1975). Bites of the brown recluse spider cause local dermonecrosis (Dillaha et al., 1964) and systemic reactions leading to death (Lessenden and Zimmer, 1960; Taylor and Denny, 1966). A. tepidariorum is a common cosmopolitan species found in and around buildings throughout Kansas (Scheffer, 1904). Its diet consists of a wide variety of arthropods and even an occasional vertebrate (McCook, 1889). Fitch (1963) identified the discarded remains of spider wasps (Sceliphron and Trypoxylon), flies, beetles, leafhoppers, roaches and harvestmen (Leiobunum) beneath webs of this species. A. tepidariorum also preys upon spiders, including the purseweb spider, Sphodros fitchi Gertsch and Platnick (Araneae: Atypidae) (Guarisco, 1988). On 25 July 1990, a female house spider in a web located between the floor and baseboard of the Kansas Biological Survey map room, rapidly approached a lone star tick crawling across the floor beneath the web. The spider immediately enswathed her prey, carried it to the center of the web and began to feed upon it. The tick and spider were captured for subsequent identification.