Baeus

Margaría, C. B., Loiácono, M. S. & Gonzaga, M. O., 2006, Two new species of Baeus (Hymenoptera: Scelionidae) from southeastern Brazil parasitoids of Anelosimus (Araneae: Theridiidae)., Zootaxa 1162, pp. 45-52 : 45

Baeus , with worldwide distribution conteins 25 species (Johnson 2004). The genus is represented by five species in the Neotropical region and two in the Andean region, according to the new biogeographic scheme (Morrone 2001), all of them associated with spiders of the families Araneidae and Theridiidae ( Brèthes 1913; Dozier 1931; Girault 1915; Ogloblin 1957; Loiácono 1973; Loiácono & Margaría 2004). However, the fauna of the neotropics remains poorly known. The first Brazilian species, for example, was not described until 2004 ( Loiácono & Margaría 2004).

This is the first known record of Baeus parasitizing eggs of Anelosimus Simon ( Theridiidae ). Females of Anelosimus take care of their egg sacs until the emergence of the spiderlings (e.g. Nentwig & Christenson 1986; Ito & Shinkai 1993; Furey 1998; Marques et al. 1998) (Fig. 1). The presence of Baeus in egg sacs of these spiders indicates that the maternal care is probably not effective against the attack of egg parasitoids. In fact, a high incidence of parasitism by Baeus was previously reported for another theridiid species with maternal care, Theridion grallator Simon , from Hawaii (Gillespie 1990). According to Austin (1985) the egg sac wall and the presence of a guarding female appear to result in a high level of protection against opportunistic scavenging predators, but specialized parasitoids of eggs show a series of adaptations (such as small size, burrowing behavior) which allow them to escape from detection.