Snatching Prey from the Mandibles of Ants, A Feeding Tactic Adopted by East African Jumping Spiders (Short Communication) (Report‪)‬

In the tropics, ants (Formicidae) are the dominant insects (Holldobler & Wilson 1990) and jumping spiders (Salticidae) are the dominant spiders (Coddington & Levi 1991), but we are only beginning to understand how salticids and ants interact (Nelson & Jackson 2005, 2006a,b; Nelson et al. 2006). Salticids are unique among spiders because of their complex eyes (Land 1969; Blest et al. 1990), exceptionally acute vision (Land & Nilsson 2002) and intricate vision-guided predatory behavior (Jackson & Pollard 1996; Harland & Jackson 2004). Most species in this large family (about 5,000 described species, Platnick 2008) appear to be active hunters that prey primarily on a variety of insects, but typically they do not prey on ants. It may not be surprising that many salticid species can detect ants by sight and then avoid coming close to them (Nelson & Jackson 2006c), particularly considering the formidable defences shown by ants (Blum 1981; Holldobler & Wilson 1990), including powerful mandibles, poison-injecting stings and formic-acid sprays, and the fact that ants are sometimes predators of salticids (Nelson et al. 2004). Yet there is a large minority of salticids (the "myrmecophagic species") that selects ants as preferred prey (Li & Jackson 1996; Clark et al. 2000; Jackson & Li 2001; Huseynov et al. 2005) and one salticid species, Cosmophasis bitaeniata (Keyserling 1882), is known to combine chemical ant mimicry with myrmecophagy (Allan & Elgar 2001) (i.e., by mimicking the cuticular hydrocarbons of the Australian weaver ant, Oecophylla smaragdina (Fabricius 1775), C. bitaeniata gains entry to the weaver ant's nest and feeds unmolested on the ant's larvae). Here we revisit a different style of exploiting ants -- robbing ants of objects they carry in their mandibles. This was first described by Bhattacharya (1936) who observed juveniles of Menemerus bivattatus (Dufour 1831) (formerly Marpissa melanognathus) in India grabbing food out of the mandibles of fire ants, Solenopsis geminata (Fabricius 1804). Our own observations show that this tactic, which we will call "snatching from ants" or just "snatching," for short, is unique neither to India nor to M. bivittatus. The baseline information we provide here is a step toward later quantitative and experimental research concerned with this poorly understood foraging method.