1977 ] 
Robinson & Valerio — Salticid Spiders 
9 
The basic predatory techniques. 
Dropping on the dragline to isolate a large prey from the sub- 
strate may be partly fortuitous in some cases. Certainly it depends 
on the prey moving off the substrate as a result of its own escape 
movements, since the salticid cannot lift it off. However, the 
case of the attacks on the ants suggests that it may be part of the 
normal predatory repertoire for dealing with some types of small 
prey. Attacking large araneids from above their dorsal surface 
presumably utilizes a technique that is part of normal prey capture 
but capitalizes on the araneid’s inability to make strong scraping 
movements against its upper surface. It is also probable that such 
attacks benefit from the fact that the spider is not standing on 
a rigid substrate when attacked. The peculiar defensive posture 
adopted by Nephila spp. in response to direct tactile stimulation of 
their dorsal surfaces (Robinson & Robinson 1973a) results in a 
“barrier” of flexed legs being erected above the spider and could 
serve to frustrate some dorsal attacks. 
Summary 
1. Some tropical salticids regularly catch prey larger and heavier 
than themselves. 
2. Such salticids may utilize a dorsal attack on the prey followed 
by dropping on a dragline to effectively isolate the prey from 
the substrate. 
3. This technique could be much more common than we know 
and definitely extends the size range for the potential prey of 
these spiders. 
4. The drop and hold technique allows the salticids to attack 
prey that would normally be protected by social defense. 
5. Salticids can make aerial attacks on araneid spiders in their 
webs and the normal defensive dropping responses of these 
spiders may, in certain circumstances, facilitate the salticid 
attack. 
References 
Bristowe, W. S. 
1941. The Comity of Spiders, Volume II. London, Ray Society. 
Eisner, Thomas and Jeffrey Dean 
1976. Ploy and counterploy in predator-prey interactions: Orb-weaving 
spiders versus bombadier beetles. Proc. Nat. Acad. Sci. USA, 73: 
1365-1367. 
