Prey availability limits fecundity and influences the movement pattern of female fishing spiders

Abstract

We conducted a food supplementation field experiment to test two hypotheses: (1) fecundity of the fishing spider Dolomedes triton is limited by a shortage of prey, and (2) the increased movement of adult female D. triton exhibited upon maturation is a foraging adaptation to lessen the impact of food limitation on egg production. Free ranging, uniquely marked adult female fishing spiders were assigned either to a food-supplemented group that received crickets in addition to their natural diet, or to a control group. Juvenile female spiders were also marked and their movement patterns were recorded, but juveniles were not offered supplemental food. Food-supplemented adult females gained weight at a faster rate and hatched more than twice as many offspring as control females. Adult females in the control group moved greater distances per day than did juvenile females. Supplemented adult females moved shorter distances per day than control females, and the movement pattern of fed adults did not differ from that of juveniles. These results support the hypotheses that adult female D. triton are food limited, and that the increased movement of adult females is a switch in foraging behavior that occurs during the reproductive period. Our finding that natural prey shortages limit egg production contrasts with laboratory-based studies of food limitation in the genus Dolomedes, and contradicts a basic assumption of a recent hypothesis that sexual cannibalism in Dolomedes is non-adaptive. These discrepancies highlight the importance of insights gained from field experiments with natural populations.

Patch quality and connectivity influence spatial dynamics in a dune wolfspider

“…Second, higher dispersal activity in the scarcely vegetated grey dunes may be due to a lack of suitable prey, such as epigeic springtails and diptera unpublished data). Likewise, Kreiter and Wise (2001) showed increased mobility in the absence of suitable prey for American populations of the fishing spider (Dolomedes triton). Female spiders live 2-3 months longer than their male conspecifics and are founders.…”

“…butterflies: Harrison et al 1988, Thomas andHarrison 1992, Thomas et al 1992;grasshoppers: Hjerman and Ims 1996, Appelt and Poethke 1997, Kuhn and Kleyer 2000. Few studies have dealt with dispersal of spiders, except for some larger Pisauridae species (Kreiter and Wise 2001). Spiders can disperse in two distinct ways: either by cursorial movement (mainly adults) or by aerial ballooning (restricted to juveniles for the larger species).…”

Colony nutrition skews reproduction in a social spider

“…Several authors have shown that spiders frequently encounter periods of prey shortage and have suggested that many spiders are energy limited in nature (Anderson 1974;Wise 1979Wise , 1993Miyashita 1992;Kreiter and Wise 2001;reviewed in Wise 2006). The prey available to a colony will vary in nutritional composition, thus affecting the availability of different nutrients to colony members (Barker et al 1998).…”

Landscape structure affects activity density, body size and fecundity of Pardosa wolf spiders (Araneae: Lycosidae) in winter oilseed rape

“…Because body size of adult spiders is to a high degree determined by food supply during pre-adult development (e.g., Uetz et al, 2002) and female body size is a major determining factor of fecundity (Beck & Connor, 1992;Kreiter & Wise, 2001) we further hypothesize that P. agrestis individuals are larger and females more fecund in complex landscapes that offer more refuges and/or prey than structurally poor landscapes.…”