Influence of prey availability and conspecifics on patch quality for a cannibalistic forager: laboratory experiments with the wolf spider Schizocosa

Wagner, John J.; Wise, David H.

doi:10.1007/s004420050107

Cited by 53 publications

(31 citation statements)

References 24 publications

(36 reference statements)

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“…This behavioral switch in activity may be comparable to the switch of many invertebrates from a sit-and-wait ambush foraging mode at high prey densities to an active search mode at low prey densities or with increasing food deprivation (e.g., Ford 1978;Griffiths 1980;Johnson and Crowley 1980;Formanowicz 1982;Formanowicz et al 1982;Inoue and Matsura 1983;Formanowicz and Bradley 1987;Wagner and Wise 1997). Helfman (1990) recognizes the similarity between these situations and optimal diet-selection models that predict a decline in prey selectivity as hunger increases (e.g., Krebs and McCleery 1984).…”

Section: Pattern Of Movementmentioning

confidence: 97%

“…Food limitation and the activity level of individuals are positively related in a number of animal taxa (see Helfman 1990; Werner and Anholt 1993 for reviews). In particular, predatory arthropods are known to switch from a sit-and-wait ambush mode at high prey densities to an active search mode at low prey densities or with increasing food deprivation (e.g., Ford 1978;Griffiths 1980;Johnson and Crowley 1980;Formanowicz 1982;Formanowicz et al 1982;Inoue and Matsura 1983;Formanowicz and Bradley 1987;Wagner and Wise 1997). In addition to moving greater distances per day, recently matured adult female D. triton respond faster and attack distant prey at a higher frequency than even large penultimate juvenile females (Kreiter 1997).…”

Section: Introductionmentioning

confidence: 98%

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

Kreiter

Wise

2001

Oecologia

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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.

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Section: Pattern Of Movementmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

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

Kreiter

Wise

2001

Oecologia

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“…Adult females weigh about 70 mg. Spiders in this study came from a mixed mesophytic forest in Madison Co., Ky., where two cryptic Schizocosa species occur (Wagner and Wise 1997). These species, Schizocosa ocreata (Hentz) and S. stridulans (Stratton), can be distinguished only in the mature male (Stratton 1991).…”

Section: Study Speciesmentioning

confidence: 98%

Growth, development, and survival of a generalist predator fed single- and mixed-species diets of different quality

1999

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It is often assumed that prey species consumed by generalist predators are largely, though not entirely, equivalent in terms of their value to the predators. In contrast to this expectation, laboratory feeding experiments uncovered distinctly varied developmental responses of a generalist predator, the wolf spider Schizocosa, to different experimental diets. Naive Schizocosa attacked and fed upon all the prey species offered; however, highly divergent patterns of survival, development, and growth of Schizocosa spiderlings reared on different single-prey diets revealed a wide spectrum of prey qualities. Spiderlings fed the collembolan Tomocerus bidentatus sustained the highest overall rates of survival, growth, and development. Fruit flies (Drosophila melanogaster) were intermediate-quality prey: spiders fed Drosophila initially exhibited rates of survival, growth, and development equal to those of spiders on a diet of T. bidentatus, but after about 3 months, rates declined markedly. Fungus gnats (Sciaridae; Bradysia sp.) and conspecfic spiderlings are low-quality prey for Schizocosa: a sole diet of either of these prey types resulted in positive but markedly submaximal rates of growth, retarded rates of development, and survival rates much lower than that supported by a diet of Drosophila. Worst were the collembolans Folsomia candida and Isotoma trispinata, and the aphid Aphis nerii: spiderlings fed solely one of these species did not grow and died without molting. A. nerii is classified as poor quality because survival was no better than that of starved controls. F. candida and I. trispinata were toxic: survival of Schizocosa hatchlings fed these collembolans was lower than that of starved controls. A mixed diet of T. bidentatus and fruit flies yielded positive synergistic effects with respect to growth, but development and rate of survival were similar to those of spiders on a sole diet of T. bidentatus. Including toxic prey did not produce a better diet, while inclusion of toxic prey with prey of higher quality created diets that were no better than the toxic prey alone. The results of these experiments suggest that prey species that are similar in morphology and behavior, and that are initially killed and consumed, may differ dramatically in their suitability as food for generalist arthropod predators.

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“…As indicated by 13 C signatures, among lycosid spiders only subadult T. terricola fed on D. melanogaster. As in epigeic Collembola, juvenile lycosid spiders, especially P. lugubris, likely beneWted from switching of other predators, most likely of subadult T. terricola, to Drosophila prey in prey-enhancement treatments thereby reducing intraguild predation (see also Wagner and Wise 1997).…”

Section: Predatorsmentioning

confidence: 99%

Utilization of prey from the decomposer system by generalist predators of grassland

2007

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We investigated the linkage between the detrital subsystem and generalist predators of meadow ecosystems by manipulating prey availability in two different ways: we increased resource availability for the decomposer subsystem and thereby decomposer prey by adding mulch materials (detritus enhancement), and we added fruitflies (Drosophila melanogaster, Diptera; prey enhancement) to fenced plots. Both supplemented materials significantly differed in their (13)C/(12)C and (15)N/(14)N ratios from those of the natural litter. We measured density responses of detritivorous, herbivorous and predaceous arthropods to the increased resource supply. We used ratios of natural stable isotopes of N and C in arthropod tissues to trace the flux from the added resources to consumers and to relate density responses of consumers to changes in resource supply. Effects of resource enhancement propagated through at least two trophic levels, resulting in higher densities of major decomposer and predator taxa. Effects of detritus enhancement were much stronger than those of prey enhancement. Signatures of delta(13)C proved density responses of Collembola taxa to be related to the added mulch materials. Among generalist predators, densities of juvenile wolf spiders (Lycosidae) responded more to detritus-enhancement than to prey-enhancement treatments. In contrast, the density of the web-building linyphiid and the non-web gnaphosid spiders remained unaffected. Each spider taxon, including those which did not respond numerically, was significantly enriched in (13)C in detritus-enhancement treatments, suggesting that they gain energy from the decomposer system. Numbers of herbivores-cicadellids and aphids-were similar in each of the treatments, indicating that they were unaffected by changes in predator density. Our results indicate that the lack of a numerical response to resource supplementation is not necessarily due to the absence of a trophic linkage, but may be caused by compensatory changes in mortality factors such as cannibalism and intraguild predation.

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Influence of prey availability and conspecifics on patch quality for a cannibalistic forager: laboratory experiments with the wolf spider Schizocosa

Cited by 53 publications

References 24 publications

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

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

Growth, development, and survival of a generalist predator fed single- and mixed-species diets of different quality

Utilization of prey from the decomposer system by generalist predators of grassland

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