Premium
Refuge from cannibalism in complex‐structured habitats: implications for the accumulation of invertebrate predators
Author(s) -
LANGELLOTTO GAIL A.,
DENNO ROBERT F.
Publication year - 2006
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1111/j.1365-2311.2006.00816.x
Subject(s) - cannibalism , wolf spider , biology , predation , habitat , generalist and specialist species , ecology , spider , invertebrate , plant litter , spodoptera littoralis , litter , interspecific competition , larva , ecosystem , noctuidae
1. Like many invertebrate predators, the wolf spider Pardosa littoralis Banks (Araneae: Lycosidae) accumulates in complex‐structured habitats replete with leaf litter (thatch). Here we test the hypothesis that P. littoralis accumulates in complex habitats to gain refuge from cannibalism. 2. A laboratory experiment examined the effects of habitat complexity (thatch present or absent) and size‐class pairing of conspecific spiders (large vs. small, small vs. small, and large vs. large) on the incidence of cannibalism. Spider survival was significantly higher (22%) in complex‐structured habitats with thatch than in simple‐structured habitats lacking thatch. Furthermore, cannibalism occurred more frequently in P. littoralis when the size of conspecifics was asymmetric (large vs. small spiders) than when spiders were of equal size. There was no interactive effect of habitat complexity and size‐class pairing on spider survival. 3. A field experiment examined the effects of habitat complexity, conspecific density, and access to alternative prey on the prevalence of cannibalism in P. littoralis . Access to alternative prey significantly increased the number of spiders recovered from field enclosures, as did the presence of leaf litter thatch. That fewer spiders were recovered when thatch and alternative prey were absent suggests that cannibalism was most prevalent under these conditions. 4. Overall, results suggest that habitat complexity reduces agonistic interactions and cannibalism among wolf spiders, providing encouragement to pest managers that the structure of agricultural habitats can be managed to maximise densities of generalist predators for enhanced pest suppression.