Prey selection by a spider wasp, Batozonellus lacerticida (Hymenoptera: Pompilidae): Effects of seasonal variation in prey species, size and density

Abstract

Prey selection by a spider wasp, Batozonellus lacerticida, was investigated at the riverside of the Toyohira River in Misumai, Sapporo, Hokkaido over 7 years from 1981 to 1987. Seventeen species of araneid spiders were found in the study area and six of them were hunted by the wasps. Most (97.3%) of the 223 prey records obtained were of three species, Araneus macacus, A. marmoreus and A. pinguis. Nesting activity of the wasps continued until mid‐August in 1981, 1982 and 1986, but stopped in July in 1984, 1985 and 1987. The length of nesting period was related to whether the wasps successfully switched prey species from A. macacus to A. marmoreus and A. pinguis and A. pinguis or not Switching seemed to occur at the phase when density of A. macacus remained high, depending on the density of larger A. marmorus and A. pinguis. This switching had large effects on species composition and size distribution of actual prey. Chesson's index α calculated at every 10 day period revealed that the wasps preferred A. macacus to the two other species and large prey to medium and small ones. The effect of prey density on preference depended on whether A. macacus was present or absent. In the presence of it there were only slight differences in preference among various conditions of prey density. However, when A. macacus was absent, densities of both A. marmoreus and A. pinguis had some complementary effects on preference. The importance of prey size selection by pompilid wasps, and implications of density effects on preference are discussed.

Does Intraguild Predation Enhance Predator Performance? A Stoichiometric Perspective

“…Prey behavior (e.g., mobility and defense), size, and toxicity can also influence risk of predation (Endo and Endo 1994, Jackson et al 1998, Toft 1999, Toft and Wise 1999b, Eubanks and Denno 2000b, Stamp 2001, Singer and Benays 2003 independent of prey nitrogen content. In fact, the behavior of both Tytthus and Grammonota alters their risk of Pardosa attack relative to what one would predict based solely on their nitrogen stoichiometry.…”

Might Nitrogen Limitation Promote Omnivory Among Carnivorous Arthropods?

“…In some cases, predators do not discriminate among prey of differing N contents (Duval and Williams 2000), and in other instances they choose less nutritious prey (Eubanks and Denno 2000b). In almost all studies of prey selection by predators, however, potential differences in prey nutrition are confounded by differences in prey behavior, size, toxicity, or abundance (Rosenheim et al 1993, Endo and Endo 1994, Strohmeyer et al 1998, Toft and Wise 1999a, Eubanks and Denno 2000b, Stamp 2001. Overall, only limited data are available to verify that, all else being equal, arthropod predators selectively attack the most nutritious prey.…”

Diet choice of a predator in the wild: overabundance of prey and missed opportunities along the prey capture sequence

“…Encounter rate, prey size and vulnerability are all known to determine prey preference and thus the probability that a predator attacks and kills a prey. When a prey is abundant, predators more often encounter this type of prey, become more experienced in handling it (Murdoch 1969, Lawton et al 1974, Endo and Endo 1994, and often prefer such prey species over those that are less abundant, i.e., they may develop a search image. This phenomenon is for example often implied in prey switching and can generate sigmoid functional responses (Murdoch 1973, Murdoch andOaten 1975).…”