Does prey mobility affect niche width and individual specialization in hunting wasps? A network‐based analysis

Abstract

Niche width and inter‐individual diet variation in predator populations are known to be affected by intrinsic factors such as body size, age, cognitive constraints, and by intra‐ and interspecific competition. By contrast, how variation in prey biological traits may affect niche width and partitioning is still a poorly explored topic. One of these candidate traits is prey mobility, which can affect the predators’ niche because acting on the rate of encounter and, assuming mobility as a proxy for escape capability, on the success of predator attacks. Here we analysed 20 wasp populations and their prey as individual‐based food‐webs to test if prey mobility may explain niche width (here defined by the Shannon entropy‐based index ) and patterns of inter‐individual diet variation (here defined by the interaction‐exclusiveness index H2′ and the interaction evenness index E2). Niche width was very variable among populations and overall network specialization (H2′) was always higher than the expected by null models. In case of high‐speed flying prey (e.g. flies, bees), wasps showed wider niches () and lower specialization (H2′) than in case of non‐flying or slow‐flying prey (e.g. spiders, beetles). Evenness (E2), on the other side, did not vary with prey mobility. Altogether, these results suggest that highly elusive prey may lead to wider predators’ niche but somehow limit their individual niche specialization.

Complex-to-Predict Generational Shift between Nested and Clustered Organization of Individual Prey Networks in Digger Wasps

“…Inter-individual variation ( E ) was detected in our aggregation in all three years studied, agreeing with previous results obtained for this species using slightly different, not network-based indices of prey overlap [17], [19]. Such resource partitioning among individuals showed, however, different shapes depending on the year.…”

“…Our results reinforce the view that network-based approaches are useful at the individual level and that they can help to uncover peculiar patterns of resource use within populations [19], [23], [34]. Inter-individual variation ( E ) was detected in our aggregation in all three years studied, agreeing with previous results obtained for this species using slightly different, not network-based indices of prey overlap [17], [19].…”

Food load manipulation ability shapes flight morphology in females of central-place foraging Hymenoptera

“…In UtM-wasps, which are also those limited to hunt for living prey, lower WL could increase manoeuvrability during prey transportation, but could also increase efficiency while pursuing a living prey (e.g. via reduced minimum flight-speed requirement and turning radius), including fast-flying insects [48]. A similar example involves bats, in which species with greater WL forage in areas where there are fewer obstacles to detect and avoid [49].…”

Nest-based information transfer and foraging activation in the common wasp (Vespula vulgaris)

“…Individual specialization in solitary wasps is driven by many factors, including predator/ prey size relationships (Polidori et al 2010), prey mobility (Polidori et al 2013), abundance (Santoro et al 2011) and nest-nest distance (Polidori et al 2012). The ultimate availability of the resources and the inter-individual information flow, together with the underlying learning processes involved, can be key for explaining individual foraging patterns both in a solitary and a social context.…”