Functional responses of three guilds of spiders: Comparing single‐ and multiprey approaches

Abstract

Spiders are successful natural enemies of pests occurring throughout the different strata of an agroecosystem. The study of their functional responses can provide information related to the potential effectiveness of different species and guilds on reducing a pest population. However, multiple prey availability may change the functional response of a predator. In this study, the functional responses of three species of spiders in single-prey and multiple-prey experiments were modelled. The spider species Haplodrassus rufipes, Araniella cucurbitina and Synema globosum were chosen as being representatives of ground runners, orb-weavers and ambushers, respectively. Three prey species were selected: a target prey, the Mediterranean fruit fly Ceratitis capitata and two alternate prey species, the flour moth Ephestia kuehniella and the house cricket Acheta domesticus. When the selected target prey C. capitata was supplied in the single-prey experiments, the most and the least efficient spider species were H. rufipes and S. globosum, respectively. However, opposite results were obtained when alternative preys were supplied. Also, A. cucurbitina significantly changed its functional response with the presence of alternative prey species. Considering the prey preference during the multiple-prey experiments, A. domesticus, used as representative of a heavy, long-sized and highly motile prey, was avoided whereas C. capitata, the target pest used as representative of light, small-sized and moderately motile prey was preferred by the three species of spiders. Ephestia kuehniella, used as representative of light, medium-sized and low motile prey was occasionally consumed. Each guild could include efficient predators against pests according to its hunting strategies and the ecological exploited niches. Orb-weavers could be efficient predators against flying pests; ambushers such as S. globosum could contribute to the reduction of the populations of flower-visiting pests, whereas active ground hunters may also play an important role preying on pests that develop a part or all of its life cycle in the ground. However, further research on feeding behaviour such as prey switching is needed for a better understanding of the effectiveness of spiders as natural enemies.

Functional Response of Chrysoperla carnea (Neuroptera: Chrysopidae) Larvae on Saissetia oleae (Olivier) (Hemiptera: Coccidae): Implications for Biological Control

“…The relative importance of C. carnea as predator of S. oleae can change depending on a variety of factors, e.g., the prey community composition (richness and/or diversity), its mean body size [59], the trophic complexity [60], the relative preference of the predator for prey or habitat complexity [61]. For example, the predatory efficiency of a generalist predator on a target prey species can shift in the presence of alternative prey [62]. Furthermore, predator persistence is maximized when the minimum prey size in the community is intermediate, but as prey diversity increases, the minimum body size could adopt a broader range of values [59].…”

Prey contaminated with neonicotinoids induces feeding deterrent behavior of a common farmland spider

“…Overkilling was repeatedly demonstrated as a feeding strategy of cursorial generalist spiders but occurs in specialized spider species as well. Overkilling positively correlates with prey density 19,23,26,27 . The reasons for the use of overkilling as a feeding strategy of spiders are unknown.…”

A Guild-Based Protocol to Target Potential Natural Enemies of Philaenus spumarius (Hemiptera: Aphrophoridae), a Vector of Xylella fastidiosa (Xanthomonadaceae): A Case Study with Spiders in the Olive Grove

“…Moreover, since it would not be wise to assume that all spider species would follow the same functional response within the same guild, this still makes mandatory to test the functional response of different predators using the same hunting strategy to uncover both patterns and exceptions. Also, the effect of a resource-based competition and prey preference could have effect on the predatory efficiency and should be investigated, for example using multiple predators and prey species in functional response assays [29]. Finally, in terms of sampling design, targeting different vertical strata (e.g., trunk and canopy of the olive tree) most likely will improve the spectrum of potential species of candidate predators.…”

“…Males and females of P. spumarius were randomly mixed and placed within the arenas (i.e., no specific sex rate was considered). Each arena was built using a round plastic cage (7.7 cm in diameter and 4.3 cm height) covered with the lid of a glass Petri dish (9 cm in diameter) [28,29].…”