Body size, body size ratio, and prey type influence the functional response of damselfly nymphs

• Published in: Oecologia Vol. 185; no. 3; pp. 339 - 346
• Main Authors: Uiterwaal, Stella F., Mares, Courtney, DeLong, John P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Science + Business Media 01.11.2017; Springer Berlin Heidelberg; Springer; Springer Nature B.V
• Subjects: Animals; Aquatic crustaceans; Aquatic insects; Biomedical and Life Sciences; Body Size; Chydorus; Copepoda; Daphnia; Daphnia - physiology; Ecology; Food Chain; Food chains; Food webs; Forage; Foraging behavior; Freshwater crustaceans; HIGHLIGHTED STUDENT RESEARCH; Hydrology/Water Resources; Life Sciences; Nymph - physiology; Plant Sciences; Predator-prey interactions; Predatory Behavior - physiology; Prey; Predator–prey interaction; Copepods; Handling time; Daphnia; Chydorus
• ISSN: 0029-8549; 1432-1939
• DOI: 10.1007/s00442-017-3963-8

Predator–prey interactions play a crucial role in structuring food webs, and the functional response is one way to measure the strength of this interaction. Here, we examine how predator and prey body size affects the functional response of a generalist predator—damselfly nymphs—feeding on three prey types: copepods, Daphnia, and Chydorus. Our results suggest that consumption of copepods is independent of predator body size, while increased predator body size is associated with an increased space clearance rate for Daphnia and a reduced space clearance rate for Chydorus. When considered together, foraging rates on Daphnia and Chydorus (both cladocerans) are consistent with a hump-shaped functional response, with peak foraging rates occurring at an intermediate predator–prey size ratio. Thus, although most food web theory assumes allometric predator–prey links or peaked functional responses at intermediate predator–prey size ratios, our results suggest that both relationships may occur in food webs, in addition to size-independent functional responses.