title: Individual variation in functional response parameters is explained by body size but not by behavioural types in a poeciliid fish.
abstract: Functional responses are per-capita feeding rate models whose parameters often scale with individual body size but the parameters may also be further influenced by behavioural traits consistently differing among individuals, i.e. behavioural types or animal personalities. Behavioural types may intrinsically lead to lower feeding rates when consistently shy, inactive and easily stressed individuals cannot identify or respond to risk-free environments or need less food due to lower metabolic rates linked to behaviour. To test how much variation in functional response parameters is explained by body size and how much by behavioural types, we estimated attack rate and handling time individually for differently sized female least killifish (Heterandria formosa) and repeatedly measured behavioural traits for each individual. We found that individual fish varied substantially in their attack rate and in their handling time. Behavioural traits were stable over time and varied consistently among individuals along two distinct personality axes. The individual variation in functional responses was explained solely by body size, and contrary to our expectations, not additionally by the existing behavioural types in exploration activity and coping style. While behavioural trait-dependent functional responses may offer a route to the understanding of the food web level consequences of behavioural types, our study is so far only the second one on this topic. Importantly, our results indicate in contrast to that previous study that behavioural types do not per se affect individual functional responses assessed in the absence of external biotic stressors.
authors: Department IV: Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany. arne.schroeder@igb-berlin.de.
authors: Arne
authors: http://orcid.org/0000-0002-8461-9622
authors: A
authors: Schröder
authors: Department IV: Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany.
authors: Gregor
authors: G
authors: Kalinkat
authors: Department IV: Biology and Ecology of Fishes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Müggelseedamm 310, 12587, Berlin, Germany.|Division of Integrative Fisheries Management, Faculty of Life Sciences, Humboldt Universität zu Berlin, Philippstraße 13, Haus 7, 10115, Berlin, Germany.
authors: Robert
authors: R
authors: Arlinghaus
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D049628:Body Size; D005260:Female; D005399:Fishes; D011235:Predatory Behavior
keywords: Allometric relationships; Food webs; Foraging; Population structure; Trait variation