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Adaptive feeding behavior of Duphnia magna in response to short‐term starvation
Author(s) -
Plath Klaus
Publication year - 1998
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1998.43.4.0593
Subject(s) - starvation , foraging , daphnia magna , appendage , biology , feeding behavior , escape response , zoology , daphnia , food intake , branchiopoda , functional response , ecology , food science , cladocera , medicine , endocrinology , crustacean , predation , toxicity , predator
Feeding behavior of Daphnia has been intensely studied, yet the generally observed behavior of maximal feedingat low food concentrations contradicts the predictions of optimal foraging theory. To explore this inconsistency, 1investigated the behavioral feeding response of Daphnia magna through direct observation of thoracic filteringappendage beat rates at low food concentrations. I observed animals that were subjected to either varying starvationperiods or to different food concentrations prior to the experiments. Starvation led to a behaviorally mediateddecrease in appendage beat rate, which depended on the food concentration at which the daphnids were cultured.Starved daphnids consistently showed an almost immediate increase in their appendage beat rate once food wasadded, irrespective of the length of the starvation period (from 1 to 3 d). Therefore, the initial decrease in appendagebeat rate displayed by animals during starvation could not have been caused by the deprivation of energy (exhaustion)alone. Furthermore, the food conditions under which the animals were cultured influenced the behavioralresponse. After 1 h of starvation, animals cultured at high food level showed no behavioral response to the additionof food, while animals cultured at low food level increased their appendage beat rate significantly. The results ofthis study contradict the maximal feeding strategy and highlight problems of the optimal foraging strategy.