Feeding choice and predation pressure of two invasive gammarids, Gammarus tigrinus and Dikerogammarus villosus, under increasing temperature

Laura Pellan, Vincent Médoc, David Renault, Thierry Spataro, Christophe Piscart
2015 Hydrobiologia  
17 In most European freshwater ecosystems, the invasive gammarids Gammarus tigrinus and 18 Dikerogammarus villosus strongly impair recipient communities through predation of a wide range of 19 native invertebrates. Due to the effects of temperature on both the physiology and the behaviour of such 20 ectotherms, understanding how global warming may influences their ecological impact is a research 21 priority. These species were therefore exposed to three different food types to determine their
more » ... detritivorous, herbivorous and carnivorous characters, and predation was measured characterizing the 23 Holling's functional response. The effect of increasing water temperatures (15, 20, 25 °C) on both the 24 food choice and predatory activities was investigated. Both species showed a significant preference for 25 animal tissues at all temperatures. The total food intake increased with temperature for G. tigrinus but 26 did not change for D. villosus, which may result from specific-species differences in metabolic 27 requirements. The consumption of live prey strongly increased with temperature. The main differences 28 were an increased searching efficiency in G. tigrinus and a decreased handling time in D. villosus as 29 temperature increased, which may result from differences in foraging strategies. These results suggest 30 that climate change is likely to increase the predation pressure of both invasive gammarids on prey 31 species. 32 33
doi:10.1007/s10750-015-2312-3 fatcat:vkl7b4ffz5eylcyeaso3ucqhqy