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

Abstract

International audienceIn most European freshwater ecosystems, the invasive gammarids Gammarus tigrinus and Dikerogammarus villosus strongly impair recipient communities through predation of a wide range of native invertebrates. Due to the effects of temperature on both the physiology and the behaviour of such ectotherms, understanding how global warming may influence their ecological impact is a research priority. These species were therefore exposed to three different food types to determine their detritivorous, herbivorous and carnivorous characters, and predation was measured characterizing the Holling’s functional response. The effect of increasing water temperatures (15, 20, 25°C) on both the food choice and predatory activities was investigated. Both species showed a significant preference for animal tissues at all temperatures. The total food intake increased with temperature for G. tigrinus but did not change for D. villosus, which may result from specific species differences in metabolic requirements. The consumption of live prey strongly increased with temperature. The main differences were an increased searching efficiency in G. tigrinus and a decreased handling time in D. villosus as temperature increased, which may result from differences in foraging strategies. These results suggest that climate change is likely to increase the predation pressure of both invasive gammarids on prey species

Additive effects of temperature and infection with an acanthocephalan parasite on the shredding activity of Gammarus fossarum (Crustacea: Amphipoda): the importance of aggregative behavior

“…Most studies have reported a lower resistance of female gammarids to different stress (pollutants, hypoxia, salinity, temperature: McCahon & Pascoe, ; Hoback & Barnhart, ; Sornom et al ., ), potentially explaining the lower food consumption of females compared to males, relative to their size, as observed in our study. Several other investigators have reported sex‐related differences in food consumption by amphipods, but, contrary to our study, in most cases, food consumption was lower in males (Foucreau et al ., , ; Pellan et al ., ).…”

“…Similarly, Schmidlin et al . () observed a slightly reduced feeding activity of G. fossarum above 16 °C, while that of males Dikerogammarus villosus decreased between 20 and 25 °C (Pellan et al ., ).…”

“…Recently, it has been demonstrated that the consumption of leaves by Gammarus pulex amphipods tended to increase, although not linearly, with rising temperatures (Foucreau et al, 2016; see also Pellan et al, 2015).…”

“…However, the functional role of gammarids as shredders has been shown to depend upon several parameters including both biotic interactions, such as the presence of other gammarid species (Piscart et al ., ; Constable & Birkby, ) or predators (Åbjörnsson et al ., ), and abiotic parameters, such as microhabitat characteristics (Felten et al ., ) or the presence of pollutants (Dedourge‐Geffard et al ., ; Andreï et al ., ). Recently, it has been demonstrated that the consumption of leaves by Gammarus pulex amphipods tended to increase, although not linearly, with rising temperatures (Foucreau et al ., ; see also Pellan et al ., ).…”

Preface: Vulnerability and resilience of freshwater and marine ecosystems

“…The work of Boudouresque et al (2015) presents a bibliographic review of the functioning of Posidonia meadows (Posidonia oceanica seagrass meadow), summarizing the services associated with the Mediterranean ecosystem, specifically its necromass, which is particularly vulnerable and plays an important role in stabilizing coastal erosion and fixing carbon. Pellan et al (2015) show the impact of global warming on the ecological success of the invasive species Dikerogammarus villosus. Rocarpin et al (2015) demonstrate the key role played by functional niche plants in temporary Mediterranean marshes, it could be useful in developing water management plans, or even planning for how to adapt to a changing environment.…”