Non-native species introductions are widespread and can affect ecosystem functioning by altering the structure of food webs. Invading plants often modify habitat structure, which may affect the suitability of vegetation as refuge and could thus impact predator-prey dynamics. Yet little is known about how the replacement of native by non-native vegetation affects predator-prey dynamics. We hypot...

Precopulatory mate guarding (PCMG) is generally assumed to be costly for both sexes. However, males may gain by displaying long-lasting mate guarding under strong male-male competition. Surprisingly, the potential for females to benefit from being held by males has been largely overlooked in previous studies. In Gammarus pulex, an amphipod crustacean, PCMG lasts several weeks, yet females are d...

In forested headwater streams, inconspicuous food resources such as epilithic microalgae can play a major role owing to their content of long chain polyunsaturated fatty acids (PUFAs) that are essential for macroinvertebrate development. Yet, the use these and consequences consumers life-history traits remain scarcely studied, especially non-herbivorous taxa. Using instream mesocosms, we aimed ...

Group living has evolved as an adaptation to predation in many animal species. In a multitude of vertebrates, the tendency to aggregate varies with the risk of predation, but experimental evidence for this is less well known in invertebrates. Here, we examine the tendency to aggregate in the freshwater amphipod Gammarus pulex in the absence and presence of predator fish odour. Without fish odou...

The purpose of this sudy was to examine the toxic effects of bufadienolides of antimicrobial peptides and alkoloids on Gammarus pulex L.(Crustacea:Amphipoda:Gammaridae) Bufadienolides (Arenobufagin, Arenobufagin hemisuberate, Arinobufagin 3sulfate, Bufalin, Bufalin hemisuberate, Bufoatlin 3-sulfate, Bufotalinin, Bufotalone, Cinobufagin, Cinobugagilon, Cinobufotalin, Desacetylcinobufagin, Gamabu...

The exoskeleton of arthropods forms an efficient protection against pathogens, but this first line of defence is periodically weakened during ecdysis, increasing the opportunity for surrounding pathogens to invade the body cavity. Since the richness of pathogens in the environment can be spatially and temporally variable, arthropods may have a fitness advantage in moulting in a place and time o...

Crustacean intersexuality is widespread and often linked to infection by sex-distorting parasites. However, unlike vertebrate intersexuality, its association with sexual dysfunction is unclear and remains a matter of debate. The 'Demon Shrimp,' Dikerogammarus haemobaphes, an amphipod that has invaded continental waterways, has recently become widespread in Britain. Intersexuality has been noted...

So far, ecotoxicological studies used biomarkers of exposure or of effects in order to investigate the impacts of contaminated areas on biota (Peakall, 1994 [6]). However, although these results are important in the ecotoxicological risk assessment, biomarkers are very specific and only provide information on the biological processes or physiological pathways targeted by the biomarkers experime...

This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and 15 °C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, sur...