In the last decade, several studies have shown that subterranean aquatic habitats harbor cryptic species with restricted geographic ranges, frequently occurring as isolated populations. Previous studies on aquatic subterranean species have implied that habitat heterogeneity can promote speciation and that speciation events can be predicted from species' distributions. We tested the prediction t...

The physiological mechanisms by which parasites with complex life cycles manipulate the behaviour of their intermediate hosts are still poorly understood. In Burgundy, eastern France, the acanthocephalan parasite Pomphorhynchus laevis inverses reaction to light in its amphipod host Gammarus pulex, but not in Gammarus roeseli, a recent invasive species. Here, we show that this difference in mani...

The freshwater genus Hyalella Smith, 1874 has a distribution restricted to the Western Hemisphere with most species being found in South America. In this report we describe a new species of Hyalella from the Atlantic Forest of the Misiones province, Argentina.

A new species of the genus Paracaprella is described based on the specimens associated with the algae Sargassum cymosum and Laurencia obtusa that were collected from infralittoral depths (0.5 to 3.0 m) at Sepultura Beach, Bombinhas and Paciência Beach, Penha, Santa Catarina State, Brazil. This new species differs from the others of the genus by the unique morphology of the males' gnathopod 2: i...

The interactive effects of changing biodiversity of consumers and their prey are poorly understood but are likely to be important under realistic scenarios of biodiversity loss and gain. We performed two factorial manipulations of macroalgal group (greens, reds, and browns) and herbivore species (amphipods, sea urchin, and fish) composition and richness in outdoor mesocosms simulating a subtida...

Genome size varies considerably across taxa, and extensive research effort has gone into understanding whether variation can be explained by differences in key ecological and life-history traits among species. The extreme environmental conditions that characterize the deep sea have been hypothesized to promote large genome sizes in eukaryotes. Here we test this supposition by examining genome s...

Neonicotinoid insecticides like thiacloprid enter agricultural surface waters, where they may affect predator-prey-interactions, which are of central importance for ecosystems as well as the functions these systems provide. The effects of field relevant thiacloprid concentrations on the leaf consumption of Gammarus fossarum (Amphipoda) were assessed over 96 h (n = 13-17) in conjunction with its...

Many parasites with complex life cycles increase the chances of reaching a final host by adapting strategies to manipulate their intermediate host's appearance, condition or behaviour. The acanthocephalan parasite Pomphorhynchus laevis uses freshwater amphipods as intermediate hosts before reaching sexual maturity in predatory fish. We performed a series of choice experiments with infected and ...

Sexual traits are especially sensitive to low food resources. Other environmental parameters (e.g., predation) should also affect sexual trait expression by favoring investment in viability traits rather than sexual traits. We know surprisingly little about how predators alter investment in sexual traits, or how predator and resource environments interact to affect sexual trait investment. We e...

As biomarkers are known to be influenced by biotic and abiotic factors (e.g. gender, temperature), we investigated over a one-year long sampling period, the influence of season and gender on reduced glutathione concentrations and its synthesis in the crustacean amphipod Gammarus roeseli. At the same time, we assessed energy reserves and malondialdehyde levels as toxic biomarker. Results have sh...