Insect communities in saline waters consist of realized but not fundamental niche specialists.

Considering how organisms adapt to stress is essential if we are to anticipate biological responses to global change in ecosystems. Communities in stressful environments can potentially be assembled by specialists (i.e. species that only occur in a limited range of environmental conditions) and/or generalist species with wider environmental tolerances. We review the existing literature on the salinity tolerance of aquatic insects previously identified as saline specialists because they were exclusively found in saline habitats, and explore if these saline realized niche specialists are also specialists in their fundamental niches or on the contrary are fundamental niche generalist species confined to the highest salinities they can tolerate. The results suggest that species inhabiting saline waters are generalists in their fundamental niches, with a predominant pattern of high survival in freshwater-low salinity conditions, where their fitness tends to be similar or even higher than in saline waters. Additionally, their performance in freshwater tends to be similar to related strictly freshwater species, so no apparent trade-off of generalization is shown. These results are discussed in the framework of the ecological and evolutionary processes driving community assembly across the osmotic stress gradient, and their potential implications for predicting impacts from saline dilution and freshwater salinization.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.

A new species of Aphelocheirus (Hemiptera: Heteroptera: Aphelocheiridae) from Morocco.

This paper provides the description of a new species of Aphelocheirus (Hemiptera: Heteroptera: Aphelocheiridae), Aphelocheirus pemae sp. nov. from Morocco. The species was found in two sites located in different basins (Sebou and Moulouya rivers) that are separated by approximately 400 km. Photographs of the dorsal habitus of the female and illustrations of the male genitalic structures are provided. A graphical key to species of the genus in Western Europe and the Maghreb is also included. The new species can be easily distinguished by the unique shape of the left and right parameres and absence of apical spines on the aedeagus.