Journal Article

Dispersal ability rather than ecological tolerance drives differences in range size between lentic and lotic water beetles (Coleoptera: Hydrophilidae)

Sánchez-Fernández, David, Calosi, Piero, Ribera, Ignacio, Abellán, Pedro, Bilton, David T., Millán, Andrés, Arribas, Paula, Velasco, Josefa, Andújar, Carmelo

2012

Overview

Aim In aquatic ecosystems, standing (lentic) and running (lotic) waters differ fundamentally in their stability and persistence, shaping the comparative population genetic structure, geographical range size and speciation rates of lentic versus lotic lineages. While the drivers of this pattern remain incompletely understood, the suite of traits making up the ability of a species to establish new populations is instrumental in determining such differences. Here we explore the degree to which the association between habitat type and geographical range size results from differences in dispersal ability or fundamental niche breadth in the members of the Enochrus bicolor complex, an aquatic beetle clade with species across the lentic–lotic divide. Location Western Mediterranean, with a special focus on North Africa, the Iberian Peninsula and Sicily. Methods DNA sequences for four loci were obtained from species of the E. bicolor complex and analysed using phylogenetic inference. Dispersal and establishment abilities were assessed in lentic–lotic species pairs of the complex, using flight wing morphometrics and thermal tolerance ranges as surrogates, respectively. Results There were clear differences in range size between the lotic and lentic taxa of the complex, which appears to have had a lotic origin with two transitions to standing waters. Only small differences were observed in temperature tolerance and acclimation ability between the two lotic–lentic sister species studied. By contrast, wing morphometrics revealed clear, consistent differences between lotic and lentic Enochrus species pairs, the latter having a higher dispersal capacity. Main conclusions We hypothesize that there have been two habitat shifts from lotic to lentic waters, which have allowed marked expansions in geographical range size in western Mediterranean species of the E. bicolor complex. Differences in dispersal rather than in establishment ability appear to underlie differences in geographical range extent, as transitions to lentic waters were associated with changes in wing morphology, but not in thermal tolerance range. In this lineage of water beetles, selection for dispersal in geologically short‐lived lentic systems has driven the evolution of larger range sizes in lentic taxa compared with those of their lotic relatives.

• Publisher: Blackwell Publishing Ltd,Blackwell Publishing,Blackwell,Wiley Subscription Services, Inc
• Subject: acclimation / Acclimatization / Animal and plant ecology / Animal behavior / Animal wings / Animal, plant and microbial ecology / Aquatic Coleoptera / Aquatic ecosystems / Aquatic habitats / Beetles / Biogeography / Biological and medical sciences / Biological taxonomies / Coleoptera / colonization capacity / Dispersal / Enochrus / Enochrus bicolor complex / Evolution / flight / Fundamental and applied biological sciences. Psychology / fundamental niche breadth / General aspects / Genetic structure / geographical range size / geographical variation / geological persistence / habitat constraints / habitat stability / habitats / heat tolerance / Hydrophilidae / Iberian Peninsula / Insect flight / Insecta / Invertebrate range dynamics / Invertebrates / lentic systems / loci / lotic systems / morphometry / Niche breadth / Northern Africa / nucleotide sequences / phylogeny / Salinity / Sicily / Speciation / Standing waters / Synecology / Taxa / temperature / Thermal stress / western Mediterranean