José M. Salgado

Ancient origin of a Western Mediterranean radiation of subterranean beetles

BackgroundCave organisms have been used as models for evolution and biogeography, as their reduced above-ground dispersal produces phylogenetic patterns of area distribution that largely match the geological history of mountain ranges and cave habitats. Most current hypotheses assume that subterranean lineages arose recently from surface dwelling, dispersive close relatives, but for terrestrial organisms there is scant phylogenetic evidence to support this view. We study here with molecular methods the evolutionary history of a highly diverse assemblage of subterranean beetles in the tribe Leptodirini (Coleoptera, Leiodidae, Cholevinae) in the mountain systems of the Western Mediterranean.ResultsCa. 3.5 KB of sequence information from five mitochondrial and two nuclear gene fragments was obtained for 57 species of Leptodirini and eight outgroups. Phylogenetic analysis was robust to changes in alignment and reconstruction method and revealed strongly supported clades, each of them restricted to a major mountain system in the Iberian peninsula. A molecular clock calibration of the tree using the separation of the Sardinian microplate (at 33 MY) established a rate of 2.0% divergence per MY for five mitochondrial genes (4% for cox1 alone) and dated the nodes separating the main subterranean lineages before the Early Oligocene. The colonisation of the Pyrenean chain, by a lineage not closely related to those found elsewhere in the Iberian peninsula, began soon after the subterranean habitat became available in the Early Oligocene, and progressed from the periphery to the centre.ConclusionsOur results suggest that by the Early-Mid Oligocene the main lineages of Western Mediterranean Leptodirini had developed all modifications to the subterranean life and were already present in the main geographical areas in which they are found today. The origin of the currently recognised genera can be dated to the Late Oligocene-Miocene, and their diversification can thus be traced to Miocene ancestors fully adapted to subterranean life, with no evidence of extinct epigean, less modified lineages. The close correspondence of organismal evolution and geological record confirms them as an important study system for historical biogeography and molecular evolution.

Ecología trófica de Lacerta lepida en la provincia de León, noroeste de España

The diet of Lacerta lepida in the province of Leon (NW Spain) was studied through the analysis of 286 faecal pellets collected during May-August. Insecta were the numerically most important prey group, and always represented more than 85 % of prey numbers. Coleoptera and Hymenoptera were the dominant orders. Other important prey groups were Heteroptera and Arachnida. The number of Orthoptera consumed increased gradually from May to August. With respect to the occurrence frequency of prey in the faecal pellets, Coleoptera and Hymenoptera occurred in more than 75% at all times. The lowest trophic diversity was detected in june-july. Seasonal changes in the diet were noteworthy within short-terms and augmented in the long-term. The average length of the invertebrate prey was within the interval 9-14 mm. In terms of energy content, Vertebrata (43.82%), Coleoptera (15.77%), Orthoptera (14.40%) and Hymenoptera (13.95%) were the principal groups. L. lepida is considered to be an opportunistic feeder, although some prey groups are apparently selected.