Testing biennialism in the butterfly Erebia palarica (Nymphalidae: Satyrinae) by mtDNA sequencing

The importance of time scale and multiple refugia: Incipient speciation and admixture of lineages in the butterfly Erebia triaria (Nymphalidae)

Evidence of four different Quaternary glacial stages has been found in NW Iberia. The different magnitude of these episodes probably conditioned the distribution of currently montane species. We examined if the population history of NW Iberian Erebia triaria butterflies reflected such an influence of different glacial stages. We also investigated whether these populations were post-glacially colonised from a single refugial area or several sources. For this, we performed phylogenetic analyses and coalescence simulations on mitochondrial DNA sequences of individuals from five NW Iberian locations. We analysed three additional populations as reference, i.e., Central Spain, the Pyrenees, and the Alps. One of the NW Iberian populations, a subspecies endemic to a particular mountain range (Xistral), showed a high level of genetic divergence from all other populations, regardless of their geographic distance. Isolation after an ancient glacial stage, and followed by allopatric differentiation, may account for such high differentiation. The genetic pattern shown by the rest of the NW Iberian population samples consisted of two lineages, likely reflecting that the ancestors of these populations sought for refuge in at least two different areas during a subsequent glacial stage. We showed evidence of both temporal and spatial divisions in the phylogeography of these butterflies. The congruence of this pattern with the geological history suggests that the Iberian Peninsula hosted several refugial areas that differed in area and location depending on the glacial stage.

Terrestrial insects along elevation gradients: species and community responses to altitude

The literature on the response of insect species to the changing environments experienced along altitudinal gradients is diverse and widely dispersed. There is a growing awareness that such responses may serve as analogues for climate warming effects occurring at a particular fixed altitude or latitude over time. This review seeks, therefore, to synthesise information on the responses of insects and allied groups to increasing altitude and provide a platform for future research. It focuses on those functional aspects of insect biology that show positive or negative reaction to altitudinal changes but avoids emphasising adaptation to high altitude per se. Reactions can be direct, with insect characteristics or performance responding to changing environmental parameters, or they can be indirect and mediated through the insect's interaction with other organisms. These organisms include the host plant in the case of herbivorous insects, and also competitor species, specific parasitoids, predators and pathogens. The manner in which these various factors individually and collectively influence the morphology, behaviour, ecophysiology, growth and development, survival, reproduction, and spatial distribution of insect species is considered in detail. Resultant patterns in the abundance of individual species populations and of community species richness are examined. Attempts are made throughout to provide mechanistic explanations of trends and to place each topic, where appropriate, into the broader theoretical context by appropriate reference to key literature. The paper concludes by considering how montane insect species will respond to climate warming.