Adaptations to local communities and current environments

Regional (meta-)populations of specialist insect species, such as myrmecophiles, may be adapted to their local environment more strongly, and at smaller scales, than is recognised in current paradigms. The aim of WP2 is to (i) investigate patterns of host specificity in European myrmecophiles, (ii) to examine sub-specific adaptations to local climate and (iii) to assess variation in dispersal in different myrmecophilous systems.

Patterns of host specificity (i) will be analysed across a spectrum of myrmecophilous life-styles by empirical studies as well as replicated lab bioassays. Analyses of the chemical compounds of the parasite-host communication system will identify the mechanisms of adaption of social parasites to regional populations of hosts. After all we will develop single site models to investigate how genetic diversity of neutral or host-linked traits establish themselves locally, and how immigrants (mutants) would perform in mutualist, parasitic, or single species systems. Relatively small adjustments to the above models will enable us to simulate metapopulations of interacting species.

(ii) Four studies will test our hypothesis that regional genotypes of European insects are optimally adapted to their local climate ± about 2^oC; one lab experiment on the physiology and fitness in Myrmica rubra (host of Annex II Maculinea nausithous) across a European climatic gradient, one study on butterfly population changes when mean temps deviate by >± 2^oC, measurements of asynchrony with foodplant phenology in Swedish Maculinea arion moved to UK climates, and measurements of the rate at which phenology in Maculinea arion adapts to new climates.

Low dispersal is a major obstacle that prevents many insects from tracking new habitat patches in modern fragmented landscapes or when their climate-windows shift. Our assessment of variation in dispersal in different myrmecophilous systems will be focused on the neglected, least-mobile end of the spectrum of social parasites, represented by the hoverflies Microdon mutabilis and M. myrmicae. We will also analyse existing MRR datasets for Maculinea species to generate parameters describing immigration rates for spatially explicit models of landscapes, as predicted habitat availability shifts under future land-uses and climates. The evolution of dispersal in different myrmecophilous systems will be a subject of the single site and metapopulation models mentioned above.