Wildfires induce a reduction in body size and morphological variation of an insular endemic insect

Abstract

Anthropogenetic disturbance is known to affect population sizes and genetic population structure of many biotas. Wildfires are a major disturbance in many regions of the world, particularly in Mediterranean regions and on the Atlantic islands. Populations of many insects, such as the Madeiran Green Bush-Cricket (Psalmatophanes barretoi), are threatened by wildfires. However, the effects of wildfires on genetic structure and diversity as well as morphological variation of the populations remain little understood. Therefore, we studied genetic diversity, structure and potential bottlenecks of this species using microsatellites. We also studied morphological variation and fluctuating asymmetry within and between populations to unravel potential effects of wildfires. We did not find any evidence for genetic differentiation of populations, but some populations had high heterozygosity excess, regardless of burning. Morphological variation in burnt areas was lower than in non-burnt areas. Fluctuating asymmetry of the wing length was significantly higher in burnt areas. Our results show that even genetically well-connected populations may suffer from bottlenecks leading to reduced morphological variation after disturbance.