The effect of habitat amount on flight‐related traits in the butterfly Hamadryas februa is sex‐dependent. (26th November 2022) - Lion, Marília Bruzzi
Abstract: Mobility in flying animals can be assessed by variations in morpho–ecological traits such as body, thorax and wing sizes, wing shape and the proportion between body mass and wing area. Habitat loss and fragmentation can promote phenotypic plasticity and microevolutionary divergencies in natural populations. In this context, sexual differences in physiology and behaviour can impose different selection pressure on morphological aspects related to flight. We evaluated the relative impact of forest patch area and habitat amount in shaping flight‐related morpho–ecological traits of the tropical butterfly Hamadryas februa . We find a marked sexual dimorphism in the species, with females being larger, having larger thorax, higher wing loadings and larger wing total area than males. These trait values indicate females as the more dispersive sex. We show that habitat amount modulates body mass allocations in both sexes, leading to an increase in thorax mass with decreasing habitat amount. The effect of habitat amount was more pronounced in females, which increased total mass and wing loading while decreasing thorax allocation with decreasing habitat amount. This outcome suggests that females increase abdominal mass in response to a reduction in habitat amount. The focal forest patch increasing area was linked to increases in hindwing lengths in both females and males. We advocate that both landscape metrics (i.e., habitat amount and patch area) should be considered in studies evaluating landscapes' impacts on insect mobility. We discuss results in terms of the species' sexual differences in flight behaviour and the relative importance of both landscape metrics. Abstract : Habitat amount reduction increases female total mass, wing loading and thorax mass while decreasing thorax mass allocation. Consequently, females are accumulating abdominal mass when less habitat is available. Both sexes decrease thorax mass with increasing habitat amount, and increase hindwing length with increasing patch area. However, dispersal between fragments may impose an extra challenge for egg‐carrying females. Habitat amount and focal patch area affect Hamadryas februa mobility and should be considered in studies evaluating habitat loss and fragmentation impacts on biodiversity.