Alone on an island : The reassessment of an enigmatic species of Handmaiden Moth (Lepidoptera, Erebidae) endemic to Mauritius

Maculonaclia florida (de Joannis, 1906) has been one of the most mysterious moths of Mauritius, a small volcanic island located some 900 km east from Madagascar. Here, we reviewed its generic placement, phylogenetic relationships and the potential evolutionary scenarios leading to the current distribution of this unique Mauritian member of Syntomini. The species, known previously only from a few old museum specimens, is redescribed based on newly collected material including both sexes and eggs. The generic affiliation to the Palaearctic Dysauxes is confirmed based on morphological and molecular data. A hypothesis is presented on the colonization of Mauritius by the ancestor of D. florida from Madagascar through the now submerged stepping stone islands of the Mascarene ridge. Behavioural data and environment preferences of D. florida are assessed for the first time. The species prefers shrubby vegetation with a humid understory, and presence of endemic shrub Ixora parviflora seems to play a role in selecting the suitable microhabitat. Additionally, based on IUCN criteria, a CR threat category is proposed, highlighting the major risk factors affecting the species. The significant variation in wing venation of D. florida is noted and provisionally correlated with environmental stress, which is the consequence of human-caused habitat degradation. Finally, the study provides further evidence for the significant role of Madagascar in the diversification of continental biota, indicating a Malagasy origin of the African syntomine Pseudonaclia puella