Revision of the African geometrid genus Zerenopsis C. &. R. Felder – moths with peculiar life histories and mating behaviours (Geometridae: Ennominae: Diptychini)

The taxonomy of the African geometrid genus Zerenopsis C. &. R. Felder, 1874, placed in the subfamily Ennominae and tribe Diptychini (cycad moths), is revised. Based on a detailed comparison of morphological characters, Diptychis C. &. R. Felder, 1874 and Paraptychodes Warren, 1894 are placed as junior subjective synonyms of Zerenopsis C. &. R. Felder, 1874 (syn. n.). Consequently, five new species combinations (comb. n.) are proposed: Zerenopsis geometrina (C. &. R. Felder, 1874), Zerenopsis meraca (Prout, 1928), Zerenopsis kedar (Druce, 1896), Zerenopsis tenuis (Butler, 1878) and Zerenopsis costimaculata (Prout, 1913). Two new species are described: Zerenopsis moi Staude & Sihvonen (sp. n.) from Mozambique and Zerenopsis flavimaculata Staude & Sihvonen (sp. n.) from Malawi, raising the total number of species in the genus Zerenopsis from one to eight. The constituent species are diagnosable by morphological characters, particularly by facies and genetic COI data, whereas the male and female genitalia are rather uniform and less diagnostic. The life histories of Z. lepida (Walker, 1854), Z. moi and Z. costimaculata and the final-instar larvae of Z. geometrina and Z. tenuis are described. All known larvae are aposematic, feed on cycads during the early stages of their life cycle and accept other, unrelated plants in later instars. Zerenopsis adults are aposematic and diurnal. Lek behaviour is described for Z. lepida, Z. tenuis and Z. moi, and evidence is presented that it also occurs in other Zerenopsis species. This mating strategy is potentially unique among Geometridae. The androconial organs of the males are described and illustrated as forming a ‘pheromone pocket’ whose development is related to the lek behaviour. Information on habitat, distribution, conservation status and genetics is provided for the majority of the species. Diagnostic characters of the adults, including of the male and female genitalia where known, are described for all species.