Distribution of Mantodea in South Africa and biological studies of selected species

Abstract

Despite human fascination with the Mantodea or praying/preying mantids over millennia, very little is known about of their diversity, biology and ecology, especially in South Africa. Praying mantids are not only important because of the ecosystem services they provide, but it is also suggested that they have a “mystical‘’ status and are regarded as a kind of oracle in some cultures. Acknowledgement of the cultural importance of the Mantodea may contribute to a positive change in people’s perceptions of arthropods, which may lead to an increase in insect appreciation. Due to the cultural value associated with Mantodea, these insects could be used as a flagship or gateway species to advance peoples’ awareness of insects, increase their appreciation and ultimately conservation. The Mantodea is a small order of insects with approximately 2400 species worldwide. The very limited literature on South African Mantodea includes a species list compiled 20 years ago. The aim of this study was to determine which species occur in South Africa and to study the biology of selected species. A checklist of the Mantodea of southern Africa was compiled from approximately 4000 specimen records, collected from 1849 to 2019, and which are kept in six national museums in South Africa. This checklist included 198 species, 60 genera and 11 families, with new distribution records for one genus and 20 species. Distribution maps were developed for 178 spp. of which 91 were regarded to be “rare” species. Museum records were further used to assess species richness thus compare mantid species diversity between different biomes of South Africa. Mantids seemed more prevalent in the Savanna, Grassland and Indian Ocean Coastal Belt biomes. Various hotspots were identified throughout South Africa and its biomes and indicated areas of "rare" mantid species conglomeration. Species that occurred in only one biome were identified since these species could be habitat specialists or possibly be rare or endangered. The distribution of Galepsus lenticularis (Mantodea: Tarachodidae), Popa spurca (Mantodea: Mantidae) and Harpagomantis tricolor (Mantodea: Galinthiadidae) were described and their biology studied under captive rearing conditions. The duration of male and female nymphal stages of G. lenticularis were similar but longevity of adult females were three times longer than that of males. This phenomenon as well as a long period (20 days) between oviposition of different oothecae, together with an incubation period of 20 days suggests a survival strategy that reduces competition between siblings. The mean number of eggs per ootheca was 49.8. Eleven Galepsus spp. were recorded in southern Africa and the first record of Galepsus centralis, in South Africa was established. The nymphal development period of P. spurca however differed between the sexes and adult longevity was significantly longer in females. The average lifespan of a P. spurca individual was 332 days. Oothecae contained an average of 84 eggs and the mean incubation period was 35 days. The mean duration of the lifecycle of H. tricolor was 191 days and the incubation period of oothecae was 144 days. This study not only provides a glimpse into a group of insects that has been overlooked in the past, but addressed a group that has basically never been studied in South Africa. Fundamental knowledge about the distribution and diversity of South African mantid fauna was developed and can be used to guide future research on the ecology of the Mantodea and to identify and mitigate possible threats.