Natural history of a South African insect pollinator assemblage (Insecta: Coleoptera, Diptera, Hymenoptera, Lepidoptera): diagnostic notes, food web analysis and conservation recommendations

Abstract

ABSTRACTWe describe activity patterns, relative abundances and pollen transport by insect floral visitors in the Skukuza Ranger District, Kruger National Park, Republic of South Africa, based on field surveys conducted during the early rainy seasons of years 2006 to 2012 (inclusive). Diagnostic notes, illustrations and natural history observations are provided for species in the families Buprestidae, Cerambycidae, Cleridae, Lycidae and Scarabaeidae (Coleoptera), Muscidae, Platystomatidae and Tabanidae (Diptera), Apidae, Halictidae, Megachilidae, Sphecidae and Vespidae (Hymenoptera), and Pieridae and Thyrididae (Lepidoptera) that transported pollen of tree or shrub species. Observations on floral phenology and pollination syndrome are presented for 27 flowering tree or shrub species. To provide a foundation for studies of the effects of drought and climate change on pollination services in the Kruger National Park, we applied methods of food web analysis to characterise this plant-pollinator assemblage. The food web analysis shows moderate levels of redundancy in plant-pollinator interactions (with connectance values averaging 0.19 for plant species and 0.20 for pollinator species), suggesting that pollination services in this system may exhibit some resilience to environmental perturbations. Possible conservation strategies for maintaining pollination services in this ecological system are discussed, including habitat management to conserve larval or nesting areas for social and solitary bees and scarab beetles, as well as further inventories and long-term monitoring of pollinator species.