Larval feeding habits of Tabanus biguttatus and Amanella emergens in South Africa (Diptera: Tabanidae)

Since little is known of the larval feeding habits of tabanids, field and laboratory observations were carried out on the larvae of Tabanus biguttatus Wied. and Cydistomyia emergens (Oldroyd) (Amanella emergens) in Cape Province, South Africa, including their distribution, natural habitats and predation. Larvae of T. biguttatus were found buried in the mud of a mountain stream near Grahamstown, each one feeding on a large tipulid larva (probably Tipula pomposa Bergr., of which the larvae are aquatic). On being transferred to the laboratory the tabanids continued to consume tipulid larvae but did not pupate. Adults of C. emergens were observed biting man on several occasions near Grahamstown. Larvae of this species were observed on the coast near Port Alfred living in sand just above the high-water mark and apparently feeding on crustacea and insect larvae. Some that were transferred to the laboratory in Grahamstown or in London (UK) fed on freshly killed nymphs of locusts and grasshoppers, and 2 of the larvae in London that were reared on locusts pupated and gave rise to adults. It is suggested that the larvae of C. emergens are opportunistic feeders and are able to eat both living and dead prey of suitable size encountered in their natural habitat of damp sand.