Most bee flies (Family Bombyliidae) are parasites. They feed externally on the larvae of bees and wasps, consuming the host when it is in a ‘quiescent stage such as the mature larva, prepupa or pupa’ (1). Some are even hyperparasites, which means that – in the larval stage – they feed on other parasites, themselves feeding on the larval stage of another insect. The adults generally feed on nectar and pollen and may play an important role as pollinators.
I have come across this fly a number of times in northern Thailand, when trying to take photographs of butterflies. It is quite large (well over 1 cm in length) and commonly rests on the ground, often near water. I am fairly sure that it is Ligyra tantalus Fabricius, 1794, which has a very wide distribution, including China, Taiwan, India, Malaya, the Philippines and Thailand.
There is a reference in an Indonesia text to Ligyra tantalus being a parasite of wasp larvae of a Campsomeris sp., which are large Scoliid wasps (2). This suggests that it might be a hyperparasite, since another Ligyra bee fly species, Ligyra satyrus, larvae are found inside cocoons of a scoliid wasp, Campsomeris tasmaniensis Saussure, which are external parasites of canegrubs (Coleoptera: Scarabaeidae) (3). So if it is a hyperparasite like L. satyrus, L. tantalus would be classed as a pest, if it were feeding on the natural enemies of a plant pest!
This photograph was taken in February in Doi Sutep-Pui NP, Chiang Mai, Thailand.
1) Yeates, David K., and David Greathead. “The evolutionary pattern of host use in the Bombyliidae (Diptera): a diverse family of parasitoid flies.” Biological Journal of the Linnean Society 60.2 (1997): 149-185.
2) Hama penyakit tanaman. http://books.google.co.uk/books?id=IHkTEjTjTkcC&dq=Ligyra+tantalus&source=gbs_navlinks_s
3) Yeates, David K., David P. Logan, and Christine Lambkin. “Immature stages of the bee fly Ligyra satyrus (F.)(Diptera: Bombyliidae): a hyperparasitoid of canegrubs (Coleoptera: Scarabaeidae).” Australian journal of entomology38.4 (1999): 300-304.
I am a retired entomologist with a background in quarantine pests and invasive invertebrates. I studied zoology at Imperial College (University of London) and did a PhD on the population dynamics of a cereal aphid (Metopolophium dirhodum) in the UK. I spent 5 years with the British Antarctic Survey studing cold hardiness of Antarctic invertebates and 17 years with the Food and Environment Research Agency. My main interests now are natural history, photography, painting and bird watching.