It was a hot day in northern Thailand when spotted an attractive Red Lacewing butterfly and started following it, hoping it would settle down so that I could get some decent photos. Eventually, it did land and I started creeping up on it, gradually getting closer and closer. It took me a little while to realise that the butterfly was actually ‘feeding’ on a dead frog! It was completely absorbed in this activity and I was able to take many shots. Lying on the grass in the hot sunshine, I slowly realised that there was a bit of a battle going on between the butterfly and a bunch of blow flies who clearly thought that the carcass was theirs and did not take kindly to the butterfly muscling in!
But first a word about what the butterfly was doing. The name given to this particular form of activity is mud-puddling. It’s a bit of a misnomer really, because butterflies commonly seek out and absorb liquids from a wide variety of substrates, not just mud; including: moist ground, animal excrement, rotting fruits, carrion, dung, bird droppings, sweat, tears and so on. Mud-puddlers are usually males, stocking up on sodium and nitrogen in preparation for forming a spermatophore. See previous blog.
Carrion-feeders have specialised on finding and ‘feeding’ on rotting meat and dung, and this specialism is thought to have evolved many times in different lineages. Because such resources are scarce, only butterflies which fly long distances or regularly patrol over wide areas, are likely to specialise on feeding on carrion.
Many tropical nymphalid butterflies are particularly attracted to carrion and it is possible that these is a greater need to replenish protein reserves in tropical regions. Or it might just be the case that carrion decomposes much more rapidly in hot climates, so a variety of nitrogen-rich molecules like amino acids become available early on in the process. Specialist carrion-feeders can smell decomposing bodies over distances of a few hundred metres. Clearly, these substances can be easily absorbed by the proboscis even though the body looks fairly dry (below).
Other butterflies which are carrion feeders include the Nawabs (Polyura species), Yeomans (Cirrochroa species) and the Rajah and Pasha butterflies (genus Charaxes). These butterflies are also strongly attracted to dung (below). But carrion-feeding is quite common and species in a number of different families – Lycaenidae, Danaidae, Nymphalidae and Satyridae – have been recorded on carrion (Rima et al., 2016)
Returning to the blow flies; it is difficult to say what species they were, but probably members of the genus Chrysomya. The females lay their eggs in carrion and sometimes engage in group oviposition where thousands of eggs are laid on a decomposing carcass. In any case, they clearly felt quite proprietorial about this dead frog and were determined to try to drive the butterfly away. They were buzzing about the butterfly (below) but this did not have any effect.
At one point, the flies got so upset that they started flying at the butterfly, bumping into its wings and knocking it over. I managed to get one shot of this aggressive behaviour (below).
Although the blue-bottle managed to knock the butterfly sideways, this did not seem to worry it very much, and it quickly righted itself and carried on puddling. The flies went back to sitting alongside, no doubt full of dipteran rage about the situation!
These images were taken last month (April 2018) in Thailand, at Doi Ang Khang, a mountain in Fang District, Chiang Mai Province with a Nikon D5600 and Sigma 150mm macro lens. The blow fly species which previal in highland areas of northern Thailand are C. pinguis, C. thanomthini, Hy. tumrasvini, L. papuensis and L. porphyrina (Moophayak et al., 2014).
Beck, J., MuÈhlenberg, E., & Fiedler, K. (1999). Mud-puddling behavior in tropical butterflies: in search of proteins or minerals?. Oecologia, 119(1), 140-148.
Boggs, C. L., & Dau, B. (2004). Resource specialization in puddling Lepidoptera. Environmental Entomology, 33(4), 1020-1024.
Molleman, F., Grunsven, R. H., Liefting, M., Zwaan, B. J., & Brakefield, P. M. (2005). Is male puddling behaviour of tropical butterflies targeted at sodium for nuptial gifts or activity?. Biological Journal of the Linnean Society, 86(3), 345-361.
Moophayak, K., Klong-Klaew, T., Sukontason, K., Kurahashi, H., Tomberlin, J. K., & Sukontason, K. L. (2014). Species composition of carrion blow flies in northern Thailand: altitude appraisal. Revista do Instituto de Medicina Tropical de São Paulo, 56(2), 179-182.
Rima, N., Meme, A., & Hossain, M. M. (2016). Puddling of butterflies in Jahangirnagar University campus and the bank of Bangshi river, Savar, Bangladesh. Jahangirnagar University Journal of Biological Sciences, 5(1), 57-70.
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.