I came across this little sand wasp digging its heart out in the sand dunes on Morouzos beach, Ria Ortigueira, Galicia, Spain (see previous blog, 1). The Hairy sand wasp (Podalonia hirsuta) is common and widely distributed throughout Europe, but easily overlooked as it goes about it life on the dunes.
This species is similar to another sand wasp, the Red-banded sand wasp (Ammophila sabulosa), but the latter have much longer thinner abdomens; the waist of Podalonia hirsuta is shorter and widens abruptly into the abdomen. Another behavioural difference, is that the Hairy sand wasp generally captures and paralyses its prey before it starts digging a nest; it is the other way round with the Red-banded sand wasp.
Apparently, the Hairy sand wasp finds and captures a caterpillar, then paralyses it, and then leaves it in a small tuft of vegetation whilst she goes about digging a nest. The one I was looking at was digging in one spot and then another, presumably looking for the best place for her offspring to reside in. When she has excavated a burrow of about 6-7 cm, she goes back and gets the caterpillar, pops the poor thing into the nest and lays an egg on it. She then seals it up and her larvae then feed and develop on the unfortunate caterpillar, which remains paralysed but not dead.
I was struck by how energetic and hard-working this little insect was, throwing up grains of sand so quickly it was difficult to catch using still photography. There was just a little puff of sand behind it!
I am an 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.