As I attempt to write about the 1,500 plus species of animals and plants I have found in Dorset since I started looking in 2007 I occasionally come across a species about which it is almost impossible to say anything and I just do not no where to start, That is where I find myself with this sawfly, Macrophya duodecimpunctata.
I suppose, for a start, we do know it is a sawfly which means it is related to bees, wasps and ants in the family Hymenoptera. Sawflies are so named because the females have an ovipositor adapted for sawing into the stem of a chosen host plant in which to lay her eggs. In this case the host plant is usually a sedge and therefore the favoured habitat is marsh and I found this one along the marshy shores of Poole Harbour at the Eastern end by Holton Lee. It is in flight as an adult from May to July. The National Biodiversity Network distribution map shows a sketchy distribution with most records from coastal areas and records from Dorset seem quite sparse. Elsewhere on the Internet however it is described as locally common in southern England and then, on another website, it is considered uncommon!
To look at is about 6 inches long and the female has a primarily black body but has two clear yellow spots, one on the back of the thorax and the other at the base of the abdomen; duo being two and punctata meaning spots. Where the decim, presumably ten comes from I cannot work out. The antennae have yellow bands. That is it, I can find nothing else!Macrophya duodecimpunctata: a sawfly