Over the past month or so we’ve had a few sightings of Drilus flavescens sent in accompanied by wonderful photos. It is a Nationally Scarce beetle species which can be found in woodland and grassland on and around the chalk downs of South East England, and has a rather strange life history.
The male is your average-looking winged beetle, just a few millimetres long with prominent combed antennae which are thought to pick up the appealing pheromones of the female. When a male follows the scent-trail, however, and finds the female, he’s in for a shock. The female is a wingless, grub-like monster weighing in about four times as big as him. When a female beetle looks like this it is called a ‘larviforme female’ and you will recognise the more familiar example of this in the form of a Glow-worm female which is also like a caterpillar. The male Glow-worm is a small black winged beetle and is attracted to the glow of the female’s curled abdomen.
Here are a couple of photos of Drilus flavescens that were sent in, they show the male and female together:
Like the Glow-worm larvae, the larvae of this species takes at least two years to mature, invading and eating about 3 or 4 snails a year, targeting progressively larger snails to sate its appetite. It moults and over-winters in an empty snail shell from about mid-September. The larvae look pretty spectacular covered in orange bristles, and their poisonous bite kills their snail prey which they then dissolve into a soup using their digestive enzymes.
Pupation and adult emergence happens around May time and adults are then recorded up until late July, or this year into August. We have about 55 records of this species in Sussex, with only 16 of these records since the year 2000. If you have spotted this species we’d be grateful if you could send in a photo to firstname.lastname@example.org with details of where and when you saw it.