Investigator

Banded Sexton Beetle (Nicrophorus investigator)

When we run our moth trap (which we've hardly done at all this year), we regularly catch a few of these big, brightly-coloured beetles over the course of the season. But this is the first time I've ever found one out "in the wild" rather than caught in the trap. It's a Banded Sexton Beetle (Nicrophorus investigator), one of Europe's so-called "burying beetles", and it was clambering around on a Common Ragwort plant in broad daylight. That's pretty unusual for this typically nocturnal insect. It looks very similar to several other species found in the UK. The small break in the red band closer to its back end is an important ID feature, as are the dark red-orange tips to its antennae. It lacks hairs on its thorax (the part of the insect right behind its head), and the tibia of its back legs are straight rather than curved – two additional features that help to distinguish it from other burying beetles. And they're amazingly stinky; we can always tell as soon as we've opened the moth trap whether we're going to find one of these beetles roaming among the egg boxes.

Like other burying beetles, this one feeds on the rotting carcasses of small animals, which it can reportedly smell from up to two miles away. Pairs of the beetles work together to bury a carcass. First, they strip all the fur or feathers off the corpse, smearing it with a secretion that kills both bacteria and fungi. They then use their heads to push the soil out from under the carcass, while simultaneously fending off rival pairs, eventually burying it as much as 8 or 9 inches (20 to 22 cm) underground. The female lays her eggs in the corpse's rotting flesh, and the larvae, which hatch within days, feast on that banquet as they grow – but only after it's been "pre-processed" by their parents. Beetles in the genus Nicrophorus are among the very few insects with parental care. The pair hang around and feed on the carrion, regurgitating a digested liquid for their larvae, which use specific postures to beg for food. This diet apparently helps to speed up their development. Tha adults also protect their offspring from potential rivals and parasites, such as fly larvae. The offspring pupate in the soil near the carcass overwinter, emerging as adults in the spring. This is a common and widespread species across the UK, found in a wide variety of habitats. While adults can be found year-round, they are most common between May and September.