Who ate the dung beetles?

Dung beetle (Trypocopris [=Geotrupes] pyrenaeus var. coruscans), Galicia, Spain

In September this year, I was walking along a forest ride in Galicia, NW Spain, looking out for insects and butterflies. I particularly like photographing these beautiful dung beetles (Trypocopris pyrenaeus var. coruscans) which are often associated with horse dung (below).

Dung beetle (Trypocopris [=Geotrupes] pyrenaeus var. coruscans), in horse dung. Galicia, Spain

The creatures responsible for depositing this lovely dung across the hills of Galicia, are of course Galician ponies!

As well as seeing dung beetles, I also came across some spoor, or dung. The dropping was so full of beetle remains – shiny wing cases (elytra) and dismembered legs (below) – that for a moment I thought they were living beetles!

Insectivore spoor, full of dung beetle remains. Galicia, Spain

What was also very interesting, was that there were some living dung beetles investigating this dropping. I suppose they were attracted to it, in the same way that they would be to any dung? But it was slightly surreal to see the living beetles next to the remains of their cousins?!

Dung beetle (Trypocopris [=Geotrupes] pyrenaeus var. coruscans), near some insectivore dropping. Galicia, Spain

It would have been interesting to have collected the specimen and dissected out the remains, but I am more involved with photography than research, these days! However, I am left wondering what sort of animal ate all these beetles? I suppose a hedgehog must be top of the list? But badgers, owls, other raptors and maybe even bats, could be possible candidates?

Close up of insectivore spoor, full of dung beetle remains.

These colourful dung beetles are usually found in horse dung, where they appear to congregate at the base of dung, above the soil or substrate (below).

Dung beetle (Trypocopris [=Geotrupes] pyrenaeus var. coruscans), in horse dung. Galicia, Spain

As I described in a previous blog, these dor beetles are earth-boring, and burrow down into the soil to construct brood chambers, where they rear their larvae. So these images of very fresh specimens (above and below) probably represent beetles that have just colonized the dung and not yet begun to dig down and provision breeding chambers with dung. Presumably they mate – in the dung? – and then dig and lay eggs in the chambers, where the larvae develop and feed on dung, until they emerge the following year?

Dung beetle (Trypocopris [=Geotrupes] pyrenaeus var. coruscans), in horse dung. Galicia, Spain.

There is so much to find out about the biology, ecology and life history of these beetles. There does not appear to be a very big literature on this species (although there may be more I don’t know about in French and Spanish journals). They are common and appear to be abundant and would make terrific organisms for research projects.

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