| Main |

What do stag beetles eat?

Before we can answer that, let's ask another question first.

Can stag beetles eat?

They can't eat any solids. Their enormous antlers are enlarged mandibles which are totally useless for eating, but can give you the odd pinch, of course.
Instead sometimes they might have a drink. Indeed, one of my early experiences is that they were rather partial to sweet juicy fruits. As you can see below the beetle is very interested in the melon.

Male stag beetle enjoying a ripe juicy melon, MF 2003.

Return to the top

Then, how do they drink?

Just look at a close up view of a male stag beetle mouth parts.

Side view of a male stag beetle drinking from a piece of melon, MF 2003.

Can you see two yellow feathery bits just about touching the melon?
Well, the beetle sucks the juice with those tubes, just as we might use two drinking straws. The female mouth parts are just the same, except for the smaller antlers.

Link:
For some good drawings of insect mouth parts click here.

Return to the top

What do they drink in the wild?

1.  In the wild stag beetles may drink from fallen fruit, for example cherries. Indeed one of their old English names, cherry-eaters, attests to that. See below a photo of a male stag beetle enjoying the juices of an overripe cherry (Prunus avium).

Male stag beetle holding a cherry, 19 July 2005. Photo by John T. Smit.

Photo taken on 19 July 2005, by John T. Smit in a sunken lane
(holle weg in Dutch), near Etzenrade, Limburg, The Netherlands.

John writes: "There were four males feasting on the cherries lying on the ground. The male on the photo is not actually carrying it, but rather defending it against me. He was using his mandibles to turn it around so that he could reach the juices from one of the cracks in the skin".

Link:
Video posted in YouTube of a Stag beetle feeding on a plum.

2.  Amazing enough, recently, I came across a female stag beetle at the end of the season drinking the moisture from a fox's poo! See below.

Female stag beetle drinking, 28 July 2011. Photo by Maria Fremlin

Female stag beetle feeding at the end of the season. Photo taken on 28 July 2011.

Thanks to that pink dot on that wing case I can tell you that I first seen her in early June. Then she was rather shiny and brisk. But now she has emerged from that log in not such a good condition, perhaps she has been busy laying some eggs? She is has lost quite a bit of weight and is rather worn out and slow. Indeed she is nearing the end of her life.

3.  In the wild stag beetles, as well as other insects, are attracted to sap runs which are very sweet and ferment easily.
However, in the UK there are no reports of such observations. If you ever see that, do not hesitate in getting in touch with me.

Return to the top

How is it that they can survive without eating?

Stag beetles have enough fat reserves to keep them going during the short time that they spend above the ground; these reserves have been accumulated by their larvae during the last stage of their long life underground.

Links:
Stag beetles feeding on oak sap - Album with examples of stag beetles on sap runs. Photos taken by Gerrit Rekers, Veluwe, The Netherlands.
Female stag beetle of another species feeding on sap in South America.

Further reading:
Fremlin, M. & Hendriks, P. (2011)  Sugaring for stag beetles - different feeding strategies of Lucanus cervus and Dorcus parallelipipedus. Bulletin of the Amateur Entomologists' Society, 70 (495): 57-67. [PDF]
Hawes, C. (2004)  Stag Beetles at Sap. White Admiral, 57.
Hongo, Y. (2005)  Diurnal activity of the Japanese stag beetle Prosopocoilus dissimilis okinawanus Nomura (Coleoptera, Lucanidae). Elytra, 33: 245-257. [PDF]
Jansson, N. (2011)  Attraction of stag beetles with artificial sap in Sweden. Bulletin of the Amateur Entomologists' Society, 70 (495): 51-56.
Krenn, H.W., Pernstich A., Messner T., Hannappel U., Paulus H.F. (2002)  Kirschen als Nahrung des männlichen Hirschkäfers, Lucanus cervus (Linnaeus 1758)(Lucanidae: Coleoptera). Entomologische Zeitschrift 112/6: 165-170.
Nash, D. (2003)  Red Admiral Butterflies at Sap. White Admiral, 56.
Ratcliffe, B.C. (1970)  Collecting slime flux feeding Coleoptera in Japan. Entomological News 81: 255-256.

Last modified: Sat Apr 28 15:58:58 BST 2012

| Main |