Stag Beetle Conservation

During the last working party at the Irvine Road Community Orchard, Feb 4, lots of people turned up to prune the trees, but I decided to clear the brambles from the log piles that we built just before Lockdown in March 2020, or else soon they would be smothered.

At the same time, I checked under the odd log in the hope of finding larvae of the two orchard iconic species: stag beetles (Lucanus cervus) and rose chafers (Cetonia aurata). Even though these beetles have very different habits in the adult stage, they are both decomposers in the larval stage and can often be found together under logs. 

We were in for a very pleasant surprise when Stephen Munson lifted a very large log for me: underneath it were one stag beetle larva and two rose chafer larvae, and a worm.

These larvae had been feeding under that log; note the abundant rose chafer faecal pellets, a bit like mouse droppings, and the fresh pillow shaped stag beetle pellet, close the the larva’s head; plus the red splinters of wood surrounding the stag beetle larva – a proof that it has been quite active for this time of the year – relatively mild winter, so far.

The stag beetle larva did not like to be disturbed and pooed for the second time while I was videoing it. This is a normal reflex with stag beetle larvae, but not so with the rose chafers. Great show!

At the beginning of the video someone was asking two pertinent questions:

1. Why do we need stag beetles? - We need stag beetles to decompose all those logs. In a stag beetle hotspot, when you cut a tree there is no need to remove the stump, they will do it for you by working in tandem with fungi (the ecosystem engineers of wood decomposition).

2. What do they provide? - Stag beetles return to the soil a lot of nutrients, great recyclers. As part of the food chain, they provide sustenance to other animals such as foxes, magpies, badgers, etc. They also provide endless enjoyment - it is a very popular protected species. To me, flying stag beetles are the highlight of early summer.

(If you think that my answers to those questions are inadequate, please say so.)

Life cycles

The rose chafer larvae were from eggs laid last summer and will pupate this summer, around June; the adults will overwinter before reproducing in 2025. The rose chafer’s life cycle is two years. The stag beetle larva was also from eggs laid in 2023, but it has to fatten up a lot before it is ready to pupate, so it will overwinter again before it pupates in 2025, and after overwintering the adults will reproduce in 2026. Around here the stag beetle’s life cycle is a minimum three years.

Conservation

Lucanus cervus has been the object of intensive conservation since it was included in the Bern Convention, 1982. So it is absolutely wonderful to see the way in which it has responded to the orchard conservation management: both stag beetle (L. cervus) and lesser stag beetle (Dorcus parallelipipedus) larvae have been found under various logs since they were installed in 2020. In our area, which is a stag beetle hotspot, when you cut a tree, please leave the stump and the logs, and plant another tree to ensure continuity. Please, think before you do any paving, decking or use weed suppressing membranes. Their urban habitat is being badly encroached, unfortunately. We must make sure that they will still be here for the future generations to enjoy,

Stag Beetles – All they need is love and wood.

Maria Fremlin, 6 February 2024