Beetles in the UK

Male Stag Beetle (Lucanus cervus), in my SE London garden.

Stag Beetle (Lucanus cervus)

The Stag Beetle is largest terrestrial beetle in the UK, but sadly their numbers are in decline. Their status is classified as 'Nationally Scarce". Males can be found up to an impressive size of 75mm and very occasionally even 90mm, although 45-60mm is more usual. These beetles are instantly recognisable due to their size. They are uniformly black in colour with chestnut coloured wing-cases. Females can sometimes have maroon coloured wing-cases. The only species that the females are sometimes confused with is the much smaller Lesser Stag Beetle (Dorcus parallelipipedus) which grows to a maximum length of around 30mm. The larvae of the Stag Beetle is a creamy-white colour with a light brown head and grows to an impressive length of around to 80mm, and sometimes even 110mm.

Female Stag Beetles, Lucanus cervus, are usually considerably larger than even the largest Lesser Stag Beetles, Dorcus parallelipipedus. The female is usually fairly close in body-length to the male, minus the large mandibles. However it's not unknown for very small specimens of Lucanus cervus to turn up occasionally. I have seen adult male Lucanus cervus specimens that were incredibly small, less than 30mm in total length! This unusually small size is probably down to the larvae depleting their food source, and being forced to pupate early. I have a dead female Lucanus cervus in my care that's just 33mm in length.

Stag Beetles spend most of their lives living underground as a larvae. This can be for as long as six years feeding primarily from rotting wood from decaying trees and bushes. Stag Beetles usually emerge as an adult beetle around June. Their lives as an adult beetle are short and most live for just six weeks or less. From the moment they emerge their sole purpose is to find a partner to mate with.

Like many of our wildlife species the Stag Beetle is thought to be in rapid decline and is now a protected species. It is commonly believed that the main reason for this decline comes from loss of habitat. This is largely due to over managing sites and the 'tidying-up' of dead wood and rotting trees that provide food and home for these magnificent creatures during the larva stage. Another possible reason for their decline is a recent increase in the umber of Magpies and Crows, which both prey on adult Stag Beetles. Domestic cats are also responsible for a huge number of Stag Beetle fatalities.

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Male Stag Beetle (Lucanus cervus)

It has often been thought that Stag Beetles eat very little or do not feed at all once in the adult beetle form. In studies Stag Beetles have been observed eating over-ripe fruit, nectar and tree sap that can be drunk rather than eaten. Research has shown that Stag Beetles are attracted to ginger. It has also been observed in the wild that Stag Beetles may on rare occasion feed on snails. One has been filmed lifting up a snail and repeatedly smashing it against the ground. The Stag Beetle was then observed to drink up or eat the liquids that ran from the broken snail shell. LINK

Male Stag Beetle (Lucanus cervus) at dusk.

Stag beetles usually hide themselves away during the daytime and are usually only seen flying at dusk once the sun has set. The best time to see them in flight is on warm, humid evenings during late May - July from 9pm - 10:30pm. They are clumsy fliers and are usually only seen flying if the conditions are right. Their distinctive silhouette, slow and clumsy flight, and large size makes them easily distinguishable from anything else. It is believed that male Stag Beetles will fly up to 500m looking for a mate. Females tend to fly close to their egg-laying site in the hope of attracting the males attention, and don't often fly more than 20m from that site. Females also release pheromones to attract the males. When Stag Beetles pair up they remain embraced together through the night and well into the next day. Mating can last for up to 24hrs. The male will often guard the female until after she has deposited her eggs in rotting wood.

Male Stag Beetle, found in SE London 15th June 2021

How can you help Stag Beetles? Because Stag Beetle larvae feed entirely on rotting wood, the best way to help them is to provide a log pyramid in your garden with the bottom of the logs buried 50cm beneath the soil. The PTES has provided information and tips on this page: Helping Stag Beetles

Or you can download their excellent help-sheet here: Helping Stag Beetles pdf.

Male Stag Beetle (Lucanus cervus)

There are many old myths and folk-stories that surround Stag Beetles. Stag Beetles have also been known as billywitches, oak-ox, thunder-beetles and horse-pinchers.

Because Stag Beetles are often seen in warm, humid, and stormy conditions, in British folklore Stag Beetles were feared as it was believed that they had the power to summon thunder and lightning storms. It was also once believed that Stag Beetles flew around with hot coals in their jaws setting fire to buildings!

In Germany the Stag Beetle was associated with Thor, the 'god of thunder' and there was a myth that if you placed a stag beetle on your head, it could protect you from being struck by lightening !

The female Stag Beetle is similar size in size to the male but lacks the large mandibles. They also have a smaller, slimmer head.

REPORT YOUR STAG BEETLE SIGHTINGS

Due to the increased rarity of Stag Beetles in the UK, the PTES are asking for all Stag Beetle sightings to be recorded using one of these links LINK LINK2

It is also believed that Stag Beetles don't seem to be reaching the same size that they once grew to.

When submitting your sightings it would be helpful to measure your Stag Beetle's total body-length and submit that with your records.

Female Stag Beetle (Lucanus cervus) in deciduous woodland on the SE London / Kent borders.

Male Stag Beetles (Lucanus cervus), found 15th June 2021, SE London.

Male Stag Beetles often wrestle to compete for mating rights with female Stag Beetles. They have incredible grip with the ends of their legs being equipped with miniature grappling hooks. It is usually the larger specimen that successfully throws its opponent off the log using its large mandibles. A video posted on Facebook shows a foreign species of Stag Beetle quickly wrestle and remove a clockwork opponent - LINK

Male Stag Beetles (Lucanus cervus), found 15th June 2021, SE London.

Why do Stag Beetles vary so much in size? It's usually down to availability and quality of food available. The larvae feed on decaying wood beneath the soil for between 2 - 6 years. The longer they spend feeding and the better the quality of food available, the bigger they grow. However if the food source runs out, decays too far or is of poor quality, from treated wood etc, then the Stag Beetle may be forced to pupate and emerge early. I have seen some incredibly small and preserved specimens of adult Stag Beetle, definitely Lucanus cervus, of around just 20mm in length. Size may also be partially due to genetics which is why males wrestle for mating rights. The bigger, stronger male usually gets the girl. Sometimes there may be no big, tough males around and the female has to settle for the little guy instead.

Male Stag Beetle (Lucanus cervus), found 15th June 2021, SE London.

Female Stag Beetle (Lucanus cervus) in deciduous woodland on the SE London / Kent borders 2015

Female Stag Beetle (Lucanus cervus) found in a residential garden in Erith, SE London. 20th June 2023

48mm adult female Stag Beetle. Found walking under a roadside hedgerow in Cliffe, Rochester, Kent. 17:45 30th June 2023

68mm male Stag Beetle, found on a tarmac footpath in Dartford, Kent, 5th June 2024.

45mmfe male Stag Beetle, found on a paved footpath in Erith, Kent, 16th June 2025.

Comparison of the Stag Beetle, on the left, and the Lesser Stag Beetle, on the right.

This image is not quite to scale. There is typically more difference in size between the Stag Beetle and the Lesser Stag Beetle.

Female Lesser Stag Beetle (Dorcus parallelipipedus), found within a large fallen and rotting tree in SE London woodland, 16th July 2021

Lesser Stag Beetle (Dorcus parallelipipedus)

At first glance the Lesser Stag Beetle looks fairly similar to a female Stag Beetle, although the Lesser Stag Beetle are considerably smaller in size, reaching a maximum length of around 32mm, with 25mm being the usual. Occasionally specimens have been known to reach 40mm. Lesser Stag Beetles also have a flatter appearance when viewed from the side, and can usually be distinguished by their matt black elytra, when compared to the satin chestnut-brown coloured elytra of the larger Stag Beetle. Occasionally Lesser Stag Beetles can also be found in a chestnut brown colour, especially with newly emerged teneral beetles. Any red colouration usually fades to black very quickly, but can take 1-4 weeks of the beetle emerging. The legs are also longer and more spindly-looking on the Stag Beetle when compared to those of the Lesser Stag Beetle, and the Stag Beetle has larger claws at the end of its legs. The head of the female Stag Beetle is much more narrow than its thorax. However, the width of the Lesser Stag Beetle’s head is much closer to that of its thorax.

Female Lesser Stag Beetles usually exhibit two small raised tubercles in the middle of the upper surface of their head. Some sources claim that these tubercles are always present on female Dorcus parallelipipedus, but as one can see from the female specimens that I've photographed this isn't always the case. I wonder if there could be different sub-species of Dorcus parallelipipedus in the UK?

Both species are found in similar environments of woodland and gardens with large trees and both species also feed off decaying wood and plant matter in larvae form. However, Lesser Stag Beetle larvae usually feed on rotting wood above ground level, whereas the Stag Beetle larvae feed on rotting wood below ground level. Both larvae look very similar and can be difficult to tell apart. The larvae of Stag Beetles tend to be considerably larger than those of the Lesser Stag Beetle, but there are exceptions to this rule. Looking closely at the larvae can reveal subtle differences though. The spiracles on the larvae of both species are C-shaped, and all face the same direction, but the Lesser Stag Beetles tend to have more curved spiracles. The head and gut contents of the Lesser Stag Beetle larvae tend to be lighter in shade due to their diet not consisting of soil-rich rotting wood.

Adult Lesser Stag Beetles feed mainly on sap but they can sometimes be found together with their larvae feeding on rotting wood.

Identifying Stag Beetle and Chafer larvae

Male Lesser Stag Beetle (Dorcus parallelipipedus) found under a rotting log in SE London 9th September 2021

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Female Lesser Stag Beetle, Dorcus parallelipipedus, on the left, and male Lesser Stag Beetle on the right.

Unlike the larger Stag Beetle, Lucanus cervus, the Lesser Stag Beetle, Dorcus parallelipipedus, is not obviously sexually dimorphic. The visual differences between the male and female Lesser Stag Beetlle, Dorcus parallelipipedus, are far more subtle. Male Dorcus parallelipipedus have slightly more robust jaws, which are set slightly further apart, and display a larger tooth on the upper inside surface. The male also has a slightly broader, squarer head. Female Lesser Stag Beetles usually exhibit two small raised tubercles in the middle of the upper surface of their head.

Unusual chestnut-brown coloured 19mm female Lesser Stag Beetle (Dorcus parallelipipedus), found under a rotting log at Pevensey Levels, 18th September 2021.

It's highly likely that this reddish-brown coloured Lesser Stag Beetle is teneral, meaning it has only recently emerged from pupation, and the red colouration usually fades to black within a week, but can occasionally take up to four weeks.

Female Lesser Stag Beetle (Dorcus parallelipipedus)

The Lesser Stag Beetle develops quicker than the larger Stag Beetle, and is usually ready to emerge as an adult beetle after around 1-2 years, but some specimens may take 3 years. Adult beetles then usually live for a further 1-2 years, and sometimes several years, unlike the larger Stag Beetle which only lives for just a few weeks as an adult beetle.

Male Lesser Stag Beetle (Dorcus parallelipipedus)

One of two male specimens found together under a log in Richmond Park, London, 19th October 2020.

Male Lesser Stag Beetle (Dorcus parallelipipedus)

One of several specimens found together under a log in Bexley, SE London, 11th June 2021.

Male Lesser Stag Beetle (Dorcus parallelipipedus)

One of several specimens found together under a log in Bexley, SE London, 11th June 2021.

Top: 14mm female Orange-shouldered Blister Beetle. Bottom left: Mating Beetles. Bottom right: Female checking out a bee burrow.

Orange-shouldered Blister Beetle / Flame-shouldered Blister Beetle - (Sitaris muralis)

The Orange-shouldered Blister Beetle is an interesting species from the family Meloidae, which contains the Blister Beetles and Oil Beetles. Beetles from this family are known for their defensive secretion of a blistering agent, cantharidin, which causes human skin to burn and blister on contact. The Orange-shouldered Blister Beetle announces its toxicity to would be predators with its aposematic colouration. These dark black beetles have bright orange coloured patches at the top of their elytra. Despite having fully developed and functional hind wings the Orange-shouldered Blister Beetle is very rarely observed to fly. Although capable of clumsy flight these beetles usually get around by walking.

Adult specimens typically grow to a body-length of around 8-14mm, with most specimens measuring 10-11mm. The females are larger than the males and have clearly distended abdomens. Males have slightly longer antennae than the females. Both sexes have strangely twisted elytra, which do not completely cover the folded hind wings, partially hidden beneath.

Like the Oil Beetles the Orange-shouldered Blister Beetle is kleptoparasitic within the nests of Digger Bees. Sitaris muralis is strongly associated with the Hairy-footed Flower-Bee, Anthophora plumipes, which typically builds its nest in old stone walls. Sitaris muralis has also been associated with the rare Potter Flower Bee, Anthophora retusa, too. In late summer the female Orange-shouldered Blister Beetle lays her eggs on the ground, near the burrows of the bees. Once the eggs hatch the larvae overwinter and become active the following spring. The larvae have three distinct stages, and forms. In the first form they are known as triungulins. The second forms are known as apodous eruciform larvae. The final form is the prepupae stage.

In the spring the newly emerged beetle larvae climb up the stems of flowers and await the visiting bees. When the bees visit the flowers, to collect pollen and nectar, the beetle larvae attach themselves to the bees and hitch a lift back to the burrows of the bees. Once in the burrows the beetle larvae search for the eggs of the bees, which they then feed upon. Once the bee's eggs have all been consumed the triungulin beetle larvae transform into their later stage of development, as apodous eruciform larvae. The beetle larvae now turn their attention to the bee's honey, which the bee had stored for the development of its own larvae, had its eggs survived. The beetle larvae continue feeding upon the honey until the end of the year, before transforming once again into their prepupae stage, which hibernate within the bee's burrow. The beetle larvae then pupate the following spring, before emerging in the late summer, of their second year, as adult beetles. It's not clear exactly what triggers the adult beetles to emerge but they often do so in mass. These adult beetles can be found, often in high numbers, on south-facing brick, or stone walls. The Adult beetles are short-lived and their primary focus is on mating and reproducing. Where the beetles are found they are often seen in mating balls, consisting of several specimens of both sexes. From my own observations the females mate repeatedly, with many different males. Likewise the males may also mate with different females too.

Sitaris muralis is described as an Eastern Palaearctic species, which is at the far NW edge of its range in England, Sitaris muralis is a rare species, especially in Britain, where it is classed as vulnerable. Records of this species in Britain have been very scarce until recent years, but they are still far from common. Most British records of this species come from the south, and south-east of England, particularly in suburban areas around the New Forest, in Hampshire, and from Dorset and Wiltshire. The Orange-shouldered Blister Beetle was once feared of being extinct in the UK. This species was found in Oxfordshire up until 1969 before disappearing completely. The Orange-shouldered Blister Beetle wasn't seen again in the UK for the next 41 years, until it turned up in Brockenhurst, in Hampshire in 2010. Before the 2010 sighting the beetle hadn't been seen in the New Forest area for over 100 years. In recent years this rare beetle seems to be making a significant comeback since 2015, and there are now dozens of new records of sightings, from southern England. It's not clear why the Orange-shouldered Blister Beetle is so rare in the UK, when its primary host, the Hairy-footed Flower-Bee, is common and widespread.

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On the 6th August 2026 I was contacted by a good friend of mine, Trevor Slatter, who had noticed large numbers, of what he believed to be Orange-shouldered Blister Beetles, climbing on the external wall of his residential block of flats, in Erith, SE London. I immediately went to investigate and found the beetles climbing all over the wall, on the bare soil beneath the wall, and upon the footpath. In total I counted 89 Orange-shouldered Blister Beetles, which were an even mixture of both male and female specimens. The patch of bare soil beneath the wall had long been home to large numbers of Digger Bees, which hadn't been identified to species level. These resilient bees had survived here for several years, despite some of the local residents trying to kill them off on occasion by pouring boiling water down their burrows. Despite these bees making this patch of soil their home for several years the Orange-shouldered Blister Beetle had never been seen in the area until this mass emergence in 2026.

a) 7th August 2026, 1 day after burn from Blister Beetle. b) 9th August 2026, 3 days after burn from Blister Beetle.

The pavement that runs into the block of flats in Erith was littered with several dead Orange-shouldered Blister Beetles, which had been accidentally trodden on by residents of the flats. There were also numerous specimens which had been trapped in the webs of juvenile Noble False Widow spiders, Steatoda nobilis, which were situated near the top of the wall. Despite the toxicity of the beetles I observed two of the Steatoda nobilis feeding upon these beetles, which had become trapped in their webs.

I captured a couple of the beetles to take home and photograph. This proved extremely difficult as the beetles were highly active and didn't stay still long enough for me to photograph. With the reputation these Meloidae beetles have for being highly irritant to human skin I was careful not to allow the beetles t touch my skin. Despite this approximately two hours after attempting to photograph the captive beetles I starting to feel a strong burning sensation on my forearm. I immediately had a bath, and thoroughly scrubbed my skin. I then generously applied Savlon antiseptic cream to the sore area and took an antihistamine pill. The burning sensation continued to increase on my forearm. The next day I awoke at 4am to find a line of blisters had started to form on my arm. Although I hadn't allowed the beetles to touch my skin at any time they had obviously left a trail of their defensive secretion on the white plastic sheet, which I was attempting to photograph them on. Obviously I hadn't noticed this secretion and had rested my arm in it when leaning on the sheet to stabilise my hands, to achieve steady shots of the beetles.

The next day I returned to the block of flats in Erith to release the beetles. Upon my arrival I was pleased to discover that the majority of the beetles were still on the wall. They were less active than they had been on the previous day though. I counted over 60 specimens still on the wall. The female specimen that I had captured was released back onto the wall. The male specimen, which had been mating with the female in captivity for the last 24 hours, had now died. I decided to keep hold of the dead male specimen and take it home for a second attempt at photographing it. It's definitely a great deal easier to photograph a dead beetle than a highly active live specimen. At the bottom of the pot, which had temporarily housed the two captive beetles, I discovered many hundreds of tiny pale eggs had been deposited. I deposited these eggs on the ground, near the burrows of the bees, as the female beetle would have done herself had I not captured her. I observed several adult female beetles wandering around the edge of, and wandering just inside, the openings of the bee burrows. They may have been depositing their eggs, or just checking for the presence of the host bees before deciding where to deposit their eggs.

On the 8th August, 2 days after the emergence of the Blister Beetles in Erith, around 60 specimens still remained on the wall, approximately the same number as the previous day. During the three days when I observed these Orange-shouldered Blister Beetles in Erith there were also three separate records from other sites in England too. One record came from Chichester, in West Sussex - LINK. The second record came from Headington, in Oxfordshire - LINK. The third record came from Swindon, in Wiltshire - LINK.

10mm male Orange-shouldered Blister Beetle, and eggs from the female.