{"id":284,"date":"2026-01-26T15:13:12","date_gmt":"2026-01-26T15:13:12","guid":{"rendered":"https:\/\/www.luketomtesting10.co.uk\/?p=284"},"modified":"2026-06-01T15:13:36","modified_gmt":"2026-06-01T15:13:36","slug":"mediterranean-oil-beetles-in-south-devon","status":"publish","type":"post","link":"https:\/\/www.luketomtesting10.co.uk\/index.php\/2026\/01\/26\/mediterranean-oil-beetles-in-south-devon\/","title":{"rendered":"Mediterranean Oil Beetles in South Devon"},"content":{"rendered":"

Oil beetles are distinctive invertebrates with an unusual life history. Termed \u2018blister beetles\u2019 in other parts of the world, they are named for the oil-like substance they secrete from their joints when threatened, which puts off any potential predators.<\/span><\/p>\n

These charismatic beetles can be up to 3.5cm long. Generally black in colour, though with some species tinted blue or violet, they have short wing cases and, in the case of the females, often bulbous abdomens.<\/span><\/p>\n

You may have spotted one of the more locally common species, the Black Oil Beetle (<\/span>Meloe\u00a0proscarabaeus<\/span><\/i>), out on coastal walks in\u00a0spring, the females\u2019 heads\u00a0down\u00a0in the ground and their abdomens up as they dig burrows in which to lay their eggs.\u00a0<\/span>\u00a0<\/span><\/p>\n

 <\/p>\n

Something of a Mystery \u2013\u00a0<\/span><\/b>Meloe\u00a0mediterraneus<\/span><\/i><\/b>\u00a0<\/span><\/h3>\n

There are five species of oil beetle found in the UK, with another four classed as extinct. This winter,\u00a0Life on the Edge (LoTE)\u00a0volunteers\u00a0helped with surveys along\u00a0the\u00a0South\u00a0Devon coastline, searching for\u00a0one of the most elusive of these, the Mediterranean\u00a0Oil\u00a0Beetle\u00a0(<\/span>Meloe\u00a0mediterraneus)<\/span><\/i>.\u00a0<\/span>\u00a0<\/span><\/p>\n

Referred to by a 2002 British Wildlife article as \u201csomething of a mystery in Britain\u201d, the\u00a0Mediterranean\u00a0Oil\u00a0Beetle\u00a0had been assumed extinct for over 100 years. Difficulties with identification due to its similarity to another species\u00a0the Rugged Oil Beetle (<\/span>Meloe\u00a0rugosus)<\/span><\/i>\u00a0are thought to have contributed to its lack of documentation.<\/span><\/p>\n

In 2012 as part of a\u00a0project run by\u00a0Buglife, local naturalist and ecologist John Walters\u00a0<\/span>rediscovered the species<\/span><\/a>\u00a0on the\u00a0South\u00a0Devon coastline.\u00a0Its rediscovery, alongside the new understanding that they are most active at nighttime, has prompted more searches in their preferred coastal grassland habitat to build a picture of how the species is\u00a0using the\u00a0landscape, and to tailor conservation actions to its very particular life history.\u00a0<\/span>\u00a0<\/span><\/p>\n

 <\/p>\n

Bees and Beetles<\/span><\/b>\u00a0<\/span><\/h3>\n

Oil beetles are\u00a0kleptoparasites, animals that\u00a0take\u00a0food or prey from other animals. They are parasites of solitary mining bees, acting as nest cuckoos. Adult\u00a0Mediterranean\u00a0Oil\u00a0Beetles\u00a0will\u00a0emerge\u00a0from late autumn through winter to feed<\/span>\u00a0<\/span>on nearby vegetation and look for a mate. Upon mating,\u00a0the\u00a0female\u00a0digs a burrow\u00a0in\u00a0the soil<\/span>\u00a0<\/span>where she lays up to 1000 eggs. The larvae, called triungulins, hatch the following spring.<\/span><\/p>\n

They are\u00a0very small\u00a0(Mediterranean\u00a0Oil\u00a0Beetle\u00a0triungulins are about 0.8mm long) and\u00a0very active, climbing up the nearest flowers and hooking themselves onto any insect that lands to pollinate it. Ideally this is a solitary mining bee, and they hitch a ride back to its nest. There the triungulin\u00a0detaches and\u00a0eats the bee\u2019s egg and pollen store before pupating into its adult form over several months. It then\u00a0emerges\u00a0in autumn\/winter, ready to start the lifecycle all over again.\u00a0<\/span>\u00a0<\/span><\/p>\n

Unfortunately,\u00a0the abundance and diversity\u00a0of solitary\u00a0mining bees\u00a0is\u00a0in decline across the country.<\/strong>\u00a0As the oil beetles\u2019 life cycle is so intertwined with that of the bees, this is thought to be a\u00a0significant\u00a0contributor to their decline in numbers, but also a clear opportunity for conservation.<\/span><\/p>\n

Species-rich grasslands are vital habitats for solitary bees<\/strong>, as are the friable coastal soils<\/span>\u00a0<\/span>that mining bees use to nest.\u00a0However,\u00a0climate change, agricultural intensification, and loss of habitat to farming, forestry, and urbanisation\u00a0has\u00a0eaten away at these precious habitats \u2013 since the 1930s,\u00a097% of species-rich grasslands across England and Wales have been lost.<\/strong><\/span>\u00a0<\/span><\/p>\n

Oil beetles have fascinating adaptations that help them through their lives. The females can lay up to 40,000 eggs in batches across their short lifetime of about two months \u2013 necessary numbers when the triungulins are taking a chance<\/span>\u00a0<\/span>on whatever lands on the flowers they climb up!\u00a0<\/span><\/p>\n

Mediterranean\u00a0Oil\u00a0Beetles\u00a0are also, following their namesake, prevalent in southern\u00a0Europe and\u00a0North Africa \u2013 the southern edge of the UK is the northernmost part of their range. Encountering predators and hot weather, the beetle is adapted so that the adults are mostly nocturnal and active over the cooler months of the year.\u00a0\u00a0<\/span>\u00a0<\/span><\/p>\n

 <\/p>\n

Night-time Surveys<\/span><\/b>\u00a0<\/span><\/h3>\n

We\u2019ve\u00a0been out onto the coast on surveys six nights this winter with our brilliant\u00a0volunteers and\u00a0found a total of\u00a041<\/span>\u00a0<\/span>Mediterranean Oil Beetles across four sites \u2013 and excitingly,\u00a0even discovered a brand-new population!<\/a><\/span><\/p>\n

Walking the coast path at night is an experience in itself \u2013 hearing the waves crashing below and experiencing\u00a0real\u00a0dark\u00a0skies\u00a0with the Milky Way glowing above on clearer nights is amazing.<\/span><\/p>\n

As well as oil beetles,\u00a0we\u2019ve\u00a0seen lots of\u00a0fungi, ground\u00a0beetles,\u00a0a type of dung beetle called the\u00a0<\/span>Common Dor<\/span><\/a>\u00a0(<\/span>Geotrupes\u00a0stercorarius<\/span><\/i>),\u00a0<\/span>Devil\u2019s Coach-horse<\/span><\/a>\u00a0(<\/span>Ocypus\u00a0olens<\/span><\/i>), the beautifully iridescent gold\u00a0<\/span>Banks\u2019s\u00a0Leaf\u00a0Beetle<\/span><\/a>\u00a0(<\/span>Chrysolina\u00a0banksii<\/span><\/i>) and the\u00a0<\/span>Ridged Violet\u00a0Ground\u00a0Beetle<\/span><\/a>\u00a0(<\/span>Carabus\u00a0problematicus)<\/span><\/i>.<\/span><\/p>\n

A huge thanks to our volunteers who\u00a0have\u00a0braved the dark and cold to help us search!\u00a0\u00a0<\/strong><\/p>\n

The survey recordings are available on\u00a0iRecord, a freely available resource that anyone can upload their sightings to. Sightings\u00a0are checked by experts, and the datasets are used by projects and national recording schemes.\u00a0<\/span><\/p>\n

LotE\u00a0will use the survey data to target habitat restoration works like planting wildflower species\u00a0needed\u00a0by\u00a0solitary\u00a0bees, and bee bank building to increase the habitat available for nesting. If we can\u00a0restore bee numbers, we can\u00a0restore oil beetles along with them. Healthy bees\u00a0mean\u00a0healthy beetles.\u00a0<\/span>\u00a0<\/span><\/p>\n

The story of the\u00a0Mediterranean\u00a0Oil\u00a0Beetle\u00a0shows the power of people getting to know the amazing\u00a0wildlife\u00a0of the landscape on their doorstep<\/strong>\u00a0\u2013 from rediscovering this insect for the first time in 100 years to finding new populations!<\/strong><\/span><\/p>\n

Who knows what assumed-to-be extinct creatures are quietly living out their lives, just waiting to be\u00a0spotted! Anyone can get involved in bringing\u00a0these species back from the brink \u2013 keep an eye out on our\u00a0<\/span>website<\/span><\/a>\u00a0and\u00a0<\/span>sign up to our mailing list<\/span><\/a>\u00a0to get involved in future surveys. The work of our volunteers directly\u00a0supports our\u00a0conservation actions, so every person and any hour that can be spared counts!<\/span>\u00a0<\/span><\/p>\n

This blog post was written by our conservation trainee Amy!<\/p>\n

Buglife\u00a0identification guide:\u00a0<\/span><\/i>https:\/\/cdn.buglife.org.uk\/2019\/08\/Oil-Beetle-national-survey-leaflet-for-web_5-species.pdf<\/span><\/i><\/a>\u00a0<\/span><\/i>\u00a0<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Oil beetles are distinctive invertebrates with an unusual life history. Termed \u2018blister beetles\u2019 in other parts of the world, they are named for the oil-like substance they secrete from their joints when threatened, which puts off any potential predators. These charismatic beetles can be up…<\/p>\n","protected":false},"author":1,"featured_media":286,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-284","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-lote-news-blog"],"_links":{"self":[{"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/284","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/comments?post=284"}],"version-history":[{"count":1,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/284\/revisions"}],"predecessor-version":[{"id":287,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/posts\/284\/revisions\/287"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/media\/286"}],"wp:attachment":[{"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/media?parent=284"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/categories?post=284"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.luketomtesting10.co.uk\/index.php\/wp-json\/wp\/v2\/tags?post=284"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}