Short-necked Oil Beetle
Latin name: Meloe brevicollis
Notable feature: Oil beetles are rather strange-looking beetles, their large abdomens protruding from under short elytra (wing cases) – they have been described as looking like some one whose waistcoat won’t button up!
Conservation Status: Vulnerable
Where in the UK: In Scotland on Isle of Coll, Tiree, Islay, Barra and Uist (Tiree, Barra and Islay populations discovered during the Species on the Edge programme). Known from two locations in South Devon and South Wiltshire in England, and one location in South Pembrokeshire, Wales
Short-necked Oil Beetle (Meloe brevicollis) © Suzanne Burgess
The Short-necked Oil Beetle (Meloe brevicollis) is a native oil beetle in the UK. It is shiny black in colour, has a rectangular-shaped thorax and short, straight antennae that thicken towards the tip. It is similar in appearance to small Black or Violet Oil Beetle, but has a rectangular-shaped thorax as opposed to a square-shaped thorax.
Males are typically smaller in size than females.
The Short-necked Oil Beetle is most commonly found in wildflower-rich coastal grassland (including machair grassland) and sand dune habitat.
There are 5 species of oil beetle in the UK; 3 are rare in the UK (2 of these are listed as Vulnerable). A further 3 species of oil beetle have become extinct in the UK – Meloe autumnalis, Meloe cicatricosis and Meloe variegatus.
There are populations found in Scotland on Isle of Coll, Tiree, Islay, Barra and Uist in Scotland (Barra and Islay population discovered during development phase of Species on the Edge: Buglife delighted with new discoveries in Scotland! – Buglife latest news). A population in Pembrokeshire, Wales which was discovered in 2020: Rare Beetle found in Wales – Buglife latest news and it is also found in Devon, England after having been rediscovered after a 60 year absence in 2007.
- Size: Adult beetles up to 24mm in length. Beetle larvae up to 0.5mm in length.
- Life span: From egg to adult approximately 1 year
- Diet: Adult oil beetles feed on the leaves and petals of flowering plants and grasses; favourites include Buttercups (Ranunculaceae), Hawkbits (Leontodon) and yellow Asteraceae (such as Dandelions). Larvae (known as triungulins) feed on stores in solitary bee nests, including the pollen and the bee egg and/or larvae. After leaving the nest, triungulins will use the above flowers to reach solitary bees.
- Reproduction: Oil beetles have one of the most extraordinary life cycles of any British insect – they are nest parasites of solitary mining bees. Females dig a short burrow into which they lay up to a thousand eggs. For Short-necked Oil Beetles, these eggs develop and hatch quickly, emerging later in the same season. Once these hatch the larvae (triungulins) climb to the top of the nearest flower and wait for a bee to arrive. They then grab onto the bee and hitch a lift back to its nest; the triungulin will then consume the pollen stores and either the egg or larvae of the bee. The triungulin will then stay in the bee’s nest, where it will pupate and emerge as an adult oil beetle when conditions are right the next spring.
- When to see: Adults can be found from March – June in flower-rich coastal grassland and sand dune habitat. They are most active on warm, sunny days. Triungulins can be found in June and July. In Scotland the species hosts are Northern Colletes (Colletes floralis) a rare and declining species of bee that is active June-August.
- Population Trend: Declining – the Short-necked Oil Beetle is classed as Nationally Rare within Great Britain and Vulnerable on the IUCN Red List
- Threats: Oil beetles are reliant on solitary bees to compete their life-cycles. The health of oil beetle populations is therefore dependent on the health and diversity of wild bees. This species of oil beetle requires species of Colletes as their host. Northern Colletes is known to be the host for the Scottish population of Short-necked Oil Beetles which requires coastal grassland. The wildflower-rich habitats that oil beetles rely upon have declined in quantity and quality due to intensive management of the countryside. Oil beetles are sensitive to changes in land management and are a good indicator of the health of our countryside.
- Fun Fact: Adult oil beetles vary in size- this is due to the amount of food they are able to consume as a larva.
How you can help:
Buglife is working to increase awareness of invertebrates and the Short-necked Oil Beetle through specific projects, such as Species on the Edge, Natur am Byth! and campaigns, but we need your help!
Join a recording scheme and log your finds – send any records/sightings to the Oil Beetle Recording Scheme or download the iRecord app and get recording!
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