In the coastal meadows of Pembrokeshire, at the Castlemartin military range, larvae of the short-necked oil beetle have been found again after an absence of almost sixty years. This discovery, made during a survey in 2026, was the result of three years of searching and has given hope for the revival of the population at the only known site in Wales.
The oil beetle (Meloe brevicollis) got its name not only from its compact body shape but also from its unusual defence: when in danger, it secretes a yellow-orange oily fluid from its knee joints. Adults live for about a year, are active from March to June and depend on solitary bees. The larvae cling to bees, enter their nests and feed on pollen stores until they turn into adult beetles. Only about one larva in ten thousand survives.
The species requires very specific conditions: bare ground for egg-laying, dense vegetation for cover and an abundance of flowering plants. Such sites in Great Britain can be counted on the fingers of one hand, and habitat loss in the twentieth century almost drove the beetle to extinction. The last records in Wales dated from the 1940s, and in 2022 and 2025 only dead adults were found at Castlemartin.
This year the picture changed: the larvae were distributed in such a way that experts suggested successful hatching from a large clutch. According to Anna Hobbs of the Bumblebee Conservation Trust, this is "very exciting" evidence of renewed breeding. The project is part of the Welsh restoration programme Natur am Byth and takes into account the needs of several rare species at once — from the carder bee to certain plants.
Such finds remind us how closely the fates of insects and their ecosystem partners are intertwined. Protecting one beetle requires preserving an entire chain: bees, flowers, soil and even a military range where the grass remains untouched.
The success at Castlemartin shows that long-term, targeted efforts in monitoring and habitat management can bring species back from the brink of extinction.
