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BUTTERFLY REPORT 2016
Oil Beetle discovery on the cliffs in Erwarton Bay Tim Gardiner & Joseph Gardiner On 7 June 2017 the authors enjoyed a stroll along the footpath around Erwarton Bay on the Stour Estuary. After briefly stopping to enjoy a weedy field corner with fumitory Fumaria officinalis, poppy Papaver rhoeas, round-leaved fluellen Kickxia spuria and sun spurge Euphorbia helioscopia, we walked back to Rose Farm Cottages along the cliff top path. The second author spotted a black oil beetle Meloe proscarabaeus (Plate 9) crawling along the footpath (at TM232341) and excitedly captured it in a pot for inspection. The black oil beetle, a priority species in the Suffolk Biodiversity Action Plan (BAP) is often found on flower-rich cliffs. The section of cliff in Erwarton Bay is small but reminiscent of the interglacial deposits of Stutton Ness and Harkstead. The find was pleasing as the first author had previously not found any in Holbrook Bay where there was a sighting in 2007. Our sighting was also close to one in a Shotley Garden in 2011. Oil beetles are declining in the intensively managed countryside due to the loss of flower-rich grassland, linked to a reliance on solitary bees to complete their life cycle (Buglife 2012). Oil beetles require bare ground in which to burrow, habitat amply provided by the cliff top path, and strong populations of solitary mining bees upon which they are a nest parasite. The food plants of the adults are lesser celandine Raunculus ficaria and soft grasses (Poaceae), but also dandelion Taraxacum officinale and buttercups (Ranunculaceae). The triungulins are often found on dandelions and a range of other wildflowers (Buglife 2012). The cliff top at Erwarton is grassy and has an abundance of buttercups and dandelions, so the habitat is ideal for the species. The second author was very adept at spotting wildflowers on our walk and noticeably he found more buttercups at the Rose Farm Cottages end of the footpath where the oil beetle was observed; perhaps an important habitat association? Further searches for the black oil beetle on the sea walls and cliffs of the Shotley Peninsula are needed to determine the distribution of this beautiful species. Reference Buglife (2012) Species management sheet – oil beetles. Buglife, Peterborough.
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Plate 9: Black oil beetle Meloe proscarabaeus at Erwarton 7 June 2017. (p. 71).
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