Meloe brevicollis Panzer, 1793
Short-Necked Oil Beetle

Along  with several other members of the genus this species has suffered a general decline during the 20th century it remains widespread and remains locally common, especially in southern and central regions, but it is missing from many of its former sites and may still be in decline due to increasingly intensive land use. The distribution includes the whole of Europe, the Mediterranean islands and North Africa and most of Asia to eastern Siberia and China. To the north it was formerly widespread in the Baltic region and Fennoscandia but the distribution is now very patchy, it is considered extinct in Norway and Finland and it has been recorded from only three sites in Sweden since 1990. In the UK it was thought to have been extinct since the 1940s due to land use and intensive farming, but a small population was discovered in Devon in 2006, in 2010 it was found to be common at four sites on the hebridean island of Coll, and there are recent records from Pembrokeshire in Wales. The species has also been discovered in Ireland (Wexford) from larval identification. Typical habitats are dry open grassland, meadows, sandy moorland, dunes and patchy maritime grassland rich in wildflowers, usually on sites that have long remained undisturbed. Adults are active from March until June or July and peak in abundance during May although this may be a little later in the north, and in southern Europe they are often active from February. After emerging they gorge themselves on a variety of foliage and become distended before mating begins, here males search for females and mating takes place on the ground, often while the female continues to search for suitable oviposition sites. Typical of the family the triungulin larvae parasitize various solitary bees and females will usually detect the bees’ nests and oviposit nearby. In Scotland the host appears to be Colletes floralis Eversmann, 1852, in the south of England it is thought to be C. similis Schenck, 1853 and in Gotland it has been associated with Anthophora retusa (Linnaeus, 1758), and Trachusa byssina (Panzer, 1798) is also thought to host the species. After finding a suitable oviposition site the female digs a series of pits in the ground, several hundred eggs are deposited into each one before it is carefully re-filled with soil and this behaviour may continue for several weeks, each female producing many thousands of eggs. Triungulins tend to emerge en masse and soon make their way up onto flowers where they will attach to suitable visiting bees, although here the majority will be unsuccessful as they will attach to any visiting insect and ultimately die-off. Once inside the nest they leave the bee and invade the brood cells, here they transform into several immobile stages that consume eggs, larvae and their food supply of pollen and nectar. After consuming the contents of a cell the larva moves on to another and so on until it is fully grown, now it pupates in situ and adults emerge the following spring. So far as is known the species is univoltine throughout the range. The biology is described in greater detail by Sörensson & Mårtensson (2007). Adults may be found by carefully searching suitable habitats; they tend to be very active, especially in warm weather, and usually occur in numbers in a small area, and for those familiar with the host species these may be a good pointer to the beetles’ presence.