Sitona hispidulus (Fabricius, 1777)

Common and often abundant throughout most of the Palaearctic region from Portugal to the far east of Russia and Japan, in Europe it extends north into the UK and southern provinces of Fennoscandia and east through the Balkans and Asia Minor, it occurs on the Atlantic Islands and most of the Mediterranean islands and is known from North west Africa. It was discovered in North America in New Jersey in 1875, presumably from imported European specimens, and is now widespread and established from Mexico to southern and eastern parts of Canada. In the UK it is generally common throughout England and Wales, including the islands, and known from a few widely scattered records in Scotland and Northern Ireland. Adults occur year-round; they overwinter in tussocks or among litter although at this time they are often active in all but the coldest weather, and are active over a long season from March until November, peaking in abundance during September and October. Overwintered adults begin feeding as soon as they emerge, the majority remaining close to where they developed, they produce irregular or U-shaped indentations in host foliage which may become very conspicuous among large infestations but which does not seriously damage the plants. Host plants include a wide range of legumes, they may become serious pests of crops such as Lucerne (Medicago sativa L.) or various commercially grown cultivars of clover but more generally they occur on a range of wild clovers (Trifolium L.) and vetches (Vicia L.), and have been recorded attacking peas grown in domestic gardens. Reproduction occurs in the spring after a period of feeding although it is likely that, at least in some areas, this also occurs in the autumn as eggs have been observed to overwinter, larvae on the other hand cannot survive the winter. Oviposition begins in May or June and may continue over a long season as adults are known to live for about a year and those that eclose late in the season may continue to oviposit well into the autumn. Eggs are deposited in small batches in the soil beneath suitable host plants and larvae emerge within a week or two, as first instars they feed on root nodules but second and third instars bore holes and galleries into roots, weakening larger roots and often severing smaller roots completely. Pupation begins towards the end of summer and adults are fully formed within about two weeks, they generally remain in situ but are stimulated to emerge and feed by lower temperatures, at this time adult populations peak and damage to foliage may become extensive before the weevils return to the soil or litter to overwinter. Larval feeding can seriously damage commercially grown legumes, both by direct physical damage and by introducing secondary pathogens. While adults can be sampled in abundance from legume crops, they tend to occur in smaller numbers wherever suitable host plants are common, typically open grassland, heaths, verges, parkland and other disturbed sites including domestic gardens, here they generally occur in small numbers but are frequent and so should soon become familiar.