Black Vine Weevil
Adult vine weevils are 8-12 mm long, have a grooved, dull black shell with patches of tiny yellow bristles. As they are well camouflaged and only active at night, they are seldom seen. If they are discovered, they play dead very convincingly.
Outdoors, adult vine weevils emerge from the soil from May onwards. They are wingless, but walk and climb exceedingly well. Male weevils have not been found. The freshly emerged females feed for about ten days, then commence laying the unfertilized eggs close to well-selected plants. Each female lays about 500 eggs, which are very small (0.8 mm diameter) and round. Initially, these eggs are white, but they turn brown as they mature. As adults are relatively long-lived, egg-laying can extend well until October.
Eggs hatch in 8-20 days, and the tiny emerging larvae burrow deep down into the compost. The larvae are C-shaped and legless. They have a creamy white colour with a shiny brown head. When fully grown, they are 10-14 mm long.
Vine weevils overwinter as larvae, which pupate in spring as temperatures rise. These pupae are cream-coloured and soft bodied. They are found in cavities several centimetres down in the soil. Adult weevils emerge some 3-4 weeks later. In heated glasshouses, the life-cycle is completed more rapidly and several different stages of vine weevil may be found at any time of the year.