Some Notes on the Biology of the Click Beetles Agriotes Obscurus L. And A. Sputator L.

Wire‐worms rarely occur in permanent arable land in sufficient numbers to cause serious damage to crops. Various workers (e.g. Roebuck, 1924; Hawkins, 1936; Miles & Cohen, 1941) have noted the reduction in numbers of wireworms in successive years on ploughed‐out grassland. At Rothamsted reductions of 62 % in one year and 85 % in two years were recorded on plots on Highfield. This reduction is certainly due in part to the exposure of wireworms to their natural enemies and to the direct effect of disturbance by implements of cultivation. It has also frequently been suggested that the beetles prefer to oviposit on grassland or clover leys and to a lesser extent on cereal crops (Bryson, 1930; Rawlins, 1934; Balachowsky & Mesnil, 1935; Miles & Cohen, 1938). A laboratory experiment to test this point was accordingly carried out in June 1940.