Capacity of Bembidion lampros and Tachyporus hypnorum to survive periods of starvation in early spring

The capacity of the polyphagous predators Bembidion lampros Herbst (Coleopt era; Carabidae) and Tachyporus hypnorum F. (Coleoptera; Staphylinidae) to s urvive starvation in early spring was investigated. The two species are of similar size and live in the same habitat. They have similar life cycles; w here adults emerge in autumn, hibernate during winter and disperse during s pring into arable fields where they reproduce and then die. Both species sh owed an ability to survive long periods of starvation after hibernation. Ho wever, B. lampros could live without food several weeks longer than T. hypn orum. Fat content was measured to estimate the energy reserves of beetles in the field. The fat content of B. lampros was at a constant level of 23% both wh en fed ad libitum in the laboratory and when collected in the field during spring. The fat content of B. lampros was reduced to a level of 7% when the y died by starvation. Fat content of T. hypnorum was more variable both whe n fed ad libitum in the laboratory (17-33%), when collected in the field du ring the spring (20-26%) and when they died by starvation (10-20%). Neither the mean longevity of starved beetles nor the fat content of specim ens collected in the field indicated that the beetles suffered high mortali ty due to a food shortage in early spring before movement into arable field s.