Ecological studies on carabid beetles : III. Winter mortality in adult Calathus melanocephalus (Linn.), egg production and locomotory activity of the population which has hibernated.
The mortality of part of the Calathus melanocephalus (Linn.) population, which showed locomotory activity during autumn 1966 was studied in the following year. 2. Mortality occurs mainly during the winter; during the winter of 1966-1967 it was about 36-41% for normal males and females at Schiermonnikoog (Table 1). 3. The data suggest that females which had hibernated and found as "spent" during April and May normally develop eggs and reproduce during the period June-September. 4. In agreement with our last paper, it could be demonstrated now that a substantial number of these females take part in a second breeding season (Table 2a and 3a; 54.5 and 76% respectively). 5. The amount of fat stored in the autumn perhaps determines the ability to survive the winter (Table 1, weak). 6. The mean egg number was high in 1967 (Table 2a and 3a; 7.3 and 9.7% respectively). 7. Locomotory activity is severely reduced during the period between the time when "spent" females are caught and when they are caught again with developing eggs. 8. There is no difference between the locomotory activity of males and females ("spent" and "developing eggs") (Fig. 2). 9. The differences in mean egg number and the lag in the recapture of females with developing eggs in one of the two study areas can be explained by: a) differences in the method of recapture b) differences in the structure of the vegetation c) differences in the reproductive capacity and the locomotory activity.
