INVESTIGATIONS ON THE LIFE-HISTORY OF NEMOSOMA-ELONGATUM L (COL, OSTOMIDAE), A BARK BEETLE PREDATOR

To estimate the influence of N. elongatum on bark beetle (Pityogenes c halcographus), regulation information about the biology of this specie s is necessary. In the laboratory, embryonic development depended on t emperature and averaged 12 days at alternating temperatures (25/15 deg rees C), mean duration of the postembryonic period was 58 days at this temperature. Prey consumption of the N. elongatum larvae (three insta rs) was approximate to 30 bark beetles (larvae, respectively, pupae) p er individual. The adult longevity averaged 3-5 months and mean fecund ity was 63.6 eggs per female at alternating temperature (20/10 degrees C) and 58.4 eggs at constant temperature (22 degrees C). The prey con sumption of the N. elongatum imagines also depended on temperature. At alternating temperatures (20/10 degrees C) the mean prey consumption was approximately one bark beetle adult per day and N. elongatum indiv idual. Due to these data this predator species must be considered as a n important and effective antagonist of Pityogenes chalcographus.