THE POTENTIAL OF ABAX-PARALLELEPIPEDUS (COL, CARABIDAE) FOR MASS BREEDING AS A BIOLOGICAL-CONTROL AGENT AGAINST SLUGS

Previous work has shown that Abax parallelepipedus Piller and Mitterpacher preys upon slugs in the field, and can be effectively employed to control slugs in polythene tunnels. To be a viable biological control agent this carabid must also be amenable to mass culturing. Manipulation of the substrate ensured that eggs were laid in soil capsules, but deposited in peat, facilitating collection and monitoring. Up to 570 eggs per beetle were laid at 20 degrees C. No cannibalism was exhibited at any stage by this species. Larvae were reared intensively in batches and fed ad libitum on live earthworms, eliminating the need for regular feeding and the removal of decaying food. Rearing experiments were undertaken under a number of different temperature regimes. At constant 20 degrees C it was found that growth was arrested in some 2nd instar larvae for long periods. Co-ordinated changes between 2nd and 3rd instar stages were induced by reduction of the temperature to 14 degrees C between days 24-31 from hatching. The complete life cycle, from newly laid egg to adult beetle, could be reduced to less than 110 days. Mortality was greatest at the late 3rd instar and pre-pupal stages, and possible reasons for this are discussed.