Some Aspects of the Developmental Biology of Blaps kollari (Coleoptera: Tenebrionidae) Under Laboratory Conditions

Abstract

The study focused on the influence of an artificial diet on the health, fecundity, duration and pattern of development, and survival rates of the beetle, Blaps kollari Seidlitz. The breeding period was confined mainly to the cooler months during which females laid their eggs; the largest number per individual was 650. Sixty-two percent of the eggs that matured in 9 d produced viable first-instar larvae. Voracious feeding from second instar onward produced an exponential weight gain; a coefficient of 400 from second to terminal eighth instar. In isolation, instar mortality was small; larvae consumed exuviae when not removed, and communal life allowed considerable cannibalism. Full larval development was quite rapid, lasting only 80 d, and terminated in a prolonged semidormant, nonfeeding pharate-pupal stage; a majority entered this stage after the seventh instar. Last-instar larvae were susceptible to a bacterial infection. Mortality and morbidity increased during pharate-pupal stage and deformity occurred also during pupal and adult molts. About 68% of pharate-pupal to pupal molts were normal. The pupal stadium averaged 15 d, during the latter half of which rudiments of the sternal gland, a characteristic of the males, appeared between sternites two and three. A majority of the pupal-to-adult molts resulted in deformed individuals. Experimental groups allowed cannibalism, and exuvial feeding fared better at this molt. A total of 8.5% healthy normal adults was obtained from all groups taken together. The pharate-pupal and newly emerged adult phases were accompanied by a significant weight loss. Within 1 mo after adult feeding was initiated, weight exceeded the maximum attained by last-instar larvae and plateaued within 2 mo.