Abstract. .Reproducing females of the firebug, Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae), reared under long‐day (LD 18:6h) photocycle (long‐day females), and diapausing females reared under short‐day (LD 12:12h) conditions (short‐day females) were analysed for temporal patterns of feeding, drinking and gut digestive enzyme activities. In long‐day females the highest activities of feeding and drinking were found at the beginning of each reproductive cycle. Significant correlation between feeding and drinking activities in both reproducing long‐day females and short‐day females during pre‐diapause state was found. In pre‐diapausing short‐day females the cyclical pattern of feeding and drinking was maintained despite the inhibition of reproduction. After entering the diapause their feeding activity became very low. Analysis of five gut enzymes revealed that short‐day females differ significantly from long‐day females in higher protease, amylase and esterase activities, in case of lipase only at certain times of their adult life; no significant difference was found in the aminopeptidase activity. Positive correlations between intensity of feeding and gut enzyme activities were observed in short‐day females. Using several protease inhibitors most protease activity in the gut of P.apterus was identified as cysteine and aspartyl proteases, and only a small part of the activity could be caused by some serine proteases.
Abstract. Macropterous females of Pyrrhocoris apterus (L.) reared under short‐day conditions (LD 12:12 h) were analysed for temporal patterns of feeding and drinking behaviour, activities of digestive enzymes in the gut, and lipid and glycogen content in the haemolymph and fat body. Peaks of drinking activity were recorded at days 3, 7 and 10 during the first 14 days after imaginal ecdysis. Feeding activity peaked on the third day, ceasing completely after the fourth day of adult life. Esterase, protease, amylase and aminopeptidase activities exhibited the highest overall activity in the first days after imaginal emergence; then enzyme activities decreased. In the fat body, the content of lipids was highest on day 5, then a decrease of about 40% was observed at day 14; the amount of glycogen was highest on day 1 at 11 μg of glucose equivalents/mg of fat body, then decreased to 2 μg at day 14 after the imaginal moult. In the haemolymph, the lipid content rose until day 8 when it reached almost 0.3 μmol/μl; at day 14 the value was slightly lower. The association of fasting with reproductive arrest in macropterous females of P. apterus, accompanied by a decrease in digestive enzyme activities and a mobilization of lipid reserves from the fat body, was demonstrated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.