Age-related changes in amino acid composition and turnover in the colorado potato beetle, Leptinotarsa decemlineata

Tenebrio molitor(Coleoptera): effect of metacestodes ofHymenolepis diminuta(Cestoda) on haemolymph amino acids

Haemolymph free amino acids (HFAAs) in adultTenebrio molitorvaried in concentration with beetle age. Between 9 and 30 days post-emergence the concentration range was 34–94 mMwith a peak occurring in 15-day-old insects. Much of this age-related variation was due to changes in the concentration of a single amino acid, proline. An analysis of concentrations of individual HFAAs in 15-day-old beetles, following infection with metacestodes ofHymenolepis diminuta, revealed that changes in female insects are more marked than those occurring in males. In the former, changes occurred in the concentration of 9 amino acids (isoleucine, leucine, arginine, serine, threonine, tyrosine, phenylalanine, proline and alanine/citrulline) whereas in the latter only 4 amino acids were affected (threonine, glycine, histidine and arginine). It is suggested thatH. diminutamay interact with the endocrine system of its beetle host.

Effect of pyriproxyfen and photoperiod on free amino acid concentrations and proteins in the hemolymph of the Colorado potato beetle, Leptinotarsa decemlineata (Say)

A North Dakota strain of the Colorado potato beetle, Leptinotarsa decemlineata (Say), was reared under both short- (8L:16D) and long-day (17L:7D) conditions. Age-related and pyriproxyfen- (JHA-) induced changes in hemolymph free amino acids and proteins were examined. Under a short-day photoperiod, the total free amino acid concentration in the hemolymph increased gradually up to 20 days of adult life, but the long-day beetles showed marked increases during the first 10 days and then decreased afterwards. Proline, glutamine and valine were the most abundant free amino acids in both sexes of beetles held under either short- or long-day photoregims. JHA treatment of diapausing adults, held under either short- or long-day conditions after treatment, terminated diapause as indicated by re-emergence from the vermiculite, feeding, mating, changes in free amino acid levels, the disappearance of diapause protein 1 and appearance of vitellogenin in the hemolymph. Furthermore, most of the JHA-treated females held under long-day conditions also matured oocytes and oviposited, but those held under short-day conditions did not.