Hexameric haemolymph protein related to adult diapause in the red firebug, Pyrrhocoris apterus (L.) (Heteroptera)

Abstract

A hexameric storage protein was electrophoretically isolated from the haemolymph of diapausing adults of the red firebug, Pyrrhocoris apterus. This protein ( M rmr ~ 480,000, glycoprotein) was found to be a monohexamer. During the penultimate and last larval instar (both in diapausing and non-diapausing bugs), its concentration increased from about 1 mg/ml up to 8 and 13 mg/ml, respectively, and declined to almost zero value during ecdysis. In diapausing adults, the titre of the protein rose steeply from day 3 and reached a level of about 21 mg/ml in females and 24 mg/ml in males. In non-diapausing adult females there was an initial rise in the protein titre during the first 6 days but subsequently it stabilized to a level of about 3 mg/ml. In males the hexameric protein content reached only 1 mg/ml after imaginal ecdysis; an increase on day 21 and 30 was observed. In 14-day-old diapausing and non-diapausing bugs the hexameric protein constitutes about 15 and 4% of all haemolymph proteins, respectively. An amino acid analysis showed that the hexameric protein is neither an arylphorin nor a methionine-rich protein.