Octopamine has been called the 'fight or flight' hormone of insects. We tested this hypothesis by measuring octopamine levels in the haemolymph of field crickets after fighting, flying, courting and escape behaviours. Octopamine levels in the cricket Gryllus bimaculatus increased during aggressive (agonistic) behaviour from baseline levels of 4.5 +/- 2.1 pg microliters-1 haemolymph to 24.3 +/- ...

BACKGROUND Antimicrobial peptides play a role as effectors substances in the immunity of vertebrate and invertebrate hosts. In the current study, antimicrobial peptide was isolated from the haemolymph of the American cockroach, Periplaneta americana. METHODS Micrococcus luteus as Gram-positive bacteria and Escherichia coli as Gram-negative bacteria were candidate for injection. Induction was ...

The aims of the present study were to describe a possible correlation between the regulation of the key glycolytic enzyme pyruvate kinase and the acid-base status in the haemolymph and in several other tissues of land snails during anoxia. To illustrate whether such a relationship exists, we determined (i) the acid-base variables in the haemolymph and tissues of the land snail Helix lucorum, (i...

The accumulation of cadmium by the shore crab Carcinus maenas (L.) is to some extent dependent upon the calcium concentration of the external medium. This effect is apparently independent of the overall salinity of the external medium and may at least partially explain previous reports of a 'salinity effect'. Haemolymph cadmium has a highly significant inverse relationship with the external cal...

1. The quantitative variations of the concentrations of uric acid, citrate, nucleic acids and total and acid-soluble phosphorus in the pupal haemolymph of Philosamia ricini during metamorphosis have been studied. 2. The mean value for total nitrogen in the haemolymph and total loss in weight of the insects during metamorphosis have also been recorded.

Owing to the great variability in ionic composition of insect haemolymph (Bone", 1944; Duchateau, Florkin & Leclerq, 1953; Sutcliffe, 1963), it is probably desirable to use haemolymph itself as an experimental medium whenever this is possible. In the present studies of proprioception in Anthercea pernyi the long time spent in dissection and the necessity for aeration rendered the use of a simpl...

Total and differential haemocyte counts following repeated haemolymph withdrawals were made in V instar larvae of P. demoleus. While total count showed a steady reduction reaching its lowest in prepupal stage, much variation was observed in the relative percentage of various cell types. Further, the repeated removals of haemolymph from V instar larvae and pupae affected imaginal moulting and le...

A larval moult in the tobacco hornworm, Manduca sexta, involves an endocrine cascade that begins with the release of a cerebral peptide hormone, the prothoracicotropic hormone (PTTH). The release of PTTH is gated, occurs during the scotophase and appears to be developmentally cued. In fourth instar Manduca larvae, PTTH release into the haemolymph occurs as a single burst over a few hours during...

In fourth instar larvae of Camptochironomus tentans, net sodium uptake from 2 mM-NaCl has an electrogenic component. During net uptake the transepithelial potential (TEP) alters from a value of approximately - 40 mV (sign refers to haemolymph), in depleted animals, to approximately o mV. The TEP in depleted larvae is dependent upon external sodium concentration above about I mM-Na+, becoming in...