1. Hairworms (phylum Nematomorpha) and mermithid nematodes (phylum Nematoda) have independently evolved almost identical life cycles: both parasites cause their terrestrial arthropod hosts to seek water, required for their aquatic free-living adult stage. Hairworms achieve this by altering host neurotransmitters, but the mechanisms used by mermithids remain unknown. 2. The physiological effects...

The osmoregulatory and respiratory responses of male and female Smeringurus mesaensis (Vaejovidae) to prolonged desiccation were measured. No significant effect of sex on mass-loss rates (MLRs) was found. Still, females maintained their haemolymph osmolality when desiccated to 10% mass loss, whereas that of males increased significantly after loss of as little as 5% of initial mass. Females had...

Ammonia is a toxic nitrogenous waste product of amino acid metabolism that may accumulate to high levels in the medium ingested by larvae of the fruit fly Drosophila melanogaster. Here we report measurements of haemolymph NH4(+) concentration and the secretion of NH4(+) by the Malpighian (renal) tubules. Measurement of NH4(+) concentrations in secreted droplets is complicated either by the requ...

There has been a considerable amount of work on the electrical potential differences and active transport processes of ions across various vertebrate epithelia (Ussing, i960). Little work of this type has been attempted on invertebrate material. As the crustacean gill epithelium has only a single layer of cells separating the body fluid and the external medium, it should be particularly suitabl...

The turnip sawfly, Athalia rosae Linnaeus, is a pest on cruciferous crops. Larvae sequester secondary plant compounds, namely glucosinolates, in their haemolymph. When attacked, their integument is easily disrupted and a droplet of haemolymph is exuded ('easy bleeding'). This has been shown to be an effective, chemical-based, defence against invertebrate predators. The efficiency of this propos...

When terrestrial slugs (Limax maximus) are dehydrated to 65-70% of their initial body weight (IBW) their feeding responsiveness is greatly decreased. There is a 90% decrease in feeding responsiveness when slugs are injected with hyperosmotic mannitol solution that raises the haemolymph osmolality to that of slugs dehydrated to 65-70% IBW (i.e. 200 mosmol kg-1 H2O). The duration of the Feeding M...

After treatment of the newly moulted last (5th) instar nymphs of the desert locust Schistocerca gregaria with 1000.0 or 62.5 ppm of the insect growth regulators (IGRs): pyriproxyfen (juvenoid), tebofenozide (ecdysone agonist) and lufenuron (chitin synthesis inhibitor), protein content was determined in the haemolymph and fat body of nymphs and adults. An inhibitory action on haemolymph proteins...

Two conflicting hypotheses have been advanced to explain the remarkable ability of the neurones of some phytophagous insect species to function in nerve cords bathed with haemolymph containing relatively low concentrations of sodium ions. The first of these attributes the maintenance of a high extraneuronal sodium level to the activity of the glial and perineurial elements (Treherne & Maddrell,...

ecological demands interfering with oxygen delivery such as environmental hypoxia (Butler et al., 1978; Wheatly and Taylor, 1981; McMahon, 1992; Reiber et al., 1992; Airries and McMahon, 1994), air exposure (Taylor and Wheatly, 1981; Airries and McMahon, 1996) or exercise (Herreid et al., 1983; Hamilton and Houlihan, 1992; Hokkanen and DeMont, 1992; Reiber, 1994; Reiber et al., 1997) with vario...