Feeding and Amines Stimulate the Growth of the Salivary Gland following Short-Term Starvation in the Black Field Cricket, .

The salivary gland of the black field cricket, Walker changed size between being starved and fed. Crickets without access to food for 72 h showed a reduction in both wet and dry mass of the glands compared with the glands from continuously fed animals at 72 h. Glands returned to size following ingestion within 10 min.

A Novel Head Capsule Labial Gland Lobe in the Black Field Cricket (Orthoptera: Gryllidae).

We describe a pair of labial gland lobes on either side of the retrocerebral complex in the head of the Australian black field cricket, Teleogryllus commodus Walker. As the retrocerebral complex includes the corpora cardiaca and corpora allata, hormones secreted by these glands can be absorbed by these lobes. These lobes of the labial gland are connected to the thoracic lobes via a relatively long duct that enters the main duct draining the thoracic lobes.

Formation and reaction of oxidants in water ice produced from the deposition of RF-discharged rare gas and water mixtures.

Thin-film water ice samples are doped with reactive species, such as OH and HO(2) and both singlet and triplet O atoms, which are produced in a discharge, in order to trace the reactions that form oxidants such as H(2)O(2) and O(2), in relation to the icy surfaces of satellites in the outer solar system. The present experiments show that, while reactions of OH formed in the discharge produce H(2)O(2), the majority of H(2)O(2) is formed via other pathways, with reactions of singlet O atoms being the most likely candidate. Strong evidence comes from thermal processing of the ices and using the matrix-isolation technique to quantify the OH abundance in the discharge, which is far below the required amount to account for the relatively high H(2)O(2) abundances measured.

Formation of methanol from methane and water in an electrical discharge.

Matrix isolation FTIR experiments have shown that methanol is a major product when argon gas doped with water and methane is exposed to an electrical discharge and condensed to a solid matrix at 11 K. Experiments with (2)H, (17)O and (18)O-labeled isotopologues show the mechanism for the methanol production is likely to be insertion of an excited oxygen atom in the (1)D state into a C-H bond of a methane molecule. In light of these experiments, the possibility of oxygen atom insertion into methane should be considered as a possible mechanism for the production of methanol in interstellar ices.

Effects of starvation and parasitism on foregut contraction in larval Manduca sexta.

Larvae of Manduca sexta are parasitised by the braconid wasp, Cotesia congregata. In this study we examined whether contraction activity of the semi-isolated foregut was affected by parasitism. Parasitised larvae fed significantly less compared with unparasitised control larvae, therefore starved unparasitised animals were used as controls.

Effect of opioid compounds on feeding and activity of the cockroach, Periplaneta americana.

Opioid peptides have been implicated in regulation of feeding in invertebrates. Studies have suggested that receptors for opioids are present in cockroaches and that these receptors play roles in affecting both behaviour and feeding. We examined the effect of micro, delta, and kappa opioid receptor agonists and antagonists on feeding, mass changes and activity in the cockroach, Periplaneta americana.

Neural regulation of discontinuous gas exchange in Periplaneta americana.

Patterns of gas exchange among terrestrial arthropods are highly variable from continuous to discontinuous with discretely partitioned phases. The underlying initiation and co-ordination of these patterns is relatively poorly understood. Here we present a novel method for the simultaneous measurement of central nervous system (CNS) activity of the metathoracic ganglion and VCO(2) in medium to large sized live terrestrial arthropods.

Effects of phosphine on the neural regulation of gas exchange in Periplaneta americana.

Phosphine is used for fumigating stored commodities, however an understanding of the physiological response to phosphine in insects is limited. Here we show how the central pattern generator for ventilation in the central nervous system (CNS) responds to phosphine and influences normal resting gas exchange. Using the American cockroach, Periplaneta americana, that perform discontinuous gas exchange (DGE) at rest, we simultaneously measure ventilatory nervous output from the intact CNS, VCO(2) and water loss from live specimens.

Cyclic gas exchange in the giant burrowing cockroach, Macropanesthia rhinoceros: effect of oxygen tension and temperature.

The giant burrowing cockroach, Macropanesthia rhinoceros, is endemic to north-eastern Australia and excavates a permanent burrow up to 1m deep into soil. Using flow-through respirometry, we investigated gas exchange and water loss at three different oxygen tensions (21%, 10% and 2% at 20 degrees C) and temperatures (10, 20 and 30 degrees C at 21% oxygen). M.

Effects of temperature and oxygen availability on water loss and carbon dioxide release in two sympatric saproxylic invertebrates.

Water loss and VCO(2) relative to temperature and oxygen tension was investigated in a log-dwelling onychophoran (Euperipatoides rowelli) and a sympatric, un-described millipede species using flow-through respirometry. Onychophorans possess a tracheal system featuring permanently open spiracles. Total body water loss was consistently very high in E.

Infrared identification of matrix isolated H2O.O2.

Theoretical studies of the H2O.O2 complex have been carried out over the past decade, but the complex has not previously been experimentally identified. We have assigned IR vibrations from an H2O.

Infrared detection of HO2 and HO3 radicals in water ice.

Infrared spectroscopy has been used to detect HO(2) and HO(3) radicals in H(2)O + O(2) ice mixtures irradiated with 0.8 MeV protons. In these experiments, HO(2) was formed by the addition of an H atom to O(2) and HO(3) was formed by a similar addition of H to O(3).

Infrared measurements and calculations on H2O.HO.

We have measured the infrared spectrum of H2O.HO in argon matrices at 11.5 +/- 0.