Maternal hatching synchronization in a subsocial burrower bug mitigates the risk of future sibling cannibalism.

Sibling cannibalism-the killing and consumption of conspecifics within broods-carries a high risk of direct and inclusive fitness loss for parents and offspring. We reported previously that a unique vibrational behavior shown by the mother of the subsocial burrower bug, (Heteroptera: Cydnidae), induced synchronous hatching. Maternal regulation may be one of the most effective mechanisms for preventing or limiting sibling cannibalism.

Maternal vibration: an important cue for embryo hatching in a subsocial shield bug.

Hatching care has been reported for many taxonomic groups, from invertebrates to vertebrates. The sophisticated care that occurs around hatching time is expected to have an adaptive function supporting the feeble young. However, details of the characteristics of the adaptive function of hatching care remain unclear.

A gene involved in the food preferences of larval Drosophila melanogaster.

To examine the mechanism by which insects change their food preferences, a simple method was developed to measure their preferences. By using this method, we demonstrated preference of Drosophila melanogaster larvae of the yw control strain for a food based on soybeans over one based on cornmeal. We then screened for mutant strains with food preferences clearly different from the control yw strain, using the Gene Search collection of P-element insertions (GS strains).

Round-the-clock homing behavior of a subsocial shield bug, Parastrachia japonensis (Heteroptera: Parastrachiidae), using path integration.

Females of the subsocial shield bug, Parastrachia japonensis (Parastrachiidae), are central-place foragers, collecting drupes for their young from nearby host trees by walking along the forest floor both during the day and at night. Because burrows are often some distance from the drupe-shedding tree, the bugs must repeatedly leave their burrows, search for drupes, and return to the burrows. After a bug leaves its burrow, it searches arduously until it encounters a drupe.

Uric acid recycling in the shield bug, Parastrachia japonensis (Hemiptera: Parastrachiidae), during diapause.

Nymphs of the univoltine shield bug, Parastrachia japonensis grow by feeding on the drupes of their sole food plant, which are available for only 2 weeks a year. The new adults soon enter a reproductive diapause and survive without feeding for at least 10 months up to 2 years. Uric acid was found to be the predominant component among four waste nitrogenous compounds, i.

Reduction of respiration rates by forming aggregations in diapausing adults of the shield bug, Parastrachia japonensis.

Parastrachia japonensis adults in diapause live mostly in aggregated conditions and can survive more than 1 year on only water. In this study, we demonstrated that diapausing adults had a high tendency to form clusters with no sexual bias. When 3-40 insects were enclosed in chambers of equal volume used to measure respiration, oxygen consumption was reduced to nearly half that when a single individual was enclosed.

Age-related changes in flight muscle mass, lipid reserves and flight capacity during adult maturation in males of the territorial damselfly Calopteryx atrata (Odonata: Calopterygidae).

In the territorial damselfly Calopteryx atrata Selys, length of the hindwing, the wing areas and the aspect ratio did not differ significantly among age classes during the pre-reproductive period, while the body mass of males increased about 2.5 times. This is due primarily to increase in mass of thorax and abdomen.

Flight capability and fatty acid level in triacylglycerol of long-distance migratory adults of the common cutworm, Spodoptera litura.

The larvae of Spodoptera litura were reared on an artificial diet, and the flight capability, and triacylglycerol (TG) level plus its fatty acid composition in 3-day-old sexually mature and non-fed adults were compared. In males, during 3 hr of tethered flight, the levels of abdominal TG and its fatty acid components did not change. But thereafter the TG and fatty acids, significantly unsaturated fatty acids in TG declined in their levels with the prolongation of flight, unsaturated fatty acids being exhausted preceding saturated fatty acid decline.

Sensitive periods for wing development and precocious metamorphosis after precocene treatment of the brown planthopper, Nilaparvata lugens.

The critical periods for juvenile hormone suppression of wing development and metamorphosis were examined in a pure brachypterous line of Nilaparvata lugens following topical application of Precocene II (PII) to various stages of the third and fourth nymphal stadia. When PII, in doses ranging from 10 pg to 100 ng, was applied to 12-h-old third or 6-h-old fourth stadium nymphs, long-wing formation (macroptery) was induced. Macropter induction ranged from 5 to 50% in females and from 30 to 50% in males, the effect being more prominent in males.

The directional homing behaviour of the subsocial shield bug, Parastrachia japonensis (Heteroptera: Cydnidae), under different photic conditions.

The female subsocial shield bug, Parastrachia japonensis, provisions its nymphs by foraging on the ground in the forest during the Japanese rainy season, and the bug uses homing navigation to drag a drupe back to its burrow by the shortest route during the day. To study whether or not this bug performs this provisioning behaviour under different photic conditions, we observed the homing behaviour and homing direction of bugs in the field around the clock and/or under various weather conditions. The bugs foraged the whole day during the busiest provisioning period, and the number of walking bugs was not affected by the different weather conditions.

Purification and characterization of biliverdin-binding vitellogenin from the hemolymph of the common cutworm, Spodoptera litura.

Biliverdin-binding vitellogenin (Vg) was purified from adult female hemolymph of the common cutworm, Spodoptera litura, by using gel filtration and ion exchange chromatographies. The molecular mass of the protein was 490 kDa and it was composed of two 188-kDa subunits. Three internal amino acid sequences obtained by digestion of the protein with lysylendopeptidase showed high similarity to those of Bombyx mori Vg, supporting the purified blue protein to be vitellogenin.