The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), is a plant feeder which feeds on gramineous grasses. It has been confirmed that the conspecific eggs are sucked dry by female and male adults. This egg predation indicates the bug is omnivorous. Fecundity and longevity of adults served wheat seedlings, as both a food source and oviposition site, were examined at 30°C, 25°C and 20°C with a 16-h photophase. The mean preoviposition period at 20°C was significantly longer than at 30°C and 25°C. The averages of the total number of eggs laid per female were 127.3, 107.7 and 107.6 at 30°C, 25°C and 20°C, respectively. Both females and males lived longer at lower temperatures. Males tended to live longer than females under all temperature conditions.
The effects of temperature on the development of three Orius species, O. sauteri, O. minutus and O. strigicollis were examined at 17, 20, 23 and 26°C by using eggs of the Mediterranean flour moth (Ephestia kuehniella Zeller) as a food source. The effects of photoperiod on the reproductive diapause in these Orius species were also examined under 15L–9D, 14L–10D, 13L–11D, 12L–12D, 11L–13D and 10L–14D at 20°C and under outdoor conditions from September to November in 2001 in Higashi-ichiki, Kagoshima. Developmental times from egg to adult were different between the three species under low temperatures, 17 and 20°C. Developmental zero (T0) and the thermal constant (K) from egg to adult were 11.0°C and 259.1 day-degrees in O. sauteri, 10.3°C and 281.3 day-degrees in O. minutus and 10.0°C and 281.9 day-degrees in O. strigicollis. Estimated annual number of generations in the three species was calculated to be 8 based on the mean air temperature in Kagoshima. Estimated critical photoperiod for diapause in O. sauteri and O. minutus was between 11L–13D and 12L–12D, while the diapause rate of O. strigicollis was low, 25.0% even under 10L–14D. In outdoor conditions, ca. 25% of O. sauteri cohorts reared from early September entered diapause. Further, ca. 80% of the cohorts of the three species reared from early October entered diapause.
The effects of the oxadiazine insecticide, indoxacarb, and its N-decarbomethoxylated metabolite (DCJW) on voltage-gated sodium channels in dorsal unpaired median (DUM) neurons isolated from American cockroach, Periplaneta americana, were studied using a whole-cell patch clamp technique. Both indoxacarb and DCJW suppressed the peak sodium currents in a time dependent manner. Indoxacarb and DCJW at 1 μM blocked the sodium currents to 39.0±5.9% (n=3) and 3.2±0.2% (n=3) of the control after 25 min of bath application. Thus, indoxacarb was less potent than DCJW in blocking sodium currents in cockroach DUM neurons. However, the potency of indoxacarb in insect neurons observed in the present study was at least 100 times higher than that in rat dorsal root ganglion neurons reported previously.
We devised a method for estimating the initial time of appearance of the first-generation nymphs of the brown-winged green bug, Plautia crossota stali, in Japanese cypress forests. Almost all hatchlings from egg batches inoculated on Japanese cypress in early June died in the second stadium, whereas the mortality rate of the second instar nymphs decreased and the adult eclosion rate increased after late June. The survival rates of the second stadium nymphs experimentally reared on cypress cones collected from the forests increased after late June or mid July depending on the year. These findings indicate that the time cypress cones become effective as food differes from year to year. As a result, the initial appearance of P. crossota stali nymphs in the forests coincides with the time when the cypress cones become effective as a food source.
Larvae of the cryptomeria bark borer, Semanotus japonicus (Lacordaire) (Coleoptera: Cerambycidae), were aseptically reared on an artificial diet. A single larva, hatched from a surface-sterilized egg, was placed in each flask containing diet. During the larval period, it was not necessary to transfer the larva to a new flask. No microorganisms were observed growing in any of the flasks. Ultimately, 50% of the larvae emerged, which is a rate similar to that obtained with non-aseptic rearing on an artificial diet. Moreover, all of the adult females oviposited eggs and approximately 80% of these eggs hatched. These results indicate that successive generations of the borer can be reared in this manner.