Survival, fecundity and insecticide susceptibility of the cat flea, Ctenocephalides felis fed on mice were evaluated. Duration from egg to cocoon formation of C. felis fed on mice was about 8 days, that from egg to adult emergence was about 18 days, and the accumulated emergence rate was 89.2%. The average number of eggs deposited was 10.3 eggs/day/(female), max. egg deposition was 21.6 eggs/day/(female) at 4 days after infestation, and total number of egg deposition was 402 eggs/(female). Longevity of C. felis reared on mice was more than 40 days. Insecticide susceptibility of mouse strain C. felis was the same as that of the cat strain. This rearing method is very simple and useful for producing a large number of cat fleas in a small space.
Oviposition habits on artificial diet and efficient methods for egg collection and diet replacement were studied in the alfalfa weevil, Hypera postica (Gyllenhal). The eggs were laid inside both the block type artificial diet and alfalfa fresh leaf stem, while abundantly laid on the surface of the flake type artificial diet. Both egg collection and diet replacement were the easiest when the insects were fed on granular diet using a cup with a gauze bottom. The eggs were collected most efficiently, when the female adults were supplied the diet during the light period (8 h) and allowed to oviposit in empty cups during the dark period (16 h).
Worker and new-queen productivity in laboratory reared colonies of B. hypocrita and B. ignitus was influenced by both delays in oviposition and first worker emergence. In B. hypocrita, colonies with a period of 20 or less days before the first oviposition produced significantly more female castes than ones with 21 or more days. In B. ignitus, colonies with 10 or less days produced significantly more female castes than ones with 11 or more days. In both species, colonies with a longer period of more than 29 days before the first worker's emergence produced fewer female castes than normal colonies in which the first worker emerged in 28 or less days. These two parameters provide an effective and practical method for identifying normal bumblebee colonies in the early stages of commercial mass-production.
The daily patterns of reproductive activity in the diamondback moth were studied outdoors in Miyazaki, Japan, between June 1998 and January 1999. Mating primarily began within one or two hours after sunset, although it also occurred during the daytime in the winter. Mating time was longer in cool seasons than in warm seasons. In June to October, oviposition occurred mainly at night with a peak at one or two hours after sunset. In November, however, some eggs were laid during the daytime. Daytime oviposition was observed more frequently in colder seasons. It is suggested that a low nighttime temperature suppresses the normal behavior of the diamondback moth, and changes the nocturnal oviposition pattern to a diurnal one. The daily rhythm of mating behavior coincided most closely with that of egg-laying behavior.
Twenty isolates of entomopathogenic fungi (Beauveria bassiana, Metarhizium anisopliae and Paecilomyces sp.) were bioassayed against groups (5 termites in 90×15 mm petri dishes) of the termite, Reticulitermes speratus. Termites were susceptible to the various isolates. Effect of termite density on susceptibility to B. bassiana and M. anisopliae was also assayed. Reared individually, termites were highly susceptible to B. bassiana and M. anisopliae. When groups of termites (10 termites in 90×15 mm petri dishes) were exposed to B. bassiana and M. anisopliae, they were highly resistant to infection.
Species diversity of heteropteran communities was investigated in the border vegetation of two paddy fields, the one (Site A) cultivated with insecticides and herbicides, and the other (Site B) with mowing and without spraying agrochemicals, in southern Ibaraki Prefecture, from May to October of 2000. A total of 73 species from 17 families were collected at the two sites, 44 species from 14 families and 56 species from 15 families from Sites A and B, respectively. Twenty-seven species were common to both sites with a similarity index (QS) 0.54. The species diversity (H′) was higher in Site B (4.26) than in Site A (3.61). The population density (93.7 individuals/sampling on the average) and fluctuations were low in Site B, while the density (330.3) was high and showed a rapid decrease after spraying herbicide and a marked increase after harvest in Site A. The rate of brachipterous species was higher in Site B (12.5 and 15.9% for numbers of species and individuals, respectively) than in Site A (6.8 and 0.6%), while the rate of species causing “pecky rice” was higher in Site A (54.5 and 80.6%) than in Site B (35.7 and 51.7%). The results suggest that the incidence of pecky rice can be kept low even in paddy fields cultivated without herbicide application.
Seasonal abundance of primary parasitoids and hyperparasitoids associated with Acyrthosiphon spp. was studied in an alfalfa field in 2000. Two species of primary parasitoids were recorded: Aphidius ervi and Praon barbatum. Mean parasitism by A. ervi and P. barbatum peaked at 3.5% on 10 July and 13.0% on 29 June. Six species of hyperparasitoids were also collected. Rates of parasitism of A. ervi and P. barbatum reached over 90% and 80%, respectively. Dendrocerus carpenteri and Asaphes suspensus were the dominant species among hyperparasitoids.
Toxicity bioassay of 18 Japanese populations of Tyrophagus similis was conducted under laboratory conditions with a field dose of DDVP (50% EC, ×1,000). Results showed that DDVP EC had high acaricidal activity in all populations. Therefore, the low control effect of DDVP under field conditions shown in the early paper (Kasuga and Amano, 2000) is speculated to be the result of chemicals particles not satisfactorily reaching mites both in the soil and on spinach plants.