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We developed 14 polymorphic microsatellite markers for the minute pirate bug Orius sauteri (Heteroptera: Anthocoridae), and tested them with five markers previously developed in O. strigicollis. Except at one locus from O. strigicollis, we obtained amplified fragments from a field population of O. sauteri. The number of alleles ranged from 2 to 14, and observed heterozygosity ranging from 0.000 to 0.900. The observed heterogeneity was negatively correlated with null allele frequencies. Linkage disequilibrium was detected in three pairs of loci. The 19 microsatellite loci were also tested for amplification and polymorphism in two congeneric species, O. minutus and O. strigicollis. Markers could be amplified at many loci, although null allele frequencies were higher in cross-species amplification than in intra-specific amplification. These microsatellite markers will be used in studies of genetic diversity in these species.

Six microsatellite markers were developed for Orius strigicollis (Poppius), and their characteristics were analyzed using seven field and two commercial populations. The markers showed enough polymorphism to be suitable to elucidate genetic diversity, although null alleles were found on two loci and three loci were sex-linked. No linkage disequilibrium was detected except for a pair of two sex-linked loci. Allele frequencies between sexes in each population were not different in field populations. No genetic differentiation was found among populations collected in southern Kyushu, suggesting that this species has a large gene pool in the field. Allelic richness was significantly smaller in commercial populations than in field ones, possibly due to bottleneck effects and genetic drifts during mass-production procedures.

We examined the reproductive potential of three Orius (Heteroptera: Anthocoridae) species, O. strigicollis (Poppius), O. sauteri (Poppius) and O. minutus (Linnaeus), at different rearing temperatures (i.e., 17, 20, 23, 26, and 29°C) using the eggs of the Mediterranean flour moth (Ephestia kuehniella Zeller) as a food source. Mean generation times of the three species were nearly the same at all temperatures. The net reproductive rate of O. minutus was higher than those of the other two species at 17, 20, 23, and 26°C, and that of O. strigicollis was the highest among the three species at 29°C. Interspecific differences of net reproductive rates were largest at 29°C. Although the intrinsic rate of natural increase did not differ among the three species from 17 to 26°C, the rate for O. strigicollis was far higher than that for O. sauteri and O. minutus at 29°C. These results suggest that interspecific differences in the reproductive potentials of the three species tend to become larger as the temperature increases. Thus, we infer that O. strigicollis is advantageous in a wider temperature range than O. sauteri and O. minutus.

Semi-solid meridic diets for rearing two related species of Pentatomidae, Nezara viridula and N. antennata, were developed. For N. viridula, development times from second nymphal stadium to adult were 27.6 to 28.2 d for females and 26.8 to 27.5 d for males reared on the meridic diets at 25°C. The nymphal survival rate of N. viridula on the diets was more than 87%. Body weight at adult emergence ranged from 157.6 to 160.1 mg for females and from 123.1 to 128.3 mg for males. The pre-oviposition period was 20.8 to 25.8 d at 25°C when fed on the meridic diets, longer than when fed on peanut and soybean seeds. Fecundity and egg hatchability of the bugs fed on the meridic diets were almost the same as those for bugs fed on seeds. Casein was the only ingredient of the meridic diets essential for nymphal development of N. viridula. Nymphal duration of N. antennata fed on the meridic diet was 31.1 d for females and 29.2 d for males at 25°C, not much different from those fed on seeds. The pre-oviposition period of N. antennata fed on the meridic diet was 23.3 d at 25°C.

Second-, third-, early and late fourth-stadium larva, and pupa of Plutella xylostella (L.) were singly presented to female Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae) in the laboratory to investigate the effects of host age on oviposition behavior and development of the parasitoid. With regard to the oviposition behavior, the following three events were recognized after encountering the host: (1) drumming by antennae, (2) ovipositor penetration and oviposition, and (3) host feeding. Host acceptance rates did not differ among the different host ages except for pupa. Time required for ovipositor penetration and oviposition tended to increase with host age. About one third to one half of the wasps showed host feeding behavior irrespective of host age. The parasitism rate for fourth-stadium host larvae was higher than that for the second- and third-stadia. There were no significant differences among mean development times of the wasp in second-, third-, and early fourth-stadium larvae. However, development times in the late fourth-stadium hosts (=prepupa) were significantly shorter than in the early fourth- and other stadia hosts. This suggests that larval development of O. sokolowskii is influenced by host physiology.

The presense of diploid males and a sex determination system in Diadegma semiclausum, a larval parasitoid of Plutella xylostella, was examined by using an allozyme as a genetic marker. Among six enzymes investigated, only phosphoglucomutase (PGM) was apparently polymorphic. Two discrete bands were detected on electrophoretic banding patterns of PGM, indicating PGM was a monomer with two alleles on one locus. After establishing pure lines of each PGM allele, the heterozygous females were allowed to mate with their sons to examine the occurrence rate of diploid males in their progenies. Thus the numbers of diploid males identified did not differ significantly from those expected from the single-locus complementary sex determination (CSD). Inbreeding and the subsequent emergence of diploid males could partly account for the male biased sex ratio in the laboratory culture of D. semiclausum.