Recent work on selected topics of particular interest for understanding insect cold hardiness is reviewed. Themes considered include the dynamic nature of cold hardiness, ice nucleation, connections between cold hardiness and desiccation, rapid cold hardening, seasonal changes in mitochondria, survival in nature, and selection for types of cold hardiness. Such seasonal adaptations have a wider range of components than has often been appreciated, including independently evolved elements. Some specific conclusions are drawn and suggestions are made for future work. Several adaptations, such as rapid cold-hardening and mitochondrial degradation, will probably prove to be much more widespread than has yet been realized. From a general perspective, understanding such diverse components and their differences requires an ecological approach that places the biochemical and timing adaptations in context with habitat conditions and demands related to the stresses of the adverse season, seasons favorable for development and reproduction, and the signals that are available in each habitat to predict future environments. Further understanding therefore depends especially on efforts to analyse the adaptations of individual species in the context of their natural environments.

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Cicadulina bipunctata (Melichar) (Homoptera: Cicadellidae) is a pest of the second planting of forage maize in central Kyushu, Japan. The effect of temperature on the development and reproduction of C. bipunctata was examined in laboratory experiments. The survivorship of eggs and nymphs was the highest at 25.3°C. The developmental periods of eggs and nymphs were significantly shortened as the temperature was increased up to 34.0°C. The developmental zero (T₀) was estimated at 14.0°C for eggs and female nymphs, 14.2°C for male nymphs, and 15.9°C for preoviposition period. A thermal constant (K) of 118.1, 182.7, 176.9, and 39.5 degree-days was estimated as the effective temperature sums for the development of the eggs, female nymphs, male nymphs, and preoviposition period, respectively. Adult longevity and fecundity were higher than those of other rice-associated leafhoppers, while net reproductive rate (R₀) and intrinsic rate of natural increase (r_m) were lower than those of other rice-associated leafhoppers. An increase of 1.29 and 1.43 generations per year following global warming was estimated for C. bipunctata by 2100, relative to 1990, in Kumamoto and Miyazaki, Japan, respectively. Thus, C. bipunctata has the potential to become a serious pest of cereal crops other than the second planting of forage maize.

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The white-backed planthopper, Sogatella furcifera, and the brown planthopper, Nilaparvata lugens, are pests of rice and migrate from south China to Japan in the rainy season of early summer. In order to achieve high-precision migration prediction, a real-time prediction system was developed. In this system, the latest meteorological data are supplied online to an advanced numerical weather prediction model, MM5. The model forecasts three-dimensional atmospheric fields at one-hour intervals. In these fields, a planthopper migration simulation model, GEARN, calculates movement of a number of modeled planthoppers and predicts their relative aerial density at three-hour intervals. The results are converted to maps and become available on the Internet. The maps of relative aerial density provide information about the timing and area of migrations over the next two days. During the main migration season in June and July 2003, the system achieved a prediction quality that was comparable to that of rainfall forecasts by the Japanese Meteorological Agency.

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The effects of constant temperature and photoperiod on the development and reproduction of Adoxophyes honmai Yasuda (Lepidoptera: Tortricidae) were investigated. The durations of the larval and pupal stages decreased in the range from 15 to 28°C, but the developmental periods were longer at 30°C than at 28°C. The developmental zero and the thermal constants were calculated to be 9.8°C and 104.1 degree-days for eggs, 9.3°C and 232.6 degree-days for larvae, 11.5°C and 76.3 degree-days for pupae, and 10.3°C and 417.0 degree-days from egg to adult emergence. The temperature significantly affected the number of eggs deposited by a single female, the proportion of eggs hatched, and the longevity of adult females. At both 15 and 20°C, larval and pupal developmental periods were significantly shorter for the long-day length of 16L:8D than for the short-day length of 10L:14D.

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Field-collected 229 colonies of a pemphigine social aphid Colophina arma, which has a soldier caste in the first instar, were examined for its population dynamics, reproductive schedule, and ecological factors related to soldier production. Colony size was small in July and became larger in August and on; this change probably reflects the flowering phenology of the host plant Clematis stans. Soldiers, which neither grow nor reproduce but are specialized for colony defense, were found throughout the seasons. Winged sexuparae, which migrate to Zelkova serrata and produce the sexual generation, appeared in late September. Midget first instar nymphs, which persist on C. stans for hibernation, were produced in October. Statistical analyses suggested that soldier proportion in colonies of C. arma might be related to the proportions of unwinged adults, colony size, and seasonal change. Sexuparae and midget nymphs were produced only in autumn, which reflects the overwintering roles of these morphs, and suggests that production of these morphs might be influenced by environmental factors related to the season, such as short photoperiod and low temperature.

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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.

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Outbreaks of the migratory locust, Locusta migratoria L., occurred in the northwestern part of China. The processes leading to the outbreaks and successful control are described based on locusts collected in infested areas and information obtained from local experts and scientists. Swarms of adults landed on the grazing and farming lands of Jiminay County, Altay Prefecture, the Xingjian Uygur Autonomous Region in 2003 and 2004, and caused substantial damage to agricultural crops and pastures. In the spring of 2004, numerous nymphs that had developed black patterns appeared in Jiminay. They and migrants from the north were sprayed with insecticides during the period from July 20 to August 6, 2004. A total of 4,200 personnel were involved in this mission. As a result, further damage to crops and migration to other areas were prevented. Morphometric measurements indicated that the migrants had reached the body dimensions typical for gregarious forms.

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Laboratory experiment was conducted to examine sublethal effects of beta-cyfluthrin (Bulldock^® 025 SC) on the sepia mutant of Drosophila melanogaster at a temperature of 25±0.5°C, 50±5% relative humidity and a photoperiod of 16 : 8 (light : dark) hours. Males and females were exposed separately to beta-cyfluthrin (one tenth of the calculated LC₅₀ value) mixed in the diet for 24, 48 and 72 h. Fecundity, hatchability, pupation, adult emergence, larval, pupal and total developmental periods were evaluated in the F₁ generation after various cross combinations. A reduction in fecundity, egg hatching, number of larvae, pupae, adults and prolongation of larval, pupal and total developmental periods was observed. A significant reduction (p<0.05) in fecundity was observed only on the treated diet after treatment of both the sexes. Maximum effects were observed after 72 h treatment followed by 48 and 24 h. Males were found to be more susceptible to beta-cyfluthrin as compared to the females.

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A study carried out across 33 weeks in a patch of taro, Colocasia esculenta L., quantified demographic parameters and density-dependent processes for a population of melon aphid, Aphis gossypii Glover. Variation in relative density of aphids per cm² of leaf tissue between consecutive weeks declined with the initial density of aphids, indicating that density dependent processes regulate populations of A. gossypii on taro. High abundance of aphids on large leaves suggest that host attributes affect the rates of colonization or reproduction of adults. Even though the incidence of winged aphids was consistently low throughout the experiment, between plant dispersal by aphids still homogenizes their spatial distribution within an array of plants, as indicated by similar relative densities of aphids on established plants and on sentinel (initially uninfested) plants 60 days following their introduction in the patch. The proportion of aphids parasitised by Aphidius colemanii Viereck and Aphelinus spp. was low (<3%), which may be attributed to a high level (>95%) of hyperparasitism. Mortality caused by two entomopathogens, Neozygites fresenii Nowakowski and Verticillium lecanii Zimmerman, averaged 12%. The proportion of fungal infection increased with the density of aphids, both on a spatial and temporal scale. However, the population of A. gossypii on taro was most likely not regulated by entomopathogens, because the proportion of diseased aphids did not influence variations of population density between consecutive weeks. The lower proportion of fungal infection on sentinel plants than on established plants suggests a limited impact of entomopathogens on taro plants recently colonized by aphids.

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The concentrations of 54 elements of the millipede Chamberlinius hualienensis and the soil including leaf litters were examined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). In all the millipedes, the Ca concentration derived from the calcium carbonate in the exoskeleton was the highest, at an average of 76 μg/mg-weight, and the other major elements were the following: Mg, K, Na, Fe, Al, Cu, Zn, Sr, Ba, Mn and Ti (>1 ng/mg-weight), whereas Ni, Cr, V, Ga, Mo, Co, Cd, etc. were at trace levels. Interestingly, the contents of Ca, Mg, K, Na, Zn, Sr, V, Co, Ag, and Sc in larvae were higher than in adult millipedes. Although the heavy metal contents, in the order of Cu>Pb>Cd, were similar to those of other invertebrates such as chilopoda, collembola, and carabidae, there was a high concentration of Cu in the millipedes. The other internal metals, As and Ag, were dependent on the soil concentrations in the habitat. Zn concentrations at sampling sites were different, but a constant level was maintained in the millipede. The results suggest that millipedes may provide information on the accumulation or regulation mechanism in the body for certain hazardous heavy metals. The C1 chondrite normalization pattern for lanthanoid series elements in both the millipede and soil indicated that the environmental habitats were well protected from pollution. The characteristics of internal elements and metal accumulation in the millipede in terms of relation to the habitat would be useful information for environmental pollution studies.

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The electrostatic application of a mycoinsecticide, Paecilomyces fumosoroseus, was tested for controlling the infestation of the silverleaf whitefly, Bemisia argentifolii, to tomato plants in greenhouses. Electrostatic application had no impact on fungal viability, measured as colony-forming units (cfu), and resulted in good fungal deposition (cfu/cm² of leaf surface) on both the adaxial and abaxial surfaces of leaves. The adaxial/abaxial surface ratio (1.8) was comparatively low, suggesting that the electrostatic application of mycoinsecticides is potentially useful for controlling greenhouse pests. However, experiments for controlling the whitefly produced unsatisfactory results, with larval mortalities of 48.1% on d 11 after the first electrostatic application of the mycoinsecticide and 23.9 and 8.1% on d 7 and 19 after the second application, respectively. It is likely that the low larval mortalities were caused by environmental conditions not conducive to fungal infection.

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I investigated seasonal changes in the levels of parasitism and the over-wintering status of tachinids on the larvae of Hyphantria cunea. Six species of tachinids were found to parasitize populations of H. cunea at Tsukuba, in central Japan. The rate of parasitism by tachinids was extremely high in the third host generation, especially during the wandering stage. The parasitization rate by the three dominant species, Exorista japonica, Drino inconspicuoides and Compsilura concinnata, was always higher in the wandering larvae than in the feeding larvae. The over-wintering strategy of tachinids differed between species; C. concinnata over-winters at the maggot stage and E. japonica at the early instar maggot and puparial stages. In E. japonica, the rate of over-wintering survival differed greatly between the two over-wintering strategies; individuals over-wintering at the maggot stage within hosts almost all succeeded in adult eclosion in the next year, whereas those over-wintering at the puparial stage out of hosts often died early in the next spring. Many E. japonica maggots over-wintered within hosts collected in late October, suggesting that parasitizing host larvae in late autumn is advantageous for E. japonica. This study provides evidence of different parasitic strategies in tachinid species that use H. cunea as a host.

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An acarid bait trap constructed from moistened, folded filter paper containing a small quantity of dry yeast was used to monitor the number of Tyrophagus similis and Rhizoglyphus robini in agricultural soils. In laboratory-based evaluations, the trap captured, on average, 88% (capture rate=no. of captured/no. of released×100 (%)) of the T. similis and 65% of the R. robini adults by 3 d after application of the trap, though the capture rate was lower for the immature stages of both species. Field trials were carried out to monitor T. similis numbers in a spinach greenhouse soil and R. robini numbers in a Welsh onion field soil using both the bait trap and the Tullgren funnel. Population trends for T. similis were similar in both trials, but T. similis numbers were consistently and significantly higher in the bait trap than in the Tullgren funnel. Numbers of R. robini obtained from the soil did not differ significantly between the two methods. These results suggest that efficient monitoring of acarids in the genera Tyrophagus and Rhizoglyphus is possible using the acarid bait trap.

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Since the concept of the ‘niche’ was proposed by Hutchinson almost 50 years ago, many researchers have investigated factors that enable species within ‘guilds’ (i.e., species that exploit a common resource and are likely to compete with one another) to co-exist and to persist. Here, development, host utilization, and life-history characteristics are compared in two species of solitary secondary hyperparasitoids, Lysibia nana and Gelis agilis, attacking pre-pupae of their primary parasitoid host, Cotesia glomerata. More than 80% of the host cocoons presented to L. nana successfully produced adult hyperparasitoids compared with only about 20% for G. agilis. Adult hyperparasitoid body mass increased with host mass, but there was little difference in the mean overall body mass of either species. However, egg-to-adult development time for L. nana was significantly less than that for G. agilis. When provided with unlimited food (honey solution), G. agilis had a lifespan that was almost twice that of L. nana. However, dissections of the ovaries of adult wasps at death revealed that L. nana usually had accumulated more than 20 mature eggs, whereas G. agilis was effectively sterile. We suggest that several eco-physiological factors, as well as differing degrees of specialization amongst the guild of secondary hyperparasitoids attacking C. glomerata cocoons, enable them to successfully co-exist in nature.

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The cherimoya is an orchard tree that is not pollinated by bees. To identify likely pollinators, and to describe community diversity, we surveyed flower visitors at four sites in Wakayama and Mie prefectures, and found 569 individuals from 31 species of arthropods. Two of these species were arachnid and the others were insects. The most abundant species in terms of per capita density was Mimemodes monstrosus (Rhizophagidae), followed by species in the genus Phloeonomus (Staphylinidae) and Cortinicara gibbosa (Lathridiidae). Two nitidulid species, Carpophilus marginellus and Haptoncus ocularis, were also common. Among them, M. monstrosus, C. marginellus and H. ocularis, especially the former two, were regarded as good candidates for pollinators. All of the dominant species were beetles. C. gibbosa was most abundant early in the flowering season, whereas Phloeonomus sp. showed two peaks, in late May and late July. Species richness, S′ (45), ranged from 5.4 to 9.0, while heterogeneity measures, 1-D and exp H′, ranged from 0.59 to 0.78 and from 3.5 to 5.9, respectively. The index of similarity, C_λ, varied from 0.04 to 0.76, whereas the rank correlation coefficient, τ, between each site varied from −0.32 to 0.23. The contents and diversities of flower visitor communities appeared to be affected by the surrounding environment and management strategy of the orchards.

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We investigated the survival and development of the braconid parasitoid Meteorus pulchricornis in nucleopolyhedrovirus (NPV)-infected Spodoptera litura larvae. The first and second molting stages of the larvae were parasitized by M. pulchricornis and were exposed to a 95% lethal concentration (LC₉₅) and 10× the LC₉₅ of S. litura NPV (SpltNPV) on the first, third, and fifth day post-parasitization (dpp). Infection of the larvae with SpltNPV was deleterious to the survival and development of M. pulchricornis. The survival of M. pulchricornis in SpltNPV-infected S. litura larvae was dependent on the interval between parasitization and viral infection, as well as on the inoculation dose of SpltNPV; few parasitoid larvae emerged from infected hosts when host larvae were exposed to 10× the LC₉₅ of SpltNPV on 1 and 3 dpp. The fecundity of M. pulchricornis that emerged from SpltNPV-infected hosts was not affected, and these parasitoids did not transmit the virus to other hosts. The number of eggs laid by M. pulchricornis females was not significantly different between the SpltNPV-infected and non-infected larvae during the first 4 d post-infection (dpi). On the other hand, at 5 dpi, M. pulchricornis females laid significantly more eggs in non-infected larvae than in SpltNPV-infected larvae.

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We purified an antibacterial peptide from the larval hemolymph of a coleopteran beetle, Acalolepta luxuriosa. Using structure analysis and cDNA cloning, this peptide was identified as a novel member of the insect defensin family and named A. luxuriosa defensin 1. A. luxuriosa defensin 1 shares high sequence similarity with other defensins, especially coleopteran defensins. A dendrogram of coleopteran insect defensins based on sequence homology revealed that A. luxuriosa defensin is closer to Tenebrionoidea defensin than to Scarabaeoidea defensin, which parallels the evolutionary relationship of these coleopteran insects. Although A. luxuriosa defensin 1 was most homologous with Tenebrio molitor tenecin 1, its antibacterial spectrum was broader, affecting the growth of Gram-positive and Gram-negative bacteria, suggesting that the variability of the antibacterial spectrum results from small sequence differences.

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The photoperiodic response curve for pupal diapause induction of the butterfly Atrophaneura alcinous was determined in several temperate and subtropical populations of the Japan Archipelago at 20°C, using Aristolocia debilis leaves as larval food. Altitude and host plant use also differed among them. For the temperate populations of Kiire, Kashihara, Fuchu, Yokosuka and Yamagata, the critical photoperiod increased with latitude, and the subtropical Ishigaki population showed the shortest critical photoperiod. Further, a change in the shape of photoperiodic response curve, but no shift in the critical photoperiod, was found in a mountain population of Kiire, giving a high incidence of diapause in long photoperiods. These results are discussed in relation to latitude, altitude, and host plant.

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To clarify the relationship between the occurrence patterns of three species of rice bugs and the developmental stage of panicles in rice fields, we carried out two experiments. In the first experiment, we observed the development of spikelets in three paddy fields (Plots A, B, and C). The rice variety ‘Sainohana’ was used in Plot A and ‘Koshihikari’ was used in Plots B and C. Dates of transplanting were on April 25, May 8, and June 19; for Plots A, B, and C, respectively. Spikelets were classified into three stages based on ovarian development: Stage I (initial), Stage II (middle), and Stage III (fullness). After the initial heading stage, changes in the average number of each stage of spikelet development were expressed in days or cumulative degree-days above a base of 10°C. In the second experiment, the incidence of each rice bug species was monitored in rice fields. Then, the relationship between rice bug incidence and cumulative degree-days was determined. Variations in the average number of spikelet development stages among the three plots expressed in cumulative degree-days were smaller than those expressed in days after the initial heading stage. The peaks of incidence of adult rice bugs were near the peak of Stage I at 50–150 degree-days. The incidence of nymphs began to increase near the peak of Stage II at 200–250 degree-days. The occurrence patterns of the rice bugs were found to be closely related to the abundance of the three stages of spikelets. Cumulative degree-days can be used to uniformly express the changes in the incidence of rice bugs among different rice varieties, seasons, and fields.

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Ultraviolet (UV) protection of a granulovirus (GV) product using iron oxide was investigated under laboratory conditions with fluorescent lamps. The UV protective activity was evaluated by comparing the pathogenicity of a GV product to the neonates of the oriental tea tortrix, Homona magnanima, in the presence or absence of iron oxide under UV irradiation. The infection rates of GV suggested that the addition of iron oxide at 1–4 mg/ml could reduce the inactivation of GV by UV irradiation to 1/6–1/18 as compared to that without it, indicating that iron oxide could be a useful UV protectant for microbial insecticide GV products.

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The production of a major component, 6-oxo-1-nonanol and a minor compound, N-3-methylbutyl acetamide in the male rectal gland of Bactrocera carambolae, a fruit pest of economic importance, increased concomitant with age, and their peak production corresponded with sexual maturity. During courtship period, these endogenous components were released unchanged into the air as visible smoke by a group of 100–150 males in a glass chamber. Male emissions elicited upwind flight via zigzag anemotaxis, and attracted more conspecific virgin females than males in wind tunnel assays. When these components were assayed individually, both 6-oxo-1-nonanol and N-3-methylbutyl acetamide elicited significant female responses toward the source chemicals, although the response was less than that for live males. The results suggested that these volatile components are involved in the intraspecific communication by playing a role as sex pheromones during courtship of B. carambolae.

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The residual activity of hinokitiol used as a repellent against the cigarette beetle was investigated. When hinokitiol was placed on filter paper at a dose of 1 mg/cm², it exhibited remarkable residual activity 24 h after the treatment. However, no significant residual activity was observed after 48 h due to rapid sublimation (90% of hinokitiol disappeared 48 h). Therefore, the development of a device in the form of repellent strips designed to affect the slow release of hinokitiol was undertaken. The strips consisted of filter paper treated with hinokitiol, a polyethylene film bilayer in which the filter paper was sealed, and an aluminum sheet sandwiched between one side of the polyethylene strip and adhesive tape. Hinokitiol was slowly released from the repellent strips through the polyethylene film. The rate of hinokitiol release was inversely proportional to the thickness of the polyethylene film. Repellent strips attached around the slits of cardboard boxes containing a food-attractant lure prevented the beetles from entering the boxes. The number of beetles in the treatment boxes was less than 20% that observed in the control boxes 64 d after making the strips. The residual activity of the repellent strips was demonstrated to last up to a maximum of 92 d after they were produced.

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The potentials of two indigenous parasitoids, Aphelinus asychis and A. albipodus, as biological control agents against three pest aphids, Aphis gossypii, Myzus persicae and Macrosiphum euphorbiae, were assessed. Six traits such as percentage of parasitism, number of aphids killed by host feeding, sex ratio, survival rate during the developmental period, developmental duration and forewing width were used as criteria. M. persicae is known to be a suitable host for A. asychis. So, the suitability of the three aphids as hosts for two parasitoids was evaluated by comparing the values of these traits with the standard values of A. asychis on M. persicae. The values for all traits of A. asychis on A. gossypii and A. albipodus on M. persicae and M. euphorbiae were not greatly different from the standard values. The percentage of parasitism of A. asychis on M. euphorbiae was considerably smaller than the standard value, but the values in the other traits were not greatly different. The percentage of parasitism and number of aphids killed by host feeding were much smaller for A. albipodus on A. gossypii than the standard values. We concluded that A. asychis could be an effective biological control agent against all three pest aphids, and A. albipodus against M. persicae and M. euphorbiae.

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