Bactrocera is a speciose genus of tephritid fruit fly that includes several important pests of fruits and vegetables. Detection and control of these pestiferous species rely heavily upon male attractants or lures, with different Bactrocera species responding to either methyl eugenol (ME) or raspberry ketone (RK; or its man-made analogue cue lure, CL). Despite their usage worldwide, the function of ME and RK/CL in the natural history of Bactrocera flies is poorly known. The purpose of this review is to summarize research on the potential role of ME and RK/CL—as pheromone precursors or components—in the sexual communication of Bactrocera species. The topics covered include i) male feeding behavior on ME or RK/CL, ii) the fate of ingested lures, iii) female and male attraction to lure-fed males, and iv) mating success of lure-fed males. Data are available for only a few species, but they provide solid evidence for a role of male lures in mating behavior. For several ME-responding species, research has shown that i) ME metabolites are incorporated and emitted along with endogenously produced components of the male sex pheromone, ii) females show preferential attraction to pheromone containing these metabolites, and iii) males fed ME (or plants containing ME) enjoy increased mating success over non-fed males. Fewer studies have been conducted on RK/CL-responding species, and these reveal i) the lure is not broken down or metabolized but is sequestered (and presumably emitted) as RK, ii) females show preferential attraction to pheromone produced by males that fed upon RK/CL, and iii) RK/CL ingestion produces a significant, but short-lived (1 d), boost in male mating success. Potentially productive avenues of future research are discussed.

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The mating status of Bombus terrestris in relation to ambient temperature, queen to male ratio in the mating cage, age and virginity of sexuals were studied in the laboratory. Results showed that ambient temperature ranging from 17 to 29°C had a significant effect on the mating percentage of individuals, with queen to male ratios of 1 : 1.5 and 1 : 2. The highest mating percentage (76.9±1.9%) was found at 23°C, with a queen to male ratio of 1 : 1.5, and the lowest percentage (67.3±2.1%) was observed at 29°C with a queen to male ratio of 1 : 2. Both virgin and previously mated males preferred young and virgin queens, and showed a statistically higher mating success, indicating that male virginity and experience had identical effects on male mating fitness. Virgin queens that failed to mate at 7 days old showed a lower percentage of mating success with increasing age, indicating that female copulation fitness depended on their age.

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Cotesia vestalis is a solitary endoparasitoid that attacks the larvae of the diamondback moth, Plutella xylostella, one of the most important pests of cruciferous crops. Since the female parasitoids do not exhibit host-feeding behavior, successful feeding on other items enhances the efficacy of the parasitoids as a biological control agent in agro-ecosystems, where sufficient amounts of food sources may not be available; however, there is little information on how they find and exploit food sources. Under laboratory conditions, we demonstrated that C. vestalis females lived significantly longer on Brassica rapa flowers than on water alone. In a dual-choice test, starved C. vestalis showed a significant preference for an inflorescence over an inflorescence stem with flowers removed. When the inflorescence and the stem were covered by clear bags to block only olfactory information, parasitoids preferred the inflorescence to the stem. Even when both were covered by brown porous bags to shut out only visual information, parasitoids preferred the inflorescence; however, non-starved parasitoids showed no significant preference between any tested sets. These results indicate that parasitoids orientate to flowers using visual and olfactory cues, respectively, depending on their own dietary state.

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Termite castes are defined by their specific characteristics. It is said that juvenile hormone (JH) plays an important role in caste differentiation and JH has been shown to highly influence imaginal-organ development, as well as soldier-specific morphogenesis in some species. To provide additional comparative data for interpreting the effects of JH on the development of alate and soldier characteristics, we performed morphological investigations on newly molted individuals from different nymphal instars of Reticulitermes speratus induced by various concentrations of JH III. As a result, each organ (especially wing (-bud) and mandible) development was shown to be strongly affected by JH III in each nymphal instar. Moreover, depending on the JH III concentration, there was a trade-off-like relationship between wing formation (alate character) and mandibular elongation (soldier character) only in molted individuals from final instar nymphs. Our results suggest that the endogenous JH titer or the threshold titer for caste-specific morphogenesis changes via nymphal development in R. speratus. This study shows that highly developmental plasticity is retained in the derived species of termites, and that it must be a driving force of caste evolution.

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Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is an important agricultural pest and may cause serious yield losses to numerous crops in eastern Asia, such as cotton (Gossypium hirsutum L.) production throughout northern China. In this paper, we determined the effect of six constant temperatures (10, 15, 20, 25, 30, and 35°C) on A. lucorum life history. Successful nymphal development and adult emergence were reported for all temperature regimes, whereas egg eclosion was not observed at 10°C. Development time decreased with increasing temperature between 10 and 30°C, slightly increasing at 35°C. Lower development thresholds of egg and nymphal stages were estimated as 3.2 and 3.7°C, and their thermal constants were 179.2 and 262.4 DD, respectively. Optimum and lethal temperatures for development were 33.8 and 42.5°C for eggs, and 31.0 and 38.5°C for nymphs, respectively. Adult longevity declined with increasing temperature. Fecundity greatly decreased at extreme temperatures (i.e., 10 and 35°C), with the highest value at 20°C. Our findings could help predict A. lucorum population dynamics in different agro-production regions of eastern Asia and subsequently develop appropriate pest forecasting and management protocols.

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Mealybug (Hemiptera: Pseudococcidae) has emerged as a new cotton pest in Pakistan in recent years. We used DNA nucleotide sequences and PCR-RFLP, respectively, as tools for mealybug characterization and species composition. Partial nucleotide sequences of nuclear (elongation factor-1 α, ribosomal DNA subunits 18S and 28S) and mitochondrial (COI) genes were used for species characterization, and the combined ITS1-5.8S-ITS2 sequences of rDNA were used for PCR-RFLP analyses. Homology searches of the nuclear genes indicated that the mealybug species damaging cotton in Pakistan belonged to the genus Phenacoccus. Further, the barcoding sequence of COI showed a significant nucleotide similarity with Phenacoccus solenopsis. PCR-RFLP analysis with three different endonucleases did not show restriction site differences among mealybug individuals collected from various host plants and geographical locations. This is the first DNA-based characterization of cotton mealybug from Pakistan and the findings will help in decision making while considering a biological control program.

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Fine leaf structures, such as leaf domatia or trichomes, are considered to affect the population abundance and diversity of foliar mites on forest trees and shrubs; however, the effect of such structures on seasonal fluctuations in foliar mite populations in forest ecosystems remains unknown. The authors conducted a 2-year survey on the outskirts of Kyoto on the mite assemblage found on Viburnum erosum var. punctatum (VEP), a deciduous shrub bearing domatia and stellate hairs, and on its seasonal fluctuations. A census was also conducted on the acarofauna on 14 sympatric tree or shrub species; these communities were then compared with those found on VEP. On VEP, fungivorous mites, Winterschmidtiidae and Tydeoidea, showed continuous occurrence from late March to November, and phytoseiid mites were recorded from May to November. Eriophyioid mites were only found in spring and autumn. Total mite density was significantly higher on plant species with fine structures, and the acarofauna on such plants showed high similarity among seasons. Our data suggest that leaf-surface structures play important roles in structuring foliar mite communities throughout the seasons.

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‘Candidatus Cardinium’, a recently described bacterium from the Bacteroidetes group, causes diverse reproductive alterations of its arthropod hosts, including cytoplasmic incompatibility (CI), parthenogenesis and feminization. We detected severe CI expression induced by Cardinium in the carmine spider mite Tetranychus cinnabarinus (Boisduval). CI was expressed as a reduction in egg hatchability and a male-biased sex ratio in crosses between uninfected females and infected males. To determine whether male age affects Cardinium-induced CI expression, uninfected females were crossed with infected virgin males at different ages. Cardinium density in males, as measured by quantitative PCR using the 16S rDNA gene, declined rapidly with increasing age. The CI level also declined rapidly with increasing age. Cardinium lost the ability to induce CI by day 12, and the Cardinium density declined to 3.0×10⁶ copies per ml. Cardinium density was positively correlated with the CI level, which is consistent with the bacterial density model of CI. Our results suggest that both male age and Cardinium density are key factors in Cardinium-induced CI expression in T. cinnabarinus, and a threshold level of Cardinium density may be required for induction of CI.

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The present article reports the fumigant and contact toxicities of eleven monoterpenes against adults of Theba pisana and third instar larvae of Spodoptera littoralis. The majority of the tested compounds were found to be toxic to both pests with variable degrees of potency. Among the tested monoterpenes, (L)-fenchone showed the highest fumigant toxicity against T. pisana and S. littoralis with LC₅₀ values of 2.51 and 2.27 mg/l, respectively. Myrcene and 1-8-cineole exhibited strong fumigant toxicity against T. pisana, while cuminaldehyde, geraniol and (−)-menthol were not active. On the other hand, 1-8-cineole and (+)-camphor revealed potent fumigant toxicity against S. littoralis. In the contact assay, the tested monoterpenes were more toxic against T. pisana than S. littoralis. Cuminaldehyde (LD₅₀=28.37 μg/snail) was significantly the most effective compound against T. pisana, followed by geraniol and (−)-limonene. Interestingly, eight of the tested monoterpenes were more toxic to adults of T. pisana than methiocarb. The results of the present study suggested that cuminaldehyde, geraniol, (−)-limonene and (+)-camphor could be used as alternative control agents for T. pisana. In addition, (L)-fenchone and 1-8-cineole could be useful as fumigants for control T. pisana and S. littoralis.

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Carabid assemblages in insecticide-free (=N) and conventionally sprayed (=S) potato fields were compared for five years using pitfall traps to evaluate the potential of carabid beetles as biotic indicators of insecticide impact in potato fields. Direct and indirect exposure of adults of major carabid species to several aphid insecticides was also examined in the laboratory. In one out of the five years, the trap catch of Bembidion morawitzi, one of the dominant species, was larger in plot N than in plot S. The species diversity indices for plot S were significantly higher than those for plot N in two years; however, on the whole, insecticides did not have a marked impact on the number of adults trapped, the number of species, indices of species diversity or seasonal changes in daily trap catches. Direct dipping tests showed that B. morawitzi was more susceptible than other carabid species and that fenitrothion was the most toxic to the carabids, but in-field soil-contact toxicity tests indicated that even fenitrothion had weak toxicity. It is likely that ground-dwelling carabids were protected from the insecticide droplets by the potato canopy. This would partly explain why the abundance of carabids in plot S was not much less that in plot N. In conclusion, carabids in potato fields were sometimes adversely affected by insecticide application, but the extent of damage was not so serious. Carabids are therefore not suitable biotic indicators of insecticide impact in potato fields.

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In the yellow peach moth, a synthetic sex pheromone consisting of (E)-10-hexadecenal and (Z)-10-hexadecenal showed significantly lower attraction than crude pheromone extracts in wind tunnel tests. Synergistic effects of a non-polar fraction (NPF) from the crude pheromone extract on the activity of a polar fraction (PF), including aldehydes, were assessed in wind tunnel tests. NPF itself showed no activity, but the number of males attracted close to the source was significantly increased when it was added to PF. Similar synergistic effects were also observed in a female body wax (FBW) extract and its NPF but not in male body waxes. Effects of NPF from both sources dose-dependently increased and the active dose range of NPF in FBW was larger than that of the crude pheromone extract. New unknown components that synergistically improve the activity of aldehyde components may be non-polar compounds in FBW. The actual sex pheromone system of the yellow peach moth may consist of aldehydes (attractive over a long distance) and non-polar components in female body wax that functions as a cue for the final recognition of females.

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A study on the seasonal occurrence and within-plant distribution of Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) and its two egg parasitoids was conducted to evaluate the effectiveness of parasitoids as a biological control agent in soybean fields. We sampled soybean plants during the planting seasons in 2007 and 2008 in Andong, Korea. Adult R. pedestris occurrence and egg deposition began at the R2–R4 stage of soybean. Nymphs started to appear during the R5 stage of soybean. Peak population densities of both eggs and adults were recorded in the R5 stage of soybean, whereas that of nymphs started in the R6 stage. Seasonal total parasitism by Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) was significantly higher than Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae). For the within-plant distribution of R. pedestris eggs, 90% were found on leaves and 70% on the under-leaf surface. Egg parasitism by O. nezarae was higher on the leaf surface than on pods. Results suggest that R. pedestris starts to occur at the R2–R4 stages of field soybeans regardless of seed sowing time, and population density peaks after the R5 stage. Sampling eggs on leaves is an alternative method to measure R. pedestris populations in the field since most eggs are found on leaves. Since O. nezarae was synchronous with the bugs' occurrence, it would be a more efficient biological control agent of R. pedestris than G. japonicum.

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The species composition of spider mites on crops in Okinawa is peculiar in that Tetranychus okinawanus and T. piercei are dominant on most islands, whereas T. urticae (green form) and T. kanzawai are not. To determine the source plants of Tetranychus species infesting crops, as well as to contribute to our understanding of the cause of this peculiar mite fauna, we collected Tetranychus mites on non-crop plants throughout Okinawa (more than 450 sites on 15 islands) and identified them. Except in the case of T. parakanzawai, the species frequently found on crops tended to occur frequently on non-crop plants, suggesting that the peculiar species composition on crops reflects that also on non-crop plants. T. parakanzawai has been rarely found on crops but frequently found on particular non-crop plants, possibly due to the narrower host range of this species. The type of host plants varied among mite species; for example, T. okinawanus was frequently found on indigenous plants inhabiting the seashore and invasive weeds, T. piercei and T. parakanzawai on inland indigenous plants, T. urticae (green form) on invasive weeds, and T. neocaledonicus on introduced trees. These results are of great significance when considering vegetation control as a tactic for the integrated management of spider mites.

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Liposome was prepared using phosphatidylcholine (PC), and calcein, a fluorescent chemical, was simultaneously enclosed within the liposome (PC-Lipo). The stability of PC-Lipo in its ability to retain calcein was evaluated under various conditions. PC-Lipo lost stability at pH 6 and pH 11–13, but was stable in the range of pH 8.3–10. PC-Lipo was stable in the temperature range of 15–30°C, but lost the stability acutely at 35°C. Ionic strength, given as the concentration of NaCl, also affects its stability, and a higher concentration of NaCl, i.e., more than 150 mM, induced a higher leak of calcein from PC-Lipo. The optimal conditions to achieve stable PC-Lipo were employed to characterize the differences in pore formation with Bacillus thuringiensis Cry1Aa, Cry1Ab and Cry1Ac toxins. These toxins were reacted with PC-Lipo under these optimal conditions, and the affinity and maximum speed of Cry1Ab to form pores on PC-Lipo was shown to be highest. Here we show these conditions and evidence of the usefulness of PC-Lipo to investigate the mode of action of Cry1A toxins.

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Steirastoma breve is one of the most important pests in cocoa plantations in the Neotropics. Preliminary studies suggest that the chemical communication system in S. breve may be modulated by kairomones produced by cocoa plants and pheromones released by males. We examined the role of Theobroma cacao brushwood in the communication system of S. breve under field conditions. Sixty kilograms of T. cacao and Bauhinia sp. branches were cut, grouped into separate piles, and placed in an experimental cocoa plantation as an odor source. The sex and number of S. breve adults landing on each pile were registered during 23 days from 9:00 to 15:00 h. Each individual arriving at a pile was marked with a coded color and then released onto the same pile. All behavioral activities undertaken by S. breve were evaluated and flight behavior towards the T. cacao piles was described. S. breve adults were attracted to T. cacao piles placed under both sunny and shaded conditions, but were not attracted to Bauhinia sp. S. breve males dispersed more in shaded piles than in those placed in the sun, and the proportion of encounters between sexes was higher in the piles at which they had first arrived. Analysis of the data confirmed the presence and importance of T. cacao kairomones in the chemical communication system of this important cocoa pest.

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An entomopathogenic fungus, Isaria javanica (anamorphic Cordycipitaceae) was isolated from diseased larvae of the gypsy moth, Lymantria dispar, in outbreak populations from Iwate Prefecture, in northern Japan in the summer of 2008. The fungus caused a mixed infection with Entomophaga maimaiga in the gypsy moth populations. The fungus forms conidial chains on phialides verticillate on conidiophores, with conidia fusiform to oval, 3.0–4.3–6.3×1.4–2.0–3.2 μm, chlamydospores and synnemata absent, and grows on SDAY medium at 10–30°C, with optimal growth at 25°C. Phylogenetic analyses, using the β-tubulin gene and internal transcribed spacer (ITS) rDNA, positioned the fungal isolates to a well supported branch where I. javanica was included. The dipping of larvae into the conidial suspension revealed a moderate virulence of the fungus to the gypsy moth (mortality 58–100% with 10⁸/ml). This is the first discovery of I. javanica on L. dispar larvae.

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When ant-tended aphids parasitize plants with extrafloral nectaries (EFNs), ant-mediated indirect interactions occur between the plants and aphids. In particular, when an aphid colony is small, the honeydew production of the colony is insufficient to attract ants, although EFNs can attract many ants. Under this condition, we asked whether a small aphid colony would gain indirect benefits from EFNs because ants would be attracted by the EFNs instead of the aphids, or whether the aphid colony would suffer strong predatory pressure from ants and/or other predators. To clarify the aphid-plant interactions, the protective services provided by two ant species, Lasius japonicus and Tetramorium tsushimae, for the survival of a small colony of Aphis craccivora were examined on the host plant, Vicia faba, with and without EFNs. More workers of both ant species were recruited to the plants with EFNs than to those without EFNs, and the larvae of a predatory ladybird beetle, Coccinella septempunctata, stayed for a shorter time and preyed on a smaller number of aphids on the plants with EFNs than on those without EFNs. In addition, no negative effects of EFNs, such as predation of the aphids by the ants, were found. Consequently, it is suggested that a small aphid colony gains indirect benefits from the EFNs of its host plant.

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Extra molting is typically observed in solitarious forms in the desert locust, Schistocerca gregaria. The present study examined the relationships between nymphal development, extra molting and adult body size in this locust by rearing solitarious hatchlings (obtained from isolated-reared locusts) under isolated conditions. Nymphs passed either five or six nymphal stadia and grew at nearly constant rates during all stadia, except for the 2nd and 3rd nymphal stadia in the group with extra molting. Development during the 2nd stadium appeared to have influenced whether the nymphs underwent extra molting, and once reaching the 3rd stadium, their development proceeded at a constant rate depending upon the body weight in this stadium. Nymphs which were relatively small at hatching had smaller body sizes during the nymphal stadia than those which were relatively large at hatching, and tended to undergo extra molting. Nymphs became larger if they underwent extra molting, but in the group with the same number of nymphal molts they tended to attain smaller adult body sizes as nymphal development was prolonged. These results suggested that phase-related nymphal development was influenced not only by body size at hatching but also by nymphal growth during the 2nd stadium.

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Since overwintering populations of brown planthopper (Nilaparvata lugens) and white-backed planthopper (Sogatella furcifera) in Taiwan are very low based on field observations, immigrant planthoppers have become the most important source of serious damage to rice crops (Oryza sativa). Backward trajectory analysis was conducted using trap catch data from 1990 to 2005 to estimate the source of immigrant planthoppers, taking into account the emigration periods and weather conditions, and showed that southern China, Vietnam and the Philippines (Luzon Island) were possible source areas. Southern China was found to be the most important source of emigration. Of all the immigration cases tested, the sources from southern China were estimated to be about 77% in the first rice crop and 65% in the second rice crop. Vietnam came second with about 37% and 56% in the first and second rice crops, respectively. Typhoons were the most important weather factor, inducing mass emigrations from China and Vietnam. Since the population properties are known to differ among the emigration regions and Taiwan, careful monitoring of these insects in the emigration sources and Taiwan is needed in order to establish better pest management practices.

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