Here we report direct evidence that cuticular hydrocarbons are responsible for nestmate recognition in Formica japonica distributing in Southern Honshu in Japan. Workers showed aggressive behavior against foreign workers but not against nestmates. A similar response was observed when a glass dummy was treated with isolated hydrocarbons from foreign workers or nestmates. Among the isolated hydrocarbons, ten hydrocarbon components were identified: five nalkanes and five (Z)-9-alkenes with odd number of carbons from 25 to 33, in different ratios in different colonies. When synthetic hydrocarbons blended in the same ratio as natural blends were presented to workers, they showed aggressive responses against foreign blends but paid less attention to those of nestmates. Neither n-alkane nor (Z)-9-alkene blends, however, caused aggression response in foreign workers. Thus, both n-alkanes and (Z)-9-alkenes are necessary to discriminate nestmates from foreign conspecifics.

Mating behavior of the scarab beetle Dasylepida ishigakiensis was observed in a sugar cane field in Miyako Is., Okinawa, Japan. In field observations of tethered females on 6 February 2002, calling behaviors were observed only within 30 min of sunset time (18:25-18:55, JST), when light intensity decreased from ca. 500 lx to 1 lx. Mating was strongly affected by temperature: adults appeared and subsequent mating occurred when the temperature at 18:00 was higher than 18°C. Females appeared from the soil, flew to settle on sugar cane leaves and commenced rhythmical abdominal expansion and contraction. Males were attracted to the calling females from leeward, landed on or near the calling female, and immediately mounted. After genital connection, the male raised his legs and suspended himself with his genitalia. Mating lasted for ca 2 h. Most mated D. ishigakiensis females neither appeared from the soil nor attracted males until the end of March, so are considered monogamous. In contrast, males appeared from the soil after mating on evenings warmer than 18°C and probably repeat mating if females are available.

The white grub Dasylepida ishigakiensis has a 2‐year life cycle and spends approximately 9 months as a nonfeeding larva, pupa and adult on a subtropical island. Evidence is presented indicating that this beetle has two diapauses that appear to synchronize this long life cycle with the seasons. Larvae exposed to 20, 22.5, 25 and 27.5 °C late in the third (last) stadium pupate rapidly except for some individuals kept at the highest temperature. The latter pupate upon transfer to 22.5 °C, indicating that larval diapause is maintained at high temperature but terminates upon transfer to a lower temperature. Pupal development is directly temperature‐dependent in the range 20–30 °C. Adults develop reproductive organs (i.e. the ovary in females and the seminal vesicles and accessory glands in males) rapidly at 15 and 20 °C, whereas those kept at 25 °C take a long time to do so. Ovarian development is completely suppressed at 30 °C but initiated upon transfer to 20 °C. In the laboratory, males with well‐developed reproductive organs mate even with sexually immature females, whereas females with undeveloped ovaries show no sexual behaviour. Although the two diapauses of this species are thermally regulated (i.e. a characteristic commonly expressed by insects in summer diapause), adults of this beetle emerge from pupae late in the autumn and remain in the soil for 2 months. Adult diapause effectively serves to synchronize the time of sexual maturation with the coldest month of the year.

Chemical components that attract males in the laboratory were extracted from the female elytra of the white-spotted longicorn beetle, Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae), and found to be comprised of several sesquiterpene hydrocarbons. Males located females that had fed on the bark of the host plant Citrus unshiu more frequently than those fed on an artificial diet in the laboratory. Male attraction was also confirmed in the corresponding sesquiterpene fractions of the host plant. The sesquiterpene fractions of female elytra and C. unshiu leaves showed quite similar GC profiles. In the field, the beetles were found on C. unshiu trees baited with intact females or males as frequently as those baited with the leaf extracts containing the sesquiterpenes at different purification levels. The beetles were found on those baited trees significantly more frequently than on unbaited control trees. Males, as well as females attracted both sexes, and the male elytra also contained the sesquiterpenes that were identical with those in female and C. unshiu. This indicated that active components in the elytra are acquired from C. unshiu by feeding, contact and/or adsorption. These sesquiterpenes may serve for intraspecific communication in A. malasiaca. The major sesquiterpenes from the C. unshiu leaves were isolated and elucidated by NMR analyses of four sesquiterpene hydrocarbons, b-elemene, b-caryophyllene, a-humulene, and a-farnesene.

A major component of female contact sex pheromone of the yellow-spotted longicorn beetle,Psacothea hilaris (Pascoe), was isolated from the elytra and identified as (Z)-21-methyl-8-pentatriacontene. The synthetic compound released the typical mating behavior including holding, mounting, and abdominal bending in males, although its activity was considerably lower than the extract of female elytra when treated on a gelatin capsule as an artificial female model.