Entomological Science最新文献

The ability of some organisms to manipulate the behavior, physiology, and morphology of other individuals to increase the chances of survival and reproduction is well known among animals with a parasitic lifestyle. In the present study we (i) report the interaction between the parasitoid wasp Eruga unilabiana and the host spider Eurymorion sp. (Linyphiidae) for the first time (plus Sphecozone sp. (Linyphiidae)), (ii) describe the normal and cocoon webs of Eurymorion sp. induced by larvae of the penultimate instar of E. unilabiana, (iii) quantify the differences between the structures of normal and cocoon webs of Eurymorion sp. and Sphecozone sp. spiders, and (iv) describe the behavior of two spider species under influence of the penultimate instar larvae of E. unilabiana. The cocoon webs built by parasitized Eurymorion sp. are structurally similar to those of Sphecozone sp. induced by the same parasitoid species. The areas of the sheets and the length of the interception threads of the cocoon webs were significantly smaller than those of normal webs. Several individuals of the two species of host spiders are induced to abandon their normal webs to build a cocoon web from scratch, a rare behavior in non-parasitized individuals.

Sexual dimorphism in timing of adult emergence is common in insects. In most insects, males emerge before female (protandry), however, some insects show earlier female emergence (protogyny). Here, I report the effects of photoperiod on protogyny in the lawn ground cricket (Polionemobius mikado). Upon exposure to different photoperiods at 26 °C, P. mikado females were found to emerge earlier than the males in the short-day photoperiod. However, no difference in the nymphal development duration was observed between the sexes in the long-day photoperiod. Protogynous development is expected to be more pronounced in the crickets that eclosed later in the year than those that eclosed earlier; therefore, its adaptive significance is closely associated with environmental seasonality that is encountered by the eclosed females.

This study examined the life history traits of Aphis coronillae Ferrari (Hemiptera: Aphididae) clones collected in Utsunomiya City, Tochigi Prefecture, eastern Japan. Results showed that the collected clones are classifiable into two life cycle forms: holocyclic and anholocyclic. No significant difference in nymphal development, fecundity, or adult longevity was observed between holocyclic and anholocyclic clones. Results also indicated that photoperiod and temperature affect sexual morph production in holocyclic clones.

We identified an alien praying mantis found in Japan as the giant Asian mantis Hierodula chinensis by observing the characteristics of male genitalia. Nymphs hatched from oothecae collected in Nara Prefecture, Japan, were reared in a breeding room and compared with nymphs of the native Japanese species H. patellifera. Different from H. patellifera, the H. chinensis individuals passed through 5–7 nymphal instars before emerging as adults. The body color of the H. chinensis nymphs was brownish gray in the first instar, whereas the second and later instars were green. Unlike H. chinensis, H. patellifera had mottled patterns all over its body during the first to third instar. The first to third instar nymphs of H. chinensis had mottled patterns on the femurs of their forelegs, which is a diagnostic characteristic that no native praying mantis species has. From the fourth instar, 7–10 dorsal spines were observed on the foreleg coxa of H. chinensis, whereas only 3 or 4 spines were observed in H. patellifera. These findings show that H. chinensis and H. patellifera can be distinguished in all nymphal instars.

Lithosiini (Lepidoptera: Erebidae: Arctiinae) is distinctive in having some species that feed on lichens, whereas the majority of moths feed on vascular plants. However, the larval diet of most Lithosiini species is poorly known. This study examines whether Lithosiini species, collected in a tropical rainforest of Borneo (nine species) and a temperate forest of Japan (eight species), feed on lichens as larvae, based on stable isotope analyses. As a result, the δ¹⁵N values for eight of nine Lithosiini species collected from Borneo were notably lower than those of nine co-occurring herbivorous non-Lithosiini species, and were similar to those of sympatric, lichen-feeding termites; however, δ¹³C and δ¹⁵N values of one Lithosiini species (Adites sp.) were significantly higher than those of the other moth species and similar to those of humus-feeding termites and predatory insects occurring at the same site. These results have suggested that the Lithosiini in the Southeast Asian tropical rainforests contain some species that feed on lichens as their larval main diet and at least one species whose larvae feed on humus or animal-derived materials. In contrast, the δ¹³C and δ¹⁵N values of all examined Lithosiini species (eight species) in the temperate forest have suggested that their larvae fed on plants and not on lichens. Our stable isotope ratio analysis presented quantitative evidence suggesting lichen-feeding by Lithosiini moths in a tropical rainforest without observation of feeding behavior during the larval stages.

The Japanese species of the genera Norellisoma Hendel, 1910 and Milania Šifner, 2010 of the Scathophagidae are reviewed. Of the three species of Norellisoma, N. ezoensis sp. nov. is described as new to science from Hokkaido, northern Japan. Generic redefinition of Milania and redescriptions of M. agrion (Séguy) and M. longiabdomina (Sun) are presented together with figures of diagnostic characteristics. A key to the Japanese species of Norellisoma and Milania is also provided.

Investigating the well-established relationships between insects and novel host plants will shed light on numerous aspects of evolution and ecology of phytophagous insects. However, in these systems, it is not always clear which plants were originally used as insect hosts, and how the focal insects adapted to the original host(s), before establishing the novel insect–host relationships. Henosepilachna vigintioctomaculata (Motschulsky) (Coleoptera: Coccinellidae) is a well-known pest of the potato Solanum tuberosum (Solanaceae), however its original host in Honshu, the main island of Japan, before the potato introduction is uncertain. A wild solanaceous weed, So. megacarpum, is the most likely candidate for the original host, although the use of this plant by H. vigintioctomaculata has never been recorded in Honshu. This study reports the occurrence of a H. vigintioctomaculata population depending almost solely on So. megacarpum at Yamagata, northern Honshu. Additionally, the host-use ability of this population was compared to that of a pest population under laboratory conditions. Based on the results obtained, it is discussed how the properties of beetles on So. megacarpum facilitated the use of the potato, assuming that So. megacarpum was the original host of H. vigintioctomaculata in Honshu.

The population of the diving beetle Cybister rugosus (Macleay, 1825) has been declining in recent years, and it is designated as “Vulnerable” (VU) in the Red List of Japan. However, there have been no quantitative studies on the feeding habits of the larval stage of this beetle. Revealing the feeding habits is indispensable for understanding the life history of C. rugosus. In the current study, we reared C. rugosus larvae on different prey taxa (Odonata nymph, fish, tadpole, and shrimp) and evaluated their growth and survival rates. Previous studies have shown that three congeneric Cybister species larvae feed mainly on invertebrates. However, all larval instars of C. rugosus were able to feed on invertebrates and vertebrates and grow. Thus, we considered C. rugosus to be a generalist compared to the other Cybister species. The larval periods were shorter for C. rugosus that fed on Odonata nymphs than on any other prey. Feeding different prey taxa had no significant effect on the body length of newly emerged adult males. However, the body length of newly emerged adult females was larger when the larvae fed on Odonata nymphs than when the larvae fed on fish. As in other Cybister species, we concluded that the Odonata nymph is an appropriate food from the viewpoint of increased growth rate in C. rugosus.