Variability and plasticity in life-history traits enhance an organism’s ability to cope with heterogeneous environmental conditions. We investigated the seasonal life cycle of the snail-feeding ground beetle Carabus (Damaster) blaptoides in a lowland riverine habitat in western Honshu, Japan, over a two-year period (2014–2015). Carabus blaptoides exhibited different seasonal activity patterns between the two years, with the duration of female reproductive activity ranging from spring to late summer or autumn, the occurrence of larvae from June to November or from May to August, and the occurrence of newly emerged adults from July to October or from June to August. Autumn larvae appeared to overwinter, which was confirmed by a field rearing experiment. The body size of adult female C. blaptoides showed substantial variation. Although egg number was unrelated to body size, larger females had larger maturing eggs, implying that they produce larger larvae with greater foraging ability. In combination with previous observations of the seasonal cycles of C. blaptoides in mountain habitats, our results indicate that C. blaptoides exhibits altitudinal variation in its seasonal life cycle: from an extended period of reproduction and larval development mostly within a year (with occasional larval overwintering) at lower altitudes, to a short midsummer reproductive period without the appearance of newly emerged adults at higher altitudes. Our study suggests that C. blaptoides possesses considerable plasticity in its seasonal life cycle and reproductive traits.

Four species belonging to the Amphipyra pyramidea group, A. pyramidea (Linnaeus, 1758), A. surnia Felder & Rogenhofer, 1874, A. horiei Owada, 1996, and A. meifengensis Chen, Speidel, Buchsbaum & Behounek, 2013, are known to occur in Japan. Species identification in this group of adults is very difficult due to their remarkable morphological similarities, and often two or three species occur in the same season and at the same locality. Therefore, for their larval stage, information on their morphology, host plants, and agricultural damage is confounded with each other. To address these issues in this group in Japan, we reviewed the followings based on field surveys: (1) morphological characteristics for species identification in the larval stage, (2) morphological characteristics for instar determination, and (3) host plants. The results are summarized as follows: (1) The last instar larvae of the four species could be discriminated by the spiracular line, the spotted pattern on the thoracic legs, and the coloration of the proleg base and planta. (2) The last instar larvae and other instars of the four species could be determined by the maximum frons width, the head markings, and the width of the planta. (3) All four species were polyphagous, and their host ranges were overlapped. Notably, up to three species were coexisted on Cerasus spp. (Rosaceae) and Hydrangea spp. (Hydrangeaceae) at the same location on the same day.

Although knowledge of larvae is essential for understanding species, research on larvae of Carabidae (Coleoptera) is limited. While Dolichus halensis is a common species wherein flying individuals also exist, we have little information on the topic. We 1) identified the species of the larvae using DNA barcoding, and clarified their larval stage, 2) investigated the behavior and morphology of the larvae, and interpreted their ecological traits from their morphology. First, to reveal the larval stage, field surveys were conducted and we examined the number of larvae and adults captured. Larvae emerged from October to April, including winter, suggesting that they are active during this period. It was previously known that the larvae overwinter, but we discovered that the third instar larvae overwinter and that their period lasts six months. We examined the morphology and inferred their ecology. Regarding the head, the mandibles were long, curved, and sharp at the tip. Both their morphology and their aggressive behavior suggest that they were carnivorous predators. As for the thorax, the ventral is soft, which is thought to allow the legs to move freely. Regarding the abdomen, the cerci are long, which suggests that they are surface runners. They had a soft, cylindrical tenth abdominal segment, which it used like a suction cup to make stops and change direction. There is little research on larvae of Carabidae, especially on their ecology, therefore we interpreted their ecology in relation to their morphology.

This study provides the first documented evidence of Miscanthus sinensis serving as a host plant for Sesamia turpis (Butler, 1879). Field surveys were conducted between June and July 2024 in semi-natural grassland in Ibaraki Prefecture, Honshu, Japan. Twelve larvae of S. turpis were collected from the culms of M. sinensis with feeding traces and frass on the leaf sheaths. They fed on fresh M. sinensis culms under laboratory conditions, and four individuals pupated and emerged as adults.

The eucalyptus shoot psyllid, Blastopsylla occidentalis Taylor, is reported in Japan for the first time. The distribution of this species, which is native to Australia, has spread globally and is known to cause significant damage to eucalyptus trees. The species has currently been found on Eucalyptus globulus trees in parks in the Kinki region of western Japan. Although substantial damage has not yet been observed in these groves, it is important to raise awareness of the potential for this species to spread and cause harm to eucalyptus trees.

An unidentified species of Phaenoserphus (Proctotrupidae) emerged from a larva of Carabus (Acoptolabrus) gehinii collected in Hokkaido, Japan. In the laboratory, the biology of this proctotrupid, development, courtship behavior, and parasitization to C. (Damaster) blaptoides, were observed. The host acceptance of the Phaenoserphus sp. was briefly tested.

The yellow-legged hornet, Vespa velutina, is native to parts of Asia, and has recently spread as an invasive species to Korea, France, and other regions of Europe. In Japan, V. velutina workers were first detected on Tsushima Island in 2013, and genetic analyses confirmed that these invasive populations originated from the subspecies V. v. nigrithorax. Although V. velutina has been captured in more than eight regions across Japan, naturalization has so far been confirmed only on Tsushima Island. Here, we examined V. velutina specimens collected in Fukuoka and Hisayama, Fukuoka Prefecture, in 2022 to trace invasion pathways. Morphological identification verified their worker caste, and mitochondrial DNA analysis identified them as V. v. nigrithorax of the H1 haplotype, which occurs in both Korean and Japanese populations but is distinct from the European H6 haplotype. Phylogenetic analysis based on 13 protein-coding mitochondrial genes suggested that the Fukuoka and Hisayama populations may represent a distinct invasion event from other Japanese populations.

A melanistic female of Corymica pryeri (Butler, 1878) was collected on Hachijojima Island, Tokyo, Japan, on May 23, 2025. The specimen exhibited aberrant dark brown wing coloration compared with the typical yellow ground color. The species identity was confirmed by DNA barcoding of the mitochondrial COI region. This represents the first documented record of a melanistic variant of C. pryeri, although similar variations have been recorded in the congeneric C. deducta.