Entomological Science最新文献

Understanding species coexistence is fundamental to community ecology and biodiversity conservation. Diving beetles serve as biodiversity indicators in wetlands, rendering an understanding of their coexistence mechanisms essential for wetland conservation efforts. Previous research in this regard have focused solely on either larvae or adults, neglecting potential spatiotemporal partitioning across life stages. We hypothesized that predatory and less mobile larvae are more likely to compete for resources than scavenging and flight-capable adults, resulting in spatiotemporal niche partitioning among larvae. To address gaps in understanding their spatiotemporal niche partitioning and habitat use, we investigated four dytiscid species—Rhantus suturalis, Hydaticus bowringii, Hydaticus grammicus and Cybister brevis—that are prevalent in Japan and often coexist in paddy environments. This study aimed to clarify their coexistence mechanisms and habitat use to develop the conservation strategies of their populations in paddy environments. Two-year field surveys were undertaken in two paddy fields, an agricultural ditch and a pond in Ibaraki Prefecture, Japan. Adults exhibited similar habitat uses, favoring paddy fields from May to July but seeking refuge in a ditch or pond following paddy field drainage. Conversely, we found spatiotemporal difference of emergence in larval abundance across the four species, which may promote their coexistence in paddy environments. We also observed interspecific differences in the feeding preferences of adult and larval diving beetles, which may help avoid competition. Our results underscore the importance of including diverse habitats in paddy environments to preserve diving beetle species diversity.

Traditionally, skippers (Hesperiidae) and moth-like butterflies (Hedylidae) were classified in separate superfamilies outside the butterfly superfamily Papilionoidea sensu stricto. However, recent molecular phylogenies including phylogenomics placed the swallowtails (family Papilionidae) as the sister group to all other butterflies, including skippers and moth-like butterflies, making the traditionally recognized Papilionoidea s.s. paraphyletic. However, no morphological studies have supported this relationship to date. Here, we conducted a cladistic analysis based on wing base characters to evaluate these competing systematic hypotheses. Our results support a sister-group relationship between skippers and moth-like butterflies and their inclusion within Papilionoidea sensu lato, consistent with molecular-based phylogenies. In contrast, the wing base morphology suggests the monophyly of Pieridae + Riodinidae + Lycaenidae, a result that contradicts both molecular and other morphological evidence, highlighting the potential limitations of this character system. Based on our morphological examinations and ancestral state reconstruction, we propose a hypothetical ground plan for the butterfly wing base.

In Japan, tribe Patrobini (subfamily Patrobinae: family Carabidae) comprises five genera: Diplous, Minypatrobus, Apenetretus, Archipatrobus, and Apatrobus. We studied the phylogenetic relationships of these genera and all known species of Apatrobus using mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 28S ribosomal RNA (28S) sequences. We also studied the phylogenetic placement of Japanese Patrobini taxa among those of North America and Eurasia using COI and 28S gene sequences. Among known Apatrobus taxa, Apatrobus hayachinensis and Apatrobus michinorii were phylogenetically determined not to belong to Apatrobus, but to be involved in the lineage of Apenetretus, which is known from Japan (Honshu) and Taiwan. We propose that these species be renamed Apenetretus hayachinensis n. comb. and Apenetretus michinorii n. comb., respectively. The remaining Apatrobus species are divided into eastern and western clades in Japan, with the eastern clade containing six closely related species of central Honshu and the western clade containing two groups of species found in Kyushu and in Shikoku and southwestern Honshu (Chugoku District and Kii Peninsula), respectively. Additionally, we examined the species status of some populations based on molecular phylogenetic and morphological analyses and describe the new species Apatrobus tsujii Dejima & Sota, n. sp., from northern Kyushu.

The study of old type series stored at The Natural History Museum, London, allows the designation of lectotype and paralectotypes, and redescription of Pristaulacus erythrocephalus Cameron, 1905 and Pristaulacus fasciatipennis Cameron, 1906. In addition, the male of the latter species is described for the first time. Two new large and remarkable overlooked species, previously hidden in the Cameron's type material of the above-mentioned species are described and illustrated, namely Pristaulacus cephalocarinatus Turrisi, sp. nov. from Indonesia (West Kalimantan) and Malaysia (Sarawak), previously treated under P. erythrocephalus, and Pristaulacus nataliae Turrisi, sp. nov., from Malaysia (Sarawak), previously treated under P. fasciatipennis. In addition, a brief taxonomic account of the Pristaulacus flavipennis species group, which comprises six species (including P. erythrocephalus and P. cephalocarinatus sp. nov.), is presented along with a key to species.

Leaf beetles have diverse life cycles and temperate species exhibit several characteristics, such as a long life cycle and long diapause. Aspidimorpha is a group of tortoise beetles in the family Chrysomelidae that inhabit the Oriental and eastern Palearctic regions, which were originally derived from tropical and subtropical regions; however, voltinism and diapause in their life cycles remain unclear. Because the tortoise beetle Aspidimorpha difformis inhabits the northernmost region of the temperate zone among Aspidimorphini, a more detailed understanding of its life history will provide insights into the evolution of its life cycle. We herein performed quantitative field research on the seasonal occurrence of A. difformis in Kanagawa Prefecture, Japan, as well as rearing experiments. In the field, adults overwintered, oviposited, and first-generation larvae occurred between mid-May and mid-July. Most larvae and adults disappeared by early August, except for several individuals in autumn and early winter. Under a constant temperature (20 or 25°C) and photoperiod (LD 12:12 or 16:8), the larval period was short (16–29 days), whereas the pre-oviposition period was long (83–197 days). In conclusion, A. difformis is mainly univoltine and partially bivoltine, which is regulated by an obligatory adult diapause. A life cycle with a long diapause may be adopted to avoid high summer temperatures and poor conditions in food because larvae fail to develop in summer. In contrast to A. miliaris, which is multivoltine with a facultative summer diapause, environments in cooler regions may favor the evolution of univoltinism in A. difformis.

Age can affect the outcomes of male–male contests, but its effects vary across species. In some species, winning probability increases with age due to increased investment in reproduction as a strategy of terminal investment, while in others, it decreases due to senescence. In the Japanese rhinoceros beetle, Trypoxylus dichotomus, males use their horns to compete for resources and mates. Previous research has shown that the horn and body size influence contest outcomes. We investigated the effect of age on winning probability in male–male contests. We also measured the daily changes in lifting and grasping forces as indicators of fighting ability. Both body size and age differences significantly affected contest outcomes, with larger or younger males being more likely to win. Fighting ability declined with age; specifically, males over 20 days of age exhibited decreased grasping and lifting forces. Given the short reproductive season and low survival rate of natural populations of this species, selection probably favors individuals that fight with full effort regardless of age. Consequently, contest outcomes are primarily determined by differences in physical abilities, and older males with reduced fighting performance are more likely to lose to younger males. This study emphasized the importance of morphological and physiological factors in determining competitive outcomes and highlighted the impact of life history on sexual selection dynamics.

Mate discrimination is important for successful mating, whereas several studies have suggested that butterflies sometimes engage in heterospecific mating. In the polymorphic swallowtail butterfly Papilio polytes (Papilionidae), male preference for mimetic and non-mimetic females has been extensively studied. On the other hand, indiscriminate mating attempts on heterospecific butterflies have also been reported in this species, raising questions about mate discriminability. However, due to the inherent rarity of opportunities to observe heterospecific mating attempts, the behavioral background in which such heterospecific interactions occur in the field is unclear, with more observational cases being awaited. In the present study, we report three observations of male P. polytes courting and pairing with heterospecific butterflies, including a male from another family, Nymphalidae. To the best of our knowledge, this is the second report in the world on the pairing between butterflies belonging to different families. Interestingly, the males attempted to mate with freshly eclosed individuals in all three observations. This indicates that active mating attempts by males toward virgin females, a behavior commonly observed in butterflies, may underlie such heterospecific interactions. This also raises questions regarding P. polytes males’ mate discriminability and their role in maintaining female-limited mimetic polymorphism.

This study examined the effects of diet mixing during the nymphal stage on the performance of the brachypterous grasshopper Podisma sapporensis during both the nymphal and adult stages. This species mainly feed on the leaves of Japanese butterbur, Petasites japonicus var. giganteus (Pjg), and also feed on the leaves of giant knotweed, Reynoutria sachalinensis (Rs), wormwood leaves, Artemisia montana, and angular Solomon's seal, Polygonatum odoratum var. maximowiczii. We investigated whether diet mixing with Pjg during the nymphal stage enhances the survival or fecundity of this grasshopper. It was revealed that feeding nutritionally inferior Rs to nymphs extended the adult lifespan. The reproductive speed per lifespan was reduced in females fed the mixed diet, as there was no significant difference in the number of eggs laid per lifespan regardless of the Rs ingested. These results indicate that diet mixing, or the additional Rs intake, had an opposite effect on the life history in the form of higher nymphal mortality and longer adult lifespan of P. sapporensis, altering the reproduction schedule.

The Dermaptera (earwigs) are widely known to the public but have been much less documented in the literature as a taxon of anthophilous insects. Here, we report on the floral utilization of two sympatric earwig species, Forficula mikado and Anechura harmandi, from summer to autumn on Rebun Island, Hokkaido, Japan. Both the nymphs and adults utilized diverse plant taxa (36 species from 15 families) as either foraging or resting sites. They often utilized flowers of the Asteraceae (15 species) and/or Apiaceae (5 species) as foraging sites, probably because of their easily accessible, exposed pollen. In A. harmandi, both nymphs and adults primarily foraged on asteraceous flowers. However, in F. mikado, nymphs frequently utilized apiaceous flowers, whereas adults primarily exploited asteraceous flowers. This ontogenetic dietary shift may be explained by an innate preference of F. mikado nymphs for apiaceous flowers rather than competition for floral resources between F. mikado and A. harmandi nymphs, because flower-visiting earwigs were not so abundant on the island.

Thickness of woody tissue of host plants may affect behaviors of wood-using insects that excavate the woody tissue during oviposition. To determine whether females of the bamboo-using lizard beetle, Doubledaya bucculenta (Coleoptera: Erotylidae: Languriinae) choose thin-walled areas of Pleioblastus simonii bamboo internodes to penetrate the wall for oviposition, we investigated the diameter and wall thickness at each of the relative heights (0 to 10 from basal node) within internodes and the distribution pattern of oviposition marks of D. bucculenta within each internode. Internodes of P. simonii were tapered and the wall was thinnest around the relative heights 7 and 8. Most oviposition marks were made where the wall was thinnest. Therefore, it is suggested that D. bucculenta females prefer thin-walled areas of P. simonii internodes for oviposition.