Entomological Science最新文献

Species of the aphid genus Metanipponaphis (Hormaphidinae: Nipponaphidini) form galls on Distylium racemosum and migrate to Castanopsis trees. Japanese species of Metanipponaphis and its allied genera were revised based on molecular phylogenetic analyses. The genera Monzenia and Lithoaphis were united with Metanipponaphis, and Metanipponaphis was adopted as the valid name for the genus. Neonipponaphis shiiae was found belonging to another clade containing Nipponaphis species. The gall or primary-host generation of M. shiicola was recorded for the first time. Little difference was found in their nucleotide sequences between M. cuspidatae, a host-alternating species, and M. ihai, a monoecious species on D. racemosum. The molecular phylogenetic analyses also showed that the monoecious M. globuli is a sister species of the host-alternating M. shiicola. The taxonomy and biology of six Metanipponaphis species and N. shiiae were reviewed, with keys to the species based on the apterous adults and first-instar nymphs on Castanopsis spp.

Two species of Cystiphora (Diptera: Cecidomyiidae) are newly recorded from Japan. A gall midge that induces leaf galls on Taraxacum species (Asteraceae) is identified as Cystiphora taraxaci (Kieffer). Another gall midge that is responsible for leaf galls on Sonchus brachyotus (Asteraceae) is described as a new species under the name Cystiphora hachijounae Yukawa and Kim based on its incised hypoproct of male terminalia and some of the pupal characteristics. Genetic analysis supported the species identifications and indicated that the Palearctic C. taraxaci has long existed in Japan. It has been diversifying geographically into intraspecific populations since at least 2.57 Ma. Our current study argues against the recent invasion of Japan by alien C. taraxaci at the time of multiple introductions of European Taraxacum species to Japan for use as food (seed oil), forage and greening material during the late 19th century. Genetic analysis of gall-bearing Taraxacum plants collected from various localities in Japan indicates that most of them were alien or hybrid plants, while native Japanese species were rare, and these plants exhibited polyploidy from 2x to 5x. Cystiphora taraxaci is considered to have expanded its host range from native Japanese to alien and hybrid species of Taraxacum without regard to polyploidy.

Dytiscids prey on a variety of items including other invertebrates but also larger prey such as frogs and fish. However, there have been no reports concerning predation on caudata adults by larvae of dytiscids. In this paper, we describe a predation event by a larva of diving beetles of the species Dytiscus marginalis Linnaeus, 1758 on an adult Iberian newt Lissotriton boscai (Lataste, 1879). This report represents the first observation of hunting behavior of larvae of diving beetles preying on a living post-metamorphic newt.

Prey defensive traits against predators can be categorized into primary defense (avoiding detection) and secondary defense (avoiding attack after detection). There are trade-offs between these two defensive traits, which consider the cost of defense. To quantify the predation avoidance efficacy of both defensive traits against common predators, we compared bird predation pressures and the corresponding avoidance measures of cocoons of two nettle moth species, which utilize contrasting avoidance strategies: Parasa lepida (investing predominantly in primary defense) and Monema flavescens (investing predominantly in secondary defense). Field censuses revealed that bird predation was the most significant mortality factor for both species. The survival rate of cocoons was significantly higher for M. flavescens than for P. lepida, although M. flavescens were more conspicuous than P. lepida. Measurement of prepupae (cocoon content) mass, and experiments on the feeding preferences of the prepupae of both species using chicks, confirmed a similar quantity and quality of both speciesʼ prepupae as prey items. Our results were explained by the advantage of cocoon hardness outweighing the disadvantage of cocoon conspicuousness. The predation behavior of wild birds suggested that they spent considerably longer handling than searching for cocoons, which accounted for their cocoon preference for P. lepida over M. flavescens in the context of optimal foraging theory. Our results suggested that secondary defense was more effective in reducing bird predation than primary defense in limacodid cocoons.

The wood-feeding cockroach Panesthia angustipennis spadica Shiraki (Blaberidae) lives in a tunnel of decayed logs and is considered as gregarious species. However, decayed logs are distributed in a forest in clumps, and woody tunnels in decaying logs provide a semi-enclosed environment for nymphs. We performed laboratory experiments to determine whether first- and second-instar nymphs of P. angustipennis spadica show gregariousness in small spaces like woody tunnels. We also compared the aggregation intensity of sibling groups and mixed groups in the second instar. The laboratory experiments demonstrated that both the first- and second-instar nymphs show gregariousness, with no difference in aggregation behavior regardless of kin relatedness. These results suggest that non-kin-based gregariousness may help to maintain colonies of P. angustipennis spadica that contain individuals derived from multiple families in a field.

Adults of the mangrove cricket, Apteronemobius asahinai, collected in the field continuously show a circatidal rhythm in their locomotor activity. However, it remained unclear whether adult crickets reared from eggs in the laboratory, without cyclic tidal influence, show the circatidal rhythm. We show that under constant red dim light, slightly less than half of crickets showed a circatidal rhythm continuously for more than 10 days. On the other hands, Some others showed a unimodal daily rhythm either before or after the tenth day in the activity recording. Thus, some environmental factors other than the laboratory conditions should be required in order for all crickets to express a clear circatidal rhythm. Even under constant light, unimodal daily rhythm appeared. The unimodal daily rhythm was entrained to light–dark cycles in some crickets, but not in the others. Therefore, we cannot conclude whether the unimodal daily rhythm is a circadian rhythm or a rhythm derived from a circatidal rhythm with its period doubled.

To better understand the relationship between biodiversity and ecosystem functioning, it is increasingly accepted that the focus of study needs to shift from taxonomic identity to the diversity of functional traits displayed by species within a community. Such an approach allows species to be grouped according to particular functional characteristics. Increasingly viewed as an extremely important group of model organisms, hoverflies have been the focus of a variety of ecological studies. Based on data regarding selected functional traits of hoverflies registered in Southeast Europe, the main aims of our study were to define hoverfly functional groups according to the similarity of these traits, as well as to compare the representation of delineated hoverfly functional groups among these vegetation types. We used fuzzy clustering to classify 568 SE European hoverfly species into five functional groups. The principle trait separating these functional groups was larval feeding type, followed by size of species range, flight ability, number of generations, inundation tolerance, and tolerance to human impact. For 9 of 11 vegetation types, the dominant functional group was characterized by species with good flight ability, having high human impact tolerance and more annual generations. The remaining two vegetation types, South-west Balkan sub-Mediterranean mixed oak forests and Mediterranean mixed forests, showed disparate dominance patterns, indicating that richness of functional groups is dependent on vegetation. Further investigation of whether and how established conservation measures enable recovery of the functional richness affected by habitat disturbance would help elucidate the importance of functional diversity in preserving biodiversity.

Differentiation in sexual traits among populations is one of the major predictions of theories of sexual selection and sexual conflict. A balance between maximizing reproductive benefits and minimizing survival costs could explain variation in sexual traits within and between populations. The false blister beetle Oedemera sexualis (Coleoptera: Oedemeridae) has exaggerated sexual traits, that is, sexually dimorphic hindlegs. In this study, we characterized scaling relationships in populations of O. sexualis to evaluate the determinants of sexual trait variation in the species. We quantified sexual dimorphism in body size and hindleg sizes in three representative populations based on distance measurements and an elliptical Fourier analysis. We found significant variation in the degree of sexual dimorphism for body and hindleg sizes among populations. In particular, differentiation in the male hind femur shape, especially the femur width, was conspicuous. Scaling relationships between male hind femur width and body size were best described by logistic models, showing that increases in male hind femur width were constrained for large individuals in all three populations. The degree of constrained growth of the hind femur width differed among populations in accordance with the population means, while the basal growth rates did not. Populations with smaller mean values for sexual traits showed more limited sexual trait exaggeration, contrary to the predictions based on resource competition among body parts. The latitudinal cline in femur widths suggests that environmental constraints on exaggeration might be responsible for sexual trait diversification in O. sexualis.