Camouflaged objects are harder to detect if the background itself is more heterogeneous, and search becomes increasingly inefficient when the scene contains multiple items resembling the target. Some adult leaf beetles (Coleoptera: Chrysomelidae) with highly specialized habits make holes on host plant leaves while feeding. We propose that leaf beetles camouflage themselves with their feeding holes. The presence of holes makes predators' visual search harder, thus giving beetles more time to escape from the leaf surface either by jumping (Galerucinae: Alticini) or rolling (rest of Chrysomelidae). Based on behavioral observations and analysis of 25 photographs of feeding leaf beetles (15 species), we demonstrate that adult leaf beetles camouflage themselves by creating holes of uniform size, approximately half of the beetle body size. Observation of the feeding behavior and anatomy of a typical hole-feeding beetle (Altica cirsicola) showed that the foregut volume and head-prothorax mobility of beetles are the two major factors that constrain the hole size. A computer-simulated visual search test showed that the greater the number of holes, and the more each hole approached beetle body size, the longer it took humans (as models) to locate a beetle on a leaf. This study reports a newly discovered kind of camouflage, hole-feeding camouflage, in leaf beetles, which makes visual detection or recognition more difficult by changing the environmental background. This type of camouflage may open up a range of new possibilities for studies in animal cognition analysis and evolution of anti-predation defenses.

Sexual behaviors are instinctually exhibited without prior training, but they are modulated by experience. One of the precopulatory behaviors in adult male mice, courtship ultrasonic vocalizations (USVs), has attracted considerable academic attention recently. Male mice emit ultrasounds as courtship behavior when encountering females. However, the modulatory effects of experience on USVs remain unclear.

Recently, expansion of the number and distribution of sika deer, Cervus nippon, in the Japanese Archipelago has resulted in the disturbance of indigenous gene pools and ecosystems. There are also concerns that the artificial introduction of sika deer to certain areas may aggravate this situation. In order to contribute to the conservation of ecosystems, I examined the current state of genetic disturbance and dispersal routes in the sika deer populations around Toyama Prefecture, one of the main areas of expanding sika deer distribution. Of 12 haplotypes detected by mitochondrial DNA D-loop sequence analysis, 10 were found to belong to a previously detected sika deer group in northern Japan, although the remaining two haplotypes corresponded to the southern Japanese sika deer group. The latter two haplotypes were detected at especially high frequencies in the southern area of Toyama Prefecture, suggesting that these haplotypes may derive from artificially introduced individuals. Occurrence patterns of indigenous haplotypes around Toyama Prefecture revealed immigration into Toyama Prefecture through different routes, mainly in the east and south-west. The genetic results presented here may have application in predicting future dispersal routes, as well as aid in the establishment of effective measures for management of sika deer.

To evaluate the colonization histories of the Japanese house mice (Mus musculus), phenotypic and genotypic admixtures of the subspecific traits were studied by evaluation of external body characteristics and mitochondrial gene elements. We analyzed mitochondrial Cytb gene and coat colorations and body dimensions as subspecific characteristics in mice from four areas of the Japanese Islands, the Sorachi, Ishikari and Iburi areas of Hokkaido, the Hidaka area of Hokkaido, and northeastern and central Honshu. Three occurrence patterns of the subspecific haplotypes of Cytb—the castaneus type only, the musculus type only, and the castaneus, musculus, and domesticus types together—were observed in the study areas. In central Honshu, the properties of haplotypes were in accord with the external characteristics as reported in previous findings. In contrast, complicated external characteristics were observed in the Hidaka area, where mice showed multiple haplotype properties. In addition, in northeastern Honshu, coat colorations were not in accord with haplotype properties and such discordance was also observed in most mice in the Sorachi, Ishikari and Iburi areas of Hokkaido. These complexities and discordances suggest that the genetic and phenotypic properties have been caused by different processes, not only through founder effects by migrations and subsequent subspecific hybridizations but also through differentiation in each study area.

Morphometric measurements are basic but essential data in morphological and ecological research. It is thus beneficial to develop a safe, convenient, multipurpose device/technique to determine body length and physical characteristics of living snakes with high accuracy/precision and low stress, and to enable the probing of snakes and collection of tissue samples. To meet these requirements, we developed an improved technique, which we named the Confining-Box Method (CBM). On measuring the body lengths of a total of 72 live snakes, we found significant differences in the accuracy and precision of measurements among the squeeze-box method, the anesthesia method, and the CBM, as well as between vertebral line and the mid-ventral line measurements. Body lengths, as measured along the vertebral line and corrected for perspective errors, using the CBM, did not differ significantly from the standard lengths measured by hand using anesthesia. The squeeze-box method produced substantial negative bias and/or less precision in ventral measurements, especially for large snakes (> 1.2 m in snout-vent length). The differences between measurers were much smaller than among the different techniques. Compared to the anesthesia technique, CBM is a fast and simple method that is also safer for snakes. Unlike the traditional squeeze-box technique, CBM can record both dorsal and ventral body images of snakes simultaneously and enable researchers to measure accurate and/or precise total length (from dorsal images), tail length (from ventral images), and snout-vent length using images from a single photography session. CBM could therefore become a standard to improve measurement consistency, allowing improved data comparison in future studies.

Acquiring information about metabolic heating is necessary for the improved understanding of nesting beaches. However, there are limited studies on metabolic heating of green turtle (Cheloniamydas, L. 1758) on Mediterranean beaches. The present study sought to determine the metabolic heating, and its effect on the feminization of green turtle hatchlings during 2016 and 2017 nesting season on Samandağ Beach, Hatay, Turkey. Moreover, the relations between metabolic heating and nest parameters, and spatio-temporal differences of metabolic heating were evaluated. Nest temperatures were recorded by using data loggers placed at the center of nests (n = 18), and the same depth was used to determine the sand temperature that was 50 cm back of the egg chamber. The mean incubation duration was calculated as 51.1 days, and the mean distance of nests from sea and the mean nest depth were measured as 32.4 meters and 67.70 cm, respectively. The mean numbers of embryo that is early, middle and late embryonic stages were found as 110.8, 93.2 and 93.05, respectively. The mean clutch size was found as 110.8. Mean metabolic heating was 0.37°C in the middle third of incubation for both years. The metabolic heating in both years was close to the as reported in the other green turtles nesting beaches in the Mediterranean. The feminization effect of metabolic heating was calculated as 6.8% in the green turtle nests on Samandağ Beach. Metabolic heating did not vary spatially, and the clutch size was the most important factor in metabolic heating and explained a large proportion of the variation in metabolic heating.

The raccoon dog (Nyctereutes procyonoides) is endemic to East Asia but has been introduced in Europe. Its high adaptability enabled its rapid colonization of European countries, where population growth has been raising concerns regarding ecosystem disturbance and the spread of zoonotic diseases. The genetic diversity and structure of endemic, source, and introduced populations from seven locations across South Korea, China, Russian Far East, Finland (spread to Finland after introduction to European part of Russia from Russian Far East), Vietnam, and Japan (Honshu and Hokkaido) were examined based on 16 microsatellite loci. Two major and significantly different (F_ST = 0.236) genetic clusters were found: continental (South Korean, Chinese, Russian, Finnish, and Vietnamese) and island (Japanese) populations. The continental raccoon dog population comprises three subpopulations (Chinese_Russian_Finnish, South Korean, and Vietnamese) and the Japanese population consists of Honshu and Hokkaido subpopulations. The genetic diversity and geographic structure of raccoon dogs in East Asia has been influenced by natural barriers to gene flow and reveals a typical central-marginal trend in genetic diversity (continental vs. island, and central vs. marginal or source vs. introduced within continental populations). The detected differences between continental and island populations agree with those reported in previous studies that considered these populations as different species.

Many species of ladybird beetles (Coccinellidae) possess vivid body colors. These colors and patterns show diversity between coccinellid species, or even within species. However, the molecular underpinnings of these striking body colors are scarcely understood. One of the candidate pigmentation molecules responsible for ladybird body color is ommochrome pigment, which is well known as the red pigment molecule responsible for the red eyes of Drosophila. Various insects also use ommochrome in body coloration. It is known that ommochrome pigment precursors are imported into appropriate cells by the ATP binding cassette (ABC) transporter proteins White and Scarlet. Thus, these ABC transporter genes are potentially involved in various color and pattern expressions seen in ladybird beetle species. In this study, in order to identify the repertory of ABC transporter genes responsible for such body colors, we performed molecular characterization of pigment-related ABC transporter genes, especially white and scarlet, in the coccinellid Harmonia axyridis. By using whole genome data for H. axyridis and subsequent RACE-PCR, six white orthologs and one scarlet ortholog were successfully identified. According to the results of functional analyses via RNA interference (RNAi), only one of these genes had a major function in eye pigmentation. Specific effects on body color and pattern were not detected by our RNAi experiments of any of these genes. This is the first report of this striking duplication of white genes and their functional analyses in insects.

Species of Temnomastax have wide morphological similarities, and differentiation is usually based on male and female genitalia. In this study, we tested whether morphometric differences contribute to differentiation of species of Temnomastax, proposed an identification key for males, and morphometrically studied the sexual dimorphism of Temnomastax hamus and Temnomastax ricardoi. Analysis was performed using 204 specimens belonging to six species; fifteen morphometric variables were used. We used MANOVA and ANOVA to test the morphometric differences among species and Discriminant Analysis for sexual distinction. Temnomastax sp. nov. 1 had the highest values in ⅓ of all analyzed variables used for morphometric distinction of males, followed by Temnomastax latens, T. ricardoi and Temnomastax sp. nov. 2, and T. hamus and Temnomastax tigris. Two groups were formed by the MANOVA, with length of body, length of hind femur, and length of tegmen as the main variables that distinguished them. Overall, females of T. hamus and T. ricardoi presented higher averages for measurement values used in morphometric distinction between sexes than conspecific males and based on discriminant analysis we found significant differences between sexes. There are significant differences in morphometric variations and the ratio between body length and tegmen length provided reliable evidence for differentiation among species, which can be used as a valid tool that complements the identification of Temnomastax species.

In the central nervous system of insects, motor patterns are generated in the thoracic ganglia under the control of brain, where sensory information is integrated and behavioral decisions are made. Previously, we established neural activity-mapping methods using an immediate early gene, BmHr38, as a neural activity marker in the brain of male silkmoth Bombyx mori. In the present study, to gain insights into neural mechanisms of motor-pattern generation in the thoracic ganglia, we investigated expression of BmHr38 in response to sex pheromone-induced courtship behavior. Levels of BmHr38 expression were strongly correlated between the brain and thoracic ganglia, suggesting that neural activity in the thoracic ganglia is tightly controlled by the brain. In situ hybridization of BmHr38 revealed that 20–30% of thoracic neurons are activated by courtship behavior. Using serial sections, we constructed a comprehensive map of courtship behaviorinduced activity in the thoracic ganglia. These results provide important clues into how complex courtship behavior is generated in the neural circuits of thoracic ganglia.

Seven (including one new) species of the polyplacophoran genus Ischnochiton (Ischnochitonidae) from the Pacific coast of Japan, namely, I. boninensis, I. comptus, I. manazuruensis, I. hakodadensis, I. hayamii sp. nov., I. paululus, and I. poppei, were investigated on the basis of DNA sequence analyses of COI, 16S rRNA, 18S rRNA, and 28S rRNA gene regions. For the latter four species, SEM observations were simultaneously carried out. A molecular phylogenetic tree based on the four gene regions for 18 chiton species indicated that the seven Japanese Ischnochiton species are polyphyletic and originated from two different clades. A haplotype network based on the COI gene region for the six Japanese Ischnochiton species, except I. hakodadensis, showed that the genetic distances among them were large. The SEM observations revealed that the denticles of the major lateral teeth in the seven Japanese Ischnochiton species were bicuspid, and an accessory process was only observed in the minor lateral teeth of I. hakodadensis. Ischnochiton hayamii sp. nov. cooccurs with I. boninensis, I. comptus, and I. manazuruensis at the two investigated localities, and was difficult to distinguish from other, similar species by naked eyes. However, these can be discriminated based on a combination of adult body size, girdle scales, and valve sculpturing in the lateral and central areas.