Population Structure of Two Flightless Weevils of Genus Scepticus Roelofs (Coleoptera, Curculionidae) with Seashore Habitat in Japan.

To elucidate the genetic population structure of two coastal weevils, Scepticus griseus and S. tigrinus, we conducted molecular phylogenetic analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) region (1308 bp) and cytochrome c oxidase subunit II (COII) region (584 bp). A total of 650 individuals (S. griseus, 444 individuals; S. tigrinus, 206 individuals) were obtained from 64 sites. The haplotype networks of both species showed three major lineages with roughly regional distribution. However, the two species show quite different genetic structures; S. griseus has a complicated structure while that of S. tigrinus is simple. We hypothesize that the genetic structure of each of these two weevil species reflects climatic oscillations during the Pleistocene, and the differences in genetic structure between S. griseus and S. tigrinus may represent a unique evolutionary history scenario in each species.

Formation of the Pecking Order during Small-Scale Floor Feeding in Helmeted Guinea Fowl (Numida meleagris).

Helmeted guinea fowl are social animals and only males form a hierarchy in the wild. Non-cage husbandry systems benefit the reproductive health of guinea fowl; however, there are concerns that the feeding duration of subordinate individuals is insufficient. Here, the pecking orders formed during small-scale floor feeding were investigated. There were three experimental categories: male-only (four males), female-only (four females), and mixed category (two males, two females). Each experimental category was set up three times and included different individuals. Behaviors were recorded for 130 h 52 min, 89 h 11 min, and 98 h 46 min in the male, female, and mixed categories, respectively. Male helmeted guinea fowls pecked other males, whereas females exhibited little pecking behavior. Male pecking behavior was not homogeneous within each experimental group. It has been suggested that males form a pecking order, whereas females have no hierarchy under small-scale floor-feeding conditions, as observed in the wild. In most cases, on the first day the number of pecking behaviors was low 20 min after the start of the experiment. The three subordinate individuals in the mixed category had little time to feed, whereas the other birds in the mixed category and all helmeted guinea fowl in the male- and female-only categories had longer feeding durations. We suggest that helmeted guinea fowl may be reared under small-scale floor feeding, and that the health of males should be managed. However, rearing females and males under small-scale floor feeding conditions should be avoided. This study contributes to improving the welfare of helmeted guinea fowl reared under small-scale floor feeding.

Metagenomic analyses of 7000 to 5500 years old coprolites excavated from the Torihama shell-mound site in the Japanese archipelago.

Coprolites contain various kinds of ancient DNAs derived from gut micro-organisms, viruses, and foods, which can help to determine the gut environment of ancient peoples. Their genomic information should be helpful in elucidating the interaction between hosts and microbes for thousands of years, as well as characterizing the dietary behaviors of ancient people. We performed shotgun metagenomic sequencing on four coprolites excavated from the Torihama shell-mound site in the Japanese archipelago. The coprolites were found in the layers of the Early Jomon period, corresponding stratigraphically to 7000 to 5500 years ago. After shotgun sequencing, we found that a significant number of reads showed homology with known gut microbe, viruses, and food genomes typically found in the feces of modern humans. We detected reads derived from several types of phages and their host bacteria simultaneously, suggesting the coexistence of viruses and their hosts. The food genomes provide biological evidence for the dietary behavior of the Jomon people, consistent with previous archaeological findings. These results indicate that ancient genomic analysis of coprolites is useful for understanding the gut environment and lifestyle of ancient peoples.

Evaluating the Phylogenetic Status of the Extinct Japanese Otter on the Basis of Mitochondrial Genome Analysis.

The Japanese otter lived throughout four main Japanese islands, but it has not been observed in the wild since 1979 and was declared extinct in 2012. Although recent taxonomic and molecular phylogenetic studies suggest that it should be treated as an independent species, International Union for Conservation of Nature Red List considers it as subspecies of Lutra lutra. Therefore, the taxonomic status of this species needs to be resolved. Here we determined the complete mitochondrial genome of two Japanese otters caught in Kanagawa and Kochi prefectures and five Eurasian otters (L. lutra). We reconstructed a molecular phylogenetic tree to estimate the phylogenetic position of the Japanese otter in Lutrinae using the Japanese otters and the other 11 Lutrinae species on the basis of ND5 (692 bp) and cytochrome b (1,140 bp) sequences. We observed that the two Japanese otters had close relationships with Eurasian otters, forming a monophyletic group (100% bootstrap probability). To elucidate detailed phylogenetic relationships among the Japanese and Eurasian otters, we reconstructed a maximum likelihood tree according to mitochondrial genome sequences (14,740 bp). The Japanese otter (JO1) collected in Kanagawa was deeply nested in the Eurasian otter clade, whereas the Japanese otter (JO2) collected in Kochi formed a distinct independent lineage in the Lutra clade. The estimated molecular divergences time for the ancestral lineages of the Japanese otters was 0.10 Ma (95%: 0.06-0.16 Ma) and 1.27 Ma (95%: 0.98-1.59 Ma) for JO1 and JO2 lineages, respectively. Thus, JO1 was identified as a member of L. lutra; JO2 represented the old Japanese otter lineage, which may be a distinct new species or subspecies of Lutra. We suggest that the ancestral population of the JO2 lineage migrated to Japan via the land bridge that existed between western Japanese islands and Asian continent at 1.27 Ma.