- 著者
- Suga Hiromu Hirano Wataru Katoh Toru Matsubayashi Kei W. Katakura Haruo
- 出版者
- Zoological Society of Japan
- 雑誌
- Zoological science (ISSN:02890003)
- 巻号頁・発行日
- vol.33, no.6, pp.603-610, 2016-12
- 被引用文献数
- 3
The ladybird beetles Propylea quatuordecimpunctata and P. japonica have largely overlapping distributions in northern Japan, and in the laboratory produce fertile hybrids. In this study, we surveyed the distribution and morphological differentiation of these species and the hybrids in natural populations, with a focus on western Hokkaido, northern Japan. Phenotypic analyses were conducted for 987 individuals collected at 90 localities. In addition, the nuclear internal transcribed spacer-II (ITS2) region (549 bp) and part of the mitochondrial cytochrome c oxidase subunit I (COI) gene (700 bp) were sequenced for 620 individuals from 53 localities. Analyses of both phenotypic and genotypic features discriminated two distinct entities assignable to P. quatuordecimpunctataand P. japonica. However, individuals with intermediate phenotypes and/or genotypes also occurred extensively, indicating natural hybridization. Putative P. quatuordecimpunctata individuals were collected across a wide range of altitudes (30-600 m), whereas those of P. japonica were found mostly lower than 300 m alt. In addition, P. quatuordecimpunctata was dominant in semi-open habitats shaded by canopy foliage, whereas P. japonica was frequent in more open habitats. The perceived altitudinal difference in the distributions may thus in part be a consequence of this different habitat preference, as open habitats are more common at lower altitudes in the study area.
- 著者
- Kakui Keiichi Hayakawa Yoshinobu Katakura Haruo
- 雑誌
- Zoological Science (ISSN:02890003)
- 巻号頁・発行日
- vol.34, no.2, pp.129-136, 2017-04
- 被引用文献数
- 5
We investigated the life cycle of the tanaidid Zeuxo sp. 1 (Crustacea: Peracarida: Tanaidacea), which lives epiphytically in dwelling tubes on the algae Sargassum spp. and Neorhodomela aculeata in Oshoro Bay, Hokkaido, Japan. We obtained data on its population size distribution, age structure, and reproductive phenology through monthly sampling from April 2011 to June 2012. From these data, we detected an overwintering group (F0) that arises from mancae that are released in autumn, overwinters, reproduces the following spring, and then disappears. The overwintering group produces mancae (F1) that reach maturity and themselves reproduce within six weeks after release; the F1, mancae give rise to an F2 and possibly an F3 generation within a single summer. We refer to individuals that reproduce in the same summer that they were released as the ‘annual group’. Reproduction overall was restricted to the period from May to October, when the seasurface temperature exceeded 10°C. During both years, overwintering females first became reproductive in May. Reproduction in the annual group began in June and continued through mid-October. Mancae were observed in samples from June through October. The two groups differed significantly in size at reproduction; compared to the annual group, females in the overwintering group reproduced at larger minimum and average body sizes, and males began to express enlarged chelae, a secondary sexual character, at a larger size. The difference in size at maturity may be related to the differences in water temperature during the main period of growth and maturation.