An FXPRLamide Neuropeptide Induces Seasonal Reproductive Polyphenism Underlying a Life-History Tradeoff in the Tussock Moth

The white spotted tussock moth, Orgyia thyellina, is a typical insect that exhibits seasonal polyphenisms in morphological, physiological, and behavioral traits, including a life-history tradeoff known as oogenesis-flight syndrome. However, the developmental processes and molecular mechanisms that mediate developmental plasticity, including life-history tradeoff, remain largely unknown. To analyze the molecular mechanisms involved in reproductive polyphenism, including the diapause induction, we first cloned and characterized the diapause hormone-pheromone biosynthesis activating neuropeptide (DH-PBAN) cDNA encoding the five Phe-X-Pro-Arg-Leu-NH(2) (FXPRLa) neuropeptides: DH, PBAN, and alpha-, beta-, and gamma-SGNPs (subesophageal ganglion neuropeptides). This gene is expressed in neurosecretory cells within the subesophageal ganglion whose axonal projections reach the neurohemal organ, the corpus cardiacum, suggesting that the DH neuroendocrine system is conserved in Lepidoptera. By injection of chemically synthetic DH and anti-FXPRLa antibody into female pupae, we revealed that not only does the Orgyia DH induce embryonic diapause, but also that this neuropeptide induces seasonal polyphenism, participating in the hypertrophy of follicles and ovaries. In addition, the other four FXPRLa also induced embryonic diapause in O. thyellina, but not in Bombyx mori. This is the first study showing that a neuropeptide has a pleiotropic effect in seasonal reproductive polyphenism to accomplish seasonal adaptation. We also show that a novel factor (i.e., the DH neuropeptide) acts as an important inducer of seasonal polyphenism underlying a life-history tradeoff. Furthermore, we speculate that there must be evolutionary conservation and diversification in the neuroendocrine systems of two lepidopteran genera, Orgyia and Bombyx, in order to facilitate the evolution of coregulated life-history traits and tradeoffs.ArticlePLOS ONE. 6(8):e24213 (2011)journal articl

Comparisons in temperature and photoperiodic-dependent diapause induction between domestic and wild mulberry silkworms

The bivoltine strain of the domestic silkworm, Bombyx mori, has two generations per year. It shows a facultative diapause phenotype determined by environmental conditions, including photoperiod and temperature, and nutrient conditions during embryonic and larval development of the mother. However, it remains unclear how the environmental signals received during development are selectively utilized as cues to determine alternative diapause phenotypes. We performed a comparative analysis between the Kosetsu strain of B. mori and a Japanese population of the wild mulberry silkworm B. mandarina concerning the hierarchical molecular mechanisms in diapause induction. Our results showed that for the Kosetsu, temperature signals during the mother's embryonic development predominantly affected diapause determination through the thermosensitive transient receptor potential ankyrin 1 (TRPA1) and diapause hormone (DH) signaling pathways. However, embryonic diapause in B. mandarina was photoperiod-dependent, although the DH signaling pathway and thermal sensitivity of TRPA1 were conserved within both species. Based on these findings, we hypothesize that TRPA1-activated signals are strongly linked to the signaling pathway participating in diapause induction in Kosetsu to selectively utilize the temperature information as the cue because temperature-dependent induction was replaced by photoperiodic induction in the TRPA1 knockout mutant.ArticleScientific Report 11(1) : 8052-(2021)journal articl

Light-Stimulated Green Coloration of Silk Glands in the Saturniid Moth, Antheraea yamamai : Influence of Ligation and Parabiosis(Physiology)

Volume: 8Start Page: 665End Page: 67

リンシモクコンチュウノヨウチュウヒョウヒニヨルサナギクチクラブンピニカンスルケンキュウ

京都大学0048新制・課程博士理学博士甲第1556号理博第349号新制||理||202(附属図書館)4317UT51-50-A365京都大学大学院理学研究科動物学専攻(主査)教授 加藤 勝, 教授 加藤 幹太, 教授 池田 次郎学位規則第5条第1項該当Kyoto UniversityDA

Variation in the prevalence of cytoplasmic incompatibility-inducing Wolbachia in the butterfly Eurema hecabe across the Japanese archipelago. Evol Ecol Res 7: 931–942

ABSTRACT Question: Is the prevalence of cytoplasmic incompatibility-inducing Wolbachia spreading throughout butterfly populations? Hypothesis: Wolbachia are self-promoting intracellular microbes and the infection spreads easily among host populations. Organism: Japanese pierid butterfly (Eurema hecabe). Field sites: Thirty-two haphazardly selected local populations throughout the Japanese archipelago. Methods: We surveyed Wolbachia infection from 1997 to 2000 using diagnostic PCR. An inter-population cross-experiment was performed to detect cytoplasmic incompatibility in 1992, 1999 and 2000. Conclusions: High Wolbachia frequencies were detected in southern populations, but no infection was found in the northern parts of Japan. Cytoplasmic incompatibility-inducing Wolbachia was found in the two main types of host (brown and yellow), which are reproductively isolated. The invasion of cytoplasmic incompatibility-inducing Wolbachia into the central Japanese populations has occurred within the last decade as shown by chronological data. Our data fit well with standard models of Wolbachia dynamics

Multiple infection with Wolbachia inducing different reproductive manipulations in the butterfly Eurema hecabe.

Wolbachia are rickettsial intracellular symbionts of arthropods and nematodes. In arthropods, they act as selfish genetic elements and manipulate host reproduction, including sex-ratio distortion and cytoplasmic incompatibility (CI). Previous studies showed that infection of feminizing Wolbachia and CI Wolbachia sympatrically occurred in the butterfly Eurema hecabe. We demonstrate that feminization-infecting individuals can rescue sperm modified by CI-infecting males. Phylogenetic analysis revealed that feminized individuals are infected with two distinct Wolbachia strains: one is shared with CI-inducing matrilines, and the other is only found in feminized matrilines. Therefore, the simultaneous double manipulation, CI rescue and feminization, is caused by different Wolbachia strains in feminized individuals, not by a single Wolbachia with two functions. This is the first finding of double infection of Wolbachia with different reproductive manipulations