- 著者
- Atsushi Miyashita Kazuhisa Sekimizu Chikara Kaito
- 出版者
- International Research and Cooperation Association for Bio & Socio-Sciences Advancement
- 雑誌
- Drug Discoveries & Therapeutics (ISSN:18817831)
- 巻号頁・発行日
- pp.2022.01058, (Released:2022-09-06)
- 参考文献数
- 25
Male crickets emit acoustic signals (i.e., songs) by chirping using their forewings. Although the mechanisms and adaptive functions of these songs are well studied, knowledge about how songs develop within a generation is relatively scarce. Our previous work demonstrated a stable peak frequency at 5.7 kHz in the calling songs recorded from mature adult male crickets (Gryllus bimaculatus). In the present study, we monitored changes in the frequency component over time from the sexual maturity stage (early adult stage). We recorded 300 calling songs from a pool of 122 adults. The peak frequency distribution was lower and unstable (i.e., greater coefficient of variance) in the early adult stage. The mean peak frequency was 4.9 kHz on day 3, but gradually converged to 5.8 kHz over the 2-week adult stage. Immature adult males (emitting immature songs) produced an appropriately tuned song with a peak frequency of 5.8 kHz in an environment of 80% helium and 20% oxygen. These results suggest that the frequency component of the calling song is acquired during the early to mid-adult stage, and may be related to sexual maturation in males. Findings from the helium substitution experiment revealed that physical resistance from surrounding gas molecules negatively affect the stability of male singing, and that muscle development and forewing hardening may contribute to the maturation of singing, suggesting that females may adaptively select sexually mature males based on song traits.
- 著者
- Atsushi Miyashita Yuuki Hirai Kazuhisa Sekimizu Chikara Kaito
- 出版者
- バイオ&ソーシャル・サイエンス推進国際研究交流会
- 雑誌
- Drug Discoveries & Therapeutics (ISSN:18817831)
- 巻号頁・発行日
- pp.2015.01000, (Released:2015-01-25)
- 参考文献数
- 11
- 被引用文献数
- 2 16
The search for new antibiotics or antifungal agents is crucial for the chemotherapies of infectious diseases. The limited resource of soil bacteria makes it difficult to discover such new drug candidate. We, therefore, focused on another bacterial resource than soil bacteria, the microbial flora of insect species. In the present study, we isolated 40 strains of bacteria and fungi from the mycangia of three species of stag beetle, Dorcus hopei binodulosus, Dorcus rectus, and Dorcus titanus pilifer. We identified those species with their ribosomal DNA sequences, and revealed that Klebsiella spp. are the most frequent symbiont in the stag beetle mycangia. We examined whether these microorganisms produce antibiotics against a Gram-negative bacterium, Escherichia coli, a Gram-positive bacterium, Staphylococcus aureus, or a fungus, Cryptococcus neoformans. Culture supernatants from 33, 29, or 18 strains showed antimicrobial activity against E. coli, S. aureus, or C. neoformans, respectively. These findings suggest that bacteria present in the mycangia of stag beetles are useful resources for screening novel antibiotics.