Kuwahara Yasumasa, Ichiki Yayoi, Morita Masashi, Tanabe Tsutomu, Asano Yasuhisa
Asano Active Enzyme Molecule Project, JST, ERATO, Kyoto Brunch, Kyoto, 602-0841, Japan,
J Chem Ecol. 2015 Jan;41(1):15-21. doi: 10.1007/s10886-014-0536-8. Epub 2014 Dec 20.
A mixture of defense compounds (benzaldehyde, benzoyl cyanide, benzoic acid, mandelonitrile, and mandelonitrile benzoate), found commonly in cyanogenic polydesmid millipedes, was identified in the non-cyanogenic millipede Niponia nodulosa. These compounds were major components in 1st-4th instars, but were absent in older instars and adults. Extracts of older instars and adults contained 1-octen-3-ol, 2-methyl-2-bornene, E-2-octen-1-ol, 2-methyl-isoborneol, and geosmin; these compounds were minor components in 1st-4th instars. This ontogenetic allomone shift may be explained by the high cost of biosynthesis of polydesmid compounds from L-phenylalanine being offset by their potency in protecting the insect during fragile and sensitive growth stages. However, as the cuticle hardens in older juveniles (5th, 6th, 7th instars) and adults, this allows for a switch in defense to using less effective and less costly volatile organic compounds (presumably microbial in origin) that are ubiquitous in the millipede's habitat or are produced by symbiotic microbes and may be readily available through food intake or aspiration.
在非氰化千足虫结节尼氏千足虫中鉴定出了通常在含氰多足千足虫中发现的防御化合物混合物（苯甲醛、苯甲酰氰、苯甲酸、扁桃腈和扁桃腈苯甲酸酯）。这些化合物是1至4龄若虫的主要成分，但在老龄若虫和成虫中不存在。老龄若虫和成虫的提取物含有1-辛烯-3-醇、2-甲基-2-冰片烯、E-2-辛烯-1-醇、2-甲基异冰片醇和土臭素；这些化合物在1至4龄若虫中是次要成分。这种个体发育阶段的利他素转变可能是由于从L-苯丙氨酸生物合成多足千足虫化合物的高成本被其在脆弱和敏感生长阶段保护昆虫的效力所抵消。然而，随着老龄若虫（第5、6、7龄）和成虫的表皮硬化，这使得防御方式转变为使用效力较低且成本较低的挥发性有机化合物（推测源自微生物），这些化合物在千足虫的栖息地普遍存在，或者由共生微生物产生，并且可能通过食物摄入或吸入很容易获得。
