Sexual communication in castniid moths: Males mark their territories and appear to bear all chemical burden

Castniid moths (Lepidoptera: Castniidae) display a butterfly-like reproductive behavior, i.e., they use visual stimuli for mate location and females have apparently lost their pheromone glands in an evolutionary context. In this paper we report for the first time the identification of three new compounds, namely n-octadecyl acetate, (Z)-9-octadecenyl acetate and (E,Z)-2,13-octadecadienyl acetate, in males of the Castniid Palm Borer, Paysandisia archon, which could be involved in its short-range courtship behavior, and also shed light on recent controversies on the sexual behavior of the species. The compounds are produced in a ring-shaped gland of the male terminalia and have occasionally been detected in very minor amounts (ng) in ovipositor extracts of females, but only while mating or just after copulation. We also report that males use the already known (E,Z)-2,13-octadecadienol to mark their territory by rubbing their midlegs against the upper side of nearby leaves, especially palm leaves. This compound, produced in large amounts, is mostly concentrated in the midleg basitarsi and its maximum production is detected on the sexually mature 1-day-old specimens. In addition, analysis of male wings extracts confirms the presence of Z,E and E,E-farnesals, which are mostly produced in the median band of hindwings of 48–53 h-old insects. The biological significance of farnesals in this species is unknown. Our results point out that the chemical communication of P. archon relies mostly on males, which appear to bear all chemical burden in this respect.

铸蛾科（鳞翅目：Castniidae）昆虫展现出类似蝴蝶的繁殖行为，即它们借助视觉刺激完成配偶定位，且雌性个体在演化进程中似乎已丧失信息素腺体。本研究首次报道了从棕榈蛀蛾（Paysandisia archon）雄性个体中鉴定出三种新型化合物，分别为乙酸正十八烷基酯、(Z)-9-十八烯基乙酸酯以及(E,Z)-2,13-十八碳二烯基乙酸酯。这些化合物可能参与该物种的近距离求偶行为，同时也为近期围绕该物种性行为的争议提供了新的阐释。上述化合物由雄性外生殖器的环形腺体合成，且仅在交配过程中或交配结束后，才能在雌性产卵器提取物中以极微量（纳克级别）被检出。本研究同时发现，雄性个体可利用已知化合物(E,Z)-2,13-十八碳二烯醇标记领地：它们通过将中足摩擦附近叶片（尤其是棕榈叶）的正面来完成标记行为。该化合物大量合成，主要集中于中足基跗节中，且在性成熟1日龄的个体中合成量达到峰值。此外，对雄性翅膀提取物的分析证实了Z,E-法尼醛与E,E-法尼醛的存在，这两种化合物主要在羽化后48~53小时个体的后翅中带区域合成。目前尚不清楚法尼醛在该物种中的生物学功能。本研究结果表明，棕榈蛀蛾的化学通讯主要依赖雄性个体，雄性承担了该物种化学通讯相关的全部职责。