柑橘凤蝶蛹发声器的显微结构及防御作用

Microstructure and defense function of the acoustic organ of Papilio xuthus(Lepidoptera:Papilionidae)pupae

【目的】动物界存在多种用于对抗捕食者的防御机制。一些鳞翅目昆虫的蛹在受到机械刺激时会发出蠕动的声音。【方法】在扫描电镜下对柑橘凤蝶Papilio xuthus蛹的发声器形态特征进行观察,并使用Audacity软件对捕获的声音进行特征分析。【结果】柑橘凤蝶蛹在腹部第4-5节和第5-6节之间的节间膜上存在发声器,有规律地发出嘶嘶声。发声器由多层甲壳素构成的刮器和板组成,刮器和板上有50~90个突起。当蛹的腹部被寄生蜂触角刺激30 s以上时,刮器和板会迅速相互摩擦,腹部反复摆动发出声音。蛹发出的声音是由一系列每2000~3000 ms发生3次的短脉冲组成的。频带很宽,主要分布在5~20 kHz范围内。新鲜蛹和越冬蛹的活性不同,声强也不同。【结论】本研究首先描述了柑橘蝴蝶蛹发声器的结构,结果支持了一些蝴蝶蛹对寄生生物进化出一种特殊的防御机制(声学防御)的假说。此外,通过比较两种生境的柑橘凤蝶蛹的声波特征,我们提出了同一物种在不同地理区域可以产生方言的假说。

【Aim】There are a variety of defense mechanisms used against predators in the animal kingdom.Some lepidopteran pupae can make a wriggling sound when they are mechanically stimulated.【Methods】We observed the morphology characteristics of acoustic organs of Papilio xuthus pupae under scanning electron microscope and analyzed the acoustic characteristics of captured sounds using Audacity software.【Results】The pupae of P.xuthus produce a regular hissing sound by their acoustic organs located in the intersegmental membranes between their 4th-5th and 5th-6th abdominal segments.The sound-producing organs are composed of scrapers and plates,both of which are composed of multiple layers of chitin.There are totally 50-90 protuberances on scrapers and plates.When the abdomen of the pupae is stimulated by the antennae of the parasitoids for more than 30 s,the scrapers and plates will quickly rub against each other repeatedly wiggling from one side to another side of the pupal abdomen to make sounds.The sounds are detected to be composed of a series of short pulses that occur three times every 2000-3000 ms.The frequency band is very wide,mainly distributed in the 5-20 kHz range.The activity of fresh pupae is different from that of overwintering ones,resulting in different sound intensities.【Conclusion】We firstly described the structure of sound-producing organs of P.xuthus pupae with mechanical stimulation and the results support the hypothesis that the pupae of some butterflies have evolved a special defense mechanism(acoustic defense)against parasitoids.In addition,the sound-producing organs of the same species at different geological areas can generate dialectal phenomena by comparing the characteristics of the acoustic waves of P.xuthus pupae from two different habitats.