草地贪夜蛾与东方黏虫的种内及种间斗争行为差异研究

The difference of intra-and inter-specific agonistic behaviors between Spodoptera frugiperda and Mythimna separata

昆虫之间存在复杂的种内及种间竞争关系,竞争中的获胜方可以占有食物、配偶等资源,其中,斗争行为是昆虫竞争的主要方式之一。草地贪夜蛾Spodoptera frugiperda是我国玉米上的重大入侵性害虫,其入侵过程伴随着与本地害虫的竞争,草地贪夜蛾与本地害虫的种内及种间竞争能力差异是其能否成功入侵、定殖甚至取代本地种群的关键。东方黏虫Mythimna separata是我国玉米上重要的本地害虫,本文分别对不同龄期草地贪夜蛾和东方黏虫幼虫的种内及种间斗争行为进行深入研究。在种内斗争行为中,不同龄期东方黏虫幼虫均表现出较高频次的攻击行为,以头部接触行为发生最为频繁;而草地贪夜蛾仅高龄幼虫对低龄幼虫表现出显著攻击性,如在6龄vs 4龄中,头部接触频次为(0.318±0.073)次/min、猛击频次为(0.313±0.059)次/min。在种间斗争行为中,不同龄期草地贪夜蛾幼虫均对东方黏虫表现出显著高频次且具有杀伤力的攻击行为,如在4龄vs 4龄、5龄vs 5龄、6龄vs 6龄、4龄vs 6龄和6龄vs 4龄中,猛击频次分别为(0.337±0.052)次/min、(0.695±0.127)次/min、(0.546±0.051)次/min、(0.362±0.043)次/min和(1.026±0.172)次/min;而东方黏虫仅4龄幼虫对同龄期草地贪夜蛾表现出显著攻击性,其他龄期幼虫的攻击和防御行为没有显著差异。该研究结果为阐明鳞翅目害虫幼虫的斗争行为提供了重要的参考依据,为阐明害虫的种内及种间互作关系提供了理论基础。

Insects engage in complicated forms of intra-and inter-specific competition to secure essential resources,including food and mates.Agonistic behaviors,notably fighting,are a crucial aspect of insect competition.The fall armyworm(Spodoptera frugiperda)is an important invasive pest in the maize fields of China,competing with local pests during its invasion.The difference in intra-and inter-specific competitive abilities between the fall armyworm and local pests is key to the successful invasion,colonization,and even replacement of the local population.The oriental armyworm(Mythimna separata)is one of the local pests in the maize fields.This study delves into the agonistic behaviors of the two pests with different instars in intra-and inter-specific competition.In the intraspecific agonistic encounters,the oriental armyworm exhibited a heightened frequency of attack behaviors,especially the head-touching behavior.The older larvae of the fall armyworm showed the conspicuously aggressive tendencies towards their younger counterparts,the head-touching and strike behaviors in the larval combination of 6th instar vs 4th instar were(0.318±0.073)and(0.313±0.059)counts per min,respectively.In the interspecific agonistic encounters,the fall armyworm consistently demonstrated significantly elevated and lethal attack behaviors towards the oriental armyworm,the strike behavior in the larval combinations of 4th instar vs 4th instar,5th instar vs 5th instar,6th instar vs 6th instar,4th instar vs 6th instar,and 6th instar vs 4th instar were(0.337±0.052),(0.695±0.127),(0.546±0.051),(0.362±0.043),and(1.026±0.172)counts per min,respectively.The oriental armyworm did not exhibit noteworthy differentials in attack and defense behaviors towards the fall armyworm,except for the predominantly aggressive behaviors in the larval combinations of 4th instar vs 4th instar.These empirical findings contribute to illustrate the agonistic behaviors of lepidopteran larvae and provide a theoretical underpinning for deciphering the intra-and inter-specific dynamics governing pest interactions.