背景:昆虫食草动物的损害可以引起广泛的植物反应,包括减少或补偿生长,改变了挥发性轮廓,或增加防御化合物的生产。具体来说,草食动物可以改变花的发育,因为植物将资源重新分配给防御和再生功能。对于依赖传粉者的物种,花卉的数量和质量对于吸引花卉游客至关重要;因此,草食动物诱导的发育效应会改变花的丰度或吸引力,这可能对植物的繁殖成功具有至关重要的意义。根据过去关于资源权衡的工作,我们假设草食动物损害诱导的效应在需要大量资源投资的结构花卉性状上更强(例如,花卉数量),随着植物将资源重新分配给防御和再生,而次生花卉性状较弱,需要较少的结构性投资(例如,花蜜奖励)。
方法:在本研究中,我们模拟了驯化的南瓜南瓜南瓜南瓜南瓜中的早期草食动物机械损伤。pepo并在60天的温室实验中测量了不同的花卉性状。
结果:我们发现机械损伤延迟了雄性花期的开始,并减少了产生的花的总量。此外,置换多变量方差分析(PERMANOVA)表明,机械损伤显著影响整体花卉挥发物分布,虽然不是倍半萜类的输出,已知能招募专门的黄瓜甲虫食草动物和南瓜蜜蜂传粉者的一类化合物。
结论:总之,我们展示了C.pepospp.pepo减少了机械损坏后对雄花生产的投资,花卉挥发物确实表现出产量的变化,指示损伤诱导的性状可塑性。在这种全球相关的栽培物种中,雄花产量的这种减少可能会降低受损植物对觅食传粉者的相对吸引力。
BACKGROUND: Damage from insect herbivores can elicit a wide range of plant responses, including reduced or compensatory growth, altered volatile profiles, or increased production of defence compounds. Specifically, herbivory can alter floral development as plants reallocate resources towards defence and regrowth functions. For pollinator-dependent species, floral quantity and quality are critical for attracting floral visitors; thus, herbivore-induced developmental effects that alter either floral abundance or attractiveness may have critical implications for plant reproductive success. Based on past work on resource trade-offs, we hypothesize that herbivore damage-induced effects are stronger in structural floral traits that require significant resource investment (e.g., flower quantity), as plants reallocate resources towards defence and regrowth, and weaker in secondary floral traits that require less structural investment (e.g., nectar rewards).
METHODS: In this study, we simulated early-season herbivore mechanical damage in the domesticated jack-o-lantern pumpkin Cucurbita pepo ssp. pepo and measured a diverse suite of floral traits over a 60-day greenhouse experiment.
RESULTS: We found that mechanical damage delayed the onset of male anthesis and reduced the total quantity of flowers produced. Additionally, permutational multivariate analysis of variance (PERMANOVA) indicated that mechanical damage significantly impacts overall floral volatile profile, though not output of sesquiterpenoids, a class of compounds known to recruit specialized cucumber beetle herbivores and squash bee pollinators.
CONCLUSIONS: In summary, we show that C. pepo spp. pepo reduces investment in male flower production following mechanical damage, and that floral volatiles do exhibit shifts in production, indicative of damage-induced trait plasticity. Such reductions in male flower production could reduce the relative attractiveness of damaged plants to foraging pollinators in this globally relevant cultivated species.