Department of Entomology and Acarology, "Luiz de Queiroz" College of Agriculture, University of São Paulo (USP), Piracicaba, São Paulo, Brazil.
State University of Mato Grosso do Sul, Cassilândia, Mato Grosso do Sul, Brazil.
PLoS One. 2020 Dec 23;15(12):e0235028. doi: 10.1371/journal.pone.0235028. eCollection 2020.
Cyclocephalini beetles of the genus Cyclocephala (Coleoptera: Melolonthidae: Dynastinae) use flowers of some plants as food, shelter, and mating sites. However, little is known about floral scent chemistry involved in this interaction. Here we show that a sesquiterpene alcohol mediates attraction of Cyclocephala paraguayensis Arrow, on bottle gourd flowers, Lagenaria siceraria (Cucurbitaceae). Both males and females started to aggregate on the flowers at twilight; after that, mating began and remained for the entire night. GC-FID/EAD analysis of the L. siceraria floral scent collected in the field revealed that only the major constituent of the airborne volatiles elicited electroantennographic responses on male and female antennae of C. paraguayensis. This compound was identified as (3S,6E)-nerolidol, which was tested in two field trapping trials in Brazil. In the first bioassay, traps baited with nerolidol (mix of isomers) captured significantly more adult C. paraguayensis than control traps. In the second field trial, catches in traps baited with a mixture of isomers or enantiopure nerolidol were significantly higher than captures in control traps, but the treatments did not differ significantly. Analysis from the gut content of adult C. paraguayensis showed the presence of pollen, suggesting that they also use bottle gourd flowers for their nourishment. Taken together, these results suggest that (3S,6E)-nerolidol plays an essential role in the reproductive behavior of C. paraguayensis by eliciting aggregation, mating, and feeding.
圆胸叩头甲属（鞘翅目：丽金龟科：犀金龟亚科）甲虫以某些植物的花为食、蔽护和交配场所。然而，人们对这种相互作用中涉及的花香化学知之甚少。在这里，我们表明一种倍半萜醇介导了圆胸叩头甲对葫芦科葫芦属的南瓜花的吸引。雄性和雌性圆胸叩头甲在黄昏时分开始聚集在花朵上；之后，交配开始，并持续了整个晚上。在野外收集的葫芦属花香的 GC-FID/EAD 分析表明，只有空气中挥发性物质的主要成分在雄性和雌性圆胸叩头甲的触角上引起了触角电位反应。这种化合物被鉴定为（3S,6E）-橙花叔醇，它在巴西的两项野外诱捕试验中进行了测试。在第一次生物测定中，用橙花叔醇（异构体混合物）诱捕的诱捕器捕获的成年圆胸叩头甲明显多于对照诱捕器。在第二次野外试验中，用异构体混合物或对映纯橙花叔醇诱捕的诱捕器的捕获量明显高于对照诱捕器，但处理之间没有显著差异。对成年圆胸叩头甲肠道内容物的分析表明存在花粉，表明它们也将南瓜花用作食物。综上所述，这些结果表明（3S,6E）-橙花叔醇通过引发聚集、交配和取食来在圆胸叩头甲的生殖行为中发挥重要作用。
