Division of Biology, Department of Earth System Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kitashirakawaoiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan.
Sci Rep. 2020 Feb 6;10(1):1995. doi: 10.1038/s41598-020-58816-8.
In the common pest cockroach, Periplaneta americana, behavioural responses to the sex and aggregation pheromones change in an age-dependent manner. Nymphs are attracted by the aggregation pheromone periplanolide-E (PLD-E) but not by the sex pheromone periplanone-B (PB) in faeces. Adults display prominent behaviours to PB but not to PLD-E. Despite the significant behavioural differences depending on postembryonic developmental stages, peripheral codings of the sex and aggregation pheromones have not been studied in the nymph of any insects as far as we know. In this study, we morphologically and electrophysiologically identified antennal sensilla that respond to PB and PLD-E in nymphal cockroaches. Although nymphs lacked the sex pheromone-responsive single-walled B (sw-B) sensilla identified in adult males, we found PB-responsive sensory neurons (PB-SNs) within newly identified sw-A2 sensilla, which exhibit different shapes but have the same olfactory pores as sw-B sensilla. Interestingly, PLD-E-responsive sensory neurons (PLD-E-SNs) were also identified in the same sensillar type, but PB and PLD-E were independently detected by different SNs. Both PB-SNs and PLD-E-SNs showed high sensitivity to their respective pheromones. The hemimetabolous insect nymph has an ability to detect these pheromones, suggesting that behaviours elicited by pheromones might be established in brain centres depending on postembryonic development.
在常见的害虫蟑螂（Periplaneta americana）中，行为对性信息素和聚集信息素的反应方式随年龄而变化。若虫被聚集信息素 periplanolide-E（PLD-E）而不是粪便中的性信息素 periplanone-B（PB）吸引。成虫对 PB 表现出明显的行为，但对 PLD-E 没有反应。尽管根据胚胎后发育阶段有显著的行为差异，但就我们所知，在任何昆虫的若虫中，都没有研究过性信息素和聚集信息素的外周编码。在这项研究中，我们从形态和电生理上鉴定了对 PB 和 PLD-E 有反应的触角感觉器。尽管若虫缺乏在成年雄性中发现的对性信息素有反应的单壁 B（sw-B）感觉器，但我们在新鉴定的 sw-A2 感觉器中发现了对 PB 有反应的感觉神经元（PB-SN），其形状不同，但与 sw-B 感觉器具有相同的嗅觉孔。有趣的是，在相同的感觉器类型中也鉴定出了对 PLD-E 有反应的感觉神经元（PLD-E-SN），但 PB 和 PLD-E 是由不同的 SN 独立检测到的。PB-SN 和 PLD-E-SN 对各自的信息素都表现出很高的敏感性。半变态昆虫的若虫具有检测这些信息素的能力，这表明信息素引发的行为可能在大脑中枢根据胚胎后发育而建立。
