Calas Delphine, Berthier Andrée, Marion-Poll Frédéric
UMR 1272 Physiologie de l'Insecte: Signalisation et Communication, INRA-UPMC--AgroParisTech, Bât. 1--Route de Saint-Cyr, 78026 Versailles cedex, France.
J Chem Ecol. 2007 Jul;33(7):1393-404. doi: 10.1007/s10886-007-9302-5.
European corn borer larvae detect and avoid feeding in the presence of phytoecdysteroids (PEs) such as 20-hydroxyecdysone (20E). Therefore, we hypothesized that females would have taste receptors similar to larvae and avoid laying eggs in the presence of 20E. We found female-specific taste sensilla on the tarsi that respond to 20E at concentrations as low as 10(-6) M, a threshold comparable to that of larvae. However, in choice tests, females laid a similar number of eggs on 20E-treated and on nontreated artificial substrates (filter paper, glass, and nylon), although they spent significantly more time in behavioral sequences related to substrate assessment when 20E was present. In contrast, when given a choice between maize plants (eight leaves) sprayed with 20E or only the solvent, females laid 70% fewer eggs on the treated than on control plants. These observations suggest that other chemical cues of plant origin must be present at the same time as 20E for females to modify their oviposition behavior.
欧洲玉米螟幼虫在存在植物蜕皮甾体（PEs）如20-羟基蜕皮酮（20E）的情况下会检测并避免取食。因此，我们推测雌虫会有与幼虫相似的味觉感受器，并在20E存在时避免产卵。我们在跗节上发现了雌性特有的味觉感受器，它们对低至10^(-6) M浓度的20E有反应，这一阈值与幼虫的相当。然而，在选择试验中，雌虫在经20E处理和未经处理的人工基质（滤纸、玻璃和尼龙）上产的卵数量相似，尽管当有20E存在时，它们在与基质评估相关的行为序列中花费的时间明显更多。相比之下，当在喷洒了20E的玉米植株（八片叶子）和仅喷洒溶剂的玉米植株之间进行选择时，雌虫在处理过的植株上产的卵比在对照植株上少70%。这些观察结果表明，为了让雌虫改变其产卵行为，必须与20E同时存在其他植物来源的化学信号。
