Gillyboeuf N, Anglade P, Lavenseau L, Peypelut L
Laboratoire de Neuroendocrinologie de l'Insecte, URA CNRS 1138, Université Bordeaux I, Av. des Facultés, 33405, Talence Cedex, France.
Station de Zoologie INRA, BP 81, 33883, Villenave d'Ornon, France.
Oecologia. 1994 Sep;99(3-4):366-373. doi: 10.1007/BF00627750.
The cold-hardening capacity of larvae of the pink maize stalk borer,Sesamia nonagrioides Lef., was examined. Supercooling points (SCPs) of field collected diapausing larvae from south-east and south-west France and non-diapausing and diapausing laboratory-reared larvae did not differ and ranged between -5 and -8°C. Thus, this insect possesses sufficient supercooling ability to avoid freezing over its normal environmental temperature ranges. Despite this, we found thatSesamia presents paradoxical cold reactions. Mortality of cold acclimated diapausing larvae after short-term exposure to temperatures above the SCP is high, supporting the view thatSesamia is cold-sensitive. On the other hand,Sesamia could survive freezing for at least 24 h to temperatures close to the SCP. This ability does not seem to be related to haemolymph trehalose, the sole cold-accumulated compound detected by gas chromatography and mass spectrometry. Despite the mildness of the winter 1990-1991, only 5% of the field population survive and pupate in April. The main part of the population died from November to January, the period during which larvae were mainly located in the part of the corn stem above the ground and experienced air temperatures. After January, all surviving larvae were excuusively located in the root, 10 cm below the soil, where they experienced milder temperatures than air. They exhibited a constant low rate of mortality, possibly independent of the cold. In their current distribution area, survival of overwintering larvae ofS. nonagrioides is only related to the microclimate of the overwintering site and freezing tolerance capacity seems to be irrelevant. This study allows us to propose a non-pollutant pest control method based on the "behavioral strategy" of this insect.
对粉红色玉米螟幼虫（Sesamia nonagrioides Lef.）的抗寒能力进行了研究。对从法国东南部和西南部田间采集的滞育幼虫以及非滞育和滞育的实验室饲养幼虫的过冷却点（SCPs）进行了测定，结果发现它们之间没有差异，范围在-5至-8°C之间。因此，这种昆虫具有足够的过冷却能力，能够在其正常环境温度范围内避免结冰。尽管如此，我们发现Sesamia呈现出矛盾的低温反应。经过冷驯化的滞育幼虫在短期暴露于高于SCP的温度后死亡率很高，这支持了Sesamia对低温敏感的观点。另一方面，Sesamia能够在接近SCP的温度下冷冻至少24小时仍存活。这种能力似乎与血淋巴海藻糖无关，通过气相色谱和质谱检测到的唯一冷积累化合物就是血淋巴海藻糖。尽管1990 - 1991年冬季较为温和，但4月份田间种群中只有5%存活并化蛹。种群的主要部分在11月至1月期间死亡，在此期间幼虫主要位于地面以上的玉米茎部分，并经历气温。1月之后，所有存活的幼虫都仅位于土壤以下10厘米处的根部，在那里它们经历的温度比气温更温和。它们的死亡率一直很低，可能与寒冷无关。在其当前分布区域，S. nonagrioides越冬幼虫的存活仅与越冬地点的小气候有关，而耐寒能力似乎并不重要。这项研究使我们能够基于这种昆虫的“行为策略”提出一种无污染的害虫防治方法。
