UMR IRD - CNRS 2724, Agropolis, 911, BP 64501, 34394 Montpellier, France.
Infect Genet Evol. 2010 May;10(4):580-5. doi: 10.1016/j.meegid.2010.01.004. Epub 2010 Feb 1.
In spite of the adult body size variability of Aedes aegypti (Linnaeus) and its likely association with life history and vectorial capacity, the causes of size variation itself have been only partially identified. In particular, possible important factors such as climatic variation have not received much attention. The objective of this 2-year study was to describe from field collections the relationship of Ae. aegypti metric properties with available climatic data. The study took place in a dengue hyperendemic area of Thailand. Fourth instar larvae (L(4)) and pupae were collected from the same breeding places allowing the comparisons between seven successive collections, four in 2007 and three in 2008. Climatic data were relative humidity (RH) and temperature (T). They were considered for the periods covering either the pre-imaginal development or, assuming heritability of size, the previous generation. The pre-imaginal period was further subdivided into embryonic and larval phases of development. Size was estimated by traditional and geometric techniques, the latter based on 18 landmarks collected at the intersections of veins also allowing estimation of shape. The shape variation of the wing followed similar patterns as for size and was shown to be a passive allometric change. No significant correlation of size or shape could be disclosed with T. In contrast, significant correlation with RH was found during two periods of examination: (i) the period affecting the generation previous to the time of collection, suggesting possible selective mechanisms on genitors, and (ii) the one occurring during pre-imaginal development. The subdivision of the latter into embryonic and larval phases allowed to evidence a possible selecting effect on embryonic development. The selection would act through the resistance to water loss which is known to depend on the relative surface of the cuticle. In conclusion, our data highlight the importance of the emerged period of Ae. aegypti eggs as a critical time for the size of future adults, and point to the relative humidity as the likely selecting factor.
尽管埃及伊蚊（Linnaeus）的成人体型存在变异性，且这种变异性可能与其生活史和媒介效能有关，但体型变化本身的原因仅部分得到确认。特别是，一些可能很重要的因素，如气候变异，尚未得到太多关注。本为期 2 年的研究目的是描述从实地采集的埃及伊蚊度量特征与现有气候数据之间的关系。该研究在泰国一个登革热高度流行区进行。从同一滋生地采集四龄幼虫（L(4)）和蛹，以便进行 7 次连续采集（2007 年 4 次，2008 年 3 次）之间的比较。气候数据为相对湿度（RH）和温度（T）。这些数据被认为是涵盖前蛹期发育或（假设体型具有遗传性）上一代的时期。前蛹期进一步细分为胚胎期和幼虫期发育阶段。体型通过传统和几何技术进行估算，后者基于在脉交叉处采集的 18 个标志点，也可以估算形状。翅膀的形状变化与体型相似，表现为被动的异速生长变化。未发现体型或形状与 T 有显著相关性。相反，在两个检查期发现与 RH 有显著相关性：(i) 影响到收集时间前一代的时期，表明可能对亲代存在选择机制；(ii) 发生在前蛹期发育期间。将后者细分为胚胎期和幼虫期发育阶段，可能证明对胚胎发育存在选择效应。这种选择可能通过已知依赖于表皮的相对表面积的失水抵抗力来发挥作用。总之，我们的数据强调了埃及伊蚊卵出蛹期作为未来成虫体型的关键时间的重要性，并指出相对湿度可能是选择因素。
