Menu F, Debouzie D
URA CNRS 243, Biométrie, Génétique et Biologie des Populations, Université Claude Bernard Lyon I, 43, bd du 11 novembre 1918, 69622, Villeurbanne Cedex, France.
Oecologia. 1993 Mar;93(3):367-373. doi: 10.1007/BF00317880.
Spreading of emergence over several years due to prolonged diapause in some larvae was shown in the chestnut weevil. Depending on the year the larvae buried themselves in the ground, 32-56% of live adults emerged after 2 or 3 years of underground life. Variability in the duration of diapause was assumed to correspond to tactics of adaptative "coin-flipping" plasticity. This plasticity must allow the chestnut weevil to respond to the unpredictability of its habitat as measured by the irregularity of chestnut production and summer drought. Indeed, fecundity and adult longevity did not lessen after 2 years of underground life. No drastic decrease in the population size of weevils occurs after bad years; for instance when the number of chestnuts on the study tree is less than 10 000, passers-by can collect all the fruit and about 95% of larvae developing in chestnuts are destroyed. Diapause nature (simple or prolonged) may be related to moisture and gas rates in the ground from October to December. These factors acting in autumn are not known to be involved in the physiological mechanisms that control the production of chestnuts.
在栗象中发现，由于一些幼虫的滞育期延长，羽化会持续数年。根据幼虫埋入地下的年份不同，经过2至3年的地下生活后，有32%至56%的存活成虫会羽化。滞育期持续时间的变异性被认为与适应性“抛硬币”可塑性策略相对应。这种可塑性必须使栗象能够应对其栖息地的不可预测性，这种不可预测性通过栗子产量的不稳定性和夏季干旱来衡量。事实上，经过2年的地下生活后，繁殖力和成虫寿命并没有降低。歉收年份后象鼻虫的种群数量不会急剧减少；例如，当研究树上的栗子数量少于10000个时，路人可以收集所有果实，大约95%在栗子中发育的幼虫会被消灭。滞育的性质（简单滞育或长期滞育）可能与10月至12月地面的湿度和气体含量有关。目前尚不清楚这些在秋季起作用的因素是否参与控制栗子产量的生理机制。
