美洲斑潜蝇发生的物候学模型

Stochastic model of vegetable leafminer Liromyza sativae Blanchard (Diptera: Agromyzidae) phenology

对美洲斑潜蝇各虫态发育与温度的关系的系统了解是利用寄生蜂防治斑潜蝇的关键。以花斑芸豆(Phaseolusvulgaris L.)为寄主 ,在 1 3、1 6、1 9、2 2、2 5、2 8、31、34℃ ,± 0 .5℃等温度下确定了美洲斑潜蝇的发育起点温度和有效积温。以 9.5℃为起点温度 ,建立了描述各虫态进程的物候学随机模型。结果表明 :各虫态占 50 %的种群数量时的有效积温量分别为 ,卵 46.97日度 ,幼虫 1 0 6.97日度 ,蛹 2 53.58日度。幼虫高峰期的积温为 75日度左右。化蛹积温在 90～ 1 2 0日度之间。成虫在 2 0 0日度开始羽化 ,30 0日度时全部个体基本羽化完成。蛹期的积温量与卵和幼虫的积温量之和相近。该模型能够很好地描述温室中变温条件下的美洲斑潜蝇种群动态过程 ,更有利于开展寄生蜂与美洲斑潜蝇之间关系的研究。

Knowledge of the temperature-dependent development of each stadium of the leafminer, Liromyza sativae Blanchard, is of crucial importance to the biological control of this pest using parasitoids. In this st udy, low developmental threshold temperatures, effective cumulative degree-days and developmental times of the leafminer were determined at constant temperatur es of 13℃、16℃、19℃、22℃、25℃、28℃、31℃、34℃，±0.5℃ on color bean P haseolus vulgaris. Developmental rates of each stadium of the leafminer increased linearly with tem perature up to 34℃ (r>0.97). More than 90% of the variation in the develop mental rate of each stadium was explained by temperature. Linear regression equa tions for developmental rates of eggs, larvae, pupae and all immature stages wer e y egg=－0.14674+0.017029t (r=0.9914), y larva=-0.166 79+0.017427t (r=0.9826), y pupa=-0.05759+0.008622t (r=0.97 50), y all immature stages=-0.03333+0.003675t (r=0.9854) respect ively. The low developmental threshold temperature (LDT) and effective acc umulated degree-days (DD) of each stadium were 8.62℃ and 58.72DD for the egg stage, 9.57℃ and 57.38DD for the larval stage, 8.98℃ and 155.98DD for the pupal stage, 9.07℃ and 272.09DD for all immature stages. The developmental t ime of eggs, larvae, pupae and all immature stages decreased from 13.15d to 2. 39d, 16.4d to 2.59d, 40.50d to 6.96d and 70.05d to 11.96d respectively as temperature increased from 13℃ to 34℃. The developmental time of eggs and larv ae was approximately equal to that of pupae. The phenology model described by Dennis et al. was used to develop a stochastic phenology model for L. sativae. The function was:P-i=Pr ［a i-1<S(t-j)≤a i］=1e In the L. sativae model, stage 1 was eggs, stage 2 larvae and stage 3 pupae. As pointed out by Dennis and Kemp, the parameter a i can be interpreted as the time (in degree-days) when only one-half of the popul ation is in stage i or below. Because the lower developmental threshold temperat ures (LDTs) of each stadium determined by linear regression were ranged from 8. 62℃ to 9.57℃, the LDT of 9.5℃ was used to calculate the degree-days of each stadium. The parameters of the model were estimated using the Nonlinear Regress ion and Least-Squares method of the STAT program. The model predicted t hat 50% of the population would advance beyond the egg, larval and pupal stages by 4 6.97, 106.97 and 253.58 DD respectively. The peak of the larval population sh ould occur at 75 DD. Third instar larvae should emerge from leaves between 90 DD and 120 DD and adults complete eclosion from 200 DD to 300 DD. The parameters e stimated using this stochastic phenology model were applied successfully to dete rmine the temperatures required to advance a particular stadium at a given time, and to simulate the process of population dynamics, thereby facilitating experi ments examining the interactions of parasitoids with each larval stage.