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【目的】荔枝蒂蛀虫Conopomorpha sinensis Bradley是荔枝龙眼上的主要害虫,以幼虫蛀果为害。本研究旨在明确荔枝蒂蛀虫幼虫龄数及不同温度下各虫态和各龄幼虫的发育历期,为该虫发生规律、预测预报和防控技术研究提供基础生物学数据。【方法】定期收集处于不同发育时期的荔枝蒂蛀虫幼虫,测量幼虫头壳宽度,对其进行频次分析,Crosby指数验证和曲线回归分析,以确定幼虫龄数。通过室内群体饲养的方法,测定了17~38℃区间8个温度梯度下荔枝蒂蛀虫各虫态和各龄幼虫的发育历期,并采用线性日度模型对其发育速率与温度的关系进行回归分析。【结果】根据荔枝蒂蛀虫幼虫头壳宽度频次分布图,其头壳宽度的频次分布可明显分为5个区域,说明其幼虫分5个龄期,符合Dyar定律。1-5龄幼虫的头壳宽度分别为:0.092~0.120,0.140~0.206,0.217~0.319,0.356~0.523和0.582~0.728 mm。温度对荔枝蒂蛀虫卵、各龄幼虫和蛹的发育历期有明显影响,其发育历期均随温度的升高而缩短,其发育速率均与温度呈显著正相关,并符合线性回归模型。在20~32℃,荔枝蒂蛀虫可完成世代发育;在17℃时,该虫只能发育至3龄幼虫;在35℃时,蛹多不能羽化;在38℃时,卵多不能孵化。在20~32℃,其世代历期为41.16~19.34 d,蛹期为12.74~5.38 d,而产卵前期为4.75~4.22 d,温度对产卵前期无明显影响。在20~35℃,荔枝蒂蛀虫幼虫可正常发育,其1龄幼虫龄期为4.50~1.17 d,2龄幼虫期为2.09~1.40 d,3龄幼虫期为2.84~1.00 d,4龄幼虫期为3.41~1.18 d,5龄幼虫期为3.00~1.37 d,预蛹期为2.41~0.69 d。在17~35℃,荔枝蒂蛀虫卵可正常孵化,其卵期为7.73~2.09 d。【结论】荔枝蒂蛀虫幼虫分5个龄期,不同于前人所报道的4个龄期。在20~32℃温度范围内,卵、各龄幼虫和蛹的发育历期均随温度升高而缩短。本研究结果有助于荔枝蒂蛀虫预测预报方案的制定和实施。
【Objective】 Conopomorpha sinensis Bradley is the major pest on litchi longan, which is harmful to larvae. The aim of this study was to determine the age of larvae and the developmental duration of larvae at various temperatures at different temperatures to provide the basic biological data for the occurrence, prediction and control of the larvae. 【Method】 Litchi borer larvae were collected regularly at different developmental stages. The larval head shell width was measured. Frequency analysis, Crosby index test and curve regression analysis were conducted to determine larval age. The developmental durations of larvae and their larvae of each litchi were determined by feeding in the indoor population at 8 temperature gradients in the range of 17 ~ 38 ℃. The linear daily model was used to regress the relationship between the developmental rate and temperature analysis. 【Result】 According to the frequency distribution of head shell width of litchi titers, the frequency distribution of the head shell width could be clearly divided into five regions, indicating that the larvae were divided into 5 stages and accorded with Dyar’s law. The first-instar larvae had a head-shell width of 0.092-0.120, 0.140-0.206, 0.217-0.319, 0.356-0.523 and 0.582-0.728 mm, respectively. Temperature had a significant effect on the developmental duration of litchi stemworm eggs, larvae and pupae of all instars, and their developmental durations were shortened with the increase of temperature. The developmental rates of them were positively correlated with temperature and in line with the linear regression model. At 20 ~ 32 ℃, lychee bumble bens can complete the development of the generation; at 17 ℃, the insects can only develop to third instar larvae; at 35 ℃, pupa can not be more than the emergence of; at 38 ℃, eggs can not hatch. At 20 ~ 32 ℃, the generational duration was 41.16 ~ 19.34 d, pupal stage was 12.74 ~ 5.38 d, while the pre-oviposition period was 4.75 ~ 4.22 d. The temperature had no significant effect on pre-oviposition. At 20 ~ 35 ℃, Litchi borer larvae could develop normally. The first instar larvae were 4.50-1.17 days, the second larvae 2.09-1.40 d, the third instar larvae 2.84-1.00 d, the fourth instar larvae From 3.41 to 1.18 days, from 3.00 to 1.37 days in the 5th instar larvae and from 2.41 to 0.69 days in the pre-pupal stage. At 17 ~ 35 ℃, litchi pedicel eggs can hatch properly, the egg period is 7.73 ~ 2.09 d. 【Conclusion】 Litchi peduncles larvae are divided into 5 stages, which is different from the 4 stages reported by our predecessors. In the temperature range of 20 ~ 32 ℃, the developmental stages of eggs, larvae and pupae of all instars all shortened with the increase of temperature. The results of this study contribute to the formulation and implementation of litchi pedicel forecasting program.