管氏肿腿蜂雌性抚育中幼虫转移行为的启动和节律

为深入理解肿腿蜂雌性抚育的行为学特征, 在室内连续观察了雌性管氏肿腿蜂Sclerodermus guani对子代幼虫的转移行为, 旨在明确雌蜂在子代蜂幼虫发育到哪一阶段时启动转移行为, 以及幼虫转移行为是否有节律。以黄粉虫Tenebrio militor蛹期在24 h内的蛹体为寄主, 根据子代蜂幼虫发育进程将其划分为低龄幼虫（1-2龄）、 高龄幼虫（3-4龄）、 老熟幼虫(自然脱落)和吐丝幼虫（开始吐丝结茧）等4个时期, 采取人工剥离（早期幼虫）或自然脱离（晚期幼虫）的方法处理子代蜂幼虫, 观察雌蜂对所表现出的行为反应; 然后以子代蜂高龄幼虫为对象, 连续观察雌蜂的30次幼虫转移行为过程。结果表明： 雌蜂对所有发育时期子代蜂幼虫均用触角拍打进行探测; 但不转移低龄幼虫, 只转移其他阶段幼虫, 转移老熟幼虫和吐丝幼虫的瞬间概率分别是转移高龄幼虫的4.09倍和7.69倍。雌蜂转移高龄、 老熟和吐丝幼虫的比例分别为96%, 100%和100%, 没有显著差异（P≥0.05）; 对高龄幼虫、 老熟幼虫和吐丝幼虫转移耗时平均分别为27.96, 34.04和32.49 s, 没有显著差异（P≥0.05）; 平均转移距离依次为4.19, 7.18和 9.43 mm, 对吐丝幼虫的转移距离显著大于高龄幼虫（P<0.05）, 但在高龄和老熟幼虫之间没有显著差异（P≥0.05）。对雌蜂连续30次幼虫转移行为的趋势和节律分析表明： 幼虫转移前探测的幼虫数总体上随幼虫转移次序增加而减少, 在间隔1次和2次之间存在显著自相关, 幼虫转移耗时在间隔1次之间存在显著自相关, 但幼虫转移距离未表现出明显的节律。本研究结果说明, 管氏肿腿蜂雌性抚育中的幼虫转移行为只在子代蜂幼虫发育到较高龄期时启动, 且幼虫转移中的某些行为特征具有节律性。

Changes in contents of the essential elements N, P, K and Ca in alfalfa organs damaged by Odontothrips loti (Thysanoptera: Thripidae)

In order to investigate the relationship between nutrient accumulation and distribution in plant organs and alfalfa resistance to thrips, changes in N, P, K and Ca contents in alfalfa organs of the resistant (R-1) and susceptible (I-1) strains to thrips were measured after alfalfa plants were infested by Odontothrips loti. The results showed that the N contents in R-1 and I-1 stems increased significantly while those in R-1 and I-1 leaves decreased significantly (P<0.05), the N content in I-1 roots decreased firstly and then increased while that in R-1 roots decreased all the time. The P content in R-1 stems increased firstly, and then decreased, and the changes in P content in I-1 stems were insignificant. The P content in R-1 leaves increased constantly under the lower density stress, and then decreased when alfalfa plants were infested by 7 adults/branch, while that in I-1 leaves decreased significantly. The P contents in R-1 and I-1 roots were significantly higher than that of the control significantly (P<0.05). The K contents in R-1 and I-1 increased firstly and then decreased both in leaves and stems, whereas that in roots decreased (P<0.05). The Ca contents in R-1 stems and leaves increased significantly after infestation (P<0.05), the changes in Ca content in roots were insignificant compared with the control. The Ca content in I-1 stems decreased firstly and then increased, that in leaves was significantly lower than that of the control when leaves were damaged by 7 adults/ branch, and that in roots was significantly lower than that of the control. Overall, the levels of essential elements in alfalfa under O. loti infestation varied with alfalfa variety, the damage index of R-1 was significantly lower than that of I-1 (P<0.01), and R-1 showed stronger insect resistance.