以黑腹果蝇为寄主的蝇蛹金小蜂生长发育、繁殖及功能反应研究

蝇蛹金小蜂是铃木氏果蝇和黑腹果蝇的重要天敌,本研究以黑腹果蝇为寄主,测定了蝇蛹金小蜂云南种群的生长发育、繁殖及寿命。并在6个寄主密度梯度条件下研究了其寄生功能反应。结果显示蝇蛹金小蜂从卵到雌、雄成蜂的平均发育历期分别为16.10 d和14.67 d,雌蜂平均寿命为49.76 d,平均产子代数为93.28头/雌,子代雌性比为55.76%。在黑腹果蝇蛹为5、10、15、20、25和30头的密度梯度下,蝇蛹金小蜂的寄生功能反应符合Holling Ⅱ模型,其方程为Na=0.6261 No/(1+0.0632 No)。理论最高寄生量为N_a_(max)=9.0171,实际最高寄生量为7.00头(寄主密度为20头),蝇蛹金小蜂的寄生搜寻效应随寄主密度的增加而降低。综上结果,采自杨梅的蝇蛹金小蜂以黑腹果蝇作为寄主时具有较高繁殖力,较强的寄主适合度,是铃木氏果蝇和黑腹果蝇有效的生物防治作用因子。     

蝇蛹金小蜂对桔小实蝇蛹的寄生功能反应

在温度25±1℃、相对湿度70±5%、光照周期（L∶D）14 h∶10 h条件下,研究了蝇蛹金小蜂对桔小实蝇蛹的寄生功能反应及干扰效应。结果表明,寄主密度、寄主日龄均影响寄生蜂的寄生效能。蝇蛹金小蜂对桔小实蝇2日龄（N=2）、4日龄（N=4）蛹的寄生功能反应均符合HollingⅡ模型,其方程分别为Na= 0.4494N2/ (1+ 0.0294N2)、Na= 0.5586N4/ (1+ 0.0253N4)。24h内单头雌成蜂最多可寄生2日龄、4日龄蝇蛹数量分别为15.29、22.08头。自身密度对蝇蛹金小蜂寄生产生一定的干扰效应,其干扰效应符合Hassell－Varley模型（a= 0.0719P－0.2526）,表明蝇蛹金小蜂雌蜂的发现域随着自身密度的增加而逐渐变小,雌蜂个体间干扰效应降低了寄生效能。     

Can competition be superior to parasitism for biological control? The case of spotted wing Drosophila (Drosophila suzukii), Drosophila melanogaster and Pachycrepoideus vindemmiae

Drosophila suzukii and Drosophila melanogaster coexist with different but overlapping resource use in the field. When forced to completely or partially share resources in the laboratory, D. melanogaster outcompetes D. suzukii. Adult D. suzukii and D. melanogaster females were allowed to compete for access to a common oviposition resource in pairwise and population scale experiments. We tracked the offspring emergence to explore the factors across life stages that might affect the success of D. suzukii in the laboratory compared to a closed field simulation cage experiment with a generalist Drosophila parasitoid, Pachycrepoideous vindemmiae. When in competition as adults, D. melanogaster produced more offspring that survived to pupation than D. suzukii. In addition, D. melanogaster produced more offspring when in competition with a conspecific than when in competition with D. suzukii. Competitor identity did not affect the number of D. melanogaster offspring in pairwise and cage experiments. However, in the presence of D. melanogaster, the number of D. suzukii offspring in both pairwise and cage experiments was dramatically reduced than in cages without this competitor. In the presence of both D. melanogaster and P. vindemmiae, there were marginally more D. suzukii than when only D. melanogaster was present. These results suggest that competition was an important factor limiting D. suzukii numbers. Limiting D. suzukii numbers through interspecies competition may eventually be an exploitable method of biocontrol in the field.     

昆虫取食和药剂熏蒸对马尾松针叶脱落酸和茉莉酸含量的影响

脱落酸(ABA)和茉莉酸(JA)在诱导植物产生抗逆性过程中具有重要作用.以马尾松为试验材料,用GC/MS检测了马尾松毛虫咬食、外源茉莉酸甲酯(MeJA)熏蒸和萜烯混合物熏蒸处理4 h后,马尾松损伤针叶、相邻姊妹针叶(处理同一轮未受损伤枝条)、系统上枝针叶(处理枝上一轮枝条)和系统下枝针叶(处理枝下一轮枝条)中ABA和JA含量的变化.结果表明,虫害4 h后,马尾松损伤针叶、相邻姊妹针叶、系统上枝针叶和系统下枝针叶的ABA和JA含量均明显升高.用10 μmol·L^-1 MeJA熏蒸和10 μmol·L^-1萜烯混合物熏蒸健康植株后,各部位枝条针叶中ABA和JA含量明显升高.说明ABA和JA是马尾松苗木伤反应信号传导途径中的重要信号分子,参与了马尾松苗木系统抗性的形成过程.     

蝇蛹金小蜂生物学特性研究

蝇蛹金小蜂Pachycrepoideus vindemmiae（Rondani）是家蝇Musca domestica I的重要天敌之一。本文研究了温度为25±1qC,相对湿度RH70±5％,光照L：D=14：10的环境下,蝇蛹金小蜂发育各阶段的主要形态特征;蝇蛹金小蜂的发育历期（从卵到成蜂羽化、产卵）是15．7d;一天中,蝇蛹金小蜂羽化主要在12点以前,高峰期是早上8～10点。     

Effect of expected offspring survival probability on host selection in a solitary parasitoid

Optimal Foraging Theory predicts that parasitoid females should optimize their host selection to maximize their lifetime fitness gain and parasitize the most profitable hosts. In particular, in solitary parasitoids, females should avoid superparasitism, at least when sufficient unparasitized hosts are available. However, when unparasitized hosts are scarce, they should prefer, among already parasitized hosts, those that provide the best survival probability to their progeny, which depends on the age and the developmental stage of the first parasitoid. To test this hypothesis in a solitary ectoparasitoid, Pachycrepoideus vindemmiae Rondani (Hymenoptera: Pteromalidae), we first assessed the survival probability of a second parasitoid according to the time elapsed since initial parasitism. We then analyzed the female selection behavior in patches containing a mixture of hosts parasitized over various time intervals. Our results showed that the older the opponent larva was, the lower the survival probability of the second parasitoid was. However, when the first individual had reached the prepupal stage, both individuals could complete their development. At this stage, the survival probability of the second parasitoid was surprisingly high but such individuals were reduced in size. Our study also showed that host acceptance by females was strongly correlated with the survival probability of their progeny when the first parasitoid was from 0 to less than 10 days‐old. When the first parasitoid had reached the prepupal stage, females usually rejected these hosts, although the survival probability of the offspring was quite high. This discordance between female host selection behavior and progeny survival probability is discussed.