The braconid wasp, Diachasmimorpha longicaudata (Ashmead), was introduced in Kenya from Hawaii for classical biological control of the invasive tephritid, Bactrocera dorsalis Hendel. Following reports that D. longicaudata had formed new associations with Ceratitis cosyra, laboratory experiments were conducted to assess the interaction between the introduced and the native parasitoid of C. cosyra; Psyttalia cosyrae (Wilkinson) under three scenarios: B. dorsalis only, C. cosyra only and mixed populations of the two species. Parasitoids were introduced to the host as sole, sequential and simultaneous releases. Host searching and probing events were five times higher for D. longicaudata than P. cosyrae with both hosts. Total parasitism was highest (78%) when D. longicaudata was released alone on C. cosyra, compared to 20% for P. cosyrae released on the same host. Releases of P. cosyrae on B. dorsalis resulted in 0% parasitism, compared to 64% parasitism by D. longicaudata. Specific parasitism for P. cosyrae was three times higher when P. cosyrae was released first in sequential releases on C. cosyra compared to when it was released after D. longicaudata. These findings suggest that the two parasitoids can both suppress C. cosyra but B. dorsalis acts as a reproductive sink for P. cosyrae. Our findings should form the basis of field investigations where options are much wider for both parasitoids.

中文翻译：

---

实验室条件下实蝇科两种寄生蜂：Diachasmimorpha longicaudata (Ashmead) 和 Psyttalia cosyrae (Wilkinson)（膜翅目：茧蜂科）之间的相互作用

茧蜂Diachasmimorpha longicaudata (Ashmead) 是从夏威夷引入肯尼亚的，用于对入侵性实蝇（ Bactrocera dorsalis Hendel）进行经典生物防治。继有报告称D. longicaudata与Ceratitis cosyra形成了新的关联后，进行了实验室实验以评估引进的C. cosyra寄生蜂与本地寄生蜂之间的相互作用；三种情况下的Psyttalia cosyrae (Wilkinson)：仅B. dorsalis 、仅C. cosyra以及两个物种的混合种群。拟寄生物以单独、顺序和同时释放的方式引入宿主。对于两种寄主， D. longicaudata的寄主搜索和探测事件比P. cosyrae高五倍。当D. longicaudata单独释放到C. cosyra上时，总寄生率最高 (78%) ，而P. cosyrae释放到同一宿主上时，总寄生率为 20%。将P. cosyrae释放到B. dorsalis上导致 0% 的寄生，而D. longicaudata的寄生率为 64% 。当P. cosyra在C. cosyra上连续释放时， P. cosyrae的特异性寄生比在D. longicaudata之后释放时高出三倍。这些发现表明，两种寄生蜂都能抑制C. cosyra，但B. dorsalis充当P. cosyra的繁殖库。我们的发现应该构成实地调查的基础，对于这两种寄生蜂来说，选择范围要广泛得多。