Bee Protection Laboratory, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand.
Graduate School, Chiang Mai University, Chiang Mai, 50200, Thailand.
Sci Rep. 2019 Sep 10;9(1):13044. doi: 10.1038/s41598-019-49662-4.
Tropilaelaps mercedesae parasitism can cause Apis mellifera colony mortality in Asia. Here, we report for the first time that tropilaelaps mites feed on both pre- and post-capped stages of honey bees. Feeding on pre-capped brood may extend their survival outside capped brood cells, especially in areas where brood production is year-round. In this study, we examined the types of injury inflicted by tropilaelaps mites on different stages of honey bees, the survival of adult honey bees, and level of honey bee viruses in 4 instar larvae and prepupae. The injuries inflicted on different developing honey bee stages were visualised by staining with trypan blue. Among pre-capped stages, 4 instar larvae sustained the highest number of wounds (4.6 ± 0.5/larva) while 2-3 larval instars had at least two wounds. Consequently, wounds were evident on uninfested capped brood (5-6 instar larvae = 3.91 ± 0.64 wounds; prepupae = 5.25 ± 0.73 wounds). Tropilaelaps mite infestations resulted in 3.4- and 6-fold increases in the number of wounds in 5-6 instar larvae and prepupae as compared to uninfested capped brood, respectively. When wound-inflicted prepupae metamorphosed to white-eyed pupae, all wound scars disappeared with the exuviae. This healing of wounds contributed to the reduction of the number of wounds (≤10) observed on the different pupal stages. Transmission of mite-borne virus such as Deformed Wing Virus (DWV) was also enhanced by mites feeding on early larval stages. DWV and Black Queen Cell Virus (BQCV) were detected in all 4 instar larvae and prepupae analysed. However, viral levels were more pronounced in scarred 4 instar larvae and infested prepupae. The remarkably high numbers of wounds and viral load on scarred or infested developing honey bees may have caused significant weight loss and extensive injuries observed on the abdomen, wings, legs, proboscis and antennae of adult honey bees. Together, the survival of infested honey bees was significantly compromised. This study demonstrates the ability of tropilaelaps mites to inflict profound damage on A. mellifera hosts. Effective management approaches need to be developed to mitigate tropilaelaps mite problems.
嗜蜂副珠带实蝇的寄生会导致亚洲的蜜蜂死亡。在这里，我们首次报告称，嗜蜂副珠带实蝇会取食未封盖和已封盖的蜜蜂幼虫。取食未封盖的幼虫可能会延长它们在封盖幼虫巢房外的存活时间，尤其是在全年都有幼虫生产的地区。在这项研究中，我们研究了嗜蜂副珠带实蝇对不同发育阶段的蜜蜂造成的伤害类型、成年蜜蜂的存活率以及 4 龄幼虫和预蛹中蜜蜂病毒的水平。通过用台盼蓝染色可以观察到不同发育阶段的蜜蜂所受到的伤害。在未封盖的幼虫中，4 龄幼虫受到的创伤最多（每头幼虫 4.6 ± 0.5 个伤口），而 2-3 龄幼虫至少有两个伤口。因此，未受感染的封盖幼虫上也有明显的创伤（5-6 龄幼虫 = 3.91 ± 0.64 个伤口；预蛹 = 5.25 ± 0.73 个伤口）。与未受感染的封盖幼虫相比，嗜蜂副珠带实蝇的感染使 5-6 龄幼虫和预蛹中的创伤数量分别增加了 3.4 倍和 6 倍。当受伤的预蛹变态为白眼蛹时，所有的伤口痕迹都随着蜕皮而消失。这种伤口的愈合导致在不同的蛹阶段观察到的伤口数量减少（≤10 个）。螨虫取食早期幼虫阶段也会促进螨虫传播的病毒，如变形翅膀病毒（DWV）。在分析的所有 4 龄幼虫和预蛹中都检测到了 DWV 和黑皇后细胞病毒（BQCV）。然而，在有疤痕的 4 龄幼虫和受感染的预蛹中，病毒水平更为显著。在有疤痕或受感染的发育中的蜜蜂上，创伤数量和病毒载量非常高，这可能导致在成年蜜蜂的腹部、翅膀、腿部、喙和触角上观察到明显的体重减轻和广泛的损伤。受感染的蜜蜂的存活率因此显著降低。本研究表明，嗜蜂副珠带实蝇能够对 A. mellifera 宿主造成严重的伤害。需要开发有效的管理方法来减轻嗜蜂副珠带实蝇的问题。
