Laboratory of Entomology, Nature Research Centre, Vilnius, Lithuania.
Life Science Center, Vilnius University, Vilnius, Lithuania.
Med Vet Entomol. 2024 Dec;38(4):530-541. doi: 10.1111/mve.12752. Epub 2024 Aug 16.
Investigations of host feeding behaviour in haematophagous insects are critical to assess transmission routes of vector-borne diseases. Understanding if a certain species has ornithophilic or mammalophilic feeding behaviour can facilitate future studies focused on pathogens transmission to and from certain host species. Culicoides Latreille (Diptera: Ceratopogonidae) are vectors of several pathogens, which include arboviruses, bacteria and parasites to a considerable diversity of vertebrate hosts. However, most of the studies focused on feeding habits target Culicoides species that could transmit the Bluetongue virus, consequently with a mammalophilic feeding behaviour, leaving aside the Culicoides species that are involved in the transmission of vector-borne parasites to birds, such as Haemoproteus Kruse (Haemosporida: Haemoproteidae). This study aimed to investigate the source of blood meals of wild-caught Culicoides using molecular-based methods and to correlate our findings with the reports of Haemoproteus parasites in Culicoides species. Engorged Culicoides females were collected using ultraviolet (UV)-light traps at seven different localities in Lithuania in 2021-2023. Biting midges were dissected, and the abdomens of engorged females were used for molecular investigation of the blood meal source. A polymerase chain reaction (PCR) protocol that amplifies a fragment of the Cytochrome B gene of vertebrates was used. Obtained sequences were compared to available information in GenBank database to confirm the source of the blood meal. In total, 258 engorged Culicoides females, representing nine different species, were analysed. The source of blood meal was identified in 29.1% of them with most of the insects having fed on birds (74.7%) and the remaining on mammals (25.3%). Culicoides segnis Campbell, Pelham-Clinton was the only species to feed exclusively on birds; Culicoides from the Obsoletus group, C. pallidicornis Kieffer and C. punctatus Latreille were found to feed exclusively on mammals; C. festivipennis Kieffer, C. kibunensis Tokunaga and C. pictipennis Staeger had an opportunistic feeding behaviour, with the first two preferably feeding on birds. Due to their feeding behaviour and the presence of Haemoproteus parasites reported in the literature, C. festivipennis, C. kibunensis, C. pictipennis, and C. segnis play an important role in the transmission of those avian vector-borne parasite in the wild. These Culicoides species were already confirmed as being able to support the development of several Haemoproteus species and lineages. Future studies focused on understanding the epidemiology of avian pathogens transmitted by Culicoides should target these species.
在吸血昆虫中研究宿主的取食行为对于评估媒介传播疾病的传播途径至关重要。了解特定物种是否具有嗜鸟性或嗜血性取食行为，可以促进未来针对特定宿主物种传播病原体的研究。库蠓属（Latreille）（双翅目：蠓科）是多种病原体的媒介，包括虫媒病毒、细菌和寄生虫，可传播给相当多的脊椎动物宿主。然而，大多数针对取食习性的研究都针对可能传播蓝舌病病毒的库蠓属物种，这些物种具有嗜血性取食行为，而忽略了参与传播鸟类媒介寄生虫的库蠓属物种，例如疟原虫（Haemosporida：疟原虫科）。本研究旨在使用基于分子的方法调查野外捕获的库蠓属吸血昆虫的血液来源，并将我们的发现与库蠓属中疟原虫寄生虫的报告相关联。2021-2023 年期间，在立陶宛的七个不同地点使用紫外线（UV）灯陷阱收集了吸血的库蠓属雌性。对饱食的库蠓属雌性进行解剖，并用分子方法检测其腹部的血液来源。使用聚合酶链反应（PCR）方案扩增脊椎动物细胞色素 B 基因的一个片段。将获得的序列与 GenBank 数据库中的可用信息进行比较，以确认血液来源。总共分析了 258 只饱食的库蠓属雌性，代表九个不同的物种。其中 29.1%的昆虫血液来源被鉴定出来，其中大多数昆虫以鸟类（74.7%）为食，其余以哺乳动物（25.3%）为食。坎贝尔、佩勒姆-克林顿库蠓属是唯一一种专门以鸟类为食的物种；属于 Obsoletus 组的库蠓属、C. pallidicornis Kieffer 和 C. punctatus Latreille 被发现专门以哺乳动物为食；C. festivipennis Kieffer、C. kibunensis Tokunaga 和 C. pictipennis Staeger 具有机会性取食行为，前两种更喜欢以鸟类为食。由于其取食行为以及文献中报道的疟原虫寄生虫的存在，C. festivipennis、C. kibunensis、C. pictipennis 和 C. segnis 在野生环境中传播那些禽媒寄生虫方面发挥着重要作用。这些库蠓属物种已被证实能够支持多种疟原虫的发育和谱系。未来针对理解库蠓属传播的禽病流行病学的研究应针对这些物种。
