Erdei Anna Laura, Szelényi Magdolna Olívia, Deutsch Ferenc, Kiss Balázs, Molnár Béla Péter
Department of Plant Protection Biology, Chemical Ecology Unit, Swedish University of Agricultural Sciences, 23422, Lomma, Sweden.
Department of Chemical Ecology, Plant Protection Institute, HUN-REN Centre for Agricultural Research, Matronvásár, Hungary.
Parasit Vectors. 2025 Jun 2;18(1):204. doi: 10.1186/s13071-025-06850-8.
The variegated fruit fly, Phortica variegata (Drosophilidae: Steganinae), is native to Europe and has emerged as a major vector of ocular nematosis caused by Thelazia callipaeda (Rhabditida: Thelaziidae), following the its introduction into Europe from Asia. Male P. variegata transmit these nematodes by feeding on tears of mammals, including wild and domestic carnivores (foxes, beech martens, wild cats, and dogs), lagomorphs, and humans. Understanding the olfactory responses of P. variegata to volatile cues is essential for developing attractant-based surveillance and control strategies, yet its olfactory ecology remains largely unexplored.
We used gas chromatography coupled electroantennography to measure antennal responses to synthetic and natural volatile blends. A comparative analysis was performed on the antennal responses of both sexes of P. variegata and its well-studied relative, Drosophila melanogaster. Components of the synthetic blends were selected based on the odorant receptor repertoire of D. melanogaster and established mosquito attractants, with the rationale that conserved olfactory receptors among dipterans may allow P. variegata to detect similar compounds. Volatile extracts collected using active carbon adsorbent traps were also tested on the antennae and analyzed using gas chromatography coupled mass spectrometry.
Male P. variegata showed higher antennal responses to phenol, 3-octanone, and sulcatone than females, indicating olfactory sexual dimorphism. Compared to D. melanogaster, the antennae of P. variegata did not respond to several common plant alcohols and terpenoids. Instead, they showed stronger responses to compounds such as anisole, ethyl propanoate, butyl propanoate, propyl acetate, 3-octanone, nonanal, and decanal, suggesting that peripheral olfaction in P. variegata may be more tuned to microbial volatiles.
Phortica variegata exhibits sexual dimorphism in olfactory responsivity, with males showing greater responsiveness to volatiles associated with host-seeking in other zoophilic dipterans, potentially guiding them to mammalian hosts for tear-feeding. Compared to D. melanogaster, P. variegata is more responsive to microbial and yeast-related volatiles and less responsive to plant-derived terpenoids, suggesting a foraging ecology linked to microbial substrates. The antennally detected volatiles identified in this study can be used as candidates for further behavioral studies to develop lures for vector management.
杂色果蝇（Phortica variegata，果蝇科：Steganinae亚科）原产于欧洲，自从亚洲引入欧洲后，已成为由结膜吸吮线虫（Thelazia callipaeda，小杆目：吸吮科）引起的眼部线虫病的主要传播媒介。雄性杂色果蝇通过吸食包括野生和家养食肉动物（狐狸、石貂、野猫和狗）、兔形目动物以及人类在内的哺乳动物的眼泪来传播这些线虫。了解杂色果蝇对挥发性线索的嗅觉反应对于制定基于引诱剂的监测和控制策略至关重要，但其嗅觉生态学在很大程度上仍未得到探索。
我们使用气相色谱-触角电位联用技术来测量触角对合成和天然挥发性混合物的反应。对杂色果蝇两性及其研究充分的近亲黑腹果蝇（Drosophila melanogaster）的触角反应进行了比较分析。基于黑腹果蝇的气味受体库和已确定的蚊子引诱剂来选择合成混合物的成分，理由是双翅目昆虫中保守的嗅觉受体可能使杂色果蝇能够检测到类似的化合物。还使用活性炭吸附阱收集的挥发性提取物对触角进行了测试，并通过气相色谱-质谱联用技术进行了分析。
雄性杂色果蝇对苯酚、3-辛酮和苏卡酮的触角反应高于雌性，表明存在嗅觉性二态性。与黑腹果蝇相比，杂色果蝇的触角对几种常见的植物醇和萜类化合物没有反应。相反，它们对诸如苯甲醚、丙酸乙酯、丙酸丁酯、乙酸丙酯、3-辛酮、壬醛和癸醛等化合物表现出更强的反应，这表明杂色果蝇的外周嗅觉可能更适应微生物挥发性物质。
杂色果蝇在嗅觉反应性方面表现出性二态性，雄性对与其他嗜动物性双翅目昆虫寻找宿主相关的挥发性物质反应更强，这可能引导它们找到哺乳动物宿主以吸食眼泪。与黑腹果蝇相比，杂色果蝇对微生物和酵母相关的挥发性物质反应更强，对植物衍生的萜类化合物反应较弱，这表明其觅食生态学与微生物底物有关。本研究中通过触角检测到的挥发性物质可作为进一步行为研究的候选物，以开发用于媒介管理的引诱剂。
