《环境昆虫学报》

昆虫触角表面密布各种类型的感器，感器的形态、功能、数量及分布模式反映了触角作为信号接收器官所承受的进化压力。作为榕属Ficus spp.植物的专性传粉昆虫，传粉榕小蜂的触角形态不仅受系统发育保守性（phylogenetic conservatism）的限制，而且被寄主特征塑造。本研究利用扫描电子显微镜技术，对来自不同属的菩提树传粉榕小蜂Platyscapa quadraticeps和壶托榕传粉榕小蜂Blastophaga sp.的触角感器进行了比较。结果表明，Blastophaga sp.和P. quadraticeps的触角总长分别为791.94 3.04 μm和672.83 5.22 μm，差异显著。其触角均呈膝状弯曲，由柄节、梗节和鞭节组成。柄节均呈三锥面体状，梗节均呈椭圆状，鞭节由特化的脊骨突、索节和棒节组成。两种榕小蜂触角上均着生有：波氏鬃毛（BB）、毛型感器（TS）、角锥型感器（OS）、刺型感器（CHS）、栓锥型乳突感器（BCPS）、锥型感器（BS）、多孔板型感器（MPS）7类感器。其中CHS-Ⅱ和BCPS-Ⅱ仅存在于Blastophaga sp.触角、MPS的亚型在P. quadraticeps触角上更为多样。两种榕小蜂的毛型感器和多孔板型感器的数量最多，占比超过50%。多孔板型感器在两种小蜂触角上覆盖面积最大，属于嗅觉感器。综上所述，虽然两种传粉榕小蜂触角的长度存在显著差异，但是整体形态相似。两种小蜂均具有脊骨凸和角锥型感器这一特化结构，该结构在榕小蜂进入榕果时具有撬起苞片，扩大通道的作用，属于榕小蜂科物种的同源性状。嗅觉感器在两种小蜂触角表面数量较多、覆盖面积最大的，表明接收气味信号是榕小蜂触角最主要的功能。这两种小蜂触角形态的比较支持稳定选择假设，因此在触角形态上表现出系统发育保守性。

英文摘要:

The surface of insect antennae is densely covered with various types of sensillae. The morphology, function, quantity, and arrangement of these sensillae reflect the evolutionary history and the ongoing selection on the antennae as signal-receiving organs. In the specialized pollinating insects of Ficus species, the antenna morphology of is constrained by phylogenetic conservatism but also shaped by host traits. In this study, we used scanning electron microscopy to compare the antennal sensillae and morphology of pollinating fig wasps from different genera: Platyscapa quadraticeps from Ficus religiosa and Blastophaga sp. from Ficus ischnopoda. The total antenna length of Blastophaga sp. and P. quadraticeps was 791.94 ± 3.04 μm and 672.83 ± 5.22 μm, respectively, with a significant difference. Both antennae were geniculate, consisting of the scape, pedicel, and flagellum. The scape was triconical, the pedicel was elliptical, and the flagellum was composed of the hook-shaped apical projection, a funicle, and a clava. On the antennae of both wasps, seven types of sensilla were identified: B?hm's bristles (BB), trichodea sensilla (TS), obscura sensilla (OS), chaetica sensilla (CHS), basiconic capitate peg sensilla (BCPS), basiconica sensilla (BS), and multiporous placoid sensilla (MPS). Among these, TS and MPS were the most abundant, representing over 50% of the sensillae. MPS are olfactory sensillae, and they covered the largest surface area of the antennae of both wasp species. In summary, although there were significant differences in antenna length between the two species of pollinating fig wasps, their overall morphology was similar. Both species possessed specialized structures such as the hook-shaped apical projection and basiconic sensillae. The modified third antennal segment is used by the wasp to lift the apical bracts of the fig and facilitate the wasp’s entry into the fig cavity. This modified third antennal segment is a synapomorphy of Agaonidae. For both species, olfactory sensilla were the most numerous sensilla and covered. Clearly, odor perception is the primary function of fig wasp antennae. The comparison of antenna morphology between these two distantly related species supports the hypothesis of stabilizing selection, and hence phylogenetic conservatism on antenna morphology.

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