{"title":"Community structure of parasitoids attacking Schizomyia sasakii (Diptera: Cecidomyiidae) and local adaptation of the gall midge in the Izu region","authors":"Tomohisa Fujii, Kazunori Matsuo, Junichi Yukawa, Keizi Kiritani, Yoshihisa Abe, Makoto Tokuda","doi":"10.1111/ens.12576","DOIUrl":null,"url":null,"abstract":"<p>Insect community structures and biological interactions vary with the distance from the mainland to islands. Gall inducers are key organisms in local arthropod communities because their galls harbor diverse arthropods. We investigated the parasitoid community of a gall-inducing cecidomyiid <i>Schizomyia sasakii</i> on the Izu Peninsula and the Izu Islands, Japan. We examined relationships between parasitism by <i>Inostemma</i> sp. and <i>Torymus hirtipennis</i>, and gall characteristics, and analyzed the directional selection on gall characteristics induced by <i>S. sasakii</i> in each locality. The species richness of parasitoids on the Izu Islands decreased with the distance from the Izu Peninsula to each island, and area of respective islands. <i>Inostemma</i> sp. preferably attacked large galls on Ohshima Island, and <i>T</i>. <i>hirtipennis</i> tended to attack relatively small galls in the Izu Peninsula. Directional selection on gall characteristics of <i>S. sasakii</i> favored the induction of larger galls and thicker tissues by <i>S. sasakii</i> on Ohshima Island. In contrast, no directional selection was detected in the gall characteristics on Hachijojima Island. The number of alternative host species of parasitoid may affect variation in parasitoid richness of <i>S. sasakii</i> on distant and small islands, because the species richness of gall midges is necessary to maintain local parasitoid populations. Our study supported the ovipositor limitation hypothesis for the torymid species, related to gall size. The directional selection of parasitoid attacks on the Izu Islands may act to favor the induction of large and hypertrophic galls by <i>S. sasakii</i> to avoid the parasitoids.</p>","PeriodicalId":11745,"journal":{"name":"Entomological Science","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Entomological Science","FirstCategoryId":"97","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1111/ens.12576","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ENTOMOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Insect community structures and biological interactions vary with the distance from the mainland to islands. Gall inducers are key organisms in local arthropod communities because their galls harbor diverse arthropods. We investigated the parasitoid community of a gall-inducing cecidomyiid Schizomyia sasakii on the Izu Peninsula and the Izu Islands, Japan. We examined relationships between parasitism by Inostemma sp. and Torymus hirtipennis, and gall characteristics, and analyzed the directional selection on gall characteristics induced by S. sasakii in each locality. The species richness of parasitoids on the Izu Islands decreased with the distance from the Izu Peninsula to each island, and area of respective islands. Inostemma sp. preferably attacked large galls on Ohshima Island, and T. hirtipennis tended to attack relatively small galls in the Izu Peninsula. Directional selection on gall characteristics of S. sasakii favored the induction of larger galls and thicker tissues by S. sasakii on Ohshima Island. In contrast, no directional selection was detected in the gall characteristics on Hachijojima Island. The number of alternative host species of parasitoid may affect variation in parasitoid richness of S. sasakii on distant and small islands, because the species richness of gall midges is necessary to maintain local parasitoid populations. Our study supported the ovipositor limitation hypothesis for the torymid species, related to gall size. The directional selection of parasitoid attacks on the Izu Islands may act to favor the induction of large and hypertrophic galls by S. sasakii to avoid the parasitoids.
昆虫群落结构和生物之间的相互作用随大陆到岛屿的距离而变化。虫瘿诱导体是当地节肢动物群落中的关键生物,因为它们的虫瘿中栖息着多种节肢动物。我们调查了日本伊豆半岛和伊豆诸岛上的引胆虫Schizomyia sasakii的寄生虫群落。我们研究了寄生虫Inostemma sp.和Torymus hirtipennis与虫瘿特征之间的关系,并分析了S. sasakii在各地诱导虫瘿特征的定向选择。伊豆群岛上寄生虫的物种丰富度随着伊豆半岛到各岛屿的距离和各岛屿的面积而降低。在大岛,Inostemma sp.更喜欢攻击大的虫瘿,而在伊豆半岛,T. hirtipennis则倾向于攻击相对较小的虫瘿。对 S. sasakii虫瘿特征的定向选择有利于大岛 S. sasakii 诱导更大的虫瘿和更厚的组织。相比之下,八丈岛的虫瘿特征没有发现定向选择。寄生虫可供选择的寄主种类的数量可能会影响寄生虫丰富度的变化,因为瘿蚊种类的丰富度是维持当地寄生虫种群的必要条件。我们的研究支持与虫瘿大小有关的卵柄限制假说。伊豆群岛上寄生虫攻击的定向选择可能有利于诱导 S. sasakii 形成大而肥大的虫瘿,以躲避寄生虫的攻击。
期刊介绍:
Entomological Science is the official English language journal of the Entomological Society of Japan. The Journal publishes original research papers and reviews from any entomological discipline or from directly allied field in ecology, behavioral biology, physiology, biochemistry, development, genetics, systematics, morphology, evolution and general entomology. Papers of applied entomology will be considered for publication if they significantly advance in the field of entomological science in the opinion of the Editors and Editorial Board.