Insect galls of the Reserva Biológica União, Rio de Janeiro, Brazil

Abstract: Several inventories of insect galls have been performed in the Atlantic Forest of Rio de Janeiro, mostly in restingas, whereas the other phytophysiognomies remain poorly sampled. The present study inventoried the insect galls of Reserva Biológica União (RJ), a protected area comprising mainly Ombrophilous Forest. Field work was performed every two months from January to October, 2013. Insect galls were collected, photographed, characterized and transported to the laboratory. Adults were obtained by rearing and immature stages by gall dissection. The insects were deposited in the Cecidomyiidae Collection of the Museu Nacional. A total of 153 gall morphotypes were found on plants representing 37 plant families, 69 genera, 55 species and 53 morphospecies. Among them, two plant genera and five species were reported for the first time as host plants in Ombrophilous Forest. REBIO União showed little similarlity of host plant species and insect gall morphotypes when compared with other investigated Ombrophilous Forest areas. The leaf was the most attacked plant organ as expected. Asteraceae, Bignoniaceae, Fabaceae and Myrtaceae, and Mikania (Asteraceae) and Myrcia (Myrtaceae) were the richest host families and genera, respectivey, in number of gall morphotypes, all previously indicated as superhosts by other Brazilian Ombrophilous Forest inventories, except Bignoniaceae. Their great species richness may be related to their great gall richness, adding evidence in support of the taxon size hypothesis. Fusiform and globose galls were the most frequent, green was the predominant color, and most morphotypes did not present an indumentum. The highest gall richness was recorded in June and August. The gallers were distributed among Diptera (Cecidomyiidae), Lepidoptera, Hymenoptera, Hemiptera and Thysanoptera, with the first being predominant, following a global pattern. Eight gall-inducing species are recorded for the first time in REBIO União and four in Ombrophilous Forest. About 25% of the gall morphotypes were occupied by dwellers other than those that created the gall. They comprised parasitoids (Hymenoptera), inquilines (Diptera: Sciaridae and Muscomorpha, Hemiptera, and Lepidoptera) and successors (Psocoptera, mites, and Hymenoptera: Formicidae). Although these taxa were previously reported by Brazilian inventories of insect galls, 12 new association with plants are recorded. The amount of new records reinforces the importance of inventories.摘要：目前在里约热内卢大西洋森林已开展多项昆虫虫瘿（insect galls）调查研究，多数聚焦于滨海沙生植被（restinga），而其他植被型的采样则严重不足。本研究对尤尼翁生物保护区（Reserva Biológica União，RJ）的昆虫虫瘿进行了编目，该保护区为保护地，主体植被为湿润常绿阔叶林（Ombrophilous Forest）。野外调查于2013年1月至10月期间每两个月开展一次。研究人员采集昆虫虫瘿、拍摄记录、进行形态特征描述并带回实验室。通过人工饲养获得成虫，通过解剖虫瘿获取幼期虫态。所有标本均保存于巴西国家博物馆（Museu Nacional）瘿蚊科（Cecidomyiidae）馆藏。本次调查共记录到153个虫瘿形态型（gall morphotypes），涉及37个植物科、69个属、55个物种及53个形态种。其中2个植物属和5个物种为首次在湿润常绿阔叶林中被报道为虫瘿寄主植物。与其他已调查的湿润常绿阔叶林区域相比，尤尼翁生物保护区的寄主植物物种与虫瘿形态型相似度极低。如预期一致，叶片是受攻击最多的植物器官。菊科（Asteraceae）、紫葳科（Bignoniaceae）、豆科（Fabaceae）和桃金娘科（Myrtaceae），以及假泽兰属（Mikania，菊科）和香桃木属（Myrcia，桃金娘科）分别是虫瘿形态型数量最多的寄主科和属；除紫葳科外，其余类群均已被巴西其他湿润常绿阔叶林虫瘿调查认定为超级寄主。这类类群的高物种丰富度可能与其高虫瘿丰富度相关，为类群大小假说（taxon size hypothesis）提供了新的佐证依据。纺锤形和球形虫瘿最为常见，绿色为主要的虫瘿颜色，多数形态型不具有毛被（indumentum）。虫瘿丰富度最高的时段为6月和8月。造瘿昆虫分属于双翅目（Diptera）、鳞翅目（Lepidoptera）、膜翅目（Hymenoptera）、半翅目（Hemiptera）和缨翅目（Thysanoptera），其中双翅目（以瘿蚊科为主）占绝对优势，符合全球虫瘿昆虫的分布格局。有8个造瘿昆虫物种为尤尼翁生物保护区的新记录，另有4个物种为湿润常绿阔叶林的新记录。约25%的虫瘿形态型栖居着非造瘿的生物类群，包括寄生性天敌（膜翅目）、客居者（inquilines）（双翅目：蕈蚊科（Sciaridae）、环裂亚目类群（Muscomorpha），半翅目及鳞翅目）以及后继栖居者（successors）（啮虫目、螨类及膜翅目：蚁科（Formicidae））。尽管这些类群此前已在巴西昆虫虫瘿调查中被报道，但其中12个类群与植物的新关联关系为本次研究首次记录。本次调查新增的大量记录进一步凸显了虫瘿编目研究的重要性。