Bratt Albertus D, Knutson Lloyd V, Murphy William L, Daniels Anthony A
(ADB) Department of Biology, Calvin College, Grand Rapids, Michigan, USA (retired); deceased 11 December 2019 at age of 86..
Zootaxa. 2020 Aug 31;4840(1):zootaxa.4840.1.1. doi: 10.11646/zootaxa.4840.1.1.
All reared larvae of flies of the genus Colobaea Zetterstedt, 1837 (Diptera: Sciomyzidae), which comprises 15 valid species, kill and consume freshwater nonoperculate pulmonate snails. New data are presented on the geographic distribution, biology, morphology of immature stages, and classification of Colobaea. Life cycle information is provided from field data and laboratory rearings for four of the 11 Palearctic species-C. bifasciella (Fallén), C. deemingi Knutson Bratt n.sp., C. pectoralis (Zetterstedt), and C. punctata (Lundbeck)-and for one of the three Nearctic species, C. americana Steyskal. Colobaea bifasciella is shown to be one of the most highly specialized parasitoid Sciomyzini, laying eggs on shells of Galba truncatula (O.F. Müller) and Stagnicola palustris (O.F. Müller) in temporary, intermittent, or vernal semiterrestrial situations. Each larva feeds in only one host snail, which is not killed until shortly before the larva completes development. Puparia are strongly modified to fit tightly within the shell of the host. The other reared species are shown to be less specialized than C. bifasciella, with eggs being laid upon vegetation, the larvae behaving as parasitoids-predators-saprophages of exposed aquatic snails, and the puparia of all four species being adapted to a lesser degree than C. bifasciella to fitting within the shell of the host snail. In nature, C. americana attacks Gyraulus parvus (Say) and Physa Draparnaud sp.; C. pectoralis attacks Anisus vortex (L.) and Bathyomphalus contortus (L.); and C. punctata attacks Gyraulus albus O.F. Müller, Lymnaea "peregra," Planorbarius corneus (L.), and Planorbis planorbis (L.). In the laboratory, these species also attacked and consumed other freshwater nonoperculate snails; C. deemingi was reared on Gyraulus intermixtus (Mousson) and Radix gedrosiana (Say), and an adult fly of the Palearctic C. distincta (Meigen) emerged from a puparium found in the shell of Anisus spirorbis (L.) collected in nature. Described and figured are eggs, larvae of all three instars, and puparia of the five laboratory-reared species. To provide perspective on features of Colobaea, diagnostic features are summarized of the immature stages of the Sciomyzini and the suprageneric categories of Sciomyzidae. The biogeography of the tribe Sciomyzini is presented, along with details of known geographical distribution. The classification and phylogenetic position of Colobaea are discussed. Included are a checklist of all known taxa of Colobaea, maps of geographic distribution, and a key to adults of the 15 valid species.
1837年泽特施泰德所命名的Colobaea属蝇类（双翅目：沼蝇科）的所有饲养幼虫都会捕杀并取食淡水无厣肺螺。本文给出了关于Colobaea属的地理分布、生物学特性、未成熟阶段形态以及分类的新数据。通过野外数据和实验室饲养，提供了11种古北区物种中的4种——双带Colobaea（法伦）、德明Colobaea（克努森、布拉特新种）、胸斑Colobaea（泽特施泰德）和点斑Colobaea（伦德贝克），以及3种新北区物种中的1种——美洲Colobaea（施泰斯卡尔）的生命周期信息。双带Colobaea被证明是最具高度专业化的寄生性沼蝇族之一，在临时的、间歇性的或春季半陆生环境中，将卵产在截口椎实螺（O.F. 米勒）和沼泽静水螺（O.F. 米勒）的壳上。每只幼虫仅在一只寄主螺中取食，直到幼虫发育即将完成前不久，寄主螺才会被杀死。蛹强烈变形，以紧密贴合在寄主的壳内。其他饲养的物种被证明不如双带Colobaea专业化，卵产在植被上，幼虫表现为暴露水生螺的寄生性捕食者-腐食者，并且这4个物种的蛹在适应寄主螺壳内的程度上都比双带Colobaea小。在自然界中，美洲Colobaea攻击微小旋螺（赛伊）和德氏膀胱螺（德拉帕尔诺）；胸斑Colobaea攻击旋螺（林奈）和扭旋巴蜗牛（林奈）；点斑Colobaea攻击白旋螺（O.F. 米勒）、“奇异”椎实螺、角螺（林奈）和平扁圆扁螺（林奈）。在实验室中，这些物种也会攻击并取食其他淡水无厣螺；德明Colobaea以混合旋螺（穆松）和格德罗西亚萝卜螺（赛伊）为食，并且一只古北区的明显Colobaea（梅根）成虫从在自然界采集的旋螺（林奈）壳中的蛹羽化而出。本文描述并绘制了5种实验室饲养物种的卵、所有三个龄期的幼虫以及蛹。为了提供关于Colobaea属特征的视角，总结了沼蝇族未成熟阶段以及沼蝇科超属类别的诊断特征。介绍了沼蝇族的生物地理学，以及已知地理分布的详细情况。讨论了Colobaea属的分类和系统发育位置。其中包括Colobaea属所有已知分类单元的清单、地理分布图以及15个有效物种成虫的检索表。
