The hidden diversity and interactions of gall midges (Cecidomyiidae), their associated microfungal symbiont(s), and parasitoid wasps in temperate saltmarshes have been little studied in Australia. Over a period of two years, we investigated the gall-associated communities of the dominant saltmarsh plants, Tecticornia arbuscula and Salicornia quinqueflora, across south-eastern Australian coastal and inland salt-lake sites. We discovered that i) many gall midge species are more widely distributed than previously thought; ii) co-distribution of species affecting different plant organs on the same host is also widespread; iii) diversity of gall midges (6 species previously named; 5 species identified here as new) and parasitoid wasps (17 sp. prov.) is likely higher than we uncovered; iv) parasitoid wasps associated with gall midges belonged to diverse lineages and appear to be widespread generalists; v) while the microfungus usually associated with most Cecidomyiinae larval chambers is Botryosphaeria dothidea, we discovered a provisional new species of Botryosphaeria associated with a novel Asphondylia sp. in western South Australia. We also show that targeted amplicon sequencing is a valuable tool for investigating all components of multi-trophic level systems. Our research has contributed to a greater understanding of the basic biology of gall midge interactions within temperate saltmarsh ecosystems in southern Australia, and highlights the value of investigating all trophic levels in these complex interactions simultaneously.

澳大利亚很少研究瘿蠓（Cecidomyiidae）、它们相关的微真菌共生体和寄生蜂在温带盐沼中的多样性和相互作用。在两年的时间里，我们调查了主要盐沼植物Tecticornia arbuscula和Salicornia quinqueflora的瘿相关群落，横跨澳大利亚东南部沿海和内陆盐湖遗址。我们发现 i) 许多瘿蚊物种的分布范围比以前认为的要广泛；ii) 影响同一宿主不同植物器官的物种的共同分布也很普遍；iii) 瘿蠓（6 种以前命名；5 种在此确定为新种）和寄生蜂（17 种省）的多样性可能比我们发现的要高；iv) 与瘿蠓相关的寄生蜂属于不同的谱系，似乎是普遍存在的通才；v) 虽然通常与大多数 Cecidomyiinae 幼虫室相关的微真菌是Botryosphaeria dothidea，但我们发现了与新型Asphondylia相关的Botryosphaeria临时新种sp. 在南澳大利亚西部。我们还表明，靶向扩增子测序是研究多营养级系统所有组件的宝贵工具。我们的研究有助于更好地了解澳大利亚南部温带盐沼生态系统中瘿蚊相互作用的基本生物学，并强调了同时调查这些复杂相互作用中所有营养水平的价值。