Winnell, ha. H., and B. 8 . lude. 1984. Associations among Chironomidae and sandy substrates in nearshore Lake Michigan. Can. 1. Chironomids and sediments were collected at 3-to 15-rn depths along the shoreline of eastern Lake Michigan from -8978 to 1980. Chironomids were the most frequently occurring (92% of samples), most diverse (41 taxa), and the second-most numerous (1634-m-~) group in this depth regime. The generalized sediment type was moderately sorted, fine sand. Sediments were grouped into three categories roughly corresponding to coarse (<24), fine (2-3+), and very fine (23+) sands. Nonpararnetric tests and a comparison of frequency distributions and densities distinguished chironsmid-substrate associations. Two species were strongly associated with coarse sand, 5 species with coarse-fine sands and fine-very fine sands, and 11 species with very fine sand. We postulate that observed chironomid-substrate associations were related in part to morphological differences among taxa. Species most strongly associated with coarse sediments were small, slender, and fast-moving forms with tough outer body integuments, morphotogica% characteristics that are necessary for survival in the ephemeral, physically controlled environment. I n the more stable, predictable environment where fine and very fine sands were most evident, species exhibited a wider variety of morphological characteristics, which included soft-bodied, tubicolous forms. De 1978 31980, Bes auteurs ont recueilli des echantillons de sediments et de chironomides dans la partie est du lac Michigan, a des profondeurs variant de 3 a 15 rn. Les chironomides constituaient le groupe le plus fr4quernment present (92% des echantillons), le plkasvarie (41 taxonset B e second en abondance (1634.m-'). Le type generalise de sediment etait'le sable fin moderement trie. Les sediments ont ete classes en trois groupes, correspondant a peu pr&s au sable grossier (<2+), fin (2 3 34) et trGs fin (234). A Ifaide de tests non parametriques et d'une comparaison des distributions des frequences et des densites, on a skpare les associations entre les chironornides et les substrats. Ainsi, 2 especes etaient etroitement associkes au sable grossier, 5 autres, aaa sable variant de grossier a fin tandis que I1 autres peuplaient le sable tres fin. Les auteurs formulent Ifhypothese que les associations observees entre les chironomides et les substrats sont reliees en partie aux differences morphologiques entre les taxons. Les esp&ces retrouvees B e plus souvent dans fes skdiments grossiers sont de petites formes minces et ragaides, aux teguments externes durscaracteristiques necessaires B la survie dans un environnernent ephernere et influence par les facteurs physiques. Dans I'environnement plus stable 012 abonde le sable fin et tres Bin, Bes especes rnontraient une pius grande variktt5 d e caracteres morphologiques, dont des formes tubicoles a corps mou.