FOOD-CONSUMPTION BY COLLEMBOLA FROM NORTHERN MICHIGAN DECIDUOUS FOREST

The present study was designed to assess food partitioning mechanisms in Collembola. Isotoma notabilis, Sminthurimus henshawi and Orchesella hexfasciata were dominant litter-dwelling Collembola in northern Mich igan deciduous forests. Little overlap in mouthpart size occurred betw een species. Isotoma notabilis had the Shortest mandible and labrum, O . hexfasciata the longest, whereas S. henshawi was intermediate. Gut c ontent analysis showed that these species fed on different food types and selected different size food particles. Selection of food particle size was related to mouthpart size. Gut contents were categorized as fungal hyphae and spores, plant material and pollen, animal remains, c olloidal materials, minerals and bacteria. Fungal hyphae and colloidal material were most abundant in the gut of I. notabilis, while S. hens hawi fed heavily on fungal spores, and O. hexfasciata incorporated div ersified foods in its diet. Type and size of food ingested were found to be species-specific, All species showed variation in dietary compon ents related to seasonal availability of foods in the field.