Autumn leaf-drop is hypothesized to be a rich seasonal source of organic matter for stream-dwelling detritivores in temperate regions.  To quantitatively assess the hypothesized benefit of autumn leaf-drop, the growth and production of Paraleptophlebia cohorts were measured during summer and autumn periods in a small coastal stream.  The instantaneous growth rates of both P. temporalis cohorts were slightly higher during the autumn, but still significantly less than that of the summer-growing P. debilis.  Production of P. temporalis during the summer was not different from that during the autumn period.  Detritivores that synchronize nymphal growth with autumn leaf-drop thus are not necessarily any more successful than other detritivores. Our study suggests that there may be more than one combination of life history characteristics by which species can exploit temporally varying environments to maximize production.