Ecology and Biogeography of a Northern Caddisfly in Cape Cod MA 1996-2002

We have documented a large population of a rarely collected northern caddisfly, Phanocelia canadensis (Banks) (Trichoptera: Limnephilidae), on Cape Cod, Massachusetts. This species' range is generally considered to be centered in northern Canada, although there are individual records of adults from eastern Maine and New Hampshire, and a single adult was collected from Sherborn, Massachusetts, in the 1920s. The scarcity of this species in collections may reflect true rarity, with populations sparsely but widely distributed across the northern part of the continent. Alternately, it may reflect a sampling bias, in that the larvae of this species were unknown until the late 1980s, adults are diurnal and fly late in the fall, and larvae occur in wetlands and are closely associated with Sphagnum, from which they make their cases. We have carried out an in-depth habitat comparison of sites in which we found or did not find larvae on Cape Cod in seven years of intensive sampling. Habitat characteristics distinguishing wetlands with and without Phanocelia include dominance by Sphagnum sp., shrub cover, and low pH. We are currently searching in similar habitats across the state for additional populations.本研究记录了采自马萨诸塞州科德角地区的一种极少被采集的北方石蛾类群——加拿大菲纳石蛾（Phanocelia canadensis (Banks)）（毛翅目Trichoptera：沼石蛾科Limnephilidae）的大型种群。该物种的分布范围通常被认为以加拿大北部为核心，尽管目前已有来自缅因州东部与新罕布什尔州的成虫个体记录，且1920年代曾在马萨诸塞州舍本地区采集到一头成虫个体。该物种在馆藏标本中的稀缺性，可能源于其真实的稀有性：其种群在北美北部区域稀疏且广泛分布；也可能源于采样偏差——该物种的幼虫直至1980年代末才被学界发现，成虫为昼行性且于秋季后期羽化飞行，幼虫栖息于湿地生境并与泥炭藓（Sphagnum）紧密共生，其构筑护壳的材料即取自该属植物。本研究团队历经七年的密集采样工作，针对科德角地区发现与未发现该物种幼虫的样地开展了深入的生境对比分析。区分是否存在加拿大菲纳石蛾（Phanocelia canadensis）的湿地生境特征包括：泥炭藓属（Sphagnum sp.）的优势盖度、灌丛覆盖度以及较低的pH值。目前我们正于该州范围内的类似生境中开展调查，以寻找该物种的其他种群。