Expanding Distribution and Evolutionary Potential of Thymelicus lineola (Lepidoptera: Hesperiidae), an Introduced Skipper, With Special Reference to its Appearance in British Columbia

Abstract

AbstractThymelicus lineola, a univoltine grass-eating skipper introduced into southern Ontario from the Palearctic prior to 1910, is spreading rapidly and extensively in North America, moving outward in all directions from its origin. Its present distribution (doubtless inadequately known) includes parts of Michigan, Ohio, New York, Pennsylvania, Maryland, New Jersey, and Connecticut; Edmundston, New Brunswick; all of southern Ontario northeast to Ottawa, plus Sudbury, Sault Ste. Marie, and Fort William; and Terrace, British Columbia. (The last record may stem from an independent introduction from Eurasia.) Dispersal and colonization are probably much aided (unwittingly) by man. Range expansion often seems to involve a sequence of events (associated with founding of initially small colonies that rather quickly reach high population densities) that may promote rapid evolutionary differentiation of populations.