REPRODUCTIVE STRATEGIES IN 2 ARCTIC PEDICULARIS SPECIES (SCROPHULARIACEAE)

A study of a number of reproductive traits in two sympatric species of Pedicularis in northern Swedish Lapland, the subarctic-alpine P. lapponica and the artic P. hirsuta, revealed that the life-history strategies of the two species differ profoundly. High fruit set and low seed abortion rate, as in P. hirsuta, is common in arctic plants in late-thawing habitats and represents a case of extreme adversity selection rather than an indication of a ruderal life-history strategy. Pedicularis lapponica, on the other hand, is a typical K-strategist (or stress-tolerator) requiring a longer period of growth for optimal reproduction. Occurring at both low and high altitudes in the area, P. lapponica tends to increase in self-compatibility with altitude, which is interpreted as an adaptation to lower pollinator visitation frequency in arctic environments. The variation in length of the protruding part of the style in P. lapponica is shown to be correlated with exposure to light. Predispersal seed predation is severe in P. lapponica at low altitudes, where the capsules are attacked by fly and moth larvae. At high altitudes, a minor proportion of the capsules of P. lapponica experience predation and only from flies, while P. hirsuta is completely unpredated.