Comparison of allozyme variability in a native and an introduced species of Lonicera

Abstract

Levels of allozyme variation are compared between a diploid invasive plant species, Lonicera japonica Thunb. (2n = 18) and its polyploid native congener, Lonicera sempervirens L. (2n = 36). Both are woody perennials and were sampled within the native range of L. sempervirens in the south-eastern United States where L. japonica has been an invader since the late 19th century. Genetic structure and allozyme diversity were determined for nine and ten populations of L. sempervirens and L. japonica, respectively. Genetic variation within L. japonica is similar to that in other species with similar life history traits (per cent polymorphic loci, Ps = 75 per cent, mean alleles per polymorphic locus, Aps = 2.28, and total genetic diversity, Ht = 0.216); L. sempervirens has even higher genetic variation than L. japonica (Ps = 91 per cent, Aps = 2.60 and Ht = 0.283). Although both species have high levels of genetic diversity, this may be less important than their life history traits to their success in early successful habitats. However, establishment of a relationship between success in naturalization for woody perennials and levels of genetic diversity is hampered by the paucity of comparable records for other native: alien congeneric pairs.