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K Ritland

Publications and source records attributed to K Ritland.

20 records · Page 2Linked to original sources

Sexual reproduction in the white pine weevil (Pissodes strobi [Peck] [Coleoptera: Curculionidae]): implications for population genetic diversity.

Controlled mating experiments in the white pine weevil (Pissodes strobi [Peck]) indicated that female weevils either stored sperm or fertilized eggs from one season to the next, and were able to colonize Sitka spruce (Picea sitchensis [Bong.] Carr.) trees without additional mating events. This was interpreted as being beneficial for the insect, in that population establishment in a new habitat could be initiated by dispersing previously mated females without participation of the male. This makes colonization and population/outbreak development more likely as it reduces the need for mate searching in the second season. Paternity identification, based on microsatellite molecular markers, established that the progeny produced in year 2 by females mated only in year 1, were often fathered by more than one male. Multiple paternity, coupled with a lack of parthenogenesis, which was also demonstrated herein, may help to account for the high degree of genetic diversity evidenced in this species.

Animals↗

Somatic mutations at microsatellite loci in western Redcedar (Thuja plicata: Cupressaceae).

A per-generation somatic mutation rate for microsatellites was estimated in western redcedar (Thuja plicata, Donn ex D. Don.: Cupressaceae). A total of 80 trees representative of the average size and age of reproductive trees were sampled in four natural populations in southwestern British Columbia. Samples of bulked haploid megagametophytes were collected from two or three positions on each tree, assuming that the collections were far enough apart that the same mutant sector was not sampled twice. All samples were genotyped at eight microsatellite loci. A single mutation corresponding to a stepwise increase in one dinucleotide repeat was detected. The estimated mutation rate for microsatellites was 6.3 x 10(-4) mutations per locus per generation (or 3.1 x 10(-4) per allele per generation), with a 95% confidence interval of 3.0 x 10(-5) to 4.0 x 10(-3) mutations per locus. Somatic mutations can contribute to a greater mutational load in trees, as compared to shorter lived plants, and genotypic mosaics within an individual have important implications for plant defense strategies and plant evolution.

Alleles↗