Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
PLoS One. 2012;7(5):e37472. doi: 10.1371/journal.pone.0037472. Epub 2012 May 24.
Levels of genetic diversity can strongly influence the dynamics and evolutionary changes of natural populations. Survival and disease resistance have been linked to levels of genetic diversity in eusocial insects, yet these relationships remain untested in gregarious insects where disease transmission can be high and selection for resistance is likely to be strong.
METHODOLOGY/PRINCIPAL FINDINGS: Here we use 8 microsatellite loci to examine genetic variation in 12 families of western tent caterpillars, Malacosoma californicum pluviale from four different island populations to determine the relationship of genetic variability to survival and disease resistance. In addition these genetic markers were used to elucidate the population structure of western tent caterpillars. Multiple paternity was revealed by microsatellite markers, with the number of sires estimated to range from one to three per family (mean ± SE = 1.92±0.23). Observed heterozygosity (H(O)) of families was not associated to the resistance of families to a nucleopolyhedrovirus (NPV) (r = 0.161, F(1,12) = 0.271, P = 0.614), a major cause of mortality in high-density populations, but was positively associated with larval survival (r = 0.635, F(1,10) = 5.412, P = 0.048). Genetic differentiation among the families was high (F(ST) = 0.269, P<0.0001), and families from the same island were as differentiated as were families from other islands.
CONCLUSION/SIGNIFICANCE: We have been able to describe and characterize 8 microsatellite loci, which demonstrate patterns of variation within and between families of western tent caterpillars. We have discovered an association between larval survival and family-level heterozygosity that may be relevant to the population dynamics of this cyclic forest lepidopteran, and this will be the topic of future work.
遗传多样性水平强烈影响自然种群的动态和进化变化。在真社会性昆虫中，生存能力和疾病抵抗力与遗传多样性水平有关，但在群居昆虫中，这些关系尚未得到验证，因为疾病传播可能很高，对抵抗力的选择很可能很强。
方法/主要发现：在这里，我们使用 8 个微卫星位点来研究来自四个不同岛屿种群的 12 个西部天幕毛虫 Malacosoma californicum pluviale 家族的遗传变异，以确定遗传变异性与生存和疾病抵抗力的关系。此外，这些遗传标记还用于阐明西部天幕毛虫的种群结构。微卫星标记揭示了多父本现象，每个家族的父亲数量估计从一个到三个不等（平均值±SE 为 1.92±0.23）。家族的观察杂合度（H(O)）与家族对核多角体病毒（NPV）的抗性无关（r=0.161，F(1,12)=0.271，P=0.614），NPV 是高密度种群中死亡率的主要原因，但与幼虫存活率呈正相关（r=0.635，F(1,10)=5.412，P=0.048）。家族之间的遗传分化很高（F(ST)=0.269，P<0.0001），来自同一岛屿的家族与来自其他岛屿的家族一样分化。
结论/意义：我们已经能够描述和描述西部天幕毛虫家族内和家族间的 8 个微卫星位点的变异模式。我们发现幼虫存活率与家族水平杂合度之间存在关联，这可能与这种周期性森林鳞翅目昆虫的种群动态有关，这将是未来工作的主题。
