Data from: Testing prerequisites to adaptation in Quercus agrifolia: Are leaf domatia a heritable trait?

On Quercus agrifolia Née, Fagaceae, (Coast Live Oak) trees in California,
small clusters of branched trichomes on the abaxial leaf surface serve as
domatia, protective structures for mites. These structures are a
distinguishing characteristic of Q. agrifolia and we hypothesize may be
shaped by natural selection. Here we test the first two of three
prerequisites for adaptation via natural selection: (1) the trait must
vary among individuals, and (2) the trait must be heritable. Trait
variance across 20 trees in a natural stand was assessed by collecting 20
leaves per tree and determining the proportion of leaf vein axils with
domatia. From the same trees, acorns were collected, germinated, and the
proportion of leaf vein axils with domatia was recorded for 12- and
18-month-old saplings. Heritability was then assessed by comparing the
resemblance between maternal trees and offspring. We find that both
prerequisites are met: maternal trees exhibit substantial variation in the
proportion of leaf vein axils with domatia, ranging from an average of
0–0.85 per leaf, and heritability estimates for 12- and 18-month-old
saplings were 0.33 ± 0.10SD and 0.53 ± 0.10SD respectively. A follow up
study is needed to assess the third prerequisite for adaptation via
natural selection, that survival and reproduction of oaks varies based on
the proportion of leaf vein axils with domatia. We hope future researchers
will pursue this line of study.