Crithidia bombi An intestinal parasite (trypanosome) of bumble bees.

Cross-pollination Pollination by pollen from another plant.

Dioecia The condition of plants with staminate and pistillate flowers borne on separate individuals.

Drone A male honey bee that does not forage for itself at flowers, but is fed by its sisters. Haplodiploid genetic sex determination in bees, ants, and wasps results in males having one set of chromosomes. Drones are haploid; their sisters have two sets of chromosomes and are diploid. Drone bees develop from unfertilized eggs.

Event selection Selection for successful genetic transformation of a plant (for example, corn) with a genetically engineered sequence.

Extinction vortex Interaction of multiple factors that progressively forces an already small population into extinction.

Fecundity Ability to reproduce regularly and easily; typically measured in plants as fruit set or seed set.

Floret A small flower in the composite (Asteraceae) inflorescence or the spike of a grass.

Founder effect Genetic drift that results from the founding of a population by a small number of individuals.

Fruit set Formation of fruit as a result of pollination and fertilization.

Geitonogamy Pollination by pollen from another flower on the same plant.

Genetic drift Change in the gene pool of a small population attributable to chance (Campbell et al., 1999).