With the bees pollinating them less effectively, the plants increasingly
self-pollinate. In a greenhouse evolution experiment, scientists have shown just how much the effects of pollinators and pests influence each other.
Another project is seeking to identify potential lucerne genotypes that have the ability to
self-pollinate in the absence of bees.
The degree to which a plant is able to
self-pollinate, depends on the position and the time of release of anthers in relation to the stigma (Free, 1993).
Alternatively, the ability to
self-pollinate might also serve to counteract pollinator unpredictability and facilitate reproductive assurance when pollinator visits are limited (Levin, 1972).
affinis are especially good pollinators, since even plants that can
self-pollinate produce more and bigger fruit when pollinated by the rusty patched bumblebee.
Most tomatoes will
self-pollinate, but sometimes insects carry pollen from one variety to another.
Heirloom seeds are from plants whose flowers
self-pollinate. Some varieties of vegetables and flowers may not have been around long enough to be called ''heirlooms,'' but still might be from self-pollinating plants.
This ability to
self-pollinate and remain relatively stable is perhaps part of the reason many heirloom varieties have survived.
First, there is an impressive body of literature that shows that many orchid species
self-pollinate when pollinators are rare or absent (Burns-Balogh & Bernhardt, 1988; Catling, 1990; Neiland & Wilcock, 1998).
