The genetic consequences of worker ant pollination in a self- compatible, clonal orchid

Abstract

The self-compatible orchid Microtis parviflora is pollinated by the flightless worker caste of the ant Iridomyrmex gracilis. The orchid is clonal and forms small patches of disconnected individual ramets. Ant pollinators visited and revisited a limited proportion of available inflorescences; 40% of all flower visits occurred within plants promoting self-pollination. Self-pollination accounted for 51% of pollen transfers. Distribution of ant movements between plants was leptokurtic with a mean of 12.4±14.9cm and a maximum of 89cm, but a high proportion of movements were within clones accentuating the level of self-pollination. However, some pollen transfers between inflorescences of unlike genotypes contributed to a low incidence (max 8%) of outcrossing. In 12 patches examined by electrophoresis, the density varied from 11-61 inflorescences m-2 and a maximum of only four genotypes were detected. -from Authors