Mechanisms of Male-Male Interference during Dispersal of Orchid Pollen

Siring success of flowering plants depends on the fates male gametophytes, which compete for access to stigmas, stylar resources, and ovules. Although rarely considered, pollen may often during dispersal, affecting processes required export stigmas: pickup, transport, deposition. We quantified dispersal interference by tracking bee-mediated stained Anacamptis morio (Orchidaceae) from individual donor flowers inferred affected mechanisms basis fit a process-based model. During trials, all recipient were either emasculated, precluding with pollen, or intact, adding potentially interfering pollinator. The presence competing pollinaria bees reduced pickup additional pollinaria, doubled overall proportion lost total 27%. Interference specifically increased loss between successive flower visits variation in deposition among it likely also contact stigmas when occurred. Thus, altering removal, deposition, male-male can significantly—and perhaps commonly—limit plant-siring success.