Floral Manipulations Reveal the Cause of Male Fitness Variation in Experimental Populations of Eichhornia paniculata (Pontederiaceae)

Abstract

In experimental populations of self-compatible, tristylous Eichhornia paniculata plants of the long-styled morph (L) consistently sire fewer seeds on the mid-styled morph (M) than do plants of the short-styled morph (S). This mating asymmetry results in gender differences between the L and S morphs. Observations of pollinators and floral manipulations of genetically marked plants in experimental populations were used to evaluate three potential causes of differential siring success: pollinators prefer the S morph leading to higher male success; long styles interfere with pollen pick-up by insect visitors; and pollen from long-level anthers of the S morph sires more seeds on the M morph than pollen from short-level anthers of the L morph (...)