Insect pollination in the African cycad Encephalartos friderici-guilielmi Lehm

Studies of the pollination ecology of the South African cycad, Encephalartos friderici-guilielmi Lehm, were carried out to determine the role played by insects and to identify the key pollinators. Surveys of insects on the male and female cones at the time of pollination indicated that three beetle species were present in sufficient numbers during pollination to be potential pollinators, i.e. an undescribed Erotylidae sp. (Cucujoidea), Metacucujus encephalarti (Cucujoidea), and Porthetes hispidus (Curculionidae). Pollen laden specimens of all three species were found on female cones with mean pollen loads ranging between 391 and 1019 pollen grains per beetle. In behavioural experiments, individuals of P. hispidus and M. encephalarti deposited fluorescent dye on the micropyles of receptive ovules. Enclosure of pollen laden specimens of P. hispidus, M. encephalarti, or Erotylidae sp. nov. on female cones resulted in seed set that was statistically similar to open controls and significantly higher than insect exclusion treatments. These data support the conclusion that E. friderici-guilielmi is insect pollinated and provide further evidence for the role of cucujoid (Erotylidae, Boganiidae) and curculionoid (Porthetes) beetles in the pollination of Encephalartos spp.