Rodent pollination in Protea nana

Floral morphology, late winter flowering time and a distinct yeasty odour in Protea nana suggest that it is adapted for rodent pollination. To test this hypothesis, rodents were trapped in a stand of P. nana, examined for presence of pollen (on their noses and in their scats) and then observed in the laboratory for pollination behaviour. Inflorescences were placed in wire and shade-cloth exclosures and seed-set compared to controls in the field. Otomys irroratus, Aethomys namaquensis, Rhabdomys pumilio and Myomyscus (Praomys) verreauxi were captured and all tested positive for the presence of protea pollen. All, except O. irroratus, displayed legitimate pollination of P. nana. Myomyscus verreauxi was regarded as the most competent pollinator as it displayed superior climbing ability in comparison to the other rodent species. R. pumilio sometimes displayed highly destructive behaviour of P. nana inflorescences and is the likely explanation for the observed 20% reduction in average number of inflorescences per plant over a two month period. Seeds per inflorescence were lowest in shade-cloth covered inflorescences (total pollinator exclusion), but not significantly lower in wire exclosures which provided access for insects. A high percentage of sugar (29.4% by weight) in the nectar of P. nana is similar to known rodent pollinated species. We conclude that P. nana is at least partially rodent pollinated. (C) 2009 SAAB. Published by Elsevier B.V. All rights reserved.