Hyobanche hanekomii(Orobanchaceae) is pollinated by non-flying mammals and birds

Abstract

AbstractH. hanekomiiwas recently described as a new member of the genusHyobancheinside the Orobanchaceae family.H. hanekomiiis a small geoflorous holoparasitic plant, which often grows under shrubs and has red-flowered inflorescences, which do not emit a scent. The plant combines characteristics from bird- and mammal-pollinated plants. Until now it was uncertain ifH. hanekomiiis pollinated by birds or by non-flying mammals, since the species is showing an intermediate morphology when compared toH. atropurpurea(mammal pollinated) andH. sanguinea(bird pollinated). Elephantulus edwardiiandNectarinia famosawere observed foraging onH. hanekomiiinflorescences indicating a mixed pollination syndrome or a transmission state between bird pollination to pollination by non-flying mammal. In this study I prove thatE. edwardiiandN. famosaare indeed pollinators ofH. hanekomii. This was done by observing the interaction between different animal species andH. hanekomiiinflorescences in their natural habitat by using camera traps and camcorders.It could be observed thatE. edwardiilicked nectar from flowers ofH. hanekomiiwith its long tongue. The animals pressed their rostra deep into the flowers. While foraging on the flowers, it could be observed that pollen was placed onto the rostra of the animals. It was also observed, that the stigma of the flower touched the animals on the same spots where pollen was placed. To drink on the flowers,Nectarinia famosainserted its beak into the flowers. While doing so, it was observed that pollen was placed on the beaks and that the stigma touched the animals. It is possible that both species transport pollen from oneH. hanekomiiflower to another while foraging on them, and that the pollen reaches the stigma of another flower. Because of this both species are considered as pollinators ofH. hanekomii.E. edwardiiwas identified as the main pollinator ofH. hanekomiias they visit the inflorescences frequently.N. famosawas detected as a secondary pollinator ofH. hanekomiias they visit the flowers infrequently. This issue has to be examined further since the rarity ofN. famosavisits could be influenced by different factors like removal of perching positions around the plants to have a better camera angel or by the cameras itself, so thatN. famosawould visit theH. hanekomiiinflorescences more often in an non altered surrounding.In addition UV photography and spectrometry revealed that no UV reflecting areas are present on the plants indicating adaption to non-flying mammal than bird pollination syndrome. The same counts for missing stinging hairs on the flowers. In contrary some of the important flower characteristics (Flower entrance width and height) are significant smaller than those of the non-flying mammal pollinated plantH. atropurpureaindicating a bird pollination syndrome.