Ornithophily on the Canary Islands

Bird pollination of Canary Island endemic plants

“…However despite their low species richness, populations of native bees are abundant on the islands and are widely utilised as pollinators by other plant species (Garcia 2000;Dupont et al 2003;Dupont and Skov 2004;Ollerton et al 2007) and often forage on flowers in close proximity to Canarina and Isoplexis (Stelzer et al 2007). It is, however, possible that the flowers might indeed have originally evolved for pollination by specialised birds as suggested by Vogel et al (1984); Valido et al (2004) and that, following extinction of these specialised avian pollinators, the switch to insect pollination might have evolved crossing an adaptive valley, while utilising generalised bird pollinators might have required fewer evolutionary modifications.…”

“…The assumption is that these pollinators vanished in the Pliocene, and so did their flowers -everywhere except in the Canaries, where the flowers survive to this day. Vogel et al (1984) further suggested that some Palaearctic bird species which colonised the islands during the Pleistocene discovered the "orphaned" bird flowers of the islands as welcome carbohydrate resources, and that they are adequately pollinated by these passerine species. Field work by various researchers since then has tended to confirm that the flowers of these plants are visited by passerine birds not specialised for flower visitation (e.g.…”

“…This discrepancy was first noted by Vogel (1954) who hypothesised that the original pollinators of these plants were sunbirds (Nectariniidae) which had become extinct. Vogel et al (1984) conjectured that the flowers are remainders of a flora that was Trans-Saharan in the Tertiary, and that the flowers were pollinated by birds specialised on nectar feeding. The assumption is that these pollinators vanished in the Pliocene, and so did their flowers -everywhere except in the Canaries, where the flowers survive to this day.…”

“…Alternatively, are the traits largely the result of earlier evolution for sunbird pollination, and non-flower specialist passerines were co-opted as secondary pollinators following dispersal of these lineages to the sunbird-free Canary Islands, or the extinction of sunbirds from these islands? Studying the reproductive biology of these plant species is also important because some of them are rare and threatened by extinction, whilst others may well already be extinct (Vogel et al 1984;Olesen 1985;Bramwell and Bramwell 2001). In this study we focussed on two of the more common bird pollinated species on the island of Tenerife: Canarina canariensis (Campanulaceae) and Isoplexis canariensis (Veronicaceae ex Scrophulariaceae).…”

The Evolution and Pollination of Oceanic Bellflowers (Campanulaceae)

“…Moreover, in oceanic islands, ornithophily and saurophily (i.e. pollination mediated by birds and lizards, respectively) have been documented for several plant species (Vogel et al 1984;Olesen 1985;Olesen and Valido 2003a, b;Rodríguez-Rodríguez and Valido 2008;Ollerton et al 2009). …”