Diversity & Evolution 4 (2004)
Electronic Supplement 5
Adaptive radiation and coevolution - pollination biology case studies.
print version: Org. Divers. Evol. 4(3): 207-224. 2004 (full
Part 1. Male Eucera barbiventris exhibiting pseudocopulation on the labellum of an Ophrys scolopax flower.
Part 2. Parts of the perianth of the Aristolochia arborea flower mimic the hat-like shape of a mushroom of the genus Marasmius.
Part 3. Mimicry of pollen and stamen signals in Iris species. (Colour plate). pdf-format, 198 KB
The impact of coevolutionary interaction between species on adaptive radiation processes is analysed with reference to pollination biology case studies. Occasional colonization of archipelagos can bring together coevolving partners and cause co-radiation of the colonizing species, e.g. the drepanidids and the lobelioids on Hawaii. Permanent reciprocal selective pressure between pairs of coevolving species can lead to a coevolutionary race and rapid evolutionary change. This is exemplified by spurred flowers and long-tongued flower-visitors. The geographic patterning of diffuse coevolution systems can lead to dramatic changes in species interactions. In different populations, interaction between pollinating and seed-parasitizing Greya moths and their host plants varies from mutualism to commensalism and antagonism, depending on the presence of co-pollinators. Asymmetrical coevolution between angiosperms and oligolectic flower-visitors may facilitate rapid reproductive isolation of populations following a food-plant switch, if the oligoleges use their specific food plants as the rendezvous sites. Diffuse coevolution between angiosperm species and pollinating insects may cause frequent convergent evolution of floral traits such as nectar reward instead of pollen reward, floral guides, zygomorphic flowers, or mimicry of pollen signals, since the multiple plant species experience similar selective pressures via the coevolving partners. Patterns of angiosperm adaptive radiation are highlighted in the context of coevolution with pollinators.
Key words: Coevolution; Adaptive radiation; Pollination; Key innovation; Zoophily