Obligate pollinator

Figure 22.1 Examples from two conceptual axes of interactions between flowers and their animal visitors. Axis 1 is a specialization-generalization spectrum of plant-pollinator interactions. Panel A depicts a guild of red Chilean flowers that share one species of hummingbird as a pollinator. In Panel D, a Perideridia umbel is visited by several families of bees, wasps and flies most are effective pollinators. Axis 2 describes relationships in which animals visit flowers for their own reproductive purposes. In panel B, a female Tegiticula moth gathers pollen from anthers of Yucca filamentosa, for which it is both obligate pollinator and seed predator. In panel C, a Drosophila fly (black arrow) is lured by appearance and smell of decaying matter to a deceptive Aristolochia flower, seen in cross-section. Floral scent plays diverse roles along these axes, including pollinator attraction in food- and sex-based mimicry. All photographs were taken by the author.

Repeated independent evolution of obligate pollination mutualism in the PhyUantheae-Epicephala association. Proceedings of the Royal Society B, 276, 417-426. 

The greenhouse and growth-chamber experiments indicated that S. divinorum is an obligate short-day plant. Plant height is a minor factor in flower development, as several (growth chamber) specimens were less than 0.5 m tall when they flowered. Pollination experiments showed that the mint is probably self-sterile, but it remains to be demonstrated that S. divinorum will set viable seed. 

Plant-associated small animals inclnde those arthropods that (i) are in obligate association with plants, (ii) are plant pests, (iii) are plant pollinators,or(iv)transmit plant diseaseagents,as well as othersmallanimals snchas nematodes forwhich tests of biological properties necessitate the use of plants. Microorganisms associated with such small animals (e.g., pathogens or symbionts) are inclnded. 

Flexibility of pollination system transitions has been studied in numerous groups of angiosperms. Some conspicuous examples are be mentioned here. Among Phyllanthaceae, in Phyllantheae, specialization to pollination by Epicephala moths evolved at least five times, involving more than 500 Phyllantheae species in this obligate association (Kawakita and Kato, 2009). 

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