Body snatchers and femmes fatales: The natural history of deception
Deception evolves when a third party invades the sensory channels by which organisms mediate cooperative interactions. The results are familiar to most ecologists, ranging from the co-option of aposematic coloration by palatable mimetic butterflies to the appropriation of insect sex pheromones as pollinator attractants by rewardless orchids. Deception is a successful strategy; one third of all orchid species are deceptive, a trend mirrored by other plant lineages that have diversified through deceit. What guiding principles have we learned about deception (as an alternative to mutualism) – particularly in pollination - and what role has natural history played in this process?
The last decade has revealed hidden nuance in the world of deceptive pollination, from the discovery of unexpected niches (e.g. floral mimicry of dead insect haemolymph) to the suggestion that some floral mimics either don’t require models or harm their models by presenting an idealized (i.e. more attractive) stimulus to their pollinators. In other cases, putative examples of deception were revealed to utilise a “bait and switch” strategy of advertising protein (as food) or carrion (a brood site) but instead rewarding with sugar. In each of these cases, seemingly mismatched chemical signals or experimental results were rationalized through careful natural history observations. Finally, the bizarre exceptions to typical, commodity-based plant-pollinator markets, which so effectively capture the attention of the lay public – witness the huge crowds that attend Titan Arum blooms! – provide powerful opportunities for educational outreach about the conditionality of mutualistic interactions. Such lessons are as valid for understanding the stability and complexity of natural communities as they are for managing food safety and agriculture in a rapidly changing pollinator landscape.