Tobacco plant thwarts caterpillar onslaught by opening flowers in the morning

Of course, these observations raise the question of why N. attenuata bothers producing night-opening flowers that attract hawkmoths in the first place. Why not just focus on luring hummingbirds? Baldwin and colleagues don't know the answer to this question, but it's possible that the hawkmoth, for all its faults, might be a more reliable and effective pollinator than the hummingbird.

Looking to the field of plant-pollinator interactions more generally, the findings have some potentially broad implications. For one, plants face another dilemma, related to the one described by Baldwin and colleagues, in which traits that attract a pollinator can also attract herbivores, resulting in an inevitable trade-off. Thus, one wonders whether herbivore-induced changes to flower phenology could be used more generally to mitigate the unwanted side effects associated with flowers that are attractive to both pollinators and herbivores. Also, in studying how the caterpillars' oral secretions induce the switch in flower phenology, Baldwin and colleagues discovered that a chemical pathway crucial to many defense responses in plants is required. The role of such a common defense pathway raises the interesting possibility that the effects of herbivore attack described in the study may be common in plants.

Taken as a whole, the findings highlight the remarkable adaptability of plants to changing circumstances and the complex, sometimes contentious, relationships between plants and their pollinators.

The researchers include Danny Kessler, Celia Diezel, and Ian T. Baldwin, at Max Planck Institute for Chemical Ecology, Jena, Germany.