June 09, 2005
Plant trickery
I notice that roses have reddish leaves near the tops of their stocks, where the new growth is. Is this a genetic accident? Wouldn't green leaves produce more energy? I suspect that roses evolved to have new leaves that are reddish because, from a distance, they resemble flowers. Thus, for little cost, the rose plant may better attract pollinating insects toward it. If a bee lands on a leave it quickly determines that the leaf hasn't nectar, so it lands on one of the plant's nearby flowers.
Walking around the yard I notice other forms of plant deception. We have a dove tree, which blooms in the spring. Our tree's blooms have just ended, and I failed to photograph them, so an example of a dove tree shown here was stollen from elsewhere. 
Around the time it is in bloom, some of the dove tree's leaves, which may be distant from a flower, appear partially (or fully) like pedals. Shown here are a couple such leaves that have fallen off. 
Notice how these are part green and part white? The white pedal-like part does not produce energy very well (if at all), and it is less hardy too. In spite of these shortcomings, the tree finds false pedal production advantageous because it likely draws more pollinators to it, much like the rose.
A final example I found in the stawberry patch. 
Rather than flagging distant bees and butterflies, the strawberry plants produce a few red leaves to help attract animals that eat their berries (and thus disperse the seeds). Yonder red leaves look like a bounty of strawberries.