Navigation Links
Wildflower colors tell butterflies how to do their jobs
Date:1/9/2011

DURHAM, N.C. The recipe for making one species into two requires time and some kind of separation, like being on different islands or something else that discourages gene flow between the two budding species.

In the case of common Texas wildflowers that share meadows and roadside ditches, color-coding apparently does the trick.

Duke University graduate student Robin Hopkins has found the first evidence of a specific genetic change that helps two closely related wildflowers avoid creating costly hybrids. It results in one of the normally light blue flowers being tagged with a reddish color to appear less appetizing to the pollinating butterflies which prefer blue.

"There are big questions about evolution that are addressed by flower color," said Hopkins, who successfully defended her doctoral dissertation just weeks before seeing the same work appear in the prestigious journal Nature.

What Hopkins found, with her thesis adviser, Duke biology professor Mark Rausher, is the first clear genetic evidence for something called reinforcement in plants. Reinforcement keeps two similar proto-species moving apart by discouraging hybrid matings. Flower color had been expected to aid reinforcement, but the genes had not been found.

In animals or insects, reinforcement might be accomplished by a small difference in scent, plumage or mating rituals. But plants don't dance or choose their mates. So they apparently exert some choice by using color to discourage the butterflies from mingling their pollen, Hopkins said.

Where Phlox drummondii lives by itself, it has a periwinkle blue blossom. But where its range overlaps with Phlox cuspidata, which is also light blue, drummondii flowers appear darker and more red. Some individual butterflies prefer light blue blossoms and will go from blue to blue, avoiding the dark reds. Other individual butterflies prefer the reds and will stick with those. This "constancy" prevents hybrid crosses.

Hybrid offspring between drummondii and cuspidata turn out to be nearly sterile, making the next generation a genetic dead-end. The persistent force of natural selection tends to push the plants toward avoiding those less fruitful crosses, and encourages breeding true to type. In this case, selection apparently worked upon floral color.

Hopkins was able to find the genes involved in the color change by crossing a light blue drummondii with the red in greenhouse experiments. She found the offspring occurred in four different colors in the exact 9-to-3-to-3-to-1 ratios of classical Mendelian inheritance. "It was 2 in the morning when I figured this out," she said. "I almost woke up my adviser."

From there, she did standard genetics to find the exact genes. The change to red is caused by a recessive gene that knocks out the production of the plant's one blue pigment while allowing for the continued production of two red pigments.

Even where the red flowers are present, about 11 percent of each generation will be the nearly-sterile hybrids. But without color-coding, that figure would be more like 28 percent, Hopkins said. Why and how the butterflies make the distinction has yet to be discovered.

Hopkins will be continuing her research as a visiting scientist at the University of Texas, and the clear message from all of her advisers is "follow the butterflies. Everyone wants to know more about the butterflies!"


'/>"/>

Contact: Karl Leif Bates
karl.bates@duke.edu
919-681-8054
Duke University
Source:Eurekalert

Related biology news :

1. College students want more information about native wildflowers
2. Wildflower armors itself against disease
3. Wildflower declines in Thoreaus Concord woods are due to climate changes
4. Hearing colors, seeing sounds: New research explores sensory overlap in the brain
5. From butterflies wings to bank notes -- how natures colors could cut bank fraud
6. Butterfly vision, wing colors linked, UCI study finds
7. Study finds monarch butterflies use medicinal plants to treat offspring for disease
8. Butterflies shed light on how some species respond to global warming
9. As monarch butterflies journey north, gardeners can help protect species, researcher says
10. Now butterflies are also being counted in China, Australia and Israel
11. Hind wings help butterflies make swift turns to evade predators, study finds
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/14/2016)... NXTD ) ("NXT-ID" or the "Company"), ... the airing of a new series of commercials on Time ... 21 st .  The commercials will air on Bloomberg TV, ... the Street show. --> NXTD ) ("NXT-ID" or ... market, announces the airing of a new series of commercials ...
(Date:3/10/2016)... , March 10, 2016 ... market research report "Identity and Access Management Market by ... Compliance, and Governance), by Organization Size, by Deployment, by ... published by MarketsandMarkets, The market is estimated to grow ... Billion by 2020, at a Compound Annual Growth Rate ...
(Date:3/9/2016)... , March 9, 2016  Crossmatch ® ... and enrollment solutions, today announced the addition of ... Altus multi-factor authentication platform. New contextual ... managers to step-up security where it,s needed most ... Washington, DC . --> ...
Breaking Biology News(10 mins):
(Date:5/2/2016)... ... , ... StarNet Communications Corp, ( http://www.starnet.com/ ) a leading publisher of remote ... modules to its flagship X-Win32 PC X server. The new modules enable X-Win32 ... PC over encrypted SSH. , Traditionally, users of PC X servers deploy the XDMCP ...
(Date:4/29/2016)... , ... April 29, 2016 , ... ... personalized pain medicine, is excited to announce the launch of the Proove ... health studies, volunteerism, and education to promote the use of personalized medicine for ...
(Date:4/29/2016)... Denver, CO (PRWEB) , ... April 29, 2016 ... ... on addressing the necessary fundamentals to transform technology into a viable company, CereScan’s ... enable growth. Mr. Kelley, a recognized leader and mentor in the Denver ...
(Date:4/29/2016)... Italy , April 29, 2016 ... 5.11, the latest update to its industry-leading treatment planning ... shown that Monaco version 5.11 ... can now attain calculation speeds up to four times ... . With the industry,s gold standard ...
Breaking Biology Technology: