The price of beauty and fragrance


451

research highlights
EVOLUTION

The price of beauty and fragrance
Science 364, 193–196 (2019).

The sweet spring season is a good time 
for life rebirth and renewal. In addition 
to enjoying the aroma of this beautiful 
season, Sergio Ramos and Florian Schiestl 
at the University of Zurich, Switzerland, 
have decoded messages on plant 
evolution from the interactions among 
blooming flowers, buzzing bees and 
wiggling caterpillars.

Pollinators and herbivores (bumble bees 
and caterpillars of cabbage butterfly in this 
study) both interact with plants but exert 
different selection pressures. Pollinators 
select attractive flowers for pollen and 
nectar, while herbivores favour plants with 
fewer defences. To track the combined 
effects of pollinators and herbivores on 
the evolution of plant reproductive traits 
over multiple generations, Ramos and 
Schiestl used rapid-cycling Brassica rapa 
plants to set up four treatment groups: 1) 
hand pollination (no bees or caterpillars); 
2) hand pollination and caterpillars (no 
bees); 3) bee pollination and caterpillars; 
and 4) bee pollination (no caterpillars). 

Interestingly, they found that group 4 
evolved larger and more fragrant flowers. 
However, when caterpillars were present 
(group 3), the selection effects fade away. 
Also, they observed that bees spent less time 
on plants with caterpillars (group 3), and 
that this group of plants showed significantly 
reduced pistil length as well as a higher 
rate of self-compatibility and autonomous 
selfing at the eighth generation. Although 
the mechanism has not yet been determined, 
this work demonstrates an important 
impact of herbivores on pollinator-induced 
reproductive evolution.

Now we know that rapid evolution 
could be driven by the previously 
overlooked interplays between mutualists 
and antagonists. Next time, when 
encountering a bee or a caterpillar, what 
would you reminisce?

Lei Lei

Published online: 25 April 2019 
https://doi.org/10.1038/s41477-019-0428-6

Credit: Antje Schulte / Alamy Stock Photo

NaTUrE PLaNTs | VOL 5 | MAY 2019 | 451 | www.nature.com/natureplants

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https://doi.org/10.1038/s41477-019-0428-6
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	The price of beauty and fragrance