Researchers discover new insect-plant interaction

Photo credit: R. Evans

Insect interactions with plants cover everything from pollination to predation. However, these are ends of a continuum that ecologically and evolutionarily have interested scientists since the time of Darwin. Biologists Dr. Kirk Hillier and Dr. Rodger Evans are the first to describe how the larvae of a small moth, Mompha capella, enters the buds of unopened flowers, and forces them to self-pollinate.  These are flowers that are normally-open pollinated, and require bees, flies or insects to transfer pollen.  Fruit then develops in a flower that has never seen the light of day. 

The larvae crawls inside and eats the flower protected on the inside of the bud.  This is a significant new finding  on a spectrum with fig-wasp or yucca moth relationships, which are famous, ‘textbook’ examples of insect pollination symbiosis. It is important to note that these insects attack a plant which is endangered in NS, Rockrose (Crocanthemum canadense). "With only 5000–5500 plants restricted to relatively few available sand barrens in Nova Scotia, C. canadense is listed as critically imperiled".

While this unique interaction damages the flower, it is very precise in that only the bases of the petals are affected causing the flower to remain unopened. While Rockrose plants have the ability to self-pollinate, producing flowers without petals later in the season that never open and self-pollinate, the relatively few “showy” flowers that are produced are necessary for genetic diversity in the population. This research has shown an infection rate of ~50% of plants over the past 3 years, indicating that M. capella’s activities may have a negative effect on the already vulnerable Rockrose population.

To read the full article and see some really cool scanning electron micrographs of reproductive biology, go to:

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