"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift

August 10, 2011

Cytinus hypocistis

For a change of pace today the blog is going to feature a parasitic plant. Cytinus hypocistis is a holoparasitic plant, which means that unlike ordinary plants it does not perform photosynthesis, but obtains all the nutrients that it needs from its host. Cytinus hypocistis is embedded entirely within the the root of its host plant, but in spring, it pokes flowers out of the ground, which are then pollinated by ants and ripen into berry-like fruits. Each of these fruits contains thousands of tiny seeds, each about 0.2 mm in length.

What makes C. hypocistis unusual is that while most fruit-bearing plants rely upon vertebrate animals to disperse their seeds, C. hypocistis mainly uses a beetle. Researchers found that the seeds collected from beetle frass (fancy name for insect poop) are just as viable as seeds which are collected directly from the fruit. While rodents and rabbits also frequently consume C. hypocistis fruits, because they have a tendency to eat immature fruits and deposit their dung (with any viable seeds) at ground level, they are not as effective as the beetles. Not only do the beetles consume only fully-ripened fruits, they also have a tendency to bury themselves into the sand during midday, which can bring the seeds closer to the roots of the host plant.

This is one of the few known case of endozoochory (where the seed is consumed and pass through the gut of an animal) which involves an insect. The researchers of this study pointed out that this type of ecological interaction may in fact be quite widespread and common, especially for plants with very small seeds. However, they have simply been overlooked because all those involved were, quite literally, lurking meekly underneath our feet.

de Vega C, Arista M, Ortiz PL, Herrera CM, Talavera S (2011) Endozoochory by beetles: a novel seed dispersal mechanism. Annals of Botany 107: 629-637.

1 comment:

  1. Thanks Tommy. I was intrigued by these pretty little flowers when bushwalking in the Var department in the south of France in May. I'd found information on Cytinus through researching the host plant Cistus, but it wasn't until reading your post that I learnt about their strange (but as you point out - possibly not uncommon!) method of seed dispersal.