Muck and Mystery
   Loitering With Intent
blog - at -
June 06, 2010

I find the ideas mentioned in Eat Dirt to be fascinating.

A number of epidemiological studies have shown that people infected with parasitic worms suffer less from allergies and other immune diseases, and research in animal models designed to mimic these diseases supports these findings. . . "When you have organisms that have lived together for hundreds of thousands of years, they become mutualistic rather than combative" . . .
They don't always become mutualistic, but those cases where they do are interesting.
Plants have a number of responses to insects and other animals that eat them (herbivory), including changing metabolism to cope with physiological stress or producing toxins that make plants more resistant, for example, said Kessler. In turn, the herbivores may develop strategies to counter the plant's defenses and influence its signaling pathways, creating a kind of arms race where herbivores and plants co-evolve. . .

the saliva of the Guatemalan potato moth larvae (Tecia solanivora) -- a major pest that forces farmers to spray plants with pesticides every two weeks -- contains compounds from the insect's foregut that elicits a systemwide response in the Colombian Andes commercial potato plant (Solanum tuberosum) to produce larger tubers.

When the larvae infested fewer than 10 percent of the tubers, the plant produced marketable yields (after infested tubers were removed) that weighed 2.5 times more than undamaged plants, according to the study. When up to 20 percent of the potatoes were damaged, marketable yields still doubled. And when as many as half of the potatoes were infested, yields equaled those of plants with no infestation.

The findings have implications for potato farmers, as the compound, once isolated, could lead to considerably higher yields in some varieties of potatoes. . .

While more research is needed, the researchers believe that compounds from the insect's saliva somehow increases the rate of the plant's photosynthesis to compensate for the tuber(s) lost to the caterpillar damage; as a result of more photosynthesis, more carbon is drawn into the plant and used to create starch, which makes for bigger tubers.

Kessler, who studies similar elicitor compounds in tobacco plants, recently received grants from the U.S. Department of Agriculture as part of the land grant system and administered though the Cornell University Agricultural Experiment Station and the National Science Foundation to identify the compounds that elicit increased plant growth and to understand the physiology of the tobacco plant's response.

I'm keenly attuned to the benefits of predation in sustaining healthy agro-ecosystems. See Habitat Management for an overview of a number of old posts that individually support portions of an exegesis of range land management.
The large ruminants make habitat for rabbits. The rabbits make habitat for herbs. The nutrient poor subsoil that they pile on the surface when digging their borrows is perfect habitat for "poverty plants". That's their ecosystem role, the niche they exploit, pioneering bare soil resulting from soil disturbance. In time, as they die and decompose, they enrich that soil making it once again suitable for grasses. And so the cycle proceeds. Not stated is that the herbs make habitat for butterflies etc. In a circuitous way cows make rabbits (and gophers and voles etc.), and rabbits make butterflies.
Humans are part of the system too and their roles are investigated a bit in the various posts linked by Habitat Management. I'll add moth spit to the list of counter-intuitive benefits of predation. I've been half-heartedly composing a post about chitin and its role in plant health. It will be a story that fits in here in a way too.

TrackBack URL for Co-Creation -


no tech magazine has a link to a 3 page article on combating desertification with grazing, thought you might enjoy it.

Posted by: josh at June 7, 2010 04:17 PM