Comments on: Fear of spiders changes bodies of grasshoppers and makes plants decay more slowly

By: oddjob

oddjob — Mon, 18 Jun 2012 16:57:57 +0000

I think David Hobby is correct.

By: suzume

suzume — Fri, 15 Jun 2012 19:51:39 +0000

Lots of studies have found sublethal effects of predators in different taxa. The mere presence of predators induces responses such as development of spike-like structures in water fleas or changes in body shape in some fish. The really nice thing about this above study is showing the potential knock-on effects for the ecosystem. Presumably there are further knock-on effects given in the presence of the predators they are reproducing less meaning less grasshoppers in the future eating anything.

By: Walter S. Andriuzzi

Walter S. Andriuzzi — Fri, 15 Jun 2012 19:35:32 +0000

This is really cool, although it’s not very realistic that dead grasshoppers would just get buried belowground instead of being first consumed by predators or scavengers. Still, above-belowground feedbacks are one of the new frontiers in ecology, and I expect more and more papers on legacy effects

… They glued together the spider chelicerae?! Where’s animal protection?

By: Allan

Allan — Fri, 15 Jun 2012 14:21:50 +0000

Interesting. I’m still unclear on how this would work. If the stressed grasshoppers switch from eating higher protein to higher carb vegetation, would not the high protein plant tissue then either be eaten by something else (that would die and return to the soil) or return to the soil when the plant tissue itself dies. That is, wouldn’t the nitrogen budget of the system be determined by the rate of fixation and deposition, not by insect grazing? Or do the grasshoppers decompose more readily than the plants? Schmitz found that spiders increased the nitrogen level in the soil because when they were around grasshoppers mainly ate goldenrod (which provided them more cover from spiders), releasing other plant species that decomposed more readily.
[Schmitz (2006) “Predators have large effects on ecosystem properties by changing plant diversity, not plant biomass”, Ecology 87(6): 1432-37]

By: mfumbesi

mfumbesi — Fri, 15 Jun 2012 06:47:11 +0000

“whose mouthparts had been glued shut, ” Thats one sick scientist there. I kid, I kid.
This is fascinating stuff.

By: David Hobby

David Hobby — Fri, 15 Jun 2012 03:09:49 +0000

In the second-to-last paragraph, it says: “He got the same results as before: the packages meant to simulate stress-free insects slowed the decay of plant litter compared to those meant to resemble stressed ones.” I think this is backwards?