Bug food again

Another visit to The Grub Kitchen at Dr Sarah Beynon's Bug Farm near St David's began with a stroll up a blackberry jam-packed lane. Stopping to pick a fruity hors d'oeuvres prior to sampling the entomophagous delights that awaited, we noticed that the lunch had already begun for this spider which was contemplating a captured grasshopper.

It was a pleasing enough shot, but googling 'spider eats grasshopper', as one does, I found an intriguing write-up of an experiment that appears to demonstrate that grasshoppers stressed by the proximity of spiders "tend to eat more carbohydrate-rich food, high in carbon. They also spend less energy on growing or reproducing, so they eat relatively less protein-rich food, high in nitrogen".  (The same is true for all animals experiencing stress.)
As a result when their bodies drop to the ground and decay they create a less nutritious environment for microbial activity.
 "dead plants decomposed three times more quickly in soils seeded with stress-free grasshoppers, compared to those laced with the stressed insects. The tiny difference in their chemical composition was enough to drastically impede the decay of plants that shared the same soil." 
The significant factor is nitrogen which attracts microbes. The lower levels of nitrogen present in the scared grasshoppers meant that the agents of decay operated more slowly to an infinitesimal, but nevertheless significant, degree. Isn't that extraordinary?

It goes to show that the presence or absence of predators may have critical knock-on effects on the ecosystem as a whole by altering the chemical composition of other living organisms - just by their presence alone.
 Nothing is entire unto itself, everything in the natural world is as interconnected as a spider's web.

If you want to read the (short) article about how the experiment was carried out it's here but please note it contains a mistake in the penultimate paragraph. It also contains the information that some of the spiders' mouths were glued up - sorry!

The Grub Kitchen turned up trumps once again; grasshoppers didn't feature but crickets did.