Wednesday, March 15, 2017

Spiders Are Your Friends - Science

For all the stuff humans eat in a day (about 400 million tons of meat and fish), spiders eat twice that much weight in insects.  (Science Daily: Spiders eat astronomical numbers of insects)

Since insects kill us at a radically higher rate than all the TV news bad guys, we're afraid of them, particularly mosquitos.  Since spiders eat them the Rockhouse will go with the Arabic guidance that the enemy of my enemy is my friend.

You go, spiders.  Eat 'em up, yum.

This is a jumping spider Phidippus regius preying on a bush cricket (Tettigoniidae)

Credit: Copyright David E. Hill, Peckham Society, Simpsonville, South Carolina

The researchers then used two simple models to calculate how much prey all the world's spiders as a whole kill per year. In their first approach, they took into account how much most spiders generally need to eat to survive, as well as census data on the average spider biomass per square meter in the various biomes. The second approach was based on prey capture observations in the field, combined with estimates of spider numbers per square meter. According to their extrapolations, 400 to 800 million tons of prey are being killed by spiders each year.  (Science Daily:  Spiders eat astronomical numbers of insects)

The astounding part is just how much weight that is relative to how much other creatures eat.

For a sense of just how much this is, take the following into account: all humans together consume an estimated 400 million tons of meat and fish annually. Whales feed on 280 to 500 million tons of seafood, while the world's total seabird population eats an estimated 70 million tons of fish and other seafood.

According to further calculations, spiders in forests and grasslands account for more than 95 percent of the annual prey kill of the global spider community. The figure reflects the fact that forests, grasslands and savannas are less frequently disturbed than for instance agricultural or urban areas, and therefore allow for greater spider biomass.

- SD

The researchers are highly aware of the Circle of Life and the important part spiders play in it.  The reason for running this one is you won't often find people manifesting so much spider love and these researchers are loaded with it.

"These estimates emphasize the important role that spider predation plays in semi-natural and natural habitats, as many economically important pests and disease vectors breed in those forest and grassland biomes," says lead author Martin Nyffeler.

According to the researchers, spiders are not only important predators, but are also valuable sources of prey. Between 8,000 and 10,000 other predators, parasitoids and parasites feed exclusively on spiders, while spiders at the same time form an important part of the diet of an estimated 3,000 to 5,000 bird species.

"We hope that these estimates and their significant magnitude raise public awareness and increase the level of appreciation for the important global role of spiders in terrestrial food webs," adds Nyffeler.

- SD

No comments: