Mind-Controlling Wasps and Zombie Spiders

In the forests of Costa Rica, there lurks a sinister variety of wasp, bent on hijacking the minds of hapless spiders for its own ends. Left unmolested, a variety of orb spider known as Plesiometa argyra spends every day of its life carefully reconstructing its perfectly round web, and feasting on the insects unfortunate enough to become snagged upon it. But should one of these spiders fall victim to this Hymenoepimecis species of wasp, the spider is stripped of its free will, and made to spend the last evening of its existence building a protective shelter for the larvae that infect it.

It is a true example of mind control in nature, and though scientists are well aware of the method of infection, they are uncertain exactly how the mind control is accomplished. When a wasp successfully attacks a host spider, the spider is temporarily paralyzed as the wasp lays eggs on the tip of the spider's abdomen. Once the wasp departs, the spider regains its ability to move, and it continues its daily web construction for the next two weeks as though nothing has changed. Meanwhile, the wasp's growing larvae cling to the spider's belly and feed on its juices through a number of small punctures.

On the night before the parasites kill their host, events take a bizarre turn. Through some unknown mechanism, the larvae compel their host spider to build a web that is very different from that it has always constructed before. Instead of a flat, round web, the spider builds a stout, reinforced platform which is much smaller. Once the new web is complete, the larvae kill their host, and cocoon themselves on the structure. It is ideal for the task, being resistant to wind and rain, and safe from the ants that inhabit the forest floor.

This behavior was first observed by Dr. William G. Eberhard at the university of Costa Rica. His observations have led him to believe that the mind control is most likely accomplished through a fast-acting chemical secreted by the larvae, but what that chemical is– and how it works– is a mystery. What he has found is that the spider's usual five-step web building process is reduced to two when held captive by these larvae, resulting in the alternate design; and he has also discovered that if he removes the larvae on the last day, just before the spider is killed, the spider will often recover after a few days of spinning the abnormal web. It is true that many parasites are able to shape their host's behavior subtly, but never before has science observed a parasite that can manipulate its host in such a detailed, specific way. As evidenced by this finding, biology certainly has many fascinating secrets yet to be discovered.

Scientific article from the Journal of Arachnology: Under the Influence

Save the Whale-shark from Non-sustainable Tourism

The Atlantis Hotel, the newest and largest resort in the nation of Dubai, is holding a whale shark captive in its aquarium. The hotel, on the exclusive Palm Jumeirah Island, originally said it had "rescued" the whale shark, an endangered species. The hotel is now refusing to say if or when the whale shark will be released.

Environmentalists and Dubai residents are demanding that the shark should be released into its natural habitat. You can join the protesters by sending the e-mail below. The shark, which could grow up to 12m (39ft), was caught off the coast of Dubai six weeks ago. The management talked about "rescuing" an animal that was in distress, but former employees have told the local press that capturing a whale shark was always part of the hotel's plan to provide an added tourist attraction.
There is a growing swell of public opinion that the animal should be released. Whale sharks are protected under the CITES convention and the plight of this endangered species has captured the public's imagination. One popular newspaper has launched a freedom campaign. Children are talking about the situation in school assemblies and
local environmentalists are strongly urging the shark's release. Remember, Arenas del Mar has animals out there but they are all treated with respect as the original owners of this land. None of them are kept captive and furthermore we actually try to upgrade their home by doing intense landscaping with native species that are food sources for them. Whale sharks are also found in Costa Rican waters and there is a "Sightings Web" were you can give your report in case you see one while snorkeling. That website is: www.pretoma.org. If you are worried about that poor whale shark in the fish tank in Dubai, please take action today at: www.all-creatures.org.

Thank you!
By: Jose Pablo Fdez, naturalist guide