Where do parasites go when their hosts become extinct?

June 2nd, 2009 - 3:23 pm ICT by IANS  

Washington, June 2 (IANS) The loss of endangered species sends alarm bells ringing among conservationists, but what happens to the parasites they host?
Although most people would side with the panda over the parasite, which group should we worry about more?

North Carolina State University (NCSU) biologist Rob Dunn and colleagues examined the concept of co-extinction, the loss of one species upon the extinction of another.

“Decline in host species could drive parasite species to switch onto alternative hosts, which could escalate the rate of emerging pathogens and parasites both for humans and our domesticated animals and plants,” Dunn said.

Regions where new human diseases, such as bird flu, are emerging coincide with the regions where the most mammal and bird species are endangered, added Dunn.

“We have long talked about the negative consequences of the endangerment of the species we love,” he said, “but getting left with their parasites is a consequence no one bargained for.”

“Put simply, when a host becomes rare, its parasites and mutualists have two choices: jump ship to another host or go extinct. Either situation is a problem,” he said.

“Since the diversity of parasitic or affiliated species, which may include viruses, ticks, lice and bacteria, and butterflies is several orders of magnitude greater than that of their hosts, the numbers of co-extinctions are also expected to be far greater than the number of extinctions of host species,” Dunn said.

These findings were published in the journal Proceedings of the Royal Society.

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