Research suggests that the loss 108 of the most threatened primates could lead to the extinction of another 176 parasite species, as they lack suitable hosts. Credit: Marie Claire Chelini and TriCEM
We have posters and t-shirts that say "save the Chimps." You won't see anyone wearing a shirt with the words "save chimpanzee lice" on it. People seem to be more conscious of the plight endangered gorillas than they are of their gut worms. Or, perhaps, more obsessed with mouse lemurs rather than their mites.
The future of our closest animal relatives is uncertain. Half of the roughly 500 primate species in the world are at risk due to human activities like hunting, trapping, and deforestation. According to a Duke University study, the loss of threatened primates could lead to more species extinctions due to parasites.
James Herrera, first author at the Duke Lemur Center, stated that if all primates are extinct and they do so, it won't be the only species to go extinct. It could also include twice as many parasites.
Herrera stated, "That's a whole world of biodiversity that could go extinct without our even realizing." "We don't know much about how they work in the body. We don't even know what's going on."
A previous study has shown that between 85% and 95% of parasitic worms of animal species are not yet known to science. This is despite the fact that the International Union for Conservation of Nature's (IUCN) authoritative Red List of extinctions was created.
Herrera acknowledges that this might seem odd to be concerned about given all the efforts we make to deworm and delouse our pets and ourselves. Herrera stated that parasites are something most people want to eliminate, not conserve.
Most people are terrified at the thought of strange creatures nestling in the warm, wet folds and wriggling inside our intestines. Herrera explained that parasites do not always cause symptoms or make hosts sick. Parasites can have surprising benefits. For example, worms in the stomach can help to prevent other infections or keep autoimmune disorders under control.
Professors Charlie Nunn at Duke and Herrera used network analysis techniques to assess the potential impact of parasites on primates. Their research was published in Philosophical Transactions B on Sept. 20, 2009.
Their model shows species connected in complex webs that involve 213 primatesmonkeys monkeys, lemurs and galagosand 763 mites and protists. The parasites that depend on one primate host for survival can't survive if it dies. If there are not enough of these connections, it can lead to a fatal cascade in which one extinction leads to another.
Herrera explained that it's somewhat like KerPlunk, a classic children's game. A clear tube is filled with marbles. It rests on top of a web made of interconnected sticks. It is not necessary to remove one or two sticks, in this instance primate hosts, from the network. The marbles will still be supported by the other sticks. As the number of sticks decreases, it becomes harder to stop the marbles falling.
The IUCN currently considers 108 of the 213 primates in their data set to be endangered. The IUCN considers 250 additional parasite species at risk if these species are lost. 176 parasite species also have no suitable host.
Study revealed that the extinction process will be more severe in isolated areas like Madagascar. The study revealed that illegal hunting, shrinking forests and the collection of pet animals are driving 95% of the lemur species to the edge. More than 60% of the lemur parasites live in one host.
At least two species of nematodeworms, for instance, depend on the aye–aye, a bushy-tailed, long-fingered lemur with beaverlike teeth and bushy tail. The worms that it carries will also die if the ayeaye is gone.
Researchers say that they can't predict how many parasites from their data could survive extinction by adapting to more plentiful hosts. Some of the most well-known diseases, including yellow fever, HIV, and malaria, originated in primates. They then spread to humans when they share a watering hole or are butchered for meat.
Herrera stated, "It's not so difficult to imagine."
This study is part of a special issue of Philosophical Transactions of the Royal Society, B that focuses on infectious disease macroecology.
