Wormy world
This blog is titled “parasitesandrocknroll”, but it has been awhile since either parasites or rock n roll has been the topic of a post. Well, there was a bit about R n R in the last post (i.e. nine inch nails). Anyways, it is definitely time for a post about parasites! Most people think that maintaining biodiversity is a good thing. We tend to feel bad when things go extinct, with the exception of dangerous diseases like smallpox. Cute or furry animals are especially high on the conservation list. However, if we want to conserve biodiversity as a general goal, regardless of the creature’s charisma, we would more or less be protecting parasites (and by extension their hosts). Parasites easily outnumber free-living species. That can serve as a nice anecdote at your next dinner party…”by the way, did you know that there are more parasitic animals than free-living animals?”. It may impress your friends, though it would probably kill most conversations. Anyhow, let me provide some evidence to back up this claim. Traditionally, species have been determined by noting and describing clear morphological differences between them. Sounds easy, but this can be exceedingly difficult when looking at 2 mm long worms. Nowadays, though, it is relatively cheap and easy to sequence a critter’s DNA and assess whether there is gene flow between different morphotypes (critter’s that look different). Broadly, if there isn’t any evidence of gene mixing, you can be rather sure you have different species. I have two friends/colleagues that work in parasite systematics that have used this approach. The first I knew in Nebraska and examined a particular parasite that had been found in many different fish species…suggestive that it is actually many parasite species. Well, after looking at the DNA, there turned out to be 5 or 6 new, previously unrecognized species. The other friend worked on tropical fish (snappers (pic) check ‘em out) from the Great Barrier Reef. Same story. He examined an understudied group of parasites both morphologically and molecularly, and turned up 11 new species. These stories are definitely not unusual. Parasite species diversity is just grossly underestimated. Think about it this way. There are about 40,000 described species of fish. Each fish species will probably have a few unique parasite species; some will harbor an incredible diversity of parasites. For example, in one fish species in one lake, there may be more than 40 different parasite species capable of infecting it. So how many parasites are there? No one knows, but we can be sure that most animals on this earth are parasites. Indeed, we live in a very wormy world.
This blog is titled “parasitesandrocknroll”, but it has been awhile since either parasites or rock n roll has been the topic of a post. Well, there was a bit about R n R in the last post (i.e. nine inch nails). Anyways, it is definitely time for a post about parasites! Most people think that maintaining biodiversity is a good thing. We tend to feel bad when things go extinct, with the exception of dangerous diseases like smallpox. Cute or furry animals are especially high on the conservation list. However, if we want to conserve biodiversity as a general goal, regardless of the creature’s charisma, we would more or less be protecting parasites (and by extension their hosts). Parasites easily outnumber free-living species. That can serve as a nice anecdote at your next dinner party…”by the way, did you know that there are more parasitic animals than free-living animals?”. It may impress your friends, though it would probably kill most conversations. Anyhow, let me provide some evidence to back up this claim. Traditionally, species have been determined by noting and describing clear morphological differences between them. Sounds easy, but this can be exceedingly difficult when looking at 2 mm long worms. Nowadays, though, it is relatively cheap and easy to sequence a critter’s DNA and assess whether there is gene flow between different morphotypes (critter’s that look different). Broadly, if there isn’t any evidence of gene mixing, you can be rather sure you have different species. I have two friends/colleagues that work in parasite systematics that have used this approach. The first I knew in Nebraska and examined a particular parasite that had been found in many different fish species…suggestive that it is actually many parasite species. Well, after looking at the DNA, there turned out to be 5 or 6 new, previously unrecognized species. The other friend worked on tropical fish (snappers (pic) check ‘em out) from the Great Barrier Reef. Same story. He examined an understudied group of parasites both morphologically and molecularly, and turned up 11 new species. These stories are definitely not unusual. Parasite species diversity is just grossly underestimated. Think about it this way. There are about 40,000 described species of fish. Each fish species will probably have a few unique parasite species; some will harbor an incredible diversity of parasites. For example, in one fish species in one lake, there may be more than 40 different parasite species capable of infecting it. So how many parasites are there? No one knows, but we can be sure that most animals on this earth are parasites. Indeed, we live in a very wormy world.
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