Monday, December 25, 2017


Post # 16
Donald A. Windsor

My catchy slogan, “Equal rights for parasites”, first appeared in the public domain in 1990 in Nature. Its most recent appearance was in 2017, 27 years later in the same journal.

Here is a bibliography of its published appearances over those years in my articles.

Windsor, Donald A. Heavenly hosts. Nature 1990 Nov 8; 348(6297): 104.
Windsor, Donald A. Guest Editorial. Equal rights for parasites. Conservation Biology 1995 Feb; 9(1): 1-2.
Windsor, Donald A. Editorial Bird parasites. The Kingbird 1996 September; 46(3): 190-2.
Windsor, Donald A. Stand up for parasites. Trends in Ecology & Evolution 1997 Jan; 12(1): 32.
Windsor, Donald A. Equal rights for parasites. Perspectives in Biology and Medicine 1997 Winter; 40(2): 222-229.
Windsor, Donald A. Equal rights for parasites. BioScience 1998 Apr; 48(4):244.
Windsor, Donald A. Most of the species on Earth are parasites. International Journal for Parasitology 1998 December; 28(12): 1939-1941.
Windsor, Donald A. Parasites’ rights gaining ground. Nature 2017 December 21/28; 552(7685): 334.

A Google search for “equal rights for parasites” (quotes necessary) turns up numerous pages of citations. This slogan is well entrenched in the scientific literature. I certainly hope that it is heeded.


Sunday, November 5, 2017


Post #15
Donald A. Windsor

Conservation of parasites seems to be an increasing concern in the literature. Good.

My first involvement with this issue started at a Symposium on the Conservation of Biological Resources back in September 1990, at Cornell University in Ithaca, NY. The Society for Conservation Biology was formed just five years earlier and many of its founders were present. At dinner they were still conversing about conservation when I interjected a statement of caution. I warned that all day the talk was about conserving hosts; no mention was made of conserving parasites. I then spontaneously uttered, “How about equal rights for parasites?”

Most of the diners frowned and some even muttered “Good riddance”. However, one of the founders smiled and repeated “Equal rights for parasites” and complimented me on the catchy rhyme.

That was a pivotal moment for me and I often pondered it after the meeting. Some parasite species can go extinct when their hosts do, so if the hosts are saved, the parasites will be also. But at that time, antibiotics were being routinely administered to anesthetized wildlife because their paradigm was that wildlife should be healthy.

Viewed from the point of parasites, free-living wildlife are habitat. Forcing wildlife to be healthy is unnatural, a crime against nature. This was not a popular opinion, so getting my views published was difficult.

But, I got a powerful break when Nature, the world’s leading scientific journal, published my terse letter to the editor. Unfortunately, the editor assigned it a cutesy title. Here is an exact retype of that letter.

Nature 1990 November 8; 348(6297): 104.
Heavenly hosts.
SIR – In the attempt to save certain species from extinction, for example the California condor, the black-footed ferret and so on, how much attention is being given to their natural parasites?
When all of the last remaining members of a species are taken into captivity, they may lose their parasites, either by the drastic change in living conditions, by treatment from zoo veterinarians or by generations of captive breeding. When they, or their offspring, are then released back to the wild, will they be able to become reinfected? Some parasites are quite host-specific in the wild and may indeed become extinct when their natural hosts are gone.
“So what?” may be a typical reaction. But, if our goal is to conserve biological diversity, then indeed all species should be considered, not just those with the most outward appeal. Many hosts evolved or, better still, co-evolved with their parasitic burden. Perhaps they deserve each other.
Equal rights for parasites!
Windsor, Donald A.
PO Box 604
Norwich, New York, USA

In spite of the uninformative title, the response was very gratifying; even the media called.

Buoyed up by that feedback, I submitted many manuscripts to various journals, but most were rejected. However, a few did get accepted. In 1995 the editor of Conservation Biology invited me to write a guest editorial.

Windsor, Donald A. Guest Editorial. Equal rights for parasites. Conservation Biology 1995 February; 9(1): 1-2.
That led to another invitation and another publication.

Windsor, Donald A. Endangered interrelationships; the ecological cost of parasites lost. Wild Earth 1995-96 Winter; 5(4): 78-83.
More publications followed.
Windsor, Donald A. Stand up for parasites. Trends in Ecology & Evolution 1997 Jan; 12(1): 32.
Windsor, Donald A. Equal rights for parasites. Perspectives in Biology and Medicine 1997 Winter; 40(2): 222-229.
Windsor, Donald A. Equal rights for parasites. BioScience 1998 Apr; 48(4):244.

One reader even sent me a bumper sticker gaudily proclaiming “Equal Rights for Parasites”.

Thursday, November 2, 2017


Posting # 14
Donald A. Windsor

When a tree falls in the forest and no one is around to hear it, does it make a sound?

When a paradigm shifts and no one in the scientific community notices, does it make any difference?

The tree question was asked by philosopher George Berkley in 1710. I ask my my paradigm question now. The vital role of paradigm shifts in science was explained by Thomas S. Kuhn in 1962.

My paradigm about parasites was published in 1998. I was advocating a paradigm shift. The newly formed concept in my paradigm turns ecology upside down and inside out.

Here is a brief backstory. My dissertation research involved parasites, but upon leaving school in 1966 my employment dealt with other subjects. When I retired in 1994, I was curious about what when on in parasitology during the previous 28 years. So I started reading the parasitology literature where I left off. When I finished in 1997 I experienced a shocking realization. Parasite species seem to be more numerous than their host species. Moreover, the important roles that parasites play in ecosystems seemed to be woefully understated and even vastly unrecognized.

Twenty years will soon have elapsed and, while my article has been cited 197 times, ecologistsists have not yet recognized this new paradigm as a shift. Maybe they never will. Regardless of what happens, I am getting too old to ever find out. Here is a brief synopsis.

The ruling paradigm in ecology holds that our biosphere is composed of free-living (non-parasitic) organisms, with parasites merely being pesky nuisances.

My paradigm contends that parasites are ubiquitous, insidious managers of our biosphere. They do not merely freeload off their hosts – parasites regulate their hosts. When competition and predation do not reign in host populations, parasites take over and prevent monocultures. The result is biodiversity. A corollary is even more astounding; some parasites enable their hosts to avoid extinction.

The validity of my paradigm can be tested, just as any other hypothesis can. If another planet, or even an asteroid, has life, but does not have parasites, then it will have few species and have large monocultures. My paradigm contends that parasitism is a property of life on Earth. Discovery of extraterrestrial life will reveal whether parasitism is a universal property of life.

I hope my paradigm becomes the current paradigm before we contaminate other worlds with our organisms and jeopardize this test.

References cited:

Berkley, George. A Treatise Concerning the Principles of Human Knowledge. 1710.

Kuhn, Thomas S. The Structure of Scientific Revolutions. Chicago, IL: University of Chicago Press. 3rd Edition. 1996. 212 pages.

Windsor, Donald A. Most of the species on Earth are parasites.
International Journal for Parasitology 1998 December; 28(12): 1939-1941.


Saturday, September 30, 2017


Post #13
Donald A. Windsor

Restriction of monocultures is the basic mechanism operating Earth’s biosphere.

When competition and predation do not control monocultures, parasitic diseases step in. The result is biodiversity and multiple ecosystems.

This simple explanation is based on observation. Monocultures, such as those planted by farmers, are quickly invaded by other species and attacked by numerous pests. Farmers have to be very diligent to protect their crops by using pesticides. Even then, other species manage to invade.

Our biosphere here on Earth is characterized by biodiversity, huge numbers of different species and interactions among all those species. Monocultures are rare and short-lived, found on newly formed islands and on disturbances leading to bare earth.

But what about life on other worlds? Does extraterrestrial life express itself as biodiversity or as monocultures? Do other worldly species interact in ecosystems? Or just dwell in monocultures?

Life on Earth is analogous to human economic forces. Without governmental regulation, unbridled capitalism results in a few very rich winners and vast hordes of poor losers. Our era of the robber barons in the late 1800s and early 1900s is a prime example. Parasites are similar to governmental regulations; they stifle exuberance.

Perhaps a world without parasites would be similar to unregulated capitalism, with a few very successful species and no or very few other species. Perhaps a middle class of species would have developed.

In the near future we may get an opportunity to discover extraterrestrial life. Will it be biodiverse? Or monoculturalistic? If parasites are present, so too will be biodiversity.


Friday, March 31, 2017


Post # 12
Donald A. Windsor

The copepod parasite that attaches to the eyes of Greenland and Pacific sleeper sharks seems to be too harmful to persist through evolution. Surely animals with their vision impaired by this parasite would be at such a competitive disadvantage that they would not live long enough to reproduce. Yet they do. In fact, Greenland sharks (Somniosus microcephalus) are the longest lived animals (1).

The standard story is that Somniosus sharks do not depend upon their eyesight to feed and reproduce (2). But, what if they did depend on their parasitic copepod?

Perhaps the copepod parasite (Ommatokoita elongata) confers some benefit to its shark hosts. I have long wondered about parasites conferring benefits to hosts but see it at the species level (3). Maybe this grotesque case of the shark and the copepod provides an example at the individual level. In fact, also at the species level because almost all individual Greenland sharks, 99%, are parasitized by this copepod (4).

Such a high level of infestation makes me wonder if this copepod is functioning as an organ. If so, then it is benefiting its host. Berland calls it a mutualism (4). Of course, all mutualisms benefit their hosts, by definition.

Perhaps the copepod acts as a vision enhancer that enables its shark to see better. Perhaps the copepod is very sensitive to vibrations and transmits the changes in vibrations into the eye and directly to the brain.

Many aquatic animals that dwell in murky water have appendages (catfish) or whiskers (seals) that do the same thing. Some aquatic animals send out electric pulses (eels, platypus) to assist their vision. Perhaps these copepods are involved in a similar process.

Perhaps in the distant past, the Greenland sharks were losing their eyesight and only those individuals that had this copepod parasite were the ones who survived.

The best explanation (so far) seems to be the one offered by the anonymous Norwegian fishermen who told Berland (4). They claimed that the parasitic copepods lure prey to the sharks. These fishermen contended that the copepods were luminous, but Berland could find no evidence for this claim.

Greenland sharks are very sluggish and Berland wondered how they managed to catch anything to eat. So luring prey, rather than chasing it, may indeed be the answer. The chief meal in Berland’s 1961 investigation was Char. However, Neilsen in 2017 reports that seals were a common food (1).

My conclusion to this bizarre case is that perhaps what we often call parasitism is really mutualism.

References cited:

1. Nielsen, Julius. Dating a Greenland shark. Natural History 2017 February; 125(2): 10-13.

2. Benz, George W. ; Borucinska, Joanna D. ; Lowry, Lloyd F. ; Whiteley, Herbert E. Ocular lesions associated with attachment of the copepod Ommatokoita elongata (Lernaeopodidae: Siphonostomatoida) to corneas of Pacific sleeper sharks Somniosus pacificus captured off Alaska in Prince William Sound. Journal of Parasitology 2002 June; 88(3): 474-481.

3. Windsor, Donald A. Parasites benefit their hosts – at the species level. Post #7 on 16 March 2014.

4. Berland, BjΓΈrn. Copepod Ommatokoita elongata (Grant) in the eyes of the Greenland shark – a possible cause of mutual dependence. Nature 1961 August 19; 191(4790): 829-830.


Saturday, October 1, 2016



Donald A. Windsor

Parasites benefit their hosts at the species level by insuring that they survive, thus ensuring their own survival. Parasites also help ecosystems survive by preventing monocultures.

Insurance provides benefits, but paying the premiums is a burden. Parasites act as insurance agents for their hosts and indeed, these agents certainly burden their hosts with payments. Parasites enable their host species to survive catastrophes that otherwise could have rendered them extinct. The result of this insurance is the enormous array of biodiversity that our biosphere exhibits.

Catastrophes are not common, but when they do occur, they can be fatal. Insurance is not used to compensate for the routine day-to-day hassles, just for serious calamities. Parasites have to confer benefits only when their hosts are at risk of extinction.

Individual organisms do not receive benefits from parasites. Species receive the benefits. The reason is that individuals do not evolve. Species evolve. Individuals die, but their species lives on, until it goes extinct. Individual parasites harm their individual hosts, by definition. By sharp contrast, at the species level, parasites benefit their hosts.

Insurance agents dole out money, but they also make money. Parasites insure hosts, but the parasites also get benefits. When a host species goes extinct, the species parasitizing that host also risk extinction. Parasitic species persist over long time periods by either keeping their host species extant or by switching to other host species. Parasitic species that do both increase their chances for survival.

Hosts and their parasites do not dwell in isolation. They live in ecosystems and they interact with other organisms. When their resident ecosystems collapse, they risk dying out. Consequently, species within ecosystems must cooperate to insure the survival of their ecosystems. Each species must fit in with the other species.

They fit in by not forming monocultures. Parasites prevent monocultures. When competition and predation are not able to retard rampant population growth, disease breaks out and monocultures are prevented. Our biosphere is biodiverse because of this process. Diseases are caused by pathogenic parasites attacking hosts already weakened by their normal parasites.

A good conceptual model is provided by financial systems. Unregulated capitalism results in wealth accumulation by a few people while most people wallow in poverty. Government regulation, taxes, black markets, and illegal schemes act as parasites on the capitalists, redistributing the wealth. Parasites fulfill this role in ecosystems.

The end result is that parasites insure that biodiversity prospers in our biosphere.


Sunday, November 8, 2015


Post #10

Donald A. Windsor

Parasitism is a property of life on Earth, because most of our species are parasites (1). However, what about life on other worlds? We are on the verge of discovering life on Mars. Will Martian life have parasites?

If parasitism is a universal property of life, then it should occur in Martian life.

If Martian life does not have any parasites, then parasitism is unique to Earth. It would have to be decided on how many potential host species would have to be examined before it could reasonably concluded that no parasites occur.

Meanwhile, we should avoid contaminating the Martian biosphere, in case it has one.

1.  Windsor, Donald A.  Most of the species on Earth are parasites. 
 International Journal for Parasitology 1998 December; 28(12): 1939-1941.