The book manages to be gross and fascinating and occasionally beautiful.
Given the age, I'm sure some of the science is outdated, perhaps even by people who grew up reading the book. But it remains one of my favorites, and it's an accessible read. If not always a comfortable one!
That was me!
First I read Peeps by Scott Westerfeld when I was ~13, where ever odd numbered chapter is the story, and every even numbered chapter describes a different parasite.
At the end of the book was a blurb that said "if you enjoyed the parasite chapters, go read Parasite Rex, which I did. I loved it.
That book inspired me to take AP Bio, then get degrees in molecular biology and bioinformatics. In college I did research on a few different species of parasitic wasp for a couple years. I've written the wikipedia page for two different parasitic wasps and given numerous presentations on my favorite wasps.
The wasps are more of a spare time passion these days, though. It's much easier to make a living with bioinformatics and robotics.
I still keep my (well-worn) copy of Parasite Rex on the nightstand.
Pity as the things nobody has ever heard of are probably the most interesting.
I wish I remembered more details so could link something.
But then I re-read it, and the second time it seemed to mean that the members of a group studying a certain animal would self select to favour those who are fascinated by and admire that animal. This also seems highly plausible to me.
Either way, it seems fitting that the world of shark study is full of "apex predator" researchers.
>I wonder if the group studying an animal slowly evolves to resemble this animal
IOW:
I wonder if the group studying an animal slowly evolves to look like this animal
likely
Frankly, this claims are starting to be a little offensive.
Biologists take baths also when needed. Exactly the same as any other people. This would be not different than claiming that people that breed pigs, ends looking and smelling like pigs. Is not a productive way to drive this kind of conversations.
The idea that you can change your personality just by choosing a field of study is for some reason very appealing to me.
May I ask how so? Is it from producing popular documentaries or something? Or is there the research grant money from conservationist institutions or societies? (I can see how that wouldn't be there for parasites).
*imaginary bug
NSF grants are still the most important and impressive for most subfields within ecology, but the competition is fierce.
cliches are stupid.
Parasites manipulating their hosts is something that really fascinates me from an evolutionary point of view. An example given in the article is T. gondii [0]:
> [...] a parasitic protozoan that boasts “Mind Control,” because it attracts its rodent host to the smell of cat urine, where the rat spreads the parasite to felines.
Infected mice also have a reduced fear from predators, likely for the same reason.
This is my absolute favorite example: https://journals.plos.org/plosone/article?id=10.1371/journal...
A parasitoid lays multiple eggs in a caterpillar host. The larvae eventually hatch out of the host's body, but do NOT kill it. They then need to pupate outside the host, which leaves them vulnerable to predation. Their former host, the caterpillar whose body they just violently erupted from, will then act as a BODYGUARD. It will body slam any insects that approach, knocking them away from the pupae. Truly the stuff of science fiction.
There's a nematomorph parasite that infects crickets, and part of its life cycle is aquatic. It will induce crickets to jump into water and drown themselves (there are some crazy videos of this on YouTube). This study found that the allochthonous input (land to water) coming from the crickets jumping into a Japenese stream was a large part of an endangered trout species' diet. In short, his trout was kept alive because of a parasite driving crickets to drown themselves.
The summary doesn't seem to follow from the finding. The fact that you mostly just eat crickets that walk up and ask to be eaten doesn't immediately imply that, if the crickets stopped doing that, you'd starve to death. It should be easy to understand the choice to go with a low-effort option even if there's also a higher-effort option available.
This one isn't really a manipulative parasite, but there is an isopod that will eat a fish's tongue: https://oceanconservancy.org/blog/2022/04/28/tongue-eating-l...
What's weird is that it then... basically acts like a tongue? It doesn't seem to be massively detrimental to its host, but it's absolutely insane to see a fish's mouth open and then there's just like, a little guy hanging out in there.
Tangentially: assuming I had the drive + health to make the change, do you feel it would be a particularly challenging move for a software engineer to abandon their career to go back to school and study insects or other arthropods? I'm not a competitive person at all, and I saw your other comment above about the field, but I still imagine the money available for studying bugs is a tiny fraction of that for writing them.
During a PhD program, you're not gonna make much money, but you will probably enjoy the classes and research, particularly if you have some money saved up from your current career to help smooth the bumps of living TA paycheck to TA paycheck. I really loved my PhD program, but was also in my early 20s and living like a poor grad student wasn't as big a deal.
As far as long-term career prospects go, I think things are a bit more challenging. There are opportunities to work for state or federal agencies, particularly if you focus on agricultural insect pests. Otherwise it's pretty much academia, and the job prospects there are pretty slim. Unlike other domains where there lots of non-professor jobs, for entomology and related fields, there are far fewer. Labs tend to be fairly small, so the total # of jobs nationally is also pretty small.
My advisor always used to say that he never knew anyone who didn't make it into a tenure-track position, if they were willing to hang on long enough. He also acknowledged that hanging on for a long time can suck! I wanted to start a family and live in a place where I had a community, so I left academia and work as a data scientist for a public transit agency near lots of friends and family.
What I'd say is that if you have a sense of the long-term career you want (agency scientist, ag researcher, tenure-track prof) and can go into grad school with a solid plan, you can make it happen. Entomology isn't a terribly expensive field, so you can do a lot without much funding, and that freedom can be really wonderful! But it's not going to be a particularly lucrative career, and competition for stable tenure track jobs is high, requiring a lot of geographic flexibility.
As you can see, I've got a lot of thoughts on this! If it's something you're seriously considering and want to talk more, let me know and I'd be happy to chat sometime.
In primates, there's some non-fear of cats too. For humans and domestic felines, this isn't much of an issue. For chimpanzees who share territory with leopards, this is more of an issue. https://www.nytimes.com/2016/02/16/science/a-parasite-leopar... (and the paper - Morbid attraction to leopard urine in Toxoplasma-infected chimpanzees https://www.sciencedirect.com/science/article/pii/S096098221... )
Having a leopard stare at you, even through a fence, does raise the heart rate. But I don't know why we regard big cats so relatively favourably, when an evolved innate repulsion, such as to spiders or snakes, would make as much sense.
1) https://en.wikipedia.org/wiki/Leopard_attack#Leopard_predati...
For a long time I've been interested in the fact that children are afraid that, if they are left alone, they will be eaten by monsters.
In the ancestral environment, this is absolutely true. But the belief is obviously innate and not learned. What's interesting is that the innate belief is correct in the details, as opposed to being something that is not necessarily true but nevertheless produces the correct behavior.
"They have a mat of messy protein extrusions in place of an exoskeleton, their eyes have no facets, and their thorax is completely indistinct from their abdomen!"
- Insect Aesthetician
While I subjectively agree about cats, "aesthetically well put together" is downstream of the "evolved innate" factors.
Beauty is objective. Taste is subjective. Hence why we can say that someone has poor taste, i.e., the subjective fails to align with the objective.
I can admire the beauty of an insect as an insect without me being an insect. Similarly, if an insect were intelligent, possessed with an intellect, it could judge the feline as a beautiful creature as a feline.
"As X" is important, because it is a matter of how well the specimen realizes the telos of its species. Hence, why defect is ugly. You wouldn't say pi is an ugly integer. You wouldn't say a hammer is a crappy saw. You wouldn't say a fish is a bad mountain hiker, except as a shorthand for "fish do not mountain hike, are not anatomically + physiologically ordered toward hiking".
And of course there degrees of good, and therefore, beauty, based on how much more you resemble the Highest Good and therefore the Most Beautiful, Goodness and Beauty as such.
Arthropods and even snakes are morphologically too distant for that. Nevertheless, people usually find large-eyed geckos more cute than armor-eyed chameleons or tiny-eyed crocodiles.
I would say that the cute cats are domesticated species, like many animals. So they wouldn't exist without humans, and it's in their benefit to behave to survive.
Compare this with dogs that are more of a "working animal." We've bread dogs to fill specific roles because they were larger to work with. If humanity had tried to find companionship in the mountain lion instead of Felis lybica (the wild cat).
Also for the how almost-domestic the African wild cats are: https://youtu.be/ZRqlSr1Yp1M
The other part of it (as I understand it) is that cats body form is not as easily selected for when compared to animals that humans have domesticated.
Dogs have a number of body sizes that can be "easily" selected for - https://embarkvet.com/products/dog-traits/traits-list/#body-... and https://embarkvet.com/products/dog-traits/traits-list/#other... (there's even a mutation of https://en.wikipedia.org/wiki/EPAS1 in wolves that was selectively bred into dogs https://academic.oup.com/mbe/article/34/3/734/2843179 )
I suspect part of the lack of range comes also from that the cats of size that don't eat us are not ones that can be crossbred with cats in the wild to introduce new useful genes. Trying to cross a domestic cat a wild cat doesn't produce a new cat that is useful in a new role ( https://en.wikipedia.org/wiki/Felid_hybrids#Confirmed_domest... ). Compare this with domestic dogs and the various wild dog species.
The 14 genes mentioned that control dog size: https://research.nhgri.nih.gov/dog_genome/study_descriptions...
The concept behind this is https://en.wikipedia.org/wiki/Phenotypic_plasticity
And linking to a reddit post about this from a while back - https://www.reddit.com/r/askscience/comments/1hhzcn/why_do_w...
Elevated basal slippage mutation rates among the Canidae - https://pubmed.ncbi.nlm.nih.gov/17437958/
> The remarkable responsiveness of dog morphology to selection is a testament to the mutability of mammals. The genetic sources of this morphological variation are largely unknown, but some portion is due to tandem repeat length variation in genes involved in development. Previous analysis of tandem repeats in coding regions of developmental genes revealed fewer interruptions in repeat sequences in dogs than in the orthologous repeats in humans, as well as higher levels of polymorphism, but the fragmentary nature of the available dog genome sequence thwarted attempts to distinguish between locus-specific and genome-wide origins of this disparity. Using whole-genome analyses of the human and recently completed dog genomes, we show that dogs possess a genome-wide increase in the basal germ-line slippage mutation rate. Building on the approach that gave rise to the initial observation in dogs, we sequenced 55 coding repeat regions in 42 species representing 10 major carnivore clades and found that a genome-wide elevated slippage mutation rate is a derived character shared by diverse wild canids, distinguishing them from other Carnivora. A similarly heightened slippage profile was also detected in rodents, another taxon exhibiting high diversity and rapid evolvability. The correlation of enhanced slippage rates with major evolutionary radiations suggests that the possession of a "slippery" genome may bestow on some taxa greater potential for rapid evolutionary change.
(and if you're interested in genetic diversity and fossil records, https://en.wikipedia.org/wiki/Cat_gap )
Of course, I'm not an expert in anything so this could be bunk.
I think there's just something viscerally, instinctually unsettling about how some arthropods move, which gives rise to arthropod-like monsters in fiction (xenomorphs, Bugs in Starship Troopers, Zerg, etc.). Spiders, the poor beasts, get the worst of our fear because they don't move their legs via muscles like we vertebrates, or even insects, do; their body pumps hemolymph into the legs, forcing them to straighten. This hydraulic-pressure system of movement is just different enough to our visual system to be really weird.
In person they can produce a different reaction.
A couple of years ago, a jaguar climbed from its habitat on the local zoo here, and put its paw over the fence to "play" with the humans.
A really unexplainable amount of people did not have a different reaction.
Still do, in parts of India and some other countries, and not just where poor people live
Wolf spiders are welcome in my basement though. They are smart enough and have good enough eyesight that the likelihood of getting bit by one is super low. They hunt down all the pests in your home.
What makes them extremely cool is that they're kinda like nature's hydraulic robots.
Mental illness or brain parasite is the only possible explanation for dog owners behavior.
Last year, there was news in The Netherlands about a case where grandparents were babysitting. Their normally docile German shepherd killed the baby within seconds.
https://www-nhnieuws-nl.translate.goog/nieuws/329594/opa-en-...
>The dog had bitten another dog two years earlier and a cat seven years before the incident with the baby, but an expert stated that aggressive behavior towards animals is no reason to assume that it is also aimed at people.
Really? These "experts" are morons. German Shepherds are well-known for their use as police and military dogs because of their size, strength, and aggressiveness. Sure, they can be trained better than some other known-to-be-vicious dogs, but they're still dangerous. Putting one in a room with an infant is pure stupidity. Even worse, this particular dog had already attacked other animals in the past. At the very best, you might be able to claim that a dog that bit a cat years ago isn't necessarily unsafe around full-grown adult humans, but a German Shepherd chomping on a person isn't an immediate death sentence, but with an infant it really is.
This article also sucks because it doesn't even tell us what ultimately happened to the dog.
Just yesterday I argued with some moron about the same thing. Obviously flagged!
"Attacks in India are still relatively common, and in some regions of the country leopards kill more humans than all other large carnivores combined.[9][10] "
It is most likely running away because it found itself completely overwhelmed by multiple attackers - it is not a hunting style big cats go for.
More often busted for breaking the speed limit.
More often founding a company.
Rodents themselves are genetically wired to fear cats. A rat that smells cat urine will go the other way. However, get that same rodent infected with toxo and it will suddenly be attracted to the scent. Thus it checks out cat urine and becomes more likely to find itself in the stomach of a cat.
So you'd think toxo is wreaking havoc with all sorts of elements within the rat, turning it into a deranged rat. Nope. Everything else remains and functions normally - olfaction, social behavior, learning and memory, and even fear behaviors all stay the same.
It takes about 6 weeks for toxo to migrate from the gut to the brain. In the brain it forms cysts in multiple locations, but mainly in the amygdala region. The amygdala is the brain's center for fear and anxiety. It is also the brain center for forming predator aversion pathways. Once in the amygdala toxo is able to take dendritic nerve cell endings and cause them to shrivel up.
Shrivel up the dendritic spine, shrivel up the fear pathway.
Taking the creepiness up several notches, recall that other fear/anxiety based behaviors remain constant. The parasite is actually locating and unwiring the very pathway it needs to destroy.
Amazingly, it does not stop there. Toxo wants to make cat urine attractive and it is able to do so by hijacking another well known pathway; sexual attraction. Part of the neural connection for sexual activity passes through the amygdala. This gets rewired and a rodent infected with toxo will no longer have a fear response to the urine but it will have activation of this sexual response pathway, resulting in attraction to the scent.
Eau de merde. C'est fantastique! They are mapping out the toxo genome. One curious element discovered is that this protozoan parasite has two genes for tyrosine hydroxylase. This is responsible in part for the production of dopamine, which is all about rewards and the anticipation of rewards (really it's the thing that gets you to do the thing needed for the reward). It acts as a catalyst in the conversion of L-tyrosine into L-DOPA, which is in turn a precursor for dopamine.
So at the right moment, the parasite secretes the enzyme, thus driving the neurons to create dopamine at the time the toxo wants them to, thus associating dopamine with the neural pathway that toxo wants used!
Do other parasites that are closely related to toxo share this gene? No. Strangely it does not have genes for other common hormones - just this one that allows it to plug into the key for mammalian reward systems. And it starts generating it after it has penetrated into the brain and formed cysts, especially cysts in the amygdala.
For humans the current clinical dogma is that it's a disaster for a fetus but otherwise runs its course and goes latent. However, a small literature exists suggesting that males in particular become more impulsive after a toxo infection and that people who are toxo infected are 3-4 times more likely to be killed in car accidents that involve reckless speeding.
He quips that this is a protozoan parasite that knows more about the neurobiology of fear and motivation than 25,000 neuroscientists standing on each others' shoulders.
And it's not alone. The rabies virus knows how to control the neurobiology of aggression. It makes the animal more likely to bite and pass on the rabies infection.
from: http://www.robertsapolskyrocks.com/toxoplasmosis.html
https://pubmed.ncbi.nlm.nih.gov/29906469/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/ https://www.mdpi.com/2077-0383/13/2/593
Martin Shkreli is still getting raked of the coals over his deraprim pricing shenanigans
https://www.ftc.gov/news-events/news/press-releases/2023/01/...
>Why do so few researchers study them?
>In the fall of 1985, Scott L. Gardner found himself standing over his toilet bowl, fishing around in the squishy output of his empty bowels with a chopstick.
fsckboy's law of headlines: If the headline asks a question, check if the first sentence has your answer
>...Gardner was prescribed an antiparasitic pill, and the next morning, he pooped out his intestines’ inhabitant—all 12 inches of it.
irl, my brother got a parasite once, a tapeworm. This was all without leaving an upscale suburb of Boston. Only "noticed" it when he, a well-built vigorous athlete, lost a lot of weight out of the blue. It was eating his lunch, so to speak.
How does that work. A tapeworm is pretty small relative to your brother (eg by mass), one would think it's caloric needs are similarly small and it would just use a small fraction of his food. Can a tapeworm really consume a significant fraction of an adult's food?
[1] https://www.kiseichu.org/e-top
[2] Visible in the tall blue case here: https://static.wixstatic.com/media/079dcd_843c7597ef244423aa...
The display has a piece of rope, so that you can get a not-too-intimate sense of its length.
google "tapeworm symptom loss of weight" and you will get the recommendation "time to see a doctor"
The weight loss isn't just a result of the parasite competing for nutrients, though that doesn't help.
https://en.wikipedia.org/wiki/Ancylostoma_duodenale
It's the stuff of nightmares.
so if one worm takes m slices of the pie, and there are n worms in the person, there will be m x n less slices available for the person, which, depending on the values of m and n, could be quite high, and therefore much more detrimental to the person
There's got to be something else to it, like that your belly feels strange and you lose your appetite.
Suddenly losing a lot of weight points toward dehydration, for one thing.
Maybe if the guy was well muscled he needed a constant influx of protein, also. Breakdown of muscle which is mostly water doesn't translate to a lot of calories.
Varies from person to person. Could take years before the thing is big enough to cause any real damage. I've seen cases where people had parasites inside them without noticing for what must have been decades without any treatment.
Doctors in endemic regions often won't even bother with tests, they'll treat you straight up. Good old albendazole, once a year. In certain places people routinely go to the doctor to ask them to prescribe the medicine whether they feel anything or not.
Tapeworms eating your food is definitely a very popular idea. Sometimes I see some exceedingly clever humans trying to use them as a poor man's semaglutide. They usually get zero results but sometimes they lose some serious weight alright, most of it water.
Pictures of parasites: https://www.atlasobscura.com/places/meguro-parasitological-m...
I know there’s Ophiocordyceps sinensis which attacks caterpillars but that’s more traditional medicine than food.
https://www.smithsonianmag.com/smart-news/five-parasitic-spe...
Parasites tend to be multicellular and relatively large (you can see them all with an optical microscope), and therefore hard to miss.
On the other hand, there are plenty of bacteria and viruses that are out there still to be discovered, many of which directly impact humans.
The thing is, discovering them is not enough, not by far. We know how to avoid a few of them - say, by washing hands, regulatory agencies requiring meat be controlled for parasites (in Germany and possibly EU, against trichinella [1]), or by heavily suggesting pregnant people not handle cat litter (to prevent toxoplasmosis). We know how to treat a few of them (mostly worms).
But we don't know how to treat a lot of them, for some of them (particularly in the veterinarian world) we're dealing with resistency developing. And a few of them remain utterly and completely deadly (Naegleria fowleri).
The problem is, as always, a lack of funding. No one wants to spend much money on parasitology (as you said: we know about most of them), and since most parasitic infections are rare in Western countries that have the money, there is not much money for treatment R&D - no matter how many people die each year worldwide (400k for worms, 600k for malaria alone).
Neither malaria nor Guinea worm affect "Western" (rich, industrial) countries directly, but people from these countries most actively work on the eradication, chiefly financed by charitable funds.
[1]: https://www.imperial.ac.uk/news/239931/mosquitoes-that-cant-...
[2]: https://www.nature.com/articles/nature.2015.18974
[3]: https://www.cartercenter.org/health/guinea_worm/index.html
I'm pretty sure there's a lot of conceptual overlap between parasitic/symbiotic organisms and economic relationships, too. E.g. I'm pretty sure this kind of thing happens all the time in scamming ecosystems:
>Often, in an effort to travel between host animals, parasites will expose their hosts to new predators, like the tapeworm Ligula intestinalis, which grows so large it changes the buoyancy of the fish it inhabits, causing the fish to swim closer to the surface and get eaten by birds.
The whole point of the field of economics is not as popularly believed to shill neoliberal, neoclassical free markets, it's kind of the opposite - to study all the ways in which economics models (and markets in general) fail (both in the abstract and in the real world) and how to fix that. (and the solutions have been known for decades at this point, but policymakers don't implement them)
At least half of it is, and that's where the money and prestige generally is. There's plenty of elaborate mathematical models being created by PhDs and postdocs relying upon neoclassical economic axioms.
I don't disagree that economists are in theory aware of economic parasitism I just think that it's one of those topics where research funding can often end up in weirdly short supply.
this simply isn't true, go actually look at what economists are doing and you will find these issues are getting studied and taught a lot, it's basic stuff
The tannins in oak are an arms race to slow many of them down. As is the thick epidermis on mature leaves. And then there are the adaptations to prioritize roots over leaves when young, which both helps them tap into the wood wide web but also I suspect helps them deal with deer. Stay small until you can get tall and then jump out of reach as fast as you can.
Additionally, graduate students tend to avoid selecting research areas they dislike or find disgusting. The most disturbing presentation I've ever watched was a slideshow given by a parasitologist in which I saw worms in parts of the human body I never imagined it possible for worms to be in. No wonder students aren't lining up to spend years of their life working with them.
I read an essay once by someone who intentionally incubated some kind of fly in himself, and wrote that, after all the effort of being infected and incubating the fly, it chose to emerge while he was at a baseball game, where, he lamented, it was immediately killed by horrified fans over his protests.
The fans were clearly in the right.
Developed nations solved parasites naturally as they developed. Infrastructure, basic sanitation, standards for food production... All of these things interrupt the natural fecal-oral lifecycle of parasites, solving the problem.
Naturally, developing nations are terrible at all of those things. To put it mildly. And thus parasites are endemic. They are literally every day things. It's actually kind of surreal.
It doesn't matter how much funding people put into parasitology, it doesn't change the fact the true solution is to develop the nation into a proper civilization.
* one could always spot the reconstructive surgeons at these conferences; they were the ones who could wander around the poster session, all while calmly nibbling away at their hors d'oeuvres.
We are likely biased and can't imagine how we are biased because of the infection! Yet the over-under for an individual is clear: try the medication and find out!
Plenty of diseases get us and most of us don't have an incentive to study what we know is statistically likely to kill us :<< . Which I think is a shame.
Out in nature, things get more complicated - there are many reports of viruses infecting parasites which in turn infect animals, for example.
https://schaechter.asmblog.org/schaechter/2011/07/viruses-th...
Well, this is a false claim. Sort of. Nobody notices or nobody cares about this researchers, is not the same as nobody studies.
the same reason why so many other disturbing things go unstudied
like certain risks to our survival, for example
i think it's a vuln humans have
Because they're the ones funding medical research! nyuk nyuk!
Seriously though, as a health nut who tries to stay on the science side of things, I still see a lot of "It's Parasites!" stuff from the pseudo-science health community. As well as bizarre cures. Walnuts, Cloves and electric shock seem to come up the most.
I have tried to find any practical advice regarding detection, symptoms and such, and beyond tapeworms, heartworms and hookworms, there isn't much information.
> Housed in a few modest rooms adjacent to a botanical collection and the floor’s only bathroom, the laboratory is the world’s largest university collection of parasites.
> the Manter Lab only receives enough funding to employ the two men
This explains why perfectly. Researchers that choose this live basically in poverty, so why would you to encourage your son to follow that career?.
This and the two billions of videos of cats on internet that everybody consumes actively all the time. Try to earn sympathy and views with a samba dancing flatworm compilation instead. It only works one or none times.
They are a big part of earth biodiversity and provide services to the ecosystem or the host. Services that sometimes no other can provide. Some parasites can clean in theory the host body of poisonous mercury. Could we train parasites to eat cankerous tumors in the future?
