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... )
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!
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...
"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.
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 )
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.
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.
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.
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.
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.
Still do, in parts of India and some other countries, and not just where poor people live
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.
"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] "
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/...
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.
[0] https://en.wikipedia.org/wiki/Toxoplasma_gondii