"The big question here is how the wasp mother can control the ladybug, transforming her into a zombie babysitter... The answer is that the wasp mother injects the ladybug not just with the egg but also with a virus. "
This strengthens my belief that insects are like tiny little robots.
The really interesting question is why don't we see these amazingly detailed and precise parasitic mechanisms elsewhere, like in mammals? Are we just doing a terrible job of finding them, or is there something more interesting going on? Del Giudice recently published a paper arguing that the baroque complexity of non-insect nervous systems may in part be an anti-parasite mechanism, by making it too hard for a distributed group of small simple parasites to find hacks: "Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation" https://www.gwern.net/docs/genetics/selection/2019-delguidic... , Del Giudice 2019 (discussion: https://slatestarcodex.com/2019/08/19/maybe-your-zoloft-stop... ).
Toxo is the exception that proves the rule here. Toxo is perhaps the best known example of any parasite having human behavioral effects, yet the causal role of toxo is still not accepted, and what it's postulated to affect is pretty random: schizophrenia, car accidents, that sort of thing. That doesn't look like any kind of planned behavioral control which might affect toxo reproduction. It just looks like a parasite causing some damage post-infection. It's unclear if it even manages to replicate the mouse effect of making humans more attracted to cats (since we contract it mostly from cats, obvious confound). You certainly cannot compare its capabilities, in rodents or primates, to the astonishingly precise and complicated behaviors that insect parasites can orchestrate. And it's not like humans in the wild don't host plenty of parasites!
Unlikely. That would be inconsistent with the heritability, for one thing, for which no genetic correlations with immune-related things have ever been reported that I've seen, and with the best attempts at finding a physical cause landing on things like under-reactive amygdalas and other things one might describe as general brain damage (like toxo) rather than any kind of cunning plan to spread a particular virus/parasite. (How would psychopathy spread a virus? It'd have to be an STD, I guess, except symptoms of psychopathy often show up in childhood and long before individuals have ever had sex, which is also problematic.) Psychopaths do seem fairly fertile, though, which is why theories sometimes invoke an evolutionary life-history explanation: it's a hawk-dove kind of strategy (adaptive if there are enough suckers around, and weak enough social constraints on psychopathic behavior, which would explain why it seems rarer in traditional rural environments and more common in modern urban environments).
Thanks for this explanation. I hadn't really thought to much about the heritability aspect - even though I had heard of it some years back... this is a good nugget of thought on psychopathy and how it may perpetuate it self...
Has anyone read this book? I've been having a craving these days for books on animals, having just finished "The Rise and Fall of Dinosaurs", and this looks pretty good.
Lots of underrated beauty in the insect world as well. Check out the last series of images in this video about manual focus stacking for short dof shots - https://youtu.be/2GmQ2Hj9WOs?t=198
This strengthens my belief that insects are like tiny little robots.
[0] https://www.mayoclinic.org/diseases-conditions/toxoplasmosis...
Another one from the same guy, have to poke around - https://www.youtube.com/watch?v=qmMcCjEU68Y
Lots more of these kinds of vids on youtube of course...