文章探讨了寄生虫如何操纵宿主行为，以及这种操纵对大脑进化的影响。从老鼠和猫、僵尸蚂蚁，到蜜蜂、蚊子等多种生物的案例，揭示了寄生虫如何通过改变宿主神经化学物质，使其被捕食，从而传播自身。甚至人类的肠道微生物也可能在无形中操纵我们的行为。

🧠 文章首先概述了寄生虫如何操纵宿主行为，例如弓形虫感染的老鼠不逃避猫反而寻求猫，或是僵尸蚂蚁被寄生虫操控爬上草茎，便于被捕食。

🦟 研究发现，寄生虫通过分泌化学物质改变宿主的神经化学过程，使其更易被捕食，从而帮助寄生虫传播到新的宿主体内。

🐜 文章列举了多种寄生虫操纵宿主行为的例子，包括寄生黄蜂操控蜘蛛织网保护其幼虫，寄生蝇让蜜蜂远离蜂巢传播幼虫，以及寄生微生物让蚊子吸取更少的血液以传播更广等。

🐛 文章还提到了肠道微生物可能对人类行为的影响，如肠道微生物为了在果蝇体内定居，会操控果蝇的食物偏好，这一过程可能也影响人类。

🧬 最后，文章指出，即使是病毒也能改变行为，例如狂犬病病毒会使狗、蝙蝠等哺乳动物变得极具攻击性，从而传播病毒。

Or at least this is the theory proposed in Brain Evolution Through The Lens Of Parasite Manipulation by Marco del Giudice.

The paper starts with an overview of parasite manipulation of host behavior. These are the stories you hear about toxoplasma-infected rats seeking out cats instead of running away from them, or zombie ants climbing stalks of grass so predators will eat them. The parasite secretes chemicals that alter host neurochemistry in ways that make the host get eaten, helping the parasite transfer itself to a new organism.

Along with rats and ants, there is a dizzying variety of other parasite manipulation cases. They include parasitic wasps who hack spiders into forming protective webs for their pupae, parasitic flies that cause bees to journey far from their hive in order to spread fly larva more widely, and parasitic microorganisms that cause mosquitoes to draw less blood from each victim (since that forces the mosquitoes to feed on more victims, and so spread the parasite more widely). Parasitic nematodes make their ant hosts turn red, which causes (extremely stupid?) birds to mistake them for fruit and eat them. Parasitic worms make crickets seek water; as the cricket drowns, the worms escape into the pond and begin the next stage of their life cycle. Even mere viruses can alter behavior; the most famous example is rabies, which hacks dogs, bats, and other mammals into hyperaggressive moods that usually result in them biting someone and transmitting the rabies virus.

Even our friendly gut microbes might be manipulating us. People talk a lot about the “gut-brain axis” and the effect of gut microbes on behavior, as if this is some sort of beautiful symbiotic circle-of-life style thing. But scientists have found that gut microbes trying to colonize fruit flies will hack the flies’ food preferences to get a leg up – for example, a carb-metabolizing microbe will secrete hormones that make the fly want to eat more carbs than fat in order to outcompete its fat-metabolizing rivals for gut real estate; there are already papers speculating that the same processes might affect humans. Read Alcock 2014 and you will never look at food cravings the same way again.