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.
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.