Happy Valentine’s Day, Everyone!!
Speaking of romance…
A while back, I posted about the difference between density-dependent and frequency-dependent disease transmission. The “typical” example of a parasite/pathogen with frequency-dependent transmission is one that is sexually transmitted.
For humans and other mammals, most STDs are caused by viruses or bacteria (e.g., HIV, gonorrhea, chlamydia). One notable exception is pubic lice. However, for things like insects, all kinds of parasite taxa can be sexually transmitted. In fact, most insect STDs are from multicellular parasites! Sexual transmission is an especially successful strategy when host organisms are mostly solitary, so that interactions are rare outside of the breeding season.
There’s a link below to a review with all kinds of insect STD info – check it out!
Knell, R.J., and K.M. Webberly. 2004. Sexually transmitted diseases of insects: distribution, evolution, ecology and host behaviour. Biol Rev 79(3): 557-81. (Direct link to PDF download)