I have hundreds+ little black and red bugs all over my property. Many of them are attached together as a pair by their posterior, I assume they are male and female. They range from very small, approximately 2mm, to 2cm or larger. Some of the bugs also have red bodies and white legs. They seem to interact with each other. I am located in Southern California, Orange County.
These are red-shouldered bugs, Jadera haematoloma. Your first and fourth images are of young nymphs, the second image is a mating pair of adults, and the third inage i of a recently molted older nymph and an adult male bug.
https://www.heartspm.com/red-shouldered-bugs.php
Thank you.
