@starlitspacecloud submitted: Found this bug outside my house today (I live in [removed], please remove location for privacy). It’s kinda hard to see in this picture, but there was a wriggling, gelatinous, almost wormlike… thing sticking out of the boundary between the dark and light brown segments of the spike extending out of the beetle(?)’s abdomen. In addition, the spike retracted into the abdomen in a telescoping manner, with the dark segment retracting into the light segment before the light segment retracted into the body, whenever I got close. The big was otherwise motionless. Any idea what kind of bug this is and what’s going on here?
This is a female broad-necked root borer, and the spike is her ovipositor. Without seeing what was coming out of her, I can't say whether or not it was eggs or something else. Normally to lay eggs, they push their ovipositor down into the dirt or leaf litter.
They do sometimes just stick their ovipositor up into the air to release pheromones to attract males, so it's possible she was pushing out some sort of gland or something to release pheromones? I couldn't find much about it when I did a brief search. Either way, I love her!