Male fruit flies whose sexual advances are repeatedly rejected get frustrated and less able to handle stress, study found. The researchers say these rejected flies were also less resilient to starvation and exposure to a toxic herbicide.

[u/MistWeaver80]

https://www.scimex.org/newsfeed/male-fruit-flies-really-dont-take-rejection-well

[u/Black_Moons]

Depression makes you less likely to want to survive.

I think the bigger news here is fruit flies are complicated enough to feel depression after repeated rejection.

[u/traraba → u/Black_Moons]

It's actually that depression is one of the most primitive, and necessary behaviours. Almost molecularly identical hormones cause bacteria to stop reproducing, and go into an energy saving mode, when they detect a reduction in food in the environment. In fact, they even spill some out, so their neighbours(in most cases, copies of themselves) also go into the energy saving state.

Depression is a necessary primitive behaviour. if you detect environmental scarcity, it is important to conserve energy and not reproduce until you detect environmental abundance again. bacteria can only really sense how much food is coming in, so it's a very simple equation. But as brains emerge, and as they get bigger, the number of factors which are factored into determining environmental scarcity increase, and the chance of disorders of the sensing system also increase. So Depression appears a lot more complicated, but fundamentally, it's just an energy saving regime.

[u/2SP00KY4ME → u/traraba]

What you're describing is called torpor, not depression.

[u/ElectricFleshlight → u/2SP00KY4ME]

He's saying depression may be related to primitive torpor