Why are bugs attracted to light?

In the summers , we have all noticed that the bugs are hovering around the porchlights , streetlights and other luminous objects. Sometimes they even dive into it , killing themselves. But what exactly cause this behaviour , which is also dangerous , and doesn't even look rewarding . (Plus there is a bonus fact at the end of the page!)

Well, unfortunately , no exact reason has been found yet . Though there are some theories that I'll share. There collected below :

1) FOLLOWING LIT AND CLEAR PATH

The first and the most obvious one , is that the bugs just follow the path they can see clearly and ultimately reach the object emitting light . After that , they just hover around as there is nothing else to see .

2) NAVIGATION 

Some suggest that the insects are used to keep sun at a certain angle from there point of view[literal point of view] . But during the night they get confused between lights and sun , then try to keep the lights at an angle from themselves , there are not able to do that as those lights are very close . So the insects just get frustated and fly around the lights to figure out the right direction in confusion.

3) A PLACE TO HANG OUT

I also read somewhere that the lights just pose as some kind of "bug hotspot" . As there is a buzz around , the bugs keep joining in the crowd , it also makes it easy for some perverts to get a chance to get laid [something scientifically called 'mating']. But this theory has some drawbacks as , if it were true , then why do the insects crash in , or , if the just create a buzz at a well light place , its sure to attract predators , which is obviously not preferable.

4) MISTAKEN TO BE FOOD 

It can also be thought that the bugs simply just mistake the lights for food [that explains why the jump in them]. As some of the lights also emit UV and so do the flowers[which are food for bugs]. (fact: using LEDs are others which don't emit UV , won't attract insects!!)

5) TO GATHER SOME HEAT 

The insects could also just be trying to get heated in the chills of the night , couldn't they? Everyone needs heat to survive.

BONUS FACT: Not all the insects are attracted to light , the ones attracted to light are called 'Positively Phototactic' like moths. And there are also some insects which avoid light , called 'Negatively Phototactic' like cockraoches . This phenomenon of insects interacting with light is called phototaxis.