I am growing long beans and winter melon in the same bed.
Earlier this summer, ants were factory-farming black aphids (black fly?) all over the the bean plant (particularly on young leaves/stems, flower buds, and on the actual long beans). In response, I used an organic soap spray and completely wiped out the black-aphids, and the aphids have not come back. This was a couple of weeks ago.
However the ants still remain, and they are doing something weird. The ants are hanging out at the end "nubs" of the plant. (I don't know bean plant anatomy at all., so by "nubs" I mean the stems that shoot out only to produce flowers and beans.) Almost every nub will have at least 3 ants camping in one position, with their heads occupied with something related to the "cavities" in each nub. (Again I don't know bean anatomy at all, and don't even know if these cavities are natural to bean plants, or something the ants dug.) Anybody know what these ants are doing?
Could I have wiped out their food supply to the point that they would eat the plant or drink it's sap? Is this something ants will resort to? And is this bad for the plant? Those are basically my questions. Please look at the pictures for more info.
FYI: I'm just guessing, but it looks like the cavities could be part of the natural plant? It's small but I don't see any honey-dew insects in the cavities, nor do the cavities seem to be increasing in size or quantity over time. Either way though, I am extremely ignorant when it comes to beans and ants. All I know is that ants are industrious and probably up to something evil, and I would like some idea what it is.