Time to quibble!
1.) Wasps as man's greatest enemy? Really?
If we were being poetic, here, then I'd say that Man's greatest enemy is Man themselves, but this is HN, so I won't. For a runner up, I would at least choose an animal that can actually kill a healthy human, rather than one that and annoy a healthy human and kill a subset with allergic reactions of venom.
2.) There are a lot of species of wasp. According to wikipedia, 160,000. Not all of them will sting, or even can sting humans. Fig wasps count among them. There are quite a few wasps that are beneficial, in that they predate upon insects that are slightly more annoying than the wasps themselves.
3.) Nectar is produced (generally) by flowers, to attract pollinators. By design, it's easily accessible by insects, and not protected by the rind of a fruit. The juice of a fruit is just juice, not nectar.