Thanks.

I think it still works, even if horses eat other things (which I think we both know is true, anyway). Because other animals like an apple on occasion, including primates including humans. Of course, many an apple will slowly rot never having attracted something to eat it and will slowly decompose where it fell. That individual is less likely to germinate and if it does is more likely to struggle and die an early death. But the system works on an evolutionary level, doesn't it? There are many an apple tree dotted across the planet. And the fruit they came from didn't all roll randomly to get to where the seeds germinated. They were carried. In bellies.

Finally, we must also remember life isn't about being 100% efficient or 100% perfect, is it? It really isn't about being anything, in fact. It just is. So long as the laws of physics that govern the universe aren't being violated, the thing works.

Regards insects, it's probably a little more complex (they reckon there's over a million named species of beetles, for example). Some plants are 'happy' allowing lots of different types of insect access to their precious pollen / nectar source. Likewise, some insects will not be that fussy about where they're getting their nectar from. Generalists. With a broad diet (in the case of the insects) and broad range of insects that get to carry their pollen (in the case of the plant / flower). Just as there are many, many generalists in both categories, there are lots and lots that are more specialised. Insects that only visit one type of flower (though the flower could theoretically be visited by other species of insect still). Plants that can only have their pollen carried by one species of insect (though the insect could theoretically still visit many other species of plant for its nectar needs). Finally, there'll even be the real close-knit relationship where a plant species exists that provides nectar to a species of insect that feeds 100% on its nectar.

The anatomy of a flower is designed (by nature that is, ie. through evolution) to accept insect visitors. Some flowers will and do allow just about any insect visitor in. Some flowers have a structure that is more restrictive preventing all but a single / few target species from getting to its nectar (and thereby, pollen).

Evolution has been happening for billions of years. We're talking incomprehensively vast numbers of individuals, some of which (in the case of insects, for example) having extremely short life cycles. Let your fruit flies escape in biology class at school and a few weeks later they could be trying to take over the school. Some such animals could see several generations being born in a year. So, in all those billions of years and with all the individuals of the species concerned, some of these interspecies relationships have really got in tune whilst others have gone wrong somewhere along the line. Take for example the orchid that mimics a bee. What possible advantage could the flower get from mimicking a bee? At a guess, I'd expect very few insects will visit them (thinking it's a bee and not a flower) but the ones that do, get to enjoy all the nectar (carrying away some of the plant's pollen, inadvertently, in return). One would have to presume it evolved from an ancestral species that also looked like a bee, an ancestral bee species, even.

Throw a load of shit against a wall and some of it will stick. It seems nature did and some of what stuck is a flower that looks like a bee. Remarkable, eh?

Anyway, it's tea time...