People notice and are attracted to fragrant flowers. Is this why it is said that insects are attracted to them because of their fragrances? Just because we “like” these odors, do insects also “like” them? Are there experiments in which fragrances, separated from their producing flowers, are shown to attract insects? And if so, couldn’t that just mean that the insects have learned to associate the fragrance with the flowers that they’re attracted to (for some other or unknown reason) ? Or have they done such experiments with newly hatched insects? The only thing I can think of is observing pollinating insects and comparing those visits with the times of days that the plants are most fragrant (to us). I understand this is a majorly naive question, but isn’t this where one goes to reduce one’s ignorance?
flowers don’t stink for your benefit but their benefit.
you get attracted to burgers for a reason.
And why can’t that just be one of those things that happens to have come along for the ride? (I can’t remember the term for those things). And lots of flowers do NOT smell. Doesn’t answer the question, as far as I’m concerned.
One obvious example of flower scent attracting insects is the genus Stapelia, whose flowers tend to smell like decaying meat/dead fish (they’re also luridly beautiful, which is why people grow them). Flies are attracted to the blooms because of the carrion-like odor. I once gave such a plant to a friend, who was oddly delighted when flies laid eggs in the flower and maggots hatched.
No, it’s the opposite. Flowers have fragrances (and colors, and every other attribute) in order to attract pollinators. The fact that we find them attractive is purely coincidental.
Flowers often have specific fragrances in order to attract a specific insect. Some fragrances are attractive to bees, some to butterflies, some to moths, some to bats. Flowers that are pollinated by birds generally are not fragrant because most birds have a poor sense of smell.
Not all floral scents are attractive to us, although they are highly attractive to their pollinators. Flowers that are pollinated by flies smell like rotting flesh, or sometimes feces. Some flowers attract male pollinators by smelling like females of the same species, and don’t smell like anything in particular to us.
Seems like it would be more than just coincidence. Makes me think there’s some biological/evolutionary connection there, too.
Seems so. But my question is how do we know that? Yes, butterflies go toward some plants and not others. How do we know it’s the fragrance that does it?
Birds are not attracted to them because of their fragrance, but are they repelled by that? How does such a pairing come about over time?
This is the most potent answer to my general question - there is some independently studied phenomenon that corroborates the observation, e.g. examining the odors of those plants and comparing that with the smell of the females.
Sheesh, so much to learn out there.
How is this any different from saying that the insects like the fragrance? That’s what most likes and dislikes amount to, even in humans: Association with something else the organism likes.
If you can discover it, you may have a cover of Science magazine in your future.
Possibly we like floral scents because places that have lots of flowers may be good places for primates to live (perhaps because there will also be lots of fruit there). But that’s pure speculation, and to the best of my knowledge there is no good evidence for a specific adaptive advantage for humans.
Studies have been done offering insects the chemicals that produce the odor. Insects are attracted to the chemicals alone in the absence of the flower itself. More simply, one could simply place a mesh bag around the flower that allowed the insect to smell it but not see it.
I didn’t say they were repelled by the absence of fragrance. Hummingbirds will visit fragrant flowers, but those flowers are not primarily adapted to attract hummingbirds.
Plants benefit when pollinators visit their own flowers and no others. That way no pollen is wasted by being spread to flowers where it does not good. Therefore many plants have evolved to produce attractants that take advantage of the sensory capabilities of particular pollinators. At the same time, they don’t produce attractants for other pollinators because visits by them are a less efficient use of nectar and pollen.
Hummingbirds see color well, but have a poor sense of smell. Many hummingbird flowers are red, because insects see this color poorly (and hence won’t attract insects competing for nectar). They are usually unscented. They have long tubular flowers, where the nectar can only be reached by long hummingbird bills. They produce a lot of nectar during the day, since hummingbirds need a lot of energy and are active by day. They may not produce very large amounts of pollen, since hummingbirds feed on insects and don’t need to eat pollen for protein.
Bees see color well, but also see into the ultraviolet. Many bee flowers have ultraviolet markings that are invisible to us. They produce a moderate amount of nectar that isn’t large enough to be attractive to most hummingbirds. Because bees feed their larvae on pollen, they produce enough to both feed the bees and their larvae.
Bats don’t see color well (and color mostly isn’t very visible at night), but have an excellent sense of smell. Many flowers visited by bats are white and produce very intense musky odors. They produce a lot of nectar (because bats are relatively big and need a lot), and protect it from other visitors by having long floral tubes so the nectar can only by reached by the long tongues of bats. They may also produce a lot of pollen for bats to feed on. Because bats are less maneuverable than hummingbirds, bat flowers often hang below the vegetation. They open or produce nectar only at night when bats are active.
And so on for other classes of pollinators. I can often tell the main pollinator of a flower just by looking at it. You can read more about pollination syndromes here.
There is an obvious one: we humans find the color & smell of these plants attractive, and so we spend effort planting & cultivating them. The whole nursery & florist industries are devoted to these plants. Which obviously works to ensure their evolutionary survival. There are probably millions of flowering plants that have gone extinct over the millenia, but these ones that humans find attractive have survived & prospered.
Cultivated flowers are only a tiny fraction of all the fragrant flower species that exist, and human cultivation of plants has been around only about 1/10,000 as long as flowering plants, so this isn’t even remotely an explanation for the existence of flowers that humans find attractive.
Interestingly (and depressingly) cultivated versions of many ornamental plants (roses are the most obvious example) have lost scent in newer cultivars/hybrids in favor of other attributes (flower size, color, length of bloom period etc.).
Since it is certainly possible to breed for fragrance, the lack of it in these ornamentals suggests it is not a big priority for most people.