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The last tulips in my garden this morning…
It is finally flower season! How I love it! However the happiness of the season is constrained somewhat by the gray squirrels, which have systematically beheaded my tulips (despite the fact that I have been simultaneously trying to ward the pests away with foul chemical sprays and appease them with nuts). Alas, most of my tulips now lie sad and beheaded beneath the cherry blossoms.
My (ineffective) struggles to protect my beloved tulips remind me of the struggles of wild flowers which face a similar arms race. The tulips I plant are propagated by big nurseries, and the squirrels don’t really want to eat the blossoms: they merely tear them apart to see if there is any food inside (and (probably) because the miserable rodents enjoy my suffering). Flowers are plant reproductive organs which exist to repopulate the species. In the case of garden tulips this involves a complicated relationship between myself, Lowes, tulip farms, nurserymen, and squirrels. In the world of wildflowers, the players are fewer and the stakes are much higher.
Buff-tailed Sicklebill (Eutoxeres condamini) by Ernst Haeckel
Flowers and their pollinators have a mutualistic relationship: the hummingbird –or bee, or moth, or bat, or whatever–gets a meal while the flower directly shares its gametes (in the form of pollen stuck to the beak or fur) with distant members of the same plant species. Some blossoms coevolve to provide nectar to specialized pollinators as with the famous sicklebill hummingbird (which feeds on the nectar of specialized Centropogon and Heliconia flowers which fit the bird’s beak and produce colors appealing to the hummingbirds).
This whole relationship falls apart sometimes though, thanks to a behavior first reported by Charles Darwin. Some animals are nectar robbers. Lacking the long proboscis or curved beak or special senses necessary to obtain the sweet nectar which the plant offers as a reward for its reproductive interlocutors, some animals simply cut through the blossoms or rip them apart to take the pollen. Although this can be beneficial (if a robber ends up pollinating a flower anyway, or forces a legitimate pollinating species to travel over a larger area—and thus provide greater genetic diversity), more often it is destructive.
Um, sure I guess…thanks, art department.
Interestingly, a recent study determined that bumble bees learn how to cut holes in flowers and steal the nectar directly from other bumble bees (you can read about the particulars of the study here). Bumble bees are not the only pollen robbers–various lepidopterans, bats, and birds are guilty in various ways–but the bumble bee example is the first case to prove Darwin’s thesis that such robbing behavior was learned by insects.
It all begins to make more sense now…
Flowers, though passive, are not helpless. Over generations, they coevolve with both the robbers and the pollinators—which is how they obtain so many convoluted and fanciful forms (and why there are so many toxicologically and pharmacologically active compounds therein). It is worth thinking about when you encounter a spring landscape of beautiful flowers—beneath the surface lies a world of sex, appetite, and larceny.
The horror!
Grains of Pollen Photographed by an Electron Microscope
In continuing celebration of spring, I’m returning to the microscopic world to appreciate the beauty of pollen grains. Ancient shamans intuited the generative nature of pollen and used it for ceremonial purposes: bright yellow pollen powder is still popular in Native American rituals today. However it was only with the advent of microscopy that we began to understand true range and beauty of pollen grains.
Acacia Pollen
Pollen grains contain male gametophytes which are ultimately meant to alight upon the proper carpel to unite with the female gametophyte cell and ultimately germinate into a genetically different offspring (my apologies to any impressionable readers out there). Spring is such a difficult time for allergy sufferers because many common trees and grasses utilize this time of year for pollination: flowers are unblocked by mature leaves and a whole growing season stretches ahead. It boggles the mind to imagine the immense community of tiny plant sex cells flying through the air around us and clinging to our bodies.
Himalayan Iris Pollen
Most of our favorite flowers and fruit have pollen which is entomophilous (i.e.carried by animals) and designed to stick to the leg of a bee or moth or some other pollinator. Such grains tend to be like burs, with all sorts of strange miniscule hooks and spikes (they thus pose less of a problem for allergy sufferers–since they never make it to the nasal cavity). Other plants literally cast their hopes upon the wind. These anemophilous pollens are lightweight explorers produced in vast quantities and they get everywhere (to the misery of those with hay fever).
Pollen Nestling in the Cilia which Lines Your Upper Respiratory Tract
A Grain of Lavender Pollen Lying on a Lavendar Petal
Of course pollen is only one component of the microscopic jungle around us. Right now you are sitting amidst an immense collection of fungal spores, infinitesimal mites, decaying skin cells, animal hair, bacteria, viruses, and even more esoteric flora and fauna. Just imagine the coming world of nanotechnology where these various biological entities will be joined by infinitesimal man-made objects…
Insect Scales, Pollen, Hair, Manmade Fibers, Fungal Spores, and Dander
ferrebeekeeper 