Many of us can relate to that moment when you accept spring’s invitation to step out and saunter in the warm sun to hear all the vibrant sounds as nature awakes from the slumber of winter, to smell all the fragrances floating on the breeze, and then it hits you, a series of powerful, uncontrollable sneezing fits! Upon recovery, your eyes are filled with tears, and your nose is running in an effort to clear that tiny nuisance, pollen. Profits are made in efforts to assist our terrible reactions to pollen, and many of us would rather it not exist, so what is it; why does it exist; and who really needs it?
Pollen is a tiny package formed to carry plant DNA, which is only half of the ingredients needed for plant reproduction. Pollen is formed by the male part of plants (stamen), and is transported to the female part (pistil) with the intent of forming seeds, which produce more of the same plants. The challenge pollen has is getting from one place to the next.
Wind, water, and pollinators are modes of transport for pollen. If it is transported by wind and water, the surface of pollen will be smooth, more aerodynamic, and sometimes may include little air sacs to capture the wind as a parachute does. If it is transported by pollinators, it will be rough and spiky, which is more conducive to sticking to things as Velcro does.
As seen below, pollen viewed under an electron microscope, is very unique, and the plant it came from can be identified by the shape, texture, and color of the pollen granule. Pollen is not always yellow; there is green, red, orange, brown, purple, blue, white, and many other colors. Plants are not all the same, so why would pollen all be the same? In fact, natural areas have pollen signatures, the composition of which is unique, and very useful to us.
This is a photo taken with an electron microscope; pollen is in the micron range of size, so not visible to the naked eye.
FUN FACT: Pollen signatures are very useful to detectives when finding a body, or location of a crime, as pollen sticks to fabric, and suspects aren’t going around committing crimes in the nude. The clothing will contain samples of the pollen signature of the place the crime occurred, making it easier to narrow a search, and often leading to justice. Who knew pollen could be a part of an investigative team? Watch a brief talk about it here: Pollen’s Story
The bottom row in this photo contains individual pollen provisions for individual mason bee eggs, which are divided with mud walls. This pollen is mixed with nectar, and will be consumed by the bee larva. Pollen is a high protein food.
Pollen is not only important to for plant reproduction, but also to bees for feeding their young. Bees are motivated and designed to carry pollen; some are better at pollinating than others, but all bees, with the exception of cuckoo bees, seek pollen.
Ceratina is a tiny black bee with a cute little face. This one thought she was hidden, but I caught her on camera!
Ceratina bees eat pollen and carry it in their transport tummies, not to be digested, but rather carried back to their nest. So, Ceratina bees have hair, but not as much as the bees who carry pollen on their bodies. Pollen is most often carried on the outside of a bee’s body.
The belly of this Leafcutter bee is orange with Lupine pollen.
One modality is scopa, which is thick curved hairs that could be located on the bottom of the abdomen, as is the case with Leafcutter bees, or on the hind legs, as is the case with Digger bees. Pollen is stuffed into these hairs by the bee as she collects it from flowers, but is not mixed and bundled with nectar.
Look at all that yellow pollen all over this digger bees hind leg scopa, and body!
Bees such as bumble and honey, carry pollen in baskets on their hind legs termed corbicula. The back of the leg is concave and smooth with basket like hairs curved around the front of it. Honeybees and bumblebees will mix the pollen with nectar and glob it onto the corbicula as seen below.
That orange ball on this bumble’s leg is pollen mixed with a little nectar to make it sticky.
The hairs of bees are hooked, and sometimes frayed at the tips to pick up the Velcro like pollen, and in addition to this, there is a charged relationship!
This is a closeup of pollen stuck to the hairs of a honeybee. Notice the branching on the hair shafts. This characteristic of bee hair is one strong reason pollen is so readily carried by bees. Photo was taken by the Centre for Electron Optical Studies at The University of Bath UK.
As if the structural relationship weren’t fascinating enough, when bees fly they generate positive electrostatic charge all over the hairs on their bodies. Flowers have an electric field across their surface area, and pollen carries a negative charge. This explains why the bumblebee below has pollen clinging to all parts of her face; more hair means more positive charge.
When the flower hasn’t been visited in a while, that surface charge is very strong, and pulls on the positively charged hairs on the bee. This signals to the bee that the nectar and pollen stores are full, and this flower is worth landing on. Before the bee even lands to get a sip of nectar, the pollen begins to jump from the flower to the bee’s hairs. This pollen is then carried from flower to flower, and eventually some brushes off onto the center of the flower, the stigma, and if it’s the correct stigma, the pollen will dig a tunnel down to the egg, and a seed will form, and more of the same flowers will bloom as a result of this perfect partnership.
Right down to the tiniest interactions, such as pollen to the hair of a bee, our world is made up of marvelous collaborations with magical results! One could never cease to be amazed when studying and learning of the natural world’s secrets.
“And above all, watch with glittering eyes the whole world around you because the greatest secrets are always hidden in the most unlikely places,” Roald Dahl.