STEP 3: COEVOLUTION; EVOLVING TOGETHER
Nature favors individuals that are best adapted to their environment. If an individual’s adaptations increase their ability to obtain resources, they are more likely to survive long enough to reproduce, thereby passing on beneficial traits. Over generations, these traits build up to produce new species specially adapted to the biotic and abiotic conditions of their environment (see Lesson 1). This is why native plants are always the best plants for pollinator gardens.
WHAT IS COEVOLUTION?
Flower size can act as a control for which pollinator species can access the nectar/pollen. Think about how big a bumblebee is: it wouldn’t be able to land on small, thin-stemmed plants without damaging them. Size can also act as a signal to pollinators, to show them where the flowers are. Large, boldly colored flowers stand out from afar for passing pollinators, especially on a bold green background.
Flower shapes come in a variety of designs to ensure they are successfully cross-pollinated. Not all pollinators have the right set of tools to access nectar and pollen from every flower species. By evolving complex flower heads, flowers can control which pollinators can gain access. For example: Long, tubular flowers hide nectar deep inside, so only pollinators with long tongues like hummingbirds and some butterfly, moth, and bee species can reach the nectar.
Fig trees are pollinated by the female fig wasp. When the fig flower is ready to be pollinated it emits a scent that attracts female fig wasps. The fig’s opening is so small that, as the wasp enters the flower, she loses her wings and parts of her antennae. She lays her eggs inside the flower and dies shortly thereafter. As her offspring emerge from the flower, they carry pollen from that flower to others and pollinate the next generation of fig trees.
These are the commonly known shapes, but most flowers will be some sort of variation or combination of these shapes.
(See the “Plant Shapes and Pollinators” chart in Step 4: Research Pollinators in Your Area)
Bees and wasps see the color black as a threat because it mimics potential predators like bears and skunks. Their eyes cannot process the color red either, so it comes up as black to them too.
Ever been stung by one and thought you didn’t deserve it? It may have been because you were wearing black or red clothes.
Body hairs or setae, found on the bodies of many pollinator species— butterflies, flies, moths and bees—are like “velcro.” As the pollinator reaches into the flower to find the nectar, pollen attaches to the hairs until it’s knocked off when entering another flower.
Bees have developed specialized hairs that form baskets on their hind legs to carry pollen back to the nest—colonial bees collect pollen to make “bee bread,” a staple food for their workers and young.
Foraging is the collection of food resources. Some pollinators methodically forage pollen and nectar. Honeybees forage in a specific way, close to their colony, so they can easily transport the nectar and pollen they collect, without wasting too much time and energy traveling between places. Also, they collect nectar and pollen from one species of flower before moving onto a different species. This type of collection increases the chances of successful cross-pollination, because the pollen will only be transferred to a flower of the same species.
Buzz pollination is another way bees have repurposed their abilities to their advantage. They vibrate their wings while they are inside the flower, dislodging large amounts of pollen that are attracted to their static hairs. This also dislodges pollen already on them, increasing pollination chances and the amount of pollen they collect.
Hovering is a flight adaptation in hummingbirds and hummingbird hawk moths that allows them to move between flowers faster than if they had to perch at each flower, like other nectar feeding birds have to do. The ability to hover gives them access to flowers not available to other pollinators.
Plants evolve to attract pollinators and/or restrict nectar access to certain species, while pollinators adapt physically or behaviourally to increase the efficiency of their resource intake. Together these adaptations increase cross-pollination success, and resource provision intake. Everyone’s a winner!
Now it’s your turn…