Pollinators

NPS/A. Schonlau

 

Rocky Mountain National Park is home to a multitude of wildflowers, from tiny alpine blooms to the large cow parsnip which can grow to five feet tall in moist meadows. Although diverse in size and appearance, wildflowers share a common purpose – they are the reproductive structures of plants. Pollen from a flower's anther needs to reach the flower's pistil to fertilize its eggs and create seeds for the next generation. The methods plants employ to accomplish this vary and can be quite spectacular.

One of the simplest approaches is for the wildflower to self-pollinate. However, this does not allow for genetic diversity. Most flowers promote cross-pollination by attracting an animal to help transfer their pollen to neighboring plants. Many flowering plants have evolved complex adaptations – advertisements, bribes and tricks – to encourage pollination by animals.

 

Hummingbird pollinating flowers

NPS photo by C. Johnson

If you stop to smell the flowers, you will find that many have a distinct odor. Some flowers produce an odor like dung or rotting flesh to attract flies. Others produce sweet scents that are more appealing to other insects such as butterflies and bees.

Perhaps one of the most interesting elements of wildflowers is the wide array of colors used to appeal to pollinators. Red, orange, and yellow flowers attract butterflies, while blue, purple, yellow and white flowers appeal to bees. Hummingbirds favor the color red. Some flowers have colors in the ultraviolet spectrum which are invisible to humans but are highly attractive to bees.

 

Bee pollinating a flower

NPS photo by A. Schonlau

Many flowers use colors, both visible and ultraviolet, in patterns called honey or nectar guides to direct pollinators to the parts of the flower where nectar bribes and pollen are available. Think of them like runway lights. The pollinators eat the nectar and carry the pollen to the next flower. Many species of flower have different ultraviolet markings. Many plants put special effort into attracting bees and ultraviolet markings is one method. Bees are faithful to one wildflower species at a time while foraging thus insuring pollen is more likely to go to an appropriate flower where it can fertilize its eggs. This makes the process more efficient and helps the plant accomplish the job of reproduction.

 

The diversity of flower shapes also attracts certain pollinators and enables them to pick up and deliver pollen. Wide open, radially symmetrical flowers such as buttercups and sunflowers allow easy access to many insects from beetles to butterflies while bilaterally symmetrical flowers such as monkshood appeal to bees who like to wiggle up inside enclosing petals. Some flowers such as elephantella use tricks such as trigger mechanisms that shoot pollen on an insect when it lands on specialized petals. Long tubular flowers such as scarlet gilia favor pollination by hummingbirds whose long tongues are able to reach the nectar hidden deep inside.

 

Animals are an effective way to transfer pollen, from bumblebees and hummingbirds to a moose calf lying in flowers and carrying pollen in its fur. The relationship between animals and flowers is intricate and astounding, and one that has contributed to the great diversity of life in Rocky Mountain National Park.

 

NPS/R. Smith