Pollination (part 3)

It’s well known that insects have a vested interest in visiting flowers – that is, they’re not merely visiting the flowers with the altruistic intention of performing a passing pollination service. They’re usually gathering nectar and/or pollen. Thus both the plant and insect benefit from their relationship with each other.

However, flowers come in all sorts of shapes and sizes, and so do insects. The flowers vary their features to appeal to their target visitors. When flowers have adapted to attract certain pollinators, they are said to have developed ‘pollination syndromes’.

Scent

Humans love fragrance, and so do insects. But different insects like different fragrances. On the one hand, sweet peas have a scent that can charm the bees. Butterflies also like fresh, but very delicate scents.

A number of flowers produce what humans would consider to be a foul stench. For example, the Vodoo Lily - Sauromatum guttatum (pictured), from the ‘Aroideae’ plant family, emits an odour that is likened to rotting flesh.

From a different plant family, the Orontiods, the Eastern Skunk Cabbage (Symplocarpus foetidus) and Western Skunk Cabbage (Lysichiton americanus), are also said to give off the horrible odour of decaying flesh.  Primarily carrion flies and beetles (i.e. flies and beetles that are attracted to dead and rotting bodies of animals etc.).

The time of day also plays a role in attracting pollinators. In some cases, flower pollination actually takes place in the evening. Flowers pollinated by bats and moths, for example, are strongly scented at night, such as night-scented Stocks, Evening primrose, and  Jasmine (Jasminum officinale).

Colors and patterns

 Like humans, bees are trichromatic. This means their eyes (like ours) have 3 color receptors. However, whereas humans base their color vision on the color receptors red, green and blue, bees base their color vision on Ultra Violet, blue and green.

Although bees cannot see red, however, they do visit red flowers. Why? Because flower petals have Ultra Violet patterns on them, not visible to humans in normal light, but visible to bees. The patterns are believed to guide the bees onto the flower ‘landing platform’, and then into the flower. With regard to red flowers, bees may also use other cues, such as scent. However, all in all, it is also thought that bees prefer different shades of blues, whites, and purple flowers.

In general, it’s believed that swathes of color are also more helpful to foraging bees and butterflies, providing a stronger visual signal that suggests ‘plenty of food here’ , and of course, it is more energy efficient for bees and other pollinators to find areas of denser food provision.

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