What's in the Sunflowers?

Jul 25, 2012

What's in the Sunflowers?

Jul 25, 2012

So you're walking through a sunflower field and you're seeing lots of honey bees foraging on the flowers.

But wait, look over there. Are those beetles?

They are.

Melyrid or blister beetles (Melyridae family) and spotted cucumber beetles (family Chrysomelidae) are frequently found on sunflowers.

The spotted cucumber beetle is known as a major agricultural pest, as it eats or damages the leaves of such crops as cucumbers, cotton, soybeans and beans. 

Are the melyrid beetles pests of sunflowers? "Yes, in the sense that they are pollen eaters," says Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis.

However, beetles can also be pollinators. And there's a word for that.

Beetle pollination is called cantharophily. And cantharophily "may be the oldest form of insect pollination," say emeritus professors Penny Gullan and Peter Cranston of the Department of Entomology, University of California, Davis, in their textbook,  The Insects, an Outline of Entomology.

As they point out in their book: "Beetles mostly visit flowers for pollen, although nutritive tissue or easily accessible nectar may be utilized  and the plant's ovaries usually are well-protected from the biting mouthparts of their pollinators." They mention several families of beetles that can be pollinators--among them Cantharidae (soldier beetles), Cerambycidae (longhorn beetles), and Cleridae (checkered beetles).

And they mention Melyridae, the soft-winged flower beetles, as being pollinators, too.

Cantharophily in the sunflower field.