Where’s the Meat? Rover Ants and Carrion Flowers

Note:  This post is not for the squeamish.

It all started when I noticed rover ants in a flower. It wasn’t just any old flower, though.

Ever seen one of these?

Commonly called carrion flowers or African starfish flowers, plants in the Genus Stapelia are low-growing (only 8 to 12 inches high), succulent perennials. They mainly grow in southern Africa, but can are treated as an interesting potted plant elsewhere. You can see the plant in the background of the photograph below.

The Stapelia flower looks weird, doesn’t? The surface is brick red, wrinkly and covered with soft hairs. It looks quite a bit like bloody mammal hide.

If you were standing with the photographer, you just might be holding your nose, too.  The common name carrion flower comes from the foul odor the flowers produce.

The odor is a powerful attractant to blow flies and other types of carrion flies.

Why does the plant do this?

The answer is stuck to this poor fly’s mouthparts. See the orange bundles? Those are the pollinia (it has two bundles). Pollinia are pouches that release pollen. The fly picks them up at one Stapelia flower and loses them at the next, pollinating the plant.

The flies are so taken in by the deception that, depending on the species, they lay eggs or larviposit (lay larvae) on the flower.

That is where the rover ants come in.

The rover ants have found a ready supply of protein in the form of fly larvae and eggs.

Ironically, the rovers have found real “meat” in a plant that is using a meaty appearance as a deception.

Other types of ants visit Stapelia flowers. In this video, you can see ants in some of the scenes.

For more in depth information about Stapelia and more photographs of ants in Stapelia flowers, see S.P. Bester’s article from the South African National Herbarium