Who are you calling a parasite?

Published 10:01 pm Tuesday, May 17, 2016

By Susan and Biff Andrews

Got ants in your plants? Well, maybe it isn’t such a bad thing. Could be, it’s all part of Mother Nature’s plan. Turns out that there are many ways in which unrelated organisms help each other meet their needs.

A symbiotic relationship can be defined as the cooperation of mutually dependent organisms. There are three types of symbiotic relationships, which often overlap: mutualism, where both organisms benefit; commensalism, where one organism benefits and the other is unhurt; and parasitism, where one organism benefits at the expense of another.

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So how did we get on this topic?

My mother-in-law asked why there were always ants on her peonies and none on her other flowers. Good question. Peonies do get covered with ants.

Apparently, the blooms on peonies are so dense and so tightly closed that Mother Nature said, “Cover your blossoms with a little nectar, and little ants will arrive to help open them.” Problem solved. The ants go away when the blossoms fully open.

Don’t spray them with an insecticide; it’s all in Ma Nature’s plan. Is this mutualism or commensalism? Yes.

The John Clayton Chapter of the Virginia Native Plant Society recently hosted a talk on moths, part of which dealt with the question, “Do Hawkmoths pollinate Jamestown Lilies, which bloom only at dusk or at night?”

Good question. They’re certainly not pollinated by regular bees or butterflies or hummingbirds or other daytime pollinators. Furthermore, Hawkmoths have long coiled pointed mouth parts, and Jamestown lilies have long floral tubes which contain their nectar.

It does sound more than slightly coincidental. The moth gets nectar at night, when many flowers close up, and the Jamestown lily gets pollinated. Everybody’s happy. Definitely mutualism.

The obvious example of parasitism is the family dog, which hosts ticks, fleas, heart worms, and so forth, which is good for the parasite but bad for the dog.

But let’s stick to plants. A plant that occurs locally is wrongly accused of parasitism — Spanish moss. This beautiful epiphyte (air feeder) does not feed on the trees it uses (usually bald cypress and live oaks hereabouts). It takes nothing from its host but its support.

It may shade out some leaves and make the tree grow slower, or it may add wind resistance and cause a few more broken branches, but it is not a parasite that “feeds” on its host. It just hangs there. A telephone pole and a wire would serve it as well.

So, from ants on plants to hawkmoths on lilies to the Spanish Moss myth — it’s all about the symbiosis.

Susan and Bradford “Biff” Andrews are retired teachers and master naturalists who have been outdoor people all their lives, exploring and enjoying the woods, swamps, rivers and beaches throughout the region for many years. Email them at b.andrews22@live.com.