Aphid Farm

It's eighty degrees Fahrenheit at nine o”clock in the morning and an eerie silence envelops the shortgrass prairie. Occasionally a lizard scampers across my path. Wildlife uses the night and early morning hours to hunt and forage for food. After that, even the most tenacious hunter seeks shelter to escape the brutal heat. Black-tailed Prairie Dogs forego barking intruder alerts and socialize in the cool bowels of their burrows. I have yet to see any young this summer. High plains vegetation barely clings to life in the unabated march of one hundred degree days and scarce rainfall.

There is one exception. Broadleaf Milkweed (asclepias latifolia) refuses to submit to the reign of drought. Robust, green sentinels dot the bleak landscape. Their stature is small compared to recent years. This favorite food of Monarch butterfly caterpillars has other roles in the struggle for survival. It also serves as a centerpiece for ant and aphid alliances.  

Mutualism is a relationship between two organisms, where each derives a benefit from their interaction. On the Llano Estacado, Broadleaf Milkweed fruit pods are a sugar-rich source of fluid aphids consume and excrete as honeydew. Ants use the honeydew as a food source. They even milk aphids by stroking them with their antennae to stimulate release of the sugary liquid. What benefit do the aphids reap? Ants aggressively defend aphids from predators and ensure their wellbeing. Aphid-herding ants carry wingless aphids to new food sources, destroy eggs of aphid predators like lady beetles. They even store aphid eggs in their subterranean nests during winter months.

© Ilija Lukić 2011

Aphid Farm

Milkweed Nursery

Silken Propellers

Splattered Milkweed