LOOK — CLING ONS A Bennett’s feather star (Oxycomanthus bennetti) holds up its arms to trap food, as it clings to a harp gorgonian (Ctenocella pectinata) off Lizard Island in Australia’s Great Barrier Reef. (Photo: Fred Bavendam / Corbis via The Guardian)
Ophiocordyceps unilateralis, also known as cordyceps, is a type of fungus that infects insects and takes over their nervous systems. The method with which they take control of nervous systems is still a mystery to science. However, the repercussions of such an infection are all too clear.
Carpenter Ants, for example, live in the canopy of the tropical rainforest. They frequently forage for food on the forest floor. Unfortunately, this is where the cordyceps fungus proliferates. A new study shows that the fungus prefers to grow on “the undersides of leaves sprouting from the northwest side of plants that grow on the forest floor” This places it in an ideal position to grow and release its spores to infect ants. Here’s how the fungus gets there in the first place.
When an ant is infected by cordyceps, it undergoes a series of behavioural changes. The fungus forces the ant to climb down from the canopy to the low leaves where the cordyceps prefers to grow. Just before dying, the ant will use its mandibles to bite down on the leaf to secure itself.
After the zombie ant dies, the fungus digests the insides of the ant to get nutrition for growth. It’s interesting to note that the cordyceps avoids digesting the muscles controlling the ant’s mandibles. These muscles are the ones that keep the ant attached to the surface. The outer husk of the ant is also left unharmed. The cordyceps uses this as a physical armor to protect against microbes and other fungi.
The fruiting body of the cordyceps will then erupt from the ants head, slowly growing longer until it matures, after which it will release the spores, which seek new hosts. Any ant in the vicinity of this event risks infection.
A single ant infection is a threat to the whole colony. As such, ant colonies go out of their way to avoid an epidemic. Worker ants will often carry an infected ant far away from where the colony forages to prevent the spread of the fungus. The fact that Carpenter Ants live in the canopy of the rainforest may be a strategy to escape the infection.
Cordyceps does not exclusively target Carpenter Ants. There are many different types of Cordyceps fungi that can infect many different insects, including moths, grasshoppers and many more.
Papua New Guinea’s Manam Volcano released a thin, faint plume on June 16, 2010, as clouds clustered at the volcano’s summit. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite took this picture the same day. Rivulets of brown rock interrupt the carpet of green vegetation on the volcano’s slopes. Opaque white clouds partially obscure the satellite’s view of Manam. The clouds may result from water vapor from the volcano, but may also have formed independent of volcanic activity. The volcanic plume appears as a thin, blue-gray veil extending toward the northwest over the Bismarck Sea.
Located 13 kilometers (8 miles) off the coast of mainland Papua New Guinea, Manam forms an island 10 kilometers (6 miles) wide. It is a stratovolcano. The volcano has two summit craters, and although both are active, most historical eruptions have arisen from the southern crater.
NASA Earth Observatory image created by Jesse Allen, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott. Instrument: EO-1 – ALI