February 21, 2013
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Has this Ophiocordyceps sent fruiting bodies up from the ant it killed? Not quite.
Since we’re on the topic of zombies, a public service announcement:
Most zombie ant photographs are upside-down.
Few insect natural history stories capture public imagination as much as “zombie ants”. These ants are infected with a brain fungus that directs them to a resting place with ideal humidity for fungal growth. The fungus then kills and eats the ant, leaving only the hard outer shell behind. When mature, the fungus sends a mushroom out to disperse spores.
Most fungus-killed ants perish on the underside of a leaf. In this arrangement, the ant is suspended upside down and the mushrooms grow downward, as in this Ecuadorian example:
A carpenter ant's last stand, glued to the bottom of a leaf in the Amazon rainforest.
The natural history is as grisly as it is fascinating. I am not surprised morbid tales of zombie ants have spread across the internet.
I am also not surprised that accompanying photos are incorrect. Consider the results of an image search:
Nearly every picture is inverted! Page after page of upright ants with skywards-pointing fruiting bodies. Aesthetically, it seems, we like our zombie ants turned the wrong way around.
Do we humans have an anthropomorphic need for insects to orient as we do? Can we not make sense of mushrooms that grow downward? It would seem so. For all my complaining, I myself fight the urge to flip my Ophiocordyceps shots. Looking over my galleries, I don’t always succeed. Upside-down, fungus-infested corpses are themselves propagating like zombies, and this pattern probably echos our innate bias for visualizing animals with their heads up.
In any case, for those of you who like your natural history accurate, here is your right-side-up Ophiocordyceps:
An Ophiocordyceps fungus grows pleasingly downward from its prey. (Belize, 2013)
Curious? There’s more:
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I have contributed to this problem! I my case, I think it was just hard to shoot the ant with it being under a low leaf: http://www.flickr.com/photos/deadmike/2252751155/
Link to thisI see more fungus-killed crikets and such on the upper surface of leaves:
http://www.flickr.com/photos/deadmike/2808569657/
Ophiocordyceps and the ‘Zombie Ants’ it produces have always fascinated me since I heard about the process in lectures on Adaptive Design. Just amazing.
Link to thisI forgot this one: http://www.flickr.com/photos/deadmike/3407159530/
Link to thisIt is pretty bizarre.