Mummified Grasshopper with “Summit Disease”

2021 April 11

On August 18, 2020, Sam told me about this big, weirdly-colored dead grasshopper she had found at the tip of a sprig of goldenrod. So, we went to check it out, and found this:


From the size and shape, I think it is a Carolina Grasshopper, Dissosteira carolina. These are our biggest local grasshoppers, and pretty common. They aren’t normally this color, though. Their normal coloration is either a kind mottled gray that looks like soil, or a brick-red color. The ghastly bone-white color of this one is clearly abnormal.

It had a literal death-grip on the top of the goldenrod stalk, it had clearly climbed to the highest point on the plant before it anchored itself there and died.


The color screams, “fungus infection”, and it is most likely the fungus Entomophaga grylli. This is also known as “summit disease”, after the tendency of infected grasshoppers to climb to the top of something and anchor themselves there to die.


This one was apparently fairly early on in the process, as aside from the coloration there is not too much evidence that the fungus had really gotten going in emitting spores yet. In this picture, if you look at the joint between the head and the thorax, it looks kind of like mold growing in there.


And, on the underside of the neck, it looks like the “hair” might actually be fungal spore heads, with a bulging spore capsule at the end of each.


The fungus benefits from getting the grasshopper to climb up on a high point, because from up there its spores will disperse better than if it was down on the ground. It probably isn’t exactly correct to call this “mind control”, since neither the grasshopper nor the fungus have what we would normally call a “mind”. Instead, we can think of it as rewiring some of the grasshopper’s reflexes so that instead of going to the ground and hiding, it instead climbs up as high as it can and exposes itself.

There are numerous strains of this fungus, each of which seems to specialize in particular species of grasshoppers and crickets, and the fungus is part of a much larger family that infects many different kinds of insects. When Entomophaga grylli gets established in an area, it is extremely effective in selectively knocking down the population of susceptible grasshoppers, while leaving other insects and wildlife unaffected. This makes it very interesting as a biological control agent. Unfortunately, no one has yet worked out a way to cultivate the spores in quantity so that it can be applied to fields, and it is only really infectious when the weather conditions are right. But still, if you manage a field so that, when the fungus appears, it will be able to spread easily, it sounds like a good way of keeping the grasshopper population from getting out of hand.

3 Responses
  1. Carole permalink
    April 11, 2021

    Had read about this, but never seen it. Thanks for sharing.

  2. April 16, 2021

    From a purely scientific point of view, all I can say is, “Ewwww!”

  3. Allen permalink
    April 22, 2021

    As an interpretive naturalist, I enjoy your site, Tim. The “mind control” concept has been a topic of interest regarding humanity, as well. The CDC has estimated that Toxoplasmosis (caused by a single-celled parasite) is a genuine health threat to pregnant women who come into contact with cat/dog litter box contents and to those who eat undercooked meats/shellfish. They estimate it may have spread to 40-million people in the US alone, and up to 50% of the world’s population.

    Decades of research to determine if T. gondii infections can cause behavioral changes involving risk-taking and neuroticism seem to show some correlation and speculation is that it might have played a role in man’s violent history. A caveat – a recent study disputes the connection. Now, me, I look at the world as being so crazy, it’s hard NOT to think there might be some truth to the idea that human civilization and cultures are under the influence of a whackjob microbe! Just to be safe, always resist the urge to climb too far out on a limb.

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