Summit disease

Definition

A behavioral syndrome in grasshoppers and related orthopterans infected by certain fungal pathogens, notably species of Entomophaga, in which moribund insects climb to elevated positions on vegetation, grasp the stem tip, and die with their bodies oriented upward. This positioning maximizes wind dispersal of conidia from the cadaver, serving as an adaptive transmission mechanism for the pathogen.

Etymology

From the characteristic position of infected insects at the summit of plants.

Example

Grasshoppers infected by Entomophaga grylli exhibit summit disease by ascending to grass stem apices and dying in a characteristic death-grip posture, ensuring that fungal spores rain down on healthy conspecifics below.

Related Terms

• entomopathogenic fungus
• behavioral manipulation
• death grip
• conidia dispersal
• Biological control
• Entomophaga

Usage Notes

The term specifically describes the elevated terminal behavior, not the pathogen itself. Summit disease is most commonly associated with Entomophaga grylli infections in grasshoppers, though similar behaviors occur with other entomopathogens. The phenomenon represents a striking example of host manipulation by a parasite to enhance transmission. Distinguish from simple climbing behavior or thermal seeking; summit disease involves the stereotyped terminal grip and elevated death position.