William C. Beckerson, Ph.D.
Zombie Research
The Molecular Compounds Driving
Behavioral Manipulation of Zombie Ants
The term "Zombie Ant" is used to describe Carpenter ants (ants of the Camponotus genus) that have been infected by one of many different species of Ophiocordyceps, fungal pathogens capable of altering the behavior of their hosts! These fungi secrete biomolecules that interact with the nervous system in the ant, causing it to act in peculiar ways.
Modified behaviors include: hyperactivity, staggers syndrome, failure to antennate, antisocial behavior, summit disease, the death grip, and disrupted circadian rhythm, some of which are demonstrated in the videos to the right! (Top: staggers syndrome, failure to antennate, antisocial behavior, Middle: the death grip, Bottom: disrupted sleep/wake cycle).
These behavioral modification are essential for the lifecycle of Ophiocordyceps. Infected ants are made to abandon their nest and climb to the periphery of nearby vegetation, a process known as "summit disease", before they are forced to clamp down with their mandibles, ensuring that the ant does not fall during the growth of the fungal fruiting body. The fungus then emerges from the back of the head, forming a mushroom containing the next generation of spores! These spores are ejected from the host and float down onto more unsuspecting ants!
The extraordinarily intricate relationship between
Ophiocordyceps and Camponotus has lead to a tight Co-evolution between the two groups, resulting in the many different host-specific pairings shown below!
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The truly remarkable nature of behavioral manipulation is not unique to zombie ants. Some Ophiocordyceps species infect other types of insects as well, including bees, beetles, and wasps. As a mater of fact, there are many other groups of fungi that infect and manipulate the behavior of insects like cicadas, beetles, and fruit flies as well!
Using C. elegans to Study the Neurological Effects of Zombie Proteins
The nematode C. elegans is exceptionally well suited for the study of animal development and neuronal biology, particularly at the molecular level. This is because of the many genetic tools available to use in the worms, their identical offspring that are easy to produce quickly (3-4 days) in a lab setting, and their transparent body that allows for clear visualization of individual neurological cells with a microscope.
Altogether, these features allow scientists to use nematodes to study biological features of other more difficult to work with organisms (like zombie fungi and ants). In our research, we use them to test the effects of zombie proteins made by the fungi by introducing them to the nervous system. This approach mirrors what we see in nature, but allows us to observe the molecular changes more easily.
We can also use the well understood genome of C. elegans to identify potential targets of these zombie proteins by using a technique called Yeast-Two Hybrid. With this approach, we clone the genome of these worms into plasmid that when in yeast allow them to grow on particular media only if they interact with a zombie protein!
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These yeast can therefore be plated on agar missing particular essential proteins, or containing various antibiotics, and compare them to determine if protein-protein interaction has occurred.
Y2H mating assays require a special apparatus for replica plating. Working with the Lili's Proto Lab at Utrecht University, I have designed a 3D-printable tool designed to work for either 90 mm or 120 mm Petri dishes! You can download the 3D model for free at my GitHub page.
Just click here! ->
