Are ants left-handed?

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In case you were wondering, ants turn out to be ambidextrous.

Instead of favoring one side or the other as we humans do with our hands, ants show no preference for working with either mandible.  That’s the conclusion of a new study by Cassill & Singh:

Abstract: The elongation and sharp teeth of ant mandibles are considered important adaptations that have contributed to ants successful colonization of terrestrial habitats worldwide. In extant ant species, mandibles function as hunting and defense weapons, as well as multipurpose tools for excavating soil, cutting leaves, capturing and butchering prey, harvesting seeds, and transporting brood. This article reports that the mandibles in the red imported fire ant, Solenopsis invicta Buren, are functionally ambidextrous. Individuals opened and closed each mandible in synchrony or independently depending on the requirement of the task at hand. Upon completion of a task, individuals were without a preference in the orientation of mandible overlap—right overlap or left overlap. Orientation of mandible overlap before and after performing a task was also examined in nine other ant species. No overlap orientation preference was observed in any of these ant species, suggesting that ambidextrous mandibles are a universal trait in ants. These findings add an increment of knowledge to the diverse functions of ant mandibles.

source: Cassill, D. L., Singh, D. 2009. Ambidextrous Mandibles in the Fire Ant Solenopsis invicta. Annals of the Entomological Society of America 102(4):713-716. 2009 doi: 10.1603/008.102.0416

5 thoughts on “Are ants left-handed?”

  1. Doesn’t this imply that ants would be using one side of their brain more than the other? Do insects even have a creative and logical side to the brain? Isn’t it all just Sugar to them?

  2. The mandibles aren’t left or right handed, but they may be chiral in which slides dorsal to the other while chomping. I see it in other insects.

  3. To my mentor Dr. Deby Cassill:

    Thank you for giving me the opportunity to do research under you. I wish you best in your future work.

  4. I arrived here doing a search on ant “handedness”. Not exactly the result I was looking for, this mandible thing, I mean.

    I became curious about side preference while observing ants coming and going along one of their scent trails on the side of a building. As an ant going out met one coming back, they almost invariably passed to the right (if I remember correctly, main thing is that they almost all passed to the same side). No confusion. Then some oddball would come along and try to pass to the left. They bumped, they stumbled… There was confusion, like two people dancing as they try to get past each other in doorway, both zigging at the same time. The smooth flow was interrupted.

    So, I was wondering, is this a side preference, or something else? A fluke with this colony, or does it happen with all ants?


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