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#26: Eusociality

Photo: Todd Ryan
Litinsects #26: Eusociality

I’m sure everyone has heard of worker bees, queen bees and drones. Bees 🐝 have a complex and interesting social structure and they are not the only ones!

There are many different kinds of social systems within the animal kingdom. Even within specific taxonomic groups, individual species can display vastly different social structures and behaviors. Today I’m talking about the highest level of social organization: EUSOCIALITY

Eusociality (with the Greek prefix “eu-“ meaning “true”) is defined by 3 GENERAL CHARACTERISTIC:

1) OVERLAPPING GENERATIONS living within the same colony
2) COOPERATIVE BROOD CARE, meaning that individuals collectively care for offspring other than their own
3) REPRODUCTIVE DIVISION OF LABOR into specialized groups

Continuing with the bee example, we know these 3 points pertain... different CASTES have specialized jobs pertaining to reproduction (queens produce offspring, drones are there for breeding, workers take care of the young), the hive is made up of multiple generations, and workers are actually raising their sisters rather than their own young.

Many hundreds of species of bees and wasps, all but a few ant species, and all termites are eusocial. These are among the most well-known examples but the phenomenon can also be found in a few species of thrips, aphids, and true bugs, one species of beetle, and the snapping shrimp (a crustacean). 

Fun fact: the only non-arthropod species known to display eusociality are in fact mammals... they are the naked mole rat and the Damaraland mole rat!

Ants, bees and wasps share a unique genetic system that makes sisters more related to each other than to their own offspring so this is one theory as to why eusociality evolved in these groups. But eusociality has actually evolved independently in different groups numerous times! Some scientists have even theorized that humans can be described as eusocial but this has been highly disputed and isn’t accepted by most.
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