Sociality
[2] Biologists suspect that pressures from parasites and other predators selected this behavior in wasps of the family Vespidae.
A eusocial taxon is one that exhibits overlapping adult generations, reproductive division of labor, cooperative care of young, and—in the most refined cases—a biological caste system.
[4] If an animal taxon shows a degree of sociality beyond courtship and mating, but lacks any of the characteristics of eusociality, it is said to be presocial.
[6] The entomologist Charles D. Michener published a classification system for presociality in 1969, building on the earlier work of Suzanne Batra (who coined the words eusocial and quasisocial in 1966).
Insect groups that contain at least some subsocial species are shown in bold italics on a phylogenetic tree of the Neoptera (note that many non-subsocial groups are omitted):[13] Embioptera (webspinners)[14][15] Blattodea (cockroaches, inc. eusocial termites)[16] Mantodea (mantises) Orthoptera (grasshoppers, crickets)[17] Dermaptera (earwigs)[18][19][20] Zoraptera (angel insects)[21] Thysanoptera (thrips)[22] Membracidae (treehoppers, thorn bugs)[23][24] Pentatomidae (shield bugs)[25] Reduviidae (predatory bugs)[26][27][28] Tingidae (lace bugs)[29][30] Psocoptera (bark lice)[33] Staphylinidae (rove beetles)[34][35][36][37][38][39][40] Silphidae (carrion beetles)[41] Passalidae (bessbugs)[42][43][44][45] Scarabaeidae (scarabs)[46][47] Tenebrionidae (leaf/flower beetles)[48][49] Erotylidae (pleasing fungus beetles)[50] Chrysomelidae (leaf beetles)[51][52][53][54][55][56][57][58][59] Raphidioptera (snakeflies) Neuroptera (lacewings, alderflies, and allies) Antliophora (true flies, scorpionflies, fleas) Trichoptera (caddisflies) Lepidoptera (butterflies and moths)[61] Hymenoptera (sawflies, wasps, ants, bees)[62] (apart from eusocial species) Solitary-but-social animals forage separately, but some individuals sleep in the same location or share nests.
[63] Some individual cetaceans adopt a solitary but social behavior, that is, they live apart from their own species but interact with humans.
Eusocial insect societies have all the characteristics of a semisocial one, except overlapping generations of adults cohabit and share in the care of young.
Eusocial societies have overlapping adult generations, cooperative care of young, and division of reproductive labor.
When organisms in a species are born with physical characteristics specific to a caste which never changes throughout their lives, this exemplifies the highest acknowledged degree of sociality.
[66] Both species are diploid and highly inbred, and they aid in raising their siblings and relatives, all of whom are born from a single reproductive queen; they usually live in harsh or limiting environments.
A study conducted by O'Riain and Faulkes in 2008 suggests that, due to regular inbreeding avoidance, mole rats sometimes outbreed and establish new colonies when resources are sufficient.
[68] Each group has one breeding female; she is protected by a large number of male defenders who are armed with enlarged snapping claws.
