Eusocial insects are animals that develop large, multigenerational cooperative societies that assist each other in the rearing of young, often at the cost of an individual's life or reproductive ability.

Such altruism is explained in that eusocial insects benefit from giving up reproductive ability of many individuals to improve the overall fitness of closely related offspring.

Thrips young are not helpless, and can immediately begin to provide for itself and to a certain extent the related individuals around them, while the soldier adults stay busy patrolling the gall for possible incursions.

Another useful factor that contributes to the use of these organisms for research into eusociality is a well-defined phylogenetic tree and access to large amounts of genetic data.

[8] Gall thrips, however, actually exhibit not only high relatedness between sisters, but also between brother-sister, a departure from the results typical of other haplodiploid eusocial insects.

This inbreeding has been proposed to have reduced the haploidy-induced relatedness symmetries, and also allowed for an explanation of biparental care among thrips, where both males and females participate in defense of the gall.

[3] The benefit from altruistic behavior occurs in two ecological modes: "life insurers" as found in social Hymenoptera, and "fortress defenders".

[9] Perhaps the most compelling evidence, therefore, is the progressive differentiation of soldier caste thrips in Kladothrips, where soldier-to-foundress reproductive allocation corresponds to eusocial life history traits in basal and derived species of a well mapped phylogenetic tree.