Ant intelligence; assigning caste (Introduction)

by David Turell , Saturday, November 23, 2024, 20:57 (8 hours, 13 minutes ago) @ David Turell

Latest study:

https://www.sciencedaily.com/releases/2024/11/241122130358.htm

"Most ants have two morphologically differentiated adult castes -- queens and workers -- each irreversibly specialized for either reproduction or nonreproductive altruism such as foraging, defense and care of maternal brood. Adult gynes (virgin queens) normally have higher body mass, wings and frontal eyes, as well as enlarged ovaries and a sperm storage organ. In contrast, workers are wingless females with smaller body size and degenerated reproductive tracts, usually without a sperm storage organ.

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"In most social insects with distinct queen (colony germline) and worker (colony soma) castes the analogous developmental differentiation happens in the larval stage and can still be hormonally reversed.

"However, in some ants colony germlines are also determined earlier, in the embryonic (egg) stage, begging the question whether that makes somatization of workers as irreversible as somatization of animal body cells as development proceeds.

'A new study from the Department of Biology at the University of Copenhagen, funded by a Villum Investigator Grant,finds that caste development is remarkably reversible in pharaoh ants, Monomorium pharaonis, a species where caste determination happens in the eggs stage.

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"'We found that hormone-treated worker ants developed many gyne-like physical characteristics, such as increased body length, three extra frontal eyes, wings and flight muscles, gyne-like brains; they even developed the gyne-specific sperm storage organ that workers of this species never have."

"However, unlike naturally developed gynes, JH-treated workers never developed ovaries, the reproductive organ that ultimately sets gynes apart from workers, show that the caste-specific JH-sensitivity window does not overlap with the egg-stage.

"The study also sheds new light on how shifts in developmental-sensitivity for growth hormone may have played a role in the emergence of new castes in other ants, such as soldiers (modified workers) or permanently wingless gynes.

"'Such novel castes often originate as mosaic phenotypes that recombine gyne- and worker traits, which may become permanent when natural selection rewards a subsequent shift in JH-sensitivity window," says Guojie Zhang, corresponding author of the study."

Comment: I could just as well reproduced this article under the biochemical controls thread. It is amazing the larva can be sent in any phenotypical direction.