> An international team of researchers, led by Adam Tofilski of the Agricultural University of Krakow and Francis Ratnieks of the University of Sussex, has now added to the catalogue of adaptations for worker self-sacrifice by describing a novel behaviour in the Brazilian ant Forelius pusillus. When external activity ends at the close of each day, a small group of workers seals the nest entrance from the outside with sand or soil. Because at night-time the external environment proves fatal to them, these workers effectively condemn themselves to death.
The case for "sacrifice" is overstated.
Many of the ants left outside do die, but not all.
Abstracts never tell the whole story, it helps to read the paper, full text linked below:
They have "strong evidence" that a "large proportion" of the ants left outside die, but not all.
The "strong evidence" in this case is based upon statements like "The remaining seven could not be found but were presumably dead".
So, "presumably", a "large proportion" of the ants do not survive the night, but they aren't exactly sure despite needing to merely sift a bowl of sand to find every dead ant. So, there could have been as many or more than ten ants still "tenant" in the bowl.
https://www.journals.uchicago.edu/doi/10.1086/591688
"Of 23 ants transferred in this way, only six (26%) were alive in the bowl the next morning. The bodies of 10 (43%) were found by carefully searching the bowl. The remaining seven could not be found but were presumably dead because nonmoving live ants started to run when the sand or wood near them was moved and so were easily seen. (Ants could not escape the bowls, as each had been covered in a layer of plastic film after the ants were placed inside.) The results of this experiment indicate that a large proportion of the ants left outside had already died by ∼0900 hours the next day, approximately 1 h before the entrances reopened naturally. Combined with the observation that no ants were seen at the nest entrances when these reopened in the morning, this provides strong evidence that most or even all of the ants that closed the entrance from the outside died as a result."
The study at issue seems to have needed someone to count ants more carefully, they should have hired an Account-Ant.
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