The ability of workers to produce male individuals
is reported here for the first time in a species of the
formicine ant genus Prolasius. We show that Prolasius
advenus workers possess ovaries and demonstrate that they
are able to produce adult males in queenless colonies. We
also experimentally tested the influence of queen volatiles
on the level of worker reproduction. Workers produced
fewer eggs in treatments where they could perceive odors
from queens. Some volatile compounds emitted by queens
may thus have a signaling or inhibitory effect on worker
reproduction. This effect of queen presence did not entirely
stop worker reproduction, however, as adult males still
emerged under these conditions. Worker-produced males
were absent only in treatments with the physical presence of
queens. Dissections of workers collected from queenright
nests in the field revealed signs of egg-laying activity in
more than half of individuals. Together, these results suggest
that in nature P. advenus workers produce males at least
in orphaned colonies or in situations where the physical
presence of queens is limited.