  We investigate the pulsation driving mechanism responsible for the
long-period photometric variations observed in LS IV-14{\deg}116, a subdwarf B
star showing a He-enriched atmospheric composition. To this end, we perform
detailed nonadiabatic pulsation computations over fully evolutionary post
He-core-flash stellar structure models, appropriate for hot subdwarf stars at
evolutionary phases previous to the He-core burning stage. We found that the
variability of LS IV-14{\deg}116 can be attributed to nonradial g-mode
pulsations excited by the {\epsilon}-mechanism acting in the He-burning shells
that appear before the star settles on the He-core burning stage. Even more
interestingly, our results show that LS IV-14{\deg}116 could be the first known
pulsating star in which the {\epsilon}-mechanism of mode excitation is
operating. Last but not least, we find that the period range of destabilized
modes is sensitive to the exact location of the burning shell, something that
might help to distinguish between the different evolutionary scenarios proposed
for the formation of this star.
