Abstract:
As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other
flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular
species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were antrepellent
at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively
correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the
behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that antrepellent
floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves
in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost
of nectar production in future studies into ant-flower interactions.
