New paper out in Journal of Ecology
Photo by Patrick Milligan
Invasive Pheidole megacephala harms trees through the roots
Postdoc Patrick Milligan has a new paper out from his dissertation work at the University of Florida, with Gabby and Beth as co-authors. Through a set of complementary greenhouse and field experiments, we show that soil-nesting invasive ants harm saplings directly, primarily by means of something they are doing to roots. Although invasive ants have frequently been associated with negative effects on plants through hemipteran tending, we did not find these negative effects here. Instead, through comparing experimental plants on which ants were allowed on (i) the whole plant (roots and shoots), (ii) roots alone, or (iii) none of the plant, we show that access to the roots alone confers most of the harm to sapling photosynthesis and carbohydrate storage. This root-directed damage also appears to generate most of the damage to saplings in the field. Field saplings in invaded areas are in worse shape than saplings in uninvaded areas, but these effects are not generated by differential herbivory, as they are for adult trees.
“We demonstrate that soil nesting near roots, a common behavior by Pheidole megacephala and other invasive ants, can directly reduce carbon fixation and storage of Acacia drepanolobium saplings.”