PLANT MEDIATION OF ANT-HERBIVORE ASSOCIATIONS: THE ROLE OF STICKY RINGS FORMED BY BOERHAVIA SPICATA

The ability of plants to interfere with ant-homopteran associations has received relatively little attention in studies of ant-homopteran-plant interactions. Given the potential of significant negative impacts to plant fitness from ant-herbivore mutualisms, one might anticipate that some plants have evolved defensive countermeasures. Here, we experimentally examined the role of sticky rings formed by Boerhavia spicata Choisy (Nyctaginaceae) in plant defense against ant-herbivore associations. We randomly assigned 67 plants to one of two treatments: sticky rings covered with diatomaceous earth and controls. Treatment plants (no rings) supported significantly higher densities of aphids (p= 0.045) and ants (p= 0.056) than did controls. Ants, predominantly Myrmecocystus depilis (Hymenoptera: Formicidae), attained significantly (p= 0.030) higher abundances on a per aphid basis on treatment plants than on controls. Densities of nonmyrmecophilous herbivores did not differ significantly between treatment groups. Sticky rings appear to disrupt the establishment of ant-aphid associations in Boerhavia spicata.