Ant-Plant Mutualism in Hawai‘i? Invasive Ants Reduce Flower Parasitism but also Exploit Floral Nectar of the Endemic Shrub Vaccinium reticulatum (Ericaceae)

Invasive ants in Hawai‘i Volcanoes National Park exhibit a previously undocumented mutualistic relationship with the endemic shrub Vaccinium reticulatum, reducing flower parasitism by introduced plume moth caterpillars while simultaneously exploiting floral nectar. This dual effect—protection from herbivory and resource exploitation—highlights a complex interaction that may alter plant reproduction dynamics. Researchers experimentally manipulated ant presence to assess impacts on flower parasitism and seed viability, finding that while ants mitigated caterpillar damage, they did not appear to act as effective pollinators, suggesting limited or absent primary pollinators like Hylaeus bees. The study underscores the unintended ecological consequences of invasive species, particularly their role in shaping plant reproductive success.

Bleil, R., Blüthgen, N., & Junker, R. R. (2011). Ant-Plant Mutualism in Hawai‘i? Invasive Ants Reduce Flower Parasitism but also Exploit Floral Nectar of the Endemic Shrub Vaccinium reticulatum (Ericaceae). Pacific Science, 65(3), 291–300. https://doi.org/10.2984/65.3.291