Abstract The missed mutualist hypothesis predicts that the absence of mutualistic partners poses a barrier to introduced species becoming invasive. Yet, some alien plants thrive despite potential dependence on certain pollinators. For example, buzz‐pollinated plants typically have specialist floral morphologies and benefit from buzz pollinator behavior for pollination. Despite this apparent specialization, some buzz‐pollinated plant species have become invasive. To understand this contradiction, we undertook field observations at three sites in one native region (Mexico), and at five sites in one invaded region (Australia), of an invasive plant with the buzz pollination syndrome ( Senna obtusifolia ; Fabaceae), to (1) identify the floral visitors and pollinators, (2) determine whether pollinator assemblages differ between regions, and (3) assess whether S. obtusifolia relied on specialized buzzing behavior for pollen transfer in both the native and invaded populations. We identified 15 different insect species (native region) and 11 species (invaded region) that contacted the stigma or carried pollen and classed these as potential pollinators. We calculated a pollination importance index based on the relative abundance, pollen load, pollen fidelity, stigma contact, and body size match index of each morphospecies; the most important pollinators were non‐buzzing bees ( Apis mellifera and Meliponini species) in both regions. We observed buzzing behavior infrequently (<9% of visits), and it was 3.8 times more common in the invaded region compared to the native region. The dominance of non‐buzzing behaviors suggests that S. obtusifolia does not rely on a distinct pollinator niche. We found no evidence for the missed mutualist hypothesis.
Lopresti et al. (Wed,) studied this question.