Ground-nesting bees use a variety of substrates in which to establish cells and complete their reproductive cycles. Here we document the highly aberrant occurrence of a solitary bee species, Anthophora squammulosa Dours, 1870 (Hymenoptera: Apidae: Anthophorini), nesting within meters of an active volcanic crater in Nicaragua, Central America. The nest location is exposed to continuous, strongly acidic gas emissions (>2.7 ppm of SO₂), and sporadic vent clearing episodes that blanket the surrounding area with ash and tephra. An assessment of floral resources available within the expected homing distance of the species was cross-referenced with pollen carried by females returning to their nests. At this site, A. squammulosa appears to forage almost exclusively on a single plant, Melanthera nivea (L.) Small, 1903 (Asteraceae), that is adapted to volcanic acidic rain, despite being widely accepted as a generalist bee in the remainder of its range. Notwithstanding the extreme nature of the site, and the co-occurrence of specialist natural enemies and predators, the possibility exists that the site is selected for its beneficial attributes, such as the loose, well-drained substrate and the absence of vegetation. The converse is that the site is sub-optimal with the population constrained by habitat patchiness and limited dispersal options.