The life cycle, nesting behaviour and diet of resin bee Megachile tosticauda (Hymenoptera: Megachilidae)

The life cycle, nesting behaviour and diet breadth of the resin bee Megachile (Hackeriapis) tosticauda (Cockerell) are described for the first time. Microscopic imaging of the larval provisions and pollen from the scopa showed that Megachile tosticauda from Adelaide, South Australia, is narrowly oligolectic and specialised on Eucalyptus pollen. Parasites of the nests were identified, and the developmental timeline was outlined. A comparison between behaviour in South Australia (SA) and Western Australia (WA) revealed similarities in nest architecture and parasitism but showed discrepancies in emergence times, nest substrate and potentially diet width. However, the diet analysis from WA was based on visual floral visitations and pollen metabarcoding, neither of which indicate active pollen collection. The difference in diet breadth of this species needs to be ascertained by assessing the larval provisions.