Leafcutting bees (
Megachile
: Megachilidae) cut leaves from various trees, shrubs, wildflowers and grasses to partition and encase brood cells in hollow plant stems, decaying logs or in the ground. The identification of preferred plant species via morphological characters of the leaf fragments is challenging and direct observation of bees cutting leaves from certain plant species are difficult. As such, data are poor on leaf preference of leafcutting bees. In this study, I use DNA barcoding of the rcbL and ITS2 regions to identify and compare leaf preference of three
Megachile
bee species widespread in Toronto, Canada. Nests were opened and one leaf piece from one cell per nest of the native
M. pugnata
Say (
N
=45 leaf pieces), and the introduced
M. rotundata
Fabricius (
N
=64) and
M. centuncularis
(L.) (
N
=65) were analysed. From 174 individual DNA sequences, 54 plant species were identified. Preference by
M. rotundata
was most diverse (36 leaf species,
H
′=3.08, phylogenetic diversity (
pd
)=2.97), followed by
M. centuncularis
(23 species,
H
′=2.38,
pd
=1.51) then
M. pugnata
(18 species,
H
′=1.87,
pd
=1.22). Cluster analysis revealed significant overlap in leaf choice of
M. rotundata
and
M. centuncularis
. There was no significant preference for native leaves, and only
M. centuncularis
showed preference for leaves of woody plants over perennials. Interestingly, antimicrobial properties were present in all but six plants collected; all these were exotic plants and none were collected by the native bee,
M. pugnata
. These missing details in interpreting what bees need offers valuable information for conservation by accounting for necessary (and potentially limiting) nesting materials.
Analysis of Antioxidant and Antimicrobial Properties of Different Plant Species Growing in Shar Mountains