Oliver & Beattie, Ecological Applications, Vol. 6, No. 2. (May, 1996), pp. 594-607.

Ecological Applications, Vol. 2, No. 2. (May, 1992), pp. 203-217

Single invasive event still enough to cause success.

he giant resin bee, Megachile sculpturalis Smith (Megachilidae: Megachilinae), is a species originally of Asia recently adventive in North America. This large and conspicuous species was first recorded at a few localities in the mid-Atlantic states of the United States, but is now found from southeastern Canada (Ontario) to Georgia, and as far west as western Pennsylvania and northwestern Alabama. Known occurrences of this species in its native distributional areas were used to generate an ecological niche model for the species, which can be used to anticipate the geographic potential for species in novel landscapes. The niche model was tested on the native range of the species for robustness in predicting independent suites of occurrence points. The niche model was then used to predict the potential distribution of M. sculpturalis in North America—our results indicate that this species has the potential eventually to occupy the entire eastern half of the continent, as far west as the Great Plains. The model also predicts that the species would find appropriate conditions along the Pacific Coast, in Mexico, and in the West Indies. Impacts of M. sculpturalis on native Megachile species are entirely unknown.

Megachile (Callomegachile) sculpturalis has been found in several parts of North Carolina, USA, prompting our surveys for it in other states. Including the reports of others, the bee is in South Carolina, Georgia, Virginia, Maryland, the District of Columbia, Pennsylvania, West Virginia, Ohio, Tennessee, New Jersey, Connecticut, Delaware, New York and Alabama. We also found it in southern Ontario, which is the first Canadian record. Its host plants include Koelreuteria paniculata, Sophora japonica [Styphnolobium japonicum], Ligustrum lucidum, Ligustrum vulgare, Oxydendrum arboreum, Catalpa speciosa, Lathyrus latifolius, Lythrum salicaria, Buddleja spp., Vitex spp., and Asclepias spp. When foraging on L. latifolius and S. japonica, M. sculpturalis sometimes punctures the standard petal with its mandibles, leaving a distinctive mark that is useful for surveys. Over half of the host plants reported here originate from Asia, which is also the native range of M. sculpturalis. Perhaps this favourable foraging environment has, in part, aided the establishment and spread of M. sculpturalis in the USA.