Epoch Year(s) Event Reference
Miocene 19 Mybp Estimated divergence date for the genus Halictus Gibbs et al., 2012
Pleistocene 30,000 ybp to 16,000 ybp Proposed migration of Halictus spp. into North America across the Bering Land Bridge Danforth et al., 1999
17,000 to 18,000 ybp Most recent glacial maximum; Northern Channel Islands united in a single land mass (Santarosae); Maximum sea-level lowering by 120 m shrinks water barrier between SCI and mainland to <6 km Miller, 1985
Holocene 1880s Honey bees (Apis mellifera) introduced to SCI Wenner et al., 2009
1988 Beginning of honey bee removal from SCI Wenner et al., 2009
2004 Last honey bee seen on SCI Wenner et al., 2009
1956 - 2020 Specimen collections for this study