Background
The authors note that "the phenology of many ecological processes is modulated by temperature, making them potentially sensitive to climate change," and they say that because of this fact, "mutualistic interactions may be especially vulnerable because of the potential for phenological mismatching if the species involved do not respond similarly to changes in temperature," which unfortunate possibility is commonly portrayed as highly likely by many of the world's climate alarmists.

What was done
In a study designed to explore this situation with real-world data as opposed to suppositions, Bartomeus et al. "present an analysis of climate-associated shifts in the phenology of wild bees, the most important pollinators worldwide, and compare these shifts to published studies of bee-pollinated plants over the same time period." More specifically, they say they "used long-term data to compare phenological shifts for 10 bee species to shifts in 106 native plant species that are visited by these same bee species," which typically "have annual cycles that include an obligatory larval or adult diapause before spring emergence." The plant data for this comparison were provided by Primack et al. (2004) and Miller-Rushing et al. (2006) for Massachusetts (AD 1885-2003), by Bradley et al. (1999) for Wisconsin (1936-1999), by Cook et al. (2008) for New York (1931-2008), and by Abu-Asab et al. (2001) for Washington, DC (1970-1999, which time interval brackets the period of greatest temperature increase), while the bee data were developed by Bartomeus et al.

What was learned
The seven scientists report that "over the past 130 years, the phenology of 10 bee species from northeastern North America has advanced by a mean of 10.4 ± 1.3 days," noting that "most of this advance has taken place since 1970, paralleling global temperature increases." And they indicate that "when the best available data are used to estimate analogous rates of advance for plants, these rates are not distinguishable from those of the bees."

What it means
Bartomeus et al. conclude that among the generalist bee species they studied, "bee emergence is keeping pace with shifts in host-plant flowering," and this finding suggests that historical global warming - which climate alarmists contend has been unprecedented over the past millennium or two - has not detrimentally interfered with the long-standing mutualistic relationship that exists between the concomitant emergence of adult wild bees and the flowering of the plants they visit.

References
Abu-Asab, M.S., Peterson, P.M., Shetler, S.G. and Orli, S.S. 2001. Earlier plant flowering in spring as a response to global warming in the Washington, DC, area. Biodiversity and Conservation 10: 597-612.

Bradley, N.L., Leopold, A.C., Ross, J. and Huffaker, W. 1999. Phenological changes reflect climate change in Wisconsin. Proceedings of the National Academy of Sciences, USA 96: 9701-9704.

Cook, B.I., Cook, E.R., Huth, P.C., Thompson, J.E. and Smiley, D. 2008. A cross-taxa phenological dataset from Mohonk Lake, NY and its relationship to climate. International Journal of Climatology 28: 1369-1383.

Miller-Rushing, A.J., Primack, R.B., Primack, D. and Mukunda, S. 2006. Photographs and herbarium specimens as tools to document phenological changes in response to global warming. American Journal of Botany 93: 1667-1674.

Primack, D., Imbres, C., Primack, R.B., Miller-Rushing, A.J. and Del Tredici, P. 2004. Herbarium specimens demonstrate earlier flowering times in response to warming in Boston. American Journal of Botany 91: 1260-1264.