SURVIVAL AND ITS IMPLICATIONS: TROPICAL HONEYBEES (HYMENOPTERA: APIDAE: MELIPONINI) AND THE CRETACEOUS-TERTIARY BOUNDARY

The asteroid theory and its after-effects at the Cretaceous-Tertiary (K/T) boundary have been a subject of much debate since the theory was proposed. By looking at survivors of the K/T mass extinction, restrictions can be placed upon the after-effects of asteroid theory. The oldest tropical honeybee, Cretotrigona prisca is found in late Cretaceous (Maastrichtian) ambers of New Jersey. C. prisca shares a cladistic association with as its modern analog, Dactylurina, meaning that Cretotrigona persisted through K/T boundary. This close association also allows the inference of modern Meliponini survival requirements onto its fossil cousin. The energy source for all modern Hymenoptera is pollen, and since Meliponini do not store honey, there must be a constant source of blooming angiosperms. Modern tropical honeybees have shown to have an optimal temperature range of 31-34°C in order to maintain vital metabolic activities. Modern Meliponini exhibit dependence upon temperature, time of day, relative humidity, and available flowers for their existence (Fowler, 1979; and Eltz, et al., 2003). Angiosperms have also shown to survive also within a temperature band to maintain photosynthesis, Krebs cycle, ect… The proposed asteroid impact theory suggests many drastic after-effects, which include a “nuclear winter”. A worldwide temperature drop of 7-12°C has been proposed. However, this decrease would drop the tropics to a temperate climate. The persistence of Cretotrigona through the boundary is inconsistent with these proposed after-effects. The temperature flux during this time could not have exceeded 2-7°C to maintain the tropical environment.