SUMMARYAlmond (Prunus dulcis) pollen was hand-and honey bee-collected (corbicular) for chemical analysis. Corbicular pollen was packed by bees into wax combs for conversion (via natural fermentation) into bee bread. Chemical analyses of 12 fatty acids, 3 sterols, 3 vitamins, inositol, titratable acidity, and 5 minerals were made on the hand-collected and corbicular pollen. The bee bread was analyzed after 7, 2l, and 42 days for all of the above except the fatty acids and sterols. Lipoidal and acidic additions by the bees constituted the greatest differences between hand-collected and corbicular pollen. Sitosterol content decreased while titratable acidity increased during conversion to bee bread. The only vitamins which decreased as the pollen was converted to bee bread were ascorbic acid and pyridoxine.

The expansion of Africanized honeybees (AHB) through the Americas has been one of the most spectacular and best-studied invasions by a biotype. African and European honeybees (EHB) hybridize, but with time, tropical and subtropical American environments have become dominated by AHB that exhibit only 20-35% genetic contribution from western European bees, and a predominance of African behavioral and physiological traits. EHB persist in temperate environments. Clines between AHB and EHB exist in ecotones of South and Central America, and are forming in North America. What individual-level genetic, behavioral and physiological traits determine the relative success of the AHB as an invader in the neotropics, and of the EHB in temperate areas? Preference for pollen versus nectar may be an important trait mediating these ecological trade-offs, as preference for pollen enhances nutrient intake and brood production for the AHB in the tropics, while a relative preference for nectar enhances honey stores and winter survival for EHB. AHB exhibit morphological (higher thorax-to-body mass ratios) and physiological (higher thorax-specific metabolic rates) traits that may improve flight capacity, dispersal, mating success and foraging intake. Enhanced winter longevity, linked with higher hemolymph vitellogenin levels, may be a key factor improving winter survival of EHB. Data from South America and distributions of AHB in the southwestern United States suggest that AHB-EHB hybrids will extend 200 km north of regions with a January maximal temperatures of 15-16°C. The formation of biotypic clines between AHB and EHB represents a unique opportunity to examine mechanisms responsible for the range limit of invaders.

High Performance Liquid Chromatography (HPLC) was used to determine specific sugar ratios (fructose, glucose and sucrose) in nectars of nine families of flowering plants. All nectars contained all three sugars with the exception of that of Asclepias. Asclepias nectar was nearly a pure sucrose solution. Sucrose/hexose ratio was correlated with flower morphology, with tubular flowers having more sucrose and open flowers having more hexose. Open flowers contained nectar whose concentration was more affected by relative humidity than tubular flowers. Available nectar in unbagged flowers was found in volumes of 0.1 to 5 μl (17.5 to 68.2% sugar). Total sugar available per blossom amounted to 0.07 to 3.54 mg. We note that care must be taken in converting % concentration to mg sugar. Energetic yield was not as variable as the other measures and ranged from 0.72 to 3.58 cal/μl. Total daily nectar production was measured in five families and 24‐hr sugar production varied from 0.64 to 5.52 mg per flower. Insect nectar feeders frequently searched many blossoms with little or no reward, but were rewarded sufficiently at rare “lucky hit” blossoms which contained relatively large nectar rewards. Insect pollinators did not seek nectars of specific sucrose‐hexose ratios, but instead took nectar where caloric reward and accessibility made it most profitable.

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