Date of Award

1987

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Entomology

Abstract

Neotropical Africanized honey bees are predicted to replace European bees and become the primary agricultural pollinators in the southern and coastal regions of the United States. This research used direct comparative studies to assess foraging activities and beekeeping-management responses which are expected to govern the performance of Africanized bees as crop pollinators. European colonies fielded on average $3\times$ as many foragers as did Africanized colonies and had percentages of colony members foraging that were nearly $3\times$ as high. European colonies also had much greater variability in foraging activity (ranges: 42-1679 foragers for European bees; 119-352 foragers for Africanized bees); European colonies had more foragers as colony size was increased from one to three kg and especially when nectar became abundant. A novel hive-entrance trap that captured returning foragers was developed for quantifying foraging populations. Colonies of Africanized bees had higher numbers and proportions of pollen foragers when nests were established with equal levels of stimuli known to regulate pollen collection. European colonies again had greater foraging activity overall. Recruitment rate to pollen resources was similar for the bee types, and does not explain the difference in foraging patterns. With regard to foraging behavior, it is concluded that the high pollen foraging tendencies of Africanized bees offset the European advantage of large foraging populations, thus leaving neither bee type as a clearly superior crop pollinator. During a two-month study simulating a pollination program, however, Africanized colonies presented problems due to population losses, excessive defensive behavior, and poor honey storage. These difficulties were the greatest problems related to commercial crop pollination with Africanized bees, and can be expected to precipitate quarantine and liability factors that might limit use of Africanized bees for crop pollination. Individual Africanized workers were more tolerant (non-overlap of 95% fiducial limits at the ${\rm LC\sb{50}})$ than European bees to topical applications of azinphosmethyl, methyl parathion and permethrin. European bees were more tolerant to carbaryl. The slight differences in tolerance between the bee types, however, are not likely to confer significant selective protection to Africanized bees exposed to insecticide sprays and residues.

Pages

114

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