• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 3
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The role of the queen in wax secretion and comb building in the Cape honeybee, Aps mellifera capensis (Escholtz)

Whiffler, Lynne Anne January 1992 (has links)
The role of the queen in wax secretion and comb building was studied in the the Cape honeybee, Apis mellifera capensis (Escholtz). The percentage of bees bearing wax and the amount of wax borne by these bees did not differ between the experiments. This meant that the queenless and queenright colonies had the potential to construct equal amounts of comb as the amounts of wax available for comb building was the same. Contrary to this prediction, queenright colonies constructed 8 times more comb than their queenless counterparts. Queenright Apis mellifera scutellata colonies constructed 4 times more comb than their queenless counterparts. The increased amount of 9-oxo-2-decanoic acid (90DA) in the A.m.capensis mandibular gland secretions could not alone account for this difference. In fact, A.m.capensis and A.m.scutellata colonies constructed similar amounts of comb when they were given their own queens or queens from the other race. Worker bees need to have direct contact with their queen for comb building to be enhanced. Even when the queen had her mandibular glands extirpated and tergite glands occluded large amounts of comb were constructed than when access to the queen was limited. Direct access to the head of a mated queen proved to be the stimulus enhancing comb building. No comb was constructed when the workers had access to the abdomen of the queen. Virgin queens did not stimulate comb building. The relatively large amounts of 90DA and 9HDA from the mandibular glands of Cape virgin queens had not influenced comb building. Worker sized cells were generally constructed. These cells were slightly smaller than those constructed by European honeybees, but were indicative of African bees. A few queen less colonies constructed cells that were of an intermediate drone and worker size. Four mandibular gland pneromones were measured by gas chromatography. No correlations between these pheromones and the comb construction measurements were found. It is unlikely that the mandibular gland pheromones are the only pheromones that stimulate comb building. Pheromones from other glands on the head may contribute towards the enhancement of comb building, and they are not present in virgin queens
2

Physico-chemical characteristics of waxes produced by the African honeybee, apis mellifera scutellata.

Kurstjens, Sef Paul. January 1990 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy / In this dissertation the physical and chemical alterations induced by mastication and manipulation of wax by the worker bee in honeycomb construction, and the subsequent contribution afforded the structural integrity of the nest, are elucidated. In comb building, the freshly secreted wax scales are mandibulated together with a frothy salivary emulsion, and added piece-meal to form honeycomb. Textural modifications were revealed using X-ray crystallography. While virgin scale wax is highly structured, with the crystallites aligned approximately perpendicular to the planar surface, comb wax has a random crystallographic arrangement. This reflects a disruption of the crystallite structure following the mechanical insult of mastication. Chemical analyses included investigation of both lipid and proteinaceous elements. Lipid composition was evaluated by enzyme-catalyzed as well as thin-layer and gas-liquid chromatographic methods. The results indicate a reduction in scale diacylglycerols with a corresponding increase in comb saturated monoaeylglycerols. Such modifications are highly suggestive of lipase activity within the salivary addition. The proteins of comb and scale wax were analyzed electrophoretically, under reduced conditions. Each wax possesses unique polypeptide fractions, in addition to sharing common protein species, It is speculated that those in common represent integral proteins, such as transport molecules, while the disparities noted may be due to salivary enzymatic degradation, or even glycosylation. The effects of these textural and chemical alterations on the mechanical behaviour of the waxes was assessed. Tensile tests were performed on a variety of scale and comb wax preparations over the range of temperatures likely to impinge on the honeybee nest. These investigations reveal the specific structural contributions made by each of the physico-chemical alterations described. Further, they demonstrate that while scales are ideal moulding materials due to their high distensibility and low stiffness, the greater resistance to deformation and lower potential for extension makes comb wax a superior structural material. The mechanical advantage for including propolis and cocoon silk within the comb structure was also investigated. Tensile testing indicates that the resultant composite material is structurally superior, largely due to the presence of silk reinforcement. / Andrew Chakane 2018
3

Effects of used brood comb and propolis on honey bees (Apis mellifera L.) and their associated bacterium, Melissococcus plutonius

Murray, Stephanie K. January 2019 (has links)
No description available.

Page generated in 0.0297 seconds