Date of Award:
5-1-1983
Document Type:
Thesis
Degree Name:
Master of Science (MS)
Department:
Biology
Department name when degree awarded
Life Sciences:Biology
Committee Chair(s)
Nabil N. Youssef
Committee
Nabil N. Youssef
Committee
Frank Parker
Committee
Frederick Post
Committee
Anne Anderson
Abstract
The present light and electron microscope study revealed that the in vivo pattern of development of A. aggregata resembles that of the in vitro development of A. apis, the only other member of the Ascospheraceae to be studied in detail by Spiltoir in 1955. As well as documenting the similarities between the two species, this study also revealed several distinct differences between the two species and answered several developmental questions left unanswered by Spiltoir's study. Nongerminated and germinating ascospores were seen within the gut lumen of the feeding larvae. After germination minimal hyphal development occurred within the gut lumen. The hyphae penetrated through the midgut wall, invading the hemoceole. All of the tissue within the hemoceole was consumed, exclusive of the cuticular elements. The fungus was never seen penetrating through the integument nor other cuticular structures. Sexual development occurred directly beneath the larval integument. The ultimate shape of the ascocyst was determined by the availability of space into which it was formed. The ascogenous hyphal system appeared to be composed of a highly interconnected meshwork of hyphae. These hyphae fused, forming membrane-bound "chambers". Into these chambers several ascus mother cells were evaginated. Sporogenesis followed the classical pattern found in the Ascomycetes. Sixteen ascospores appeared to be produced per ascus. After the ascospores were formed the outer membranes of the asci degenerated releasing individual ascospores into the chamber. The limiting membrane of the chamber held the ascospores in tight groupings. Eventually this membrane degenerated, leaving the mature ascospores in a tightly packed spherical structure, the spore ball.
Recommended Citation
McManus, William R., "In Vivo Development of Acosphaera aggregata Skou in the Alfalfa Leafcutting Bee, Megachile rotundata(Fabricus): A Light and Electron Microscope Study" (1983). Biology. 506.
https://digitalcommons.usu.edu/etd_biology/506
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