Age determination in the blackfly Simulium woodi, a vector of onchocerciasis in Tanzania
作者:
T. Q. HOC,
T. J. WILKES,
期刊:
Medical and Veterinary Entomology
(WILEY Available online 1995)
卷期:
Volume 9,
issue 1
页码: 16-24
ISSN:0269-283X
年代: 1995
DOI:10.1111/j.1365-2915.1995.tb00112.x
出版商: Blackwell Publishing Ltd
关键词: Simulium woodi;ovary;ovariole;parity;physiological age;ovarian oil injection technique;diagnostic reliability index;basal body;granular basal body;age grading;Tanzania
数据来源: WILEY
摘要:
Abstract.Age‐dependent changes in the ovarioles ofSimulium woodi(Diptera: Simuliidae) and the age structure of a wild population of this species in the Amani hills of north‐eastern Tanzania were studied using the ovarian oil injection technique. Contrary to previous theories, egg sacs degenerate completely and do not form dilatations. The physiological age of the females could be determined only by gonotrophic dilatations formed from degenerating follicles during gonotrophic cycles. In individual females, the proportions of ovarioles with degenerating follicles were 3–54% (mean 22%) in the first cycle and 8–61% (mean 36%) in the second gonotrophic cycle. Agonotrophic degenerating follicles occurred in 2% of ovarioles in 12% of females. Additional information with regard to the degree of parity is given by the level of granulation in the basal body of each ovariole, a group of six to eight cells in the calyx wall enclosed by the end of the ovariolar sheath. Their granulation progressively increased in intensity following each subsequent ov
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