Bulletin of Entomological Research (1995) 85, 339-344

A.I. Gryaznov (1995)
Age-grading in blackflies (Diptera: Simuliidae) by ovariolar morphology
Bulletin of Entomological Research 85 (3), 339-344
Abstract: A method for physiological age determination in blackflies is described from studies on Simulium equinum (Linnaeus), S. ornatum Meigen, S. erythrocephalum (De Geer), and S. nigrum (Meigen) in Russia, and S. vittatum (Zetterstedt), and S. verecundum-venustum supercomplex in Canada. The method uses neutral red to stain the ovariolar structures which indicate preceding gonotrophic cycles. Two different processes can occur in the ovariole during the gonotrophic cycle: egg development with ovulation, or degeneration of a terminal follicle. Egg-sacs are resorbed and form zones of granulation which accumulate in the ovariole at each gonotrophic cycle. Following- degeneration of the terminal follicle, a follicular relic (=gonotrophic dilatation) forms. The sum of zones of granulation plus follicular relics in each ovariole can indicate the number of completed gonotrophic cycles. However the number of follicular relics alone does not correspond to the number of preceding gonotrophic cycles and cannot reliably be used for determination of the parity of a female. Female flies collected in nature were categorized as: nulliparous; 1-parous; or multiparous. In multiparous females, most ovarioles have no more than two zones of granulation or a combination consisting of one zone of granulation and a follicular relic. Females in this category are considered to be 2-parous. In some ovarioles of parous females the germarium and terminal follicles were found to have disappeared.
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Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Simulium vittatum
	Simulium ornatum
	Simulium erythrocephalum
	Simulium equinum		Russia (Eur.)
	Simulium equinum		Russia (W Asia)