Ovariolar ‘basal body’ development and physiological age of the mosquito Aedes aegypti

Abstract

Dissection of the ovaries of the mosquito Aedes aegypti (Diptera: Culicidae) revealed, in each ovariole, a group of seven to nine specialized epithelial cells in a region of the calyx wall that is enclosed by the end of the ovariolar sheath. This group of cells is termed the basal body. During ovulation, the mature oocyte passes from the ovariole into the calyx lumen through the basal body. Subsequently, granulation occurs in the basal body cells. The granular basal bodies differ from all previously described ovarian structures. In multiparous females the size and optical density of the granular basal bodies increase after each ovulation. Examination of the granular basal bodies in intact ovaries, stained with neutral red, provides an easy method for distinguishing parous from nulliparous females, and has potential as a new method of age grading.

The ovariole structure of Anopheles gambiae (Diptera: Culicidae) and its use in determining physiological age

“…The age-related changes that occurred in the ovarioles of A. gambiae are generally similar to those that occurred in some other species of mosquito and blackfly (Diptera: Simuliidae) (Hoc, 1974;Hoc & Charlwood, 1990;Hoc & Schaub, 1995;Hoc & Wilkes, 1995; see also Service, 1993;Fox & Brust, 1994). Firstly, contrary to the conventional view (Detinova, 1962), serial ovulation did not produce a chain of distinct dilatations with age, but gave rise to only one granular basal body at the posterior end of the ovarioles.…”

“…The counts were to be made on intact ovaries (Spencer, 1979) or on dissected ovaries using the oil-injection technique (Sokolova, 1983;Sokolova & Lange, 1989). In contrast, Hoc & Schaub (1995) emphasized that in Aedes aegypti (Linnaeus) egg sacs degenerate almost completely within 1-2 days after oviposition and the granular structures that are most often observed in parous females are granular basal bodies, a group of specialized epithelial cells of the calyx wall enclosed by the end of the ovariolar sheath.…”

Age‐grading adult insects: a review of techniques

“…With each subsequent ovulation, granulation increases; this has been used to distinguish parous and nulliparous females and has potential for determining the degree of parity. The basal body of the mosquitoes, Aedes aegypti (L.) ( Hoc & Schaub 1995) and Anopheles gambiae Giles ( Hoc & Wilkes 1995b) shows a similar progressive granulation with increasing parity.…”

“…These are small bodies formed in the ovariole after oviposition or egg resorption and known also as corpora lutea, yellow bodies, residual bodies, follicular remnants and by a number of other terms ( Tyndale‐Biscoe 1984). Depending on the site of accumulation, however, follicular relics may be categorized as dilatations, yellow bodies ( Tyndale‐Biscoe 1984) or granular basal bodies ( Hoc & Schaub 1995).…”

Improved accuracy of the transcriptional profiling method of age grading in Aedes aegypti mosquitoes under laboratory and semi-field cage conditions and in the presence of Wolbachia infection

“…To date, there have been a wide variety of techniques employed to determine the age of an insect. Techniques such as monitoring changes to ovarian morphology (Hoc & Schaub, 1995) and pteridine concentration (Wu & Lehane, 1999) are subject to high levels of inaccuracy because of environmental variation, and are increasingly imprecise for older, epidemiologically important mosquitoes (Hugo et al ., 2008). More recently developed methods have involved observing changes to insect cuticular hydrocarbon (CHC) profiles, as some CHCs have been shown to exhibit age‐dependent changes in expression (Brei et al ., 2004; Hugo et al ., 2006).…”