Reproductive output of female Anopheles gambiae (Diptera: Culicidae): comparison of molecular forms

• Published in: Journal of medical entomology Vol. 43; no. 5; pp. 833 - 839
• Main Authors: Yaro, A.S, Dao, A, Adamou, A, Crawford, J.E, Traoré, S.F, Touré, A.M, Gwadz, R, Lehmann, T
• Format: Journal Article
• Language: English
• Published: England 01.09.2006
• Subjects: Animals; Anopheles - genetics; Anopheles - parasitology; Anopheles - physiology; Anopheles arabiensis; Anopheles gambiae; body size; Body Size - physiology; clutch size; cytogenetics; egg masses; egg size; fecundity; Female; Fertility - physiology; insect egg quality; insect reproduction; M molecular form; molecular genetics; Ovum - chemistry; Ovum - physiology; Plasmodium falciparum - isolation & purification; protein content; Proteins - analysis; S molecular form; species differences; Species Specificity; Mali
• ISSN: 0022-2585; 1938-2928
• DOI: 10.1603/0022-2585%282006%2943%5B833%3AROOFAG%5D2.0.CO%3B2

Knowledge of ecological differences between the molecular forms of Anopheles gambiae Giles (Diptera: Culicidae) might lead to understanding of their unique contribution to disease transmission, to better vector control, and to identification of the forces that have separated them. We compared female fecundity measured as egg batch size in relation to body size between the molecular forms in Mali and contrasted them with their sibling species, Anopheles arabiensis Patton. To determine whether eggs of different egg batches are of similar "quality," we compared the total protein content of first-stage larvae (L1s), collected <2 h after hatching in deionized water. Egg batch size significantly varied between An. gambiae and An. arabiensis and between the molecular forms of An. gambiae (mean batch size was 186.3, 182.5, and 162.0 eggs in An. arabiensis and the M and the S molecular form of An. gambiae, respectively). After accommodating female body size, however, the difference in batch size was not significant. In the S molecular form, egg protein content was not correlated with egg batch size (r = -0.08, P > 0.7) nor with female body size (r = -0.18, P > 0.4), suggesting that females with more resources invest in more eggs rather than in higher quality eggs. The mean total protein in eggs of the M form (0.407 &mgr;g per L1) was 6% higher than that of the S form (0.384 &mgr;g per L1), indicating that the M form invests a greater portion of her resources into current (rather than future) reproduction. A greater investment per offspring coupled with larger egg batch size may reflect an adaptation of the M form to low productivity larval sites as independent evidence suggests.