Effect of temperature on the ovarian development in the pupa of Glossina pallidipes Austen I: Estimation of the environmental temperature exposure from the size of the first egg follicle

Abstract

Newly-deposited pupae of Glossina pallidipes were incubated until emergenceat constant temperature (20.5, 22.5, 25.0, 27.5, and 29.5°C) and compared with pupae held at ambient conditions (19 to 31°C). Egg follicles and enclosed oocytes of newly-emerged females were dissected and their lengths measured together with the lengths of the cutting blade of the hatchet cell of the right and left wings. Linear discriminant functions analysis showed that the mean length of egg follicle A accounted for 80% of the temperature-related variability. We therefore used a simple predictive equation for temperature experience based on mean follicle length in small batches of newly-emerged females. The equation predicted with reasonable accuracy the temperature experience of 19 monthly samples of newly-emerged G. pallidipes reared in an insectary under ambient conditions. Mean sizes of egg follicle A of the newly-emerged tsetse may therefore be of utility in estimating temperature experience of pupae.