TITLE:
Laboratory Growth of Anopheles gambiae (Diptera: Culicidae) and Morphological Determinism of Moulting
AUTHORS:
Henri Gabriel Tsila, Patrick Akono Ntonga, Alvine Larissa Meyabeme Elono, Timoleon Tchuinkam, Mpoame Mbida
KEYWORDS:
Anopheles gambiae, Larva, Growth, Determinism, Body Sizes, Moulting
JOURNAL NAME:
Advances in Entomology,
Vol.9 No.4,
October
19,
2021
ABSTRACT: Growth in arthropods in general and in insects in particular, is supposed
to be discontinuous and occurs during moulting. In Culicidae in general and Anopheles in particular,
the number of moults is five with the fourth which gives the pupae. It is known
that moulting in insects is a genetic and physiological phenomenon. Most physiological reactions are triggered by
chemical or physical stimuli. The pressure exerted by the growth of the larval
body on the exocuticle is one of the triggers of moulting. The objective of
this work was therefore to determine the exact timing of the first three moults
that determine the growth of An. gambiae larvae from
egg hatch to pupation to highlight the role of increased larval size in the
stimulation of moulting. We therefore, undertook to rear larvae of this
anopheline species in the laboratory under conditions close to their
natural environment from hatching to pupation. The length and width of the
head, thorax and abdomen were recorded daily. Data analysis showed that the
size of the head and thorax remained constant for the first three days (D0 to
D2) of development and abdomen’s length for the first two days and then
increased daily until day seven (D7) when it stopped. These observations led us
to say that the M1 moult occurs at end of the third day of development and the
M3 moult at end of the eighth day; the M2 moult could not be determined. All these
observations led to the conclusion that the
larval growth of An. gambiae has a continuous regimen and the growth of the head and thorax of the larva plays a crucial role
in the onset of moulting.