Morphological description of the pupa of Aedes aegypti (Diptera: Culicidae) using a scanning electron microscope

Abstract

Yellow fever mosquito, Aedes aegypti, has been associated with several severe human diseases. Larvae and adults of Ae. aegypti has been widely studied, but pupae have not received much attention. In this study, external morphology and chaetotaxy of Ae. aegypti pupae were investigated using scanning electron microscopy (SEM) to determine additional morphological characteristics for proper species identification. Ae. aegypti pupae exhibit high mobility with rapid submergence in response to external disturbances. Pupae contact air through paired respiratory horns. A pupal body is covered with a translucent cuticle composed of a cephalothorax and a narrow, articulated abdomen. Anterior region of cephalothorax is occupied by mouthparts and a flattened head. Adult's compound eyes are visible on both sides of their head. Before compound eyes, antennae emerge in upper part and are bent in reverse along sides of thorax. First abdominal segment has two straightforward palmate bundles, essential for maintaining pupal body above water's surface. Compared to other eight abdominal segments, ninth is relatively tiny; it holds a couple of movable appendages called paddles which are fundamental organs in pupal movement, and a midrib supports them. This morphological analysis of pupae attributes of Ae. aegypti is critical for controlling mosquito-borne diseases and taxonomy.