Alimentary Canal of the Adult Blow Fly,Chrysomya megacephala(F.) (Diptera: Calliphoridae)—Part I: Ultrastructure of Salivary Glands

Worachote Boonsriwong,Kom Sukontason,Roy C Vogtsberger,Kabkaew L Sukontason,Tarinee Chaiwong,Urai Chaisri

doi:10.1155/2012/382917

Abstract

The salivary gland ultrastructure of the adult male blow fly, Chrysomya megacephala (F.) (Diptera: Calliphoridae), was investigated at the ultrastructural level using light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The salivary glands are paired structures composed of a single median deferent duct bifurcated into two long, narrow efferent ducts connected to the coiled tubular glands. The SEM image of the gland surface revealed that the basal lamina is relatively smooth in general, but the whole surface appeared as a trace of rough swollen insertion by intense tracheal ramification. Ultrastructurally, the salivary gland is enclosed within the basal lamina, and interdigitation cytoplasmic extensions were apparent between the adjacent gland cells. The basement membrane appeared infoldings that is similar to the complex of the labyrinth channel. The cytoplasm characteristic of the gland revealed high activity, based on the abundance of noticeable secretory granules, either singly or in an aggregated reservoir. In addition, mitochondria were found to intersperse among rich parallel of arrays rough endoplasmic reticulum. Thick cuticle, which was well-delineated and electron dense, apically lined the gland compartments, with discontinuity of the double-layer cuticle revealing a trace of secretion discharged into the lumen. Gross anatomy of the adult salivary gland was markedly different from that of the third instar of the same species, and structural dissimilarity is discussed briefly.

Highlights

Chrysomya megacephala (F.), or the Oriental latrine fly, is a medically important blow fly species
In northern Thailand, systematic surveys revealed that C. megacephala is the most common species collected in many habitats, ranging from urban human to rural and forest environments, from which the number of C. megacephala collected was more than that for the house fly, Musca domestica [10]
Observation of the whole excised alimentary canal of male C. megacephala under light microscopy (LM) demonstrated that the salivary glands were a paired structure situated in the foregut region (Figure 1(a))

Summary

Introduction

Chrysomya megacephala (F.), or the Oriental latrine fly, is a medically important blow fly species. Its adults are annoying to humans and animals, but they act as a potential mechanical disseminator of pathogens that may cause diseases [1, 2]. In some Southeast Asian countries, adult flies cause damage in fermented fish when females oviposit on this product, resulting in infestation of fly larvae [3]. C. megacephala is distributed widely over continents worldwide, extending from Oriental Asia, Australasia, Africa, Europe, the Mediterranean to North and South America [7,8,9]. In northern Thailand, systematic surveys revealed that C. megacephala is the most common species collected in many habitats, ranging from urban human to rural and forest environments, from which the number of C. megacephala collected was more than that for the house fly, Musca domestica [10]

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