Observations of the third instar larva and puparium of Chrysomya bezziana (Diptera: Calliphoridae)

Abstract

Observations on the ultrastructure of the third instar larva and puparium of the Old World screw-worm fly, Chrysomya bezziana, are presented utilizing both light microscopy (LM) and scanning electron microscopy (SEM). Results of this study indicate that the shape of the intersegmental spines between the pro- and mesothorax markedly differ from other blow fly species (Chrysomya megacephala, Chrysomya rufifacies, Chrysomya nigripes, Lucilia cuprina) in being broad-based with sharp recurved tips. Other characters such as the posterior spiracles, number of papillae on the anterior spiracles, oral grooves, and posterior spiracular hairs also differ. The strong and robust mouthhooks may explain the ability of larvae to penetrate deeply into human tissues. Perforated sieve plates covered with antler-like projections were observed within the anterior spiracles of the puparium of C. bezziana. The posterior spiracular discs each bear three spiracular slits with approximately 2-microm wide openings that were viewed either open or closed by a membrane underneath. This study expands our knowledge of the fine details of the external morphology of both the third instar larva and puparium of C. bezziana, which is an obligatory myiasis-producing species in many regions. A key to differentiate the third instar of C. bezziana from other blow flies in Thailand is given.

Occurrence of Chrysomya bezziana in a buffalo in Jammu

“…1). The larvae were collected in normal saline and processed in the laboratory for identification according to Zumpt (1965) and Sukontason et al (2006).…”

Connecting the Dots: From an Easy Method to Computerized Species Determination

“…This is very time-consuming and requires living larvae. Other methods based on light microscopy rely on the morphological characteristics of the larvae, like the shape of the cephalopharyngeal skeleton (CPS), spiracles, or spinebands [13,14,15,16,17,18,19,20,21,22]. These methods can be hindered by the fragmentation or discoloration of the specimen by poor preservation.…”

Blow Fly (Diptera: Calliphoridae) in Thailand: Distribution, Morphological Identification and Medical Importance Appraisals

“…Pupa stage: The pupa is mahogany brown to dark brown in color and coarctate and barrel shaped. Morphology of puparium has been studied widely under LM [29] and SEM [30][31][32][33][34][35]. A simply key to identify the puparium of some blow fly species of Thailand was summarized by Sukontason et al [29].…”

“…Analysis of cuticular muscle attachment sites is reported currently as a new method for species determination in third instar larvae of saprophagous blow flies [22]. Medically important blow fly larvae of Thailand (C. megacephala, A. rufifacies, A. villeneuvi, C. nigripes, L. cuprina, H. ligurriens) have been studied by observing under SEM [23][24][25][26][27][28]. The identification key for third instar of some important blow fly species in Thailand (C. megacephala, A. rufifacies, C. nigripes and L. cuprina) was reported previously by Sukontason et al, [20].…”

“…A simply key to identify the puparium of some blow fly species of Thailand was summarized by Sukontason et al [29]. The main characteristics for identification include body appearance (with or without tubercle), such as the 3 rd thoracic segment to 1 st abdominal segment, distance between right and left posterior spiracles, number of bubble membranes and papillae on the anterior spiracle [29][30][31][32][33][34][35].…”