First instar larvae of endemic Australian Miltogramminae (Diptera: Sarcophagidae)

Abstract

The first instar larva of a species of the Australian endemic genus Aenigmetopia Malloch is described for the first time, along with the first instar larvae of three other Australian species representing the genera Amobia Robineau-Desvoidy and Protomiltogramma Townsend. Larval morphology was analysed using a combination of light microscopy, confocal laser scanning microscopy and scanning electron microscopy. The following morphological structures are documented: pseudocephalon, antennal complex, maxillary palpus, facial mask, modifications of thoracic and abdominal segments, anal region, spiracular field, posterior spiracles and details of the cephaloskeleton. Substantial morphological differences are observed between the three genera, most notably in the labrum and mouthhooks of the cephaloskeleton, sensory organs of the pseudocephalon, spinulation, sculpture of the integument and form of the spiracular field. The first instar larval morphology of Aenigmetopia amissa Johnston, Wallman, Szpila & Pape corroborates the close phylogenetic affinity of Aenigmetopia Malloch with Metopia Meigen, inferred from recent molecular analysis. The larval morphology of Amobia auriceps (Baranov), Protomiltogramma cincta Townsend and Protomiltogramma plebeia Malloch is mostly congruent with the morphology of Palaearctic representatives of both genera.

Larval morphology of the avian parasitic genusPasseromyia: playing hide and seek with a parastomal bar

“…7A-C This study provides the first comprehensive documentation of the cephaloskeleton of muscid species obtained by confocal laser scanning microscopy (CLSM). Despite earlier evidence of the utility of CLSM in visualizing morphological structures, this powerful tool has rarely been used on immature stages of Diptera (Grzywacz et al, 2014a;Szpila et al, 2016Szpila et al, , 2021Li et al, 2021). The main obstacles are high costs, equipment availability and lack of standard protocols for the preparation and visualization of specimens.…”

“…The main obstacles are high costs, equipment availability and lack of standard protocols for the preparation and visualization of specimens. The available protocols for the preparation of material for CLSM turn out to be only basic guidelines, and modifications are often required for individual preparations (Grzywacz et al, 2014; Szpila et al, 2021). Throughout this study, we found that the condition of material, the presence of impurities, previous storage conditions and the time of specimen maceration are critical to a successful CLSM analysis.…”

“…Therefore, larval specimens prepared with Hoyer's 6 medium and newly obtained ethanol-preserved material were transferred to 10% potassium hydroxide (KOH). Material was prepared according to the protocol by Szpila et al (2021) with the following modifications: 1) adjustment of the tissue maceration interval for specimens of various sizes (16-18 h for first instar larvae to 24-50 h for second and third instars larvae) to avoid over-maceration and consequent CLSM image quality reduction; 2) the placement of larvae in a drop of viscous glycerine. Following tissue maceration in KOH, larval specimens were transferred to 80% EtOH to dehydrate for 15 minutes.…”

“…The application of confocal laser scanning microscopy (CLSM) overcomes these issues because it allows the visualisation of fine, complex, autofluorescent larval structures (Grzywacz et al, 2014a). CLSM provides high resolution, high-fidelity imaging and 3D reconstruction of examined structures (Szpila et al, 2021).…”

“…Existing literature concerning the larval morphology of Passeromyia encompasses two early contributions that were limited in material and scope (Skidmore, 1985; Zumpt, 1965). The well‐established relationship between larval cephaloskeletal structure and evolutionary adaptation to feeding strategy (Ferrar, 1979; Roberts, 1970; Skidmore, 1985) has been utilized in taxonomic and systematic research (Grzywacz et al, 2021; Szpila, 2010). Morphological analysis of the larval stages has traditionally involved examination by light microscopy, and more recently, light microscopy combined with scanning electron microscopy (SEM) (e.g., Grzywacz, 2013; Grzywacz & Pape, 2014; Velásquez et al, 2013).…”