Third instar larva morphology of Hydrotaea cyrtoneurina (ZETTERSTEDT, 1845) (Diptera: Muscidae) – a species of forensic interest

Abstract

ABSTRACT. The muscid Hydrotaea cyrtoneurina (ZETTERSTEDT, 1845) is a Palaearctic species whose adults are known for their forensic importance. The third instar larva morphology of H. cyrtoneurina, hitherto unknown, is described herein with the application of light and scanning electron microscopy. The characters of larval morphology enabling this species to be distinguished from other forensically important third instar larvae of Muscidae are discussed as well. Some details of the cephaloskeleton are discussed, and modifications in terminology are proposed based on the literature data and the results of this study.

Morphology successfully separates third instar larvae of Muscina

“…Except for the most recent studies (e.g. Grzywacz, 2013;Grzywacz et al, 2013Velasquez et al, 2013;Grzywacz & Pape, 2014), none of the previous reports observed sensilla surrounding the spiracular field in third instars of Muscidae. However, the studies by Grzywacz et al (2013) and Velasquez et al (2013) are incomplete because these authors did not recognize the sensilla resembling sensilla ampullacea (i.e.…”

“…Except for the most recent studies (e.g. Grzywacz, ; Grzywacz et al ., , ; Velasquez et al ., ; Grzywacz & Pape, ), none of the previous reports observed sensilla surrounding the spiracular field in third instars of Muscidae. However, the studies by Grzywacz et al .…”

“…In Muscina spp. and also in some Hydrotaea Robineau‐Desvoidy (Diptera: Muscidae) (Grzywacz, ; Grzywacz et al ., ), SDF ratios overlap, strongly reducing the suitability of this metric for species identification. The ratio has been observed to increase during the maturation of larvae as the distance between both spiracles increases during larval growth while spiracle size remains constant.…”

“…() for general larval morphology, with a few modifications proposed by Szpila & Pape (). For family‐specific structures Skidmore's () terminology was applied with a few modifications proposed by Grzywacz (). The following measurements were recorded in both young and mature larvae: maximum body length and width; distance between posterior spiracles ( dps ); width of posterior spiracle in horizontal plain ( wps ), and spiracular distance factor (SDF) defined after van Emden () as the ratio of the distance between the posterior spiracles to the width of the posterior spiracle.…”

“…The following measurements were recorded in both young and mature larvae: maximum body length and width; distance between posterior spiracles ( dps ); width of posterior spiracle in horizontal plain ( wps ), and spiracular distance factor (SDF) defined after van Emden () as the ratio of the distance between the posterior spiracles to the width of the posterior spiracle. However, the latter ratio was modified after Grzywacz () and expressed as the maximum horizontal diameter of the spiracle rather than its greatest width. Measurements were taken with a Nikon Eclipse E200 microscope or Nikon SMZ 1500 stereomicroscope, both equipped with a micrometer eyepiece.…”