Sensilla coeloconica ringed by microtrichia in host‐seeking biting midges

Abstract

The distribution and morphology of antennal sensilla coeloconica in parasitic and predaceous biting midges were studied in females of Forcipomyia (feeding on the blood of frogs), Atrichopogon (feeding on haemolymph), Austroconops, Culicoides (feeding on the blood of birds and mammals) and Brachypogon (feeding on haemolymph and dissolved tissues of insects) (all: Diptera: Ceratopogonidae). A Lower Cretaceous female of Archiculicoides (Diptera: Ceratopogonidae) from Lebanese amber, which fed on the blood of unknown vertebrates, was also examined. In sensilla coeloconica ringed by microtrichia, the peg is grooved longitudinally and protrudes distinctly from the pit. We suggest that the microtrichia encircling the protruding peg form a structure resembling a picket fence in order to maintain a higher level of humidity, which facilitates the capture and transport of odour molecules through the channels in the peg wall. Sensilla coeloconica ringed by microtrichia function as very effective chemoreceptors in host- and prey-seeking activity. During the evolution of Ceratopogonidae, sensilla coeloconica with a fence of microtrichia have evolved twice in groups feeding on the blood of vertebrates (i.e. in the basal lineage: Lower Cretaceous or earlier) and in the subgenus Lasiohelea of Forcipomyia (Palaeogene). Sensilla coeloconica ringed by microtrichia are described for the first time in the relict genus Austroconops.

Ultrastructure of antennal and posterior abdominal sensilla in Chlorophorus caragana females

“…Mostly, these sensory cones protrude from the antennal surface, in which case they are called sensilla styloconica. However, when the sensory cones are set in a chamber embedded beneath the antennal surface, they are called sensilla coeloconica, and this type of sensillum is often seen in the Dipteran genera Forcipomyia, Atrichopogon, Austroconops and Brachypogon (Urbanek et al, 2014).…”

The Phylogenetic Relationships of Cretaceous Biting Midges, with a Key to All Known Genera (Diptera: Ceratopogonidae)

“…Presence or absence ofsensilla coeloconica on flagellomere 1 Szadziewski (1996), Szadziewski and Poinar (2005), Szadziewski et al (2015b, and Urbanek et al (2014) considered the presence (fig. 4B) or absence of sensilla coeloconica on the "proximal" flagellomeres (actually on only flagellomere 1) as characteristic of Archiculicoi¬ des and Protoculicoides (in their sense), respectively.…”

“…In summary, the phylogenetic conclusion above indicates the generic concepts of Protoculicoides and Archiculicoides as defined by previous publications requires revision. Some of the species placed in either Protoculicoides (Borkent, 2000a;Choufani et al, 2015;Perez-de la Fuente et al, 2011;Szadziewski, 1996;Szadziewski and Arillo, 1998) or Archiculicoides Urbanek et al, 2014) are here placed in the following new genus (table 1).…”

The antenna of horse stomach bot flies: morphology and phylogenetic implications (Oestridae, Gasterophilinae: Gasterophilus Leach)

“…Diptera antennae offer an abundance of structures that provide excellent taxonomic and phylogenetic characters. Antennal ultrastructure has been used in classification and phylogenetic reconstruction at least since the beginning of last century 18 , yet new information continues to emerge 19 20 21 . There are numerous studies of antennal ultrastructure in Calyptratae, but they mainly focus on morphology, physiology and function speculation.…”