Pedicellar structures in Reduviidae (Heteroptera) - comments on cave organ and trichobothria

Abstract

Abstract. Sensillar structures of the antennal pedicel are investigated in Reduviidae and Pachynomidae. The cave organ, a pre sumably chemoreceptive structure, previously reported only for haematophagous Triatominae, is described here also for representa tives of Peiratinae, Reduviinae and Stenopodainae. The systematic implication of the occurrence of this sensillar structure is discussed. Further, four sclerites located in the membrane between pedicel and preflagelloid are described and used as landmarks for the recognition of individual trichobothria in Reduviidae and Pachynomidae. Characters of the trichobothrial socket are studied and discussed systematically. Homology of the distalmost trichobothrium of Reduviidae with the single trichobothrium in Pachynomidae is proposed. This hypothesis is based on the structure of the cuticle surrounding the trichobothria and on the trichobothrial position relative to the four sclerites of the pedicello-flagellar articulation. The single trichobothrium present in most nymphs corresponds to the distalmost trichobothrium in adult Reduviidae in position and structural detail. A reasonable hypotheses on the homology of indi vidual trichobothria of the proximal row or field seen in most Reduviidae can so far only be formulated for Peiratinae.

Cladistic analysis of Reduviidae (Heteroptera: Cimicomorpha) based on morphological characters

“…This character was used to diagnose Hammacerinae by Readio (1927), Costal Lima (1935), and Usinger (1943), and is a synapomorphy of Hammacerinae. Shape of campaniform sensillar sclerite and dorsal sclerite on pedicellus : short (0), very long (1). Weirauch (2003b) described and figured these two sclerites in the pedicello‐flagellar membrane (her Fig. 1a, d), and emphasized that very elongate sclerites occurred in only two species of Cetherinae ( Cethera musiva , Eupheno pallens ) among examined Reduviidae.…”

“…The present cladistic analysis contributes to our knowledge of higher‐level relationships among Reduviidae through the use of morphological characters. In addition to relying on characters that were previously used in reduviid systematics, but are in many cases documented here for the first time, the present study takes advantage of additional, recently published comparative morphological studies (Weirauch, 2003a, b, 2004, 2005, 2006a, b, c). Furthermore, novel morphology was studied during this project, using light microscopical, histological and scanning electron microscopical techniques to document mouthpart characters, head sclerites, thoracic and abdominal structures, and male and female genitalia where necessary.…”

A comparative study of the abdominal trichobothria of Trichophora, with emphasis on Lygaeoidea (Hemiptera: Heteroptera)

“…The strong, central mechanoreceptive seta on the AT corresponds to the structure called hair shaft by Gaffal (1976), trichobothrial seta by Weirauch (2003) or simply "hair" by Meßlinger (1987). It is generally circular in cross-section, straight or curved, not twisted and usually with grooves running its whole length (Fig.…”

“…In addition to early microscopic studies (Tullgren, 1918), comprehensive surveys include works on the fi ne structure of trichobothria occurring on the femora of Miridae (Schuh, 1975) and antennae of Pachynomidae and Reduviidae (Mclver & Siemicki, 1984;Wygodzinsky & Lodhi, 1989;Catalá, 1997;Weirauch, 2003). In spite of the vast literature on the spatial distribution of abdominal trichobothria in Trichophora, there is virtually no data on their individual morphology except for the SEM photographs of a few taxa scattered in the literature (Schuh, 1975;Davidová-Vilímová & Štys, 1993;Schuh & Slater, 1995;Gao & Bu, 2009) and no comparative study of the various taxa.…”

“…7a-i). The AT is innervated by one or several sensory neurons (Keil, 1997;Weirauch, 2003) and the articulation at their base allows defl ection of each sensillum in only one exactly defi ned plane (Keil, 1997). Sensilla of different lengths usually also have different functions (Drašlar, 1973).…”