Electron microscopic studies of antennal sensilla in the ambrosia beetle Trypodendron lineatum (Olivier) (Scolytidae)

Abstract

The antennae of the ambrosia beetle Trypodendron lineaturn (Olivier) were examined with the light and electron microscopes to determine the types, distribution, and structure of sense organs found thereon. Six main types of sense organs are present, with an additional seventh cuticular structure, the hypodermal gland pore, which is thought to be non-sensory.Sensilla chaetica possess one bipolar neuron terminating in a scolopale at the base of the thick-walled articulated hair.Type I sensilla trichodea are short articulated hairs of unknown fine structure and innervation. Type 11 sensilla trichodca are sharp-pointed hairs of intermediate length, with thin, perforated hair walls, and two neurons with slightly branched dendrites in the hair lumen. Type I11 sensil la trichodea are blunt-tipped, reversely curved hairs possessing a double lumen and four to scven bipolar neurons. the unbranched dendrites of which extend to the hair tip.Sensilla basiconica are short t hin-walled perforated hairs or pegs. possessing two neurons each, with many-branched dendrites. The relationship of dendrite branches to hair perforations is not clear.Sensilla campaniformia consist of a subsurface dome in the center of which lies the nerve ending of one neuron similar to that of the sensilla chaetica.Evidence is presented, indicating the probable absence of sensory axon fusion in the antennae.

Comparative Study of the Antennae of Dendroctonus rhizophagus and Dendroctonus valens (Curculionidae: Scolytinae): Sensilla Types, Distribution and Club Shape

“…For example, the ST 1 identiÞed in this study for both species appears to be the same as that described for D. valens by Chen et al (2010), but is apparently equivalent to sensilla ST 2 recognized in other Dendroctonus species (Payne et al 1973), trichodea type II from Typodendrum lineatum (Moeck 1968), sensilla trichodea from Scolytus multistratus (Borg and Norris 1971), single-walled sensilla type II from Ips typographus (Hallberg 1982), and trichodea type I from Tomicus species (Wang et al 2012). In the same sense, the ST 2 described here for both species corresponds to that previously documented in D. valens (Chen et al 2010), whereas it resembles ST 3 of other Dendroctonus species (Payne et al 1973) .…”

“…The sensilla chaetica in both species occurred predominantly in the antennal scape and funicle, but in other bark and ambrosia beetles, such as Dendroctonus terebrans (Olivier) and Dendroctonus ponderosae, these sensilla were found on all segments of the antenna (Borden and Wood 1966, Moeck 1968, Borg and Norris 1971, Payne et al 1973, Wang et al 2012). Morphological differences in species of Dendroctonus have been observed between the sensilla chaetica of the scape and funicle and those found within and between the sensory bands of the club (Payne et al 1973).…”

“…Morphological differences in species of Dendroctonus have been observed between the sensilla chaetica of the scape and funicle and those found within and between the sensory bands of the club (Payne et al 1973). Based on electrophysiological and anatomical data, several authors agree that these sensilla in bark beetles likely have a mechanoreceptor function associated with exploration of the environment through contact with the substrate (Borden and Wood 1966, Borden 1968, Moeck 1968, Borg and Norris 1971, Payne et al 1973, Dickens and Payne 1978, Wang et al 2012. Both mechanosensory and gustatory functions have been attributed to sensilla chaetica in other beetles species within Curculionidae (Bland 1981, Alm and Hall 1986, Isidoro and Solinas 1992, Coccinellidae (Jourdan et al 1995), Tenebrionidae (Harbach and Larson 1977) and Chrysomelidae (Isidoro et al 1998, Bartlet et al 1999.…”

“…The antennae were brushed with a paintbrush to remove foreign matter before their observation under ESEM (model Evo 40 VP,Carl Zeiss,Oberkochen,Germany). Past studies on the morphological and ultrastructural organization of bark beetle antennae have identiÞed four types of sensilla: chaetica, trichodea, ßuted (grooved), and basiconica, which have been associated with mechano-, chemo-, or thermoreceptor functions (Borden and Wood 1966;Borden 1968;Moeck 1968;Borg and Norris 1971;Payne et al 1973;Dickens and Payne 1977;Whitehead 1981;Hallberg 1982;Dickens et al 1985;Faucheux 1989Faucheux , 1994Chen et al 2010;Wang et al 2012). For this study, sensilla were classiÞed based on their length and morphological features following Schneider (1964).…”

Antennal sensilla of the ground beetle Platynus dorsalis (Pontoppidan, 1763) (Coleoptera, carabidae)

“…While s.ca.1 occur in all specimens, s.ca.2 were observed only in some of them, regardless of the sex. Campaniform sensilla have been found on the antennae in Elateridae, Carabidae, Scolytidae, Curculionidae and others (Alm and Hall, 1986;Kim and Yamasaki, 1996;Merivee, 1992;Merivee et al, 1998Merivee et al, , 1999Merivee et al, , 2000Moeck, 1968). Frequently, campaniform sensilla concentrate near articulations or on structures subject to cuticular distortion, such as legs and halteres.…”