Addendum to "The Loci of Contact Chemoreceptors in Insects."

CONTACT CHEMORECEPTION IN THE TARNISHED PLANT BUG LYGUS LINEOLARIS

“…Contact of the labial tip with the substrate is one of the first behavioral events of host recognition in Oncopeltus faseiatus and seems to provide information important for further feeding (Beck et al, 1958;Feir & Beck, 1963; Bongers, 1969). Although Frings & Frings (1949)concluded that there were contact chemoreceptors at the labial tip, since stimulation of these with sucrose resulted in ingestion of the solution, it was later pointed out by Miles (1958) that it was also possible for a test ingestion to occur, resulting in fluid contact with epipharyngeal chemoreceptors which in turn resulted in ingestion.The rostral sensilla in Dysdercusfulfonige'r and Dysdercus koenigii were shown by Schoonhoven and Henstra (1972) to consist of 24 sensilla basi,conica and two sensilla trichodea arranged in two sensory fields. Ultrastructurally the sensilla basiconica of these species and of D.fasciatus (Peregrine, 1972a) resembled contact chemoreceptors and preliminary electrophysiological studies by Schoonhoven and Henstra (t972) also supported a chemosensory role.…”

“…Contact of the labial tip with the substrate is one of the first behavioral events of host recognition in Oncopeltus faseiatus and seems to provide information important for further feeding (Beck et al, 1958;Feir & Beck, 1963; Bongers, 1969). Although Frings & Frings (1949)concluded that there were contact chemoreceptors at the labial tip, since stimulation of these with sucrose resulted in ingestion of the solution, it was later pointed out by Miles (1958) that it was also possible for a test ingestion to occur, resulting in fluid contact with epipharyngeal chemoreceptors which in turn resulted in ingestion.…”

“…As was pointed out by Frings & Frings (1949) local stimulation with a chemical that results in an observable behavior can be taken as an indication of chemosensory input; however, if no observable behavior results, this does not necessarily indicate that chemosensory input is absent. From the redundancy of chemoreceptors on the mouthparts of locusts and lepidopterous larvae (Haskell & Schoonhoven, 1969;Haskell & Mordue, 1969;Ma, 1972) one might expect to find receptors that could be stimulated locally without an immediate behavioral output.…”

10. Sensilla and Proprioceptors

“…As on the oviscapt these sensilla belong to two different groups, tactile and bimodal chemoreceptive/tactile sensilla. The presence of the chemosensory sensilla on the tarsi of Lepidoptera was demonstrated by Minnich (1929) and Frings and Frings (1949).…”

“…10.3 A; 10.4 C; 10.5 A, C, D). Frings & Frings (1949) demonstrated that contact chemoreceptors was located to the antennae and legs of adult lepidopterans, and subsequently it was shown that the s. chaeticum has a combined taste-and mechanoreceptive function (Zacharuk 1985). This sensillum type has a stout cuticular hair with a circular socket.…”