Ultrastructure of antennal sensilla of the peach aphid Myzus persicae Sulzer, 1776

Abstract

The antennal sensilla of alate Myzus persicae were mapped using transmission electron microscopy and the ultrastructure of sensilla trichoidea, coeloconica, and placoidea are described. Trichoid sensilla, located on the tip of the antennae, are innervated by 2-4 neurons, with some outer dendrites reaching the distal end of the hair. Coeloconic sensilla in primary rhinaria are of two morphological types, both equipped with two dendrites. Dendrites of Type II coeloconic sensilla are enveloped in the dendrite sheath, containing the sensillum lymph. In sensilla coeloconica of Type I, instead, dendrites are enclosed by an electron opaque solid cuticle, with no space left for the sensillum lymph. The ultrastructure of big placoid sensillum reveals the presence of three groups of neurons, with 2-3 dendrites in each neuron group, while both small placoid sensilla are equipped with a single group of neurons, consisting of three dendrites. Both large and small placoid sensilla bear multiple pores on the outer cuticle. The function of these sensilla is also discussed.

Characterization of Antennal Sensilla and Immunolocalization of Odorant-Binding Proteins on Spotted Alfalfa Aphid, Therioaphis trifolii (Monell)

“…Coeloconic sensilla have been reported that they are involved in thermo-/hygroreceptive functions in both Lepidoptera and Diptera (Sutcliffe, 1994). Similar to what was described in other aphid species (Bromley et al, 1980), two types of trichoid sensilla have been reported in our study, which could be involved in mechanosensing and/or in contact chemoreception (Bromley et al, 1980;Sun et al, 2013;Ban et al, 2015). Type II trichoid sensilla localized on the antennal tip and crowned by five blunt tipped uniporous hair, implying a gustatory function for these sensilla (De Biasio et al, 2015).…”

“…As previously described, we also observed the presence of multiple pores on the surface of the outer cuticle of placoid sensilla (Bromley et al, 1979), indicating they are typical olfactory chemoreceptors (Steinbrecht, 1984). We found that the number of secondary rhinaria (placoid sensilla) on the antenna are very similar between alate and apterous T. trifolii (Table 1), while secondary rhinaria were seldom found in apterous morphs of other aphids such as M. persicae and A. pisum (Table 1; Shambaugh et al, 1978;Sun et al, 2013;Ban et al, 2015;De Biasio et al, 2015). In addition, the ultrastructure of secondary rhinaria (placoid sensilla) is also very similar between alate and apterous morphs in T. trifolii, and further studies need to confirm this phenomenon in other aphids.…”

“…The cuticular projections of type I hair were usually characterized by a crown of six cuticular projections (Figure 4A), while type II hair exhibits a more complicated morphology of the peg ending with more cuticular projections, usually closely packed (Figure 4B). These sensilla of the SAA were similar to that found in peach aphids Myzus persicae (Ban et al, 2015).…”

“…Compared to other aphids, these aphids present two stellate sensilla but with two small placoid sensilla absent (Table 1), indicating these sensilla may be substitutes for the latter sensilla. The ultrastructure of these two type sensilla supported that they were similar, in that both of them are with three bipolar neurons (Ban et al, 2015). Similar to placoid sensilla, stellate sensilla also have many pores on the surface (Shambaugh et al, 1978;Ban et al, 2015), suggesting their chemosensory FIGURE 5 | Immunocytochemical localization OBP6, OBP7, and OBP8 in sensilla placoidea on the 3rd and 6th segments of antennae in spotted alfalfa aphid.…”

The function of spineless in antenna and wing development of the brown planthopper, Nilaparvata lugens

“…Many sensilla are present on the antennae, and their number and type vary amongst different species. The sensory plaque organ is a common type of sensillum in hemipteran insects, including Delphacidae, Aphididae and Fulgoridae (Bourgoin and Deiss, ; Shih and Yang, ; Liang, ; Park and Hardie, ; Ban et al , ). Previous studies have not focused on the genes that regulate development of the sensory plaque organ.…”