Comparative Study of Antennal Sensilla of Corixidae and Micronectidae (Hemiptera: Heteroptera: Nepomorpha: Corixoidea)

Abstract

The goal of this study was to analyze the types and distributional patterns of sensilla in Corixoidea, which is part of the approach to the phylogeny study of Nepomorpha, based on the morphological characters of sensilla. This paper presents the results of the study, with the use of a scanning electron microscope (SEM), on the antennae of species from the families Corixidae and Micronectidae. The antennal sensilla of eleven species from Corixidae and two species from Micronectidae were studied. Five main types of sensilla with several subtypes of sensilla trichodea were found and described. The study has shown that the family Corixidae has a strong uniformity when it comes to antennal sensilla (similar patterns of sensilla trichodea and basiconica), and a similarity to the types and distributions of sensilla in two species of the family Micronectidae. However, significant differences between the families were also discovered (differences in sensilla presence on the first and second antennomeres, lack of sensilla coeloconica on the third antennomere in Micronectidae), which leads to a supportive conclusion of the systematic position of Micronectidae as a family.

The variability of antennal sensilla in Naucoridae (Heteroptera: Nepomorpha)

“…In contrast with other nepomorphans previously studied, regarding their shapes, the sensillum ST3, ST4 and additional ST5 found in Naucoridae are new types of mechanosensilla. Nepoidea's sensillum ST3 and Corixioidea’s sensilla ST3 and ST4 are straight, thick structures with a rounded or pointed tip and ribbed surface 33 – 35 , and are different than the sensilla described in the present study as ST3 and ST4: Cheirochelinae species show a long, straight sensilla, flattened and with almost the same width through the whole length. On the other hand, ST1 and ST2 sensilla as described in Ochteridae, Gelastocoridae and Aphelocheiridae are identical to naucorid species 34 .…”

“…In total, five main types of sensilla were found on the antennae, including sensilla trichodea (ST), sensilla campaniformia (SCa), sensilla basiconica (SB), sensilla coeloconica (SCo) and sensilla ampullacea (SA). We follow the terminology and classification of sensilla reported in other papers 6 , 33 – 35 . The detailed distributions of the sensilla in each of the studied species are presented in Table 2 .…”

“…In comparison to other nepomorphan families, the antennae of the Naucoridae are the most diverse, and various types of antennae can be found within the subfamilies. In other families, the subfamilies or at least the genera are usually characterized by a similar shape of antennae 33 – 35 . A possible process of oligomerization of the third and fourth antennomeres was observed in the Limnocoris pusillus .…”

“…Although ST1 and ST2 are common types of sensilla in naucorids (Table 2 ) and other nepomorphans 33 – 35 , their configuration of having only ST1 and ST2 on the last antennomere, could be treated as a unique character (autapomorphy?) of Cryphocricos montei .…”

“…In this study, we characterize and determine the abundance and distribution of the antennal sensilla of these nepomorphan bugs using scanning electron microscopy (SEM), we compare antennal sensilla among the subfamilies of Naucoridae with emphasis on their adaptations to different habitats, and we compare our results with other nepomorphan families 24 , 33 – 35 , in particular with Aphelocheiridae.…”