The Leg Sensilla of Insects from Different Habitats-Comparison of Strictly Aquatic and Riparian Bugs (Corixidae, Ochteridae, Gelastocoridae: Nepomorpha: Insecta: Heteroptera)

The aim of this study was to analyze morphological types and arrangement of the leg sensilla of Corixidae, Ochteridae and Gelastocoridae, in relation to their various habitats. The leg sensilla of four species of Corixidae, six of Gelastocoridae and two of Ochteridae were studied. Eight main types of sensilla with six subtypes of sensilla trichodea and four subtypes of sensilla chaetica were found and described. The greatest variability was observed among mechanoreceptive sensilla. The study showed differences in the shape of the legs between strictly aquatic and terrestrial taxa. It is the first attempt to describe leg sensilla among nepomorphan taxa.

Report on antennal sensilla of Aphelocheirus ellipsoideus (Hemiptera, Heteroptera, Aphelocheiridae)

The comparative morphology study on antennal sensilla of Aphelocheirus ellipsoideus from the family Aphelocheiridae, carried out with the use of a scanning electron microscope, is provided. Five main types of mechano-, chemo-, and thermo-hygroreceptive sensilla with two subtypes of sensilla basiconica were found and described on their surface, including sensilla trichodea, campaniformia, basiconica, ampullacea, and plate-like. Antennal sensilla of A. ellipsoideus on macropterous and brachypterous forms were different.

Morphology of the Antennal Sensilla of Notonectoidea and Comparison of Evolutionary Changes in Sensilla Types and Distribution in Infraorder Nepomorpha (Insecta: Heteroptera)

Simple Summary

Antennal sensilla are important sensory organs for insects. According to their morphological structures, they respond to different chemical or mechanical stimuli. The antennae of the studied families of water insects (Notonectidae, Pleidae and Helotrephidae) are short and concealed under the head, leaving a small amount of space for the existence of sensory structures. Nevertheless, six main types of sensilla have been discovered on the surfaces of these antennae. The morphological types described in this study were further compared with other studies on the antennal sensilla of water bugs (Nepomorpha) in order to compare their evolutionary changes within the group.

Abstract

This article introduces the results of a study of three families of Nepomorpha and is the last part of a series of studies that sums up our work on the morphologies of the antennal sensory structures in this taxon. The morphologies and distribution of the sensilla in the families Notonectidae, Pleidae and Helotrephidae were studied under a scanning electron microscope. Six main types (sensilla trichodea, chaetica, campaniformia, basiconica, ampullacea and coeloconica) and ten subtypes (five subtypes of sensilla trichodea and five subtypes of sensilla basiconica) were described. The results were compared with other studies on the antennal sensilla of Nepomorpha in order to assess evolutionary changes within the infraorder. With the use of cladistics analysis, the monophyly of the families Nepidae, Micronectidae, Corixidae and Gelastocoridae was supported. On the other hand, the occurrence of some clades forming superfamilies was weakly supported by bootstrap analysis. These results, supported by presence of the numerous autapomorphies, suggest that antennal sensilla evolved within inner groups.

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

The morphology and distribution of sensilla on the surface of the antennae of the naucorids' species were studied via scanning electron microscopy. Eleven types of sensilla were identified regarding specific sensory modalities, based on their cuticular morphology. Cuticle morphology identifies five types of sensilla trichodea, four types of sensilla basiconica, one type of sensillum coeloconicum and sensillum ampullaceum. Three new types of mechanosensitive sensilla were found. Moreover, the morphological diversity between the antennae allowed the distinction of ten different antennal types that correspond to different sensillar sets. The sensilla found in Naucoridae share similarities with the sensilla of other nepomorphan taxa, as well as of terrestrial insects. However, no sensillar synapomorphy was found between Naucoridae and Aphelocheiridae.

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

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.