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.

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.

Insect evolution toward aquatic habitats; reassessment of antennal sensilla in the water bug families Ochteridae, Gelastocoridae and Aphelocheiridae (Hemiptera: Heteroptera: Nepomorpha)

The first comparative morphology study on antennal sensilla of Ochteridae, Gelastocoridae and Aphelocheiridae, carried out with the use of a scanning electron microscope, is provided. Our research hypothesis was: the antennal sensilla of the studied families reflect their different adaptations for use in aquatic habitats, while maintaining a common set of sensilla similar to other water bugs (Nepomorpha). Therefore, the number and placement of antennal sensilla of several species in the mentioned families were studied using scanning electron microscopy. Nine main types of mechano- chemo- and thermo-hygroreceptive sensilla were confirmed on their surface, including sensilla trichodea, chaetica, club-like, campaniformia, basiconica, coeloconica, plate-like, ampullacea and sensilla placodea multilobated. While seven of these were already documented in other species, two of them (sensilla plate-like and placodea multilobated) were yet to be documented on the antennae of Nepomorpha. All families display differences in the shape and length of antennae as well as among sensilla types. These findings support our hypothesis regarding differences in sensillar structures among families adapted differently to suitable niches. Differences between these families and previously studied nepomorphan taxa (Nepoidea) were also documented. However, the general set of sensilla observed on the antennae of the studied species is very similar to the one documented in Nepoidea. Therefore, we confirmed our assumptions regarding similarities in antennal sensilla between the studied families and other nepomorphan insects.

Sexual morphs of Pterocomma tremulae Börner, 1940 (Aphididae, Aphidinae) with description of male reproductive system

Paper presents the first description of the so far unknown sexual generation of Pterocomma tremulae (Aphididae, Aphidinae): oviparous female and alate male. It also provides detailed description of the male reproductive system. Discussion focuses on comparative analysis of male reproductive system with other aphid groups and possible importance of its structure in resolving phylogenetic interrelationships within the genus Pterocomma. A key is provided to the known males of European Pterocomma species.

Morphological study of the antennal sensilla in Gerromorpha (Insecta: Hemiptera: Heteroptera)

The external morphology and distribution of the antennal sensilla of 21 species from five families of semiaquatic bugs (Gerromorpha) were examined using scanning electron microscopy. Nine main types were distinguished based on their morphological structure: sensilla trichoidea, sensilla chaetica, sensilla leaflike, sensilla campaniformia, sensilla coeloconica, sensilla ampullacea, sensilla basiconica, sensilla placoidea and sensilla bell-mouthed. The specific morphological structure of one type of sensilla (bell-mouthed sensilla) was observed only in Aquarius paludum. Several subtypes of sensilla are described, differentiated by number, location and type of sensillum characteristic for each examined taxon. The present study provides new data about the morphology and distribution of the antennal sensilla in Gerromorpha.