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

SIMPLE SUMMARY: Insects’ antennae are an important location for the structures responsible for sensorial perception. These structures have different morphologies and respond to different mechanical and chemical stimuli. Corixidae and Micronectidae are groups of insects living in water. Because of that, their antennae are much smaller than the antennae of terrestrial insects. Apart from that, their position on the evolutionary tree has been changed over the years. We analyzed the antennae of different species of Corixidae and Micronectidae and found five different types of sensillar structures. Moreover, by comparing the two groups together and with other water insects, we established similarities and differences when it comes to the types and distributions of these structures. These findings allowed us to support the current systematic position of the studied insects. 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.