The antennae of damselfly larvae

Area of Science:

• Entomology
• Sensory Biology
• Comparative Morphology

Background:

• Dragonfly larvae (Odonata) inhabit diverse aquatic environments, utilizing antennae for sensory input.
• Antennal sensilla are crucial for detecting environmental cues, but their diversity across species is not fully understood.

Purpose of the Study:

• To investigate and compare the antennal sensilla of two Zygoptera species, Calopteryx haemorroidalis and Ischnura elegans.
• To identify similarities and differences in sensilla types and distribution between these species and other Odonata larvae.

Main Methods:

• Scanning Electron Microscopy (SEM) for surface morphology.
• Transmission Electron Microscopy (TEM) for internal ultrastructure.
• Comparative analysis with existing data on other dragonfly species.

Main Results:

• Both C. haemorroidalis and I. elegans possess similar types and distribution patterns of antennal sensilla, predominantly on the apical portion.
• Identified sensilla include coeloconic sensilla (potential chemoreceptors, thermo-hygroreceptors) and apical setae (mechanoreceptors).
• A unique apical glandular-like structure was observed in both species and other studied dragonflies, indicating a conserved feature.

Conclusions:

• Larval antennae in Zygoptera exhibit conserved sensory structures and distribution, irrespective of habitat or antennal morphology.
• The widespread presence of the apical glandular-like structure warrants further investigation into its function in Odonata larvae.