Understandig the unusual organ disparity of the antennal hearts in insects

• Applicant: Dr. Benjamin Wipfler
• Subject Area: Systematics and Morphology (Zoology)
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556730801

One of the most intriguing questions in comparative morphology is the origin of evolutionary novelties, i.e. the development of new body parts or organs. This is particularly interesting for organs with extreme disparity, i.e. a strong variability. One of the organs with the greatest disparity among insects is the muscular antennal heart, an auxiliary pulsatile device that transports hemolymph into the tip of the antennae via pumping musculature. This organ evolved several times independently from non-pulsatile antennal circulatory systems. So far, various different constructions including seven different muscles have been described and our preliminary results show that there is even more diversity. With its comparatively simple construction, the muscular antennal heart can be studied with established methods for a large taxon sampling covering the entire diversity of insects. Additionally, it was hypothesized that the cause both for the origin and the disparity of the pulsatile antennal heart can be found in varying spatial constraints within the head capsule caused by changes of the orientation of the head capsule, the feeding mode or the length of the antennae. The muscles associated with the antennal heart are considered to derive from pharyngeal dilators that changed their attachment site. All of these hypotheses can be tested with a workflow comprising different methodological approaches such as geometric morphometrics and evolutionary mapping that was established for the current proposal. This combination of extreme disparity, the ability to study a large taxon sampling and the possibility to test several sound hypotheses for origin and cause of the antennal heart and it´s diversity make it a unique model system for understanding evolutionary novelties and organ diversity. The current proposal will address these topics for a taxon sampling of 285 species covering all lineages of insects.

• DFG Programme: Research Grants