Sucking millipedes: evolution of sucking pumps in arthropods
Sucking millipedes have adapted mouthparts and live in moist environments. © Leif Moritz
Whether nectar-sucking butterflies or blood-sucking mosquitoes – the ingestion of liquid food has long been known for many insects and other arthropods. Researchers at the LIB and the University of Bonn now show that millipedes also use a sucking pump to ingest liquid food. A sucking pump has thus evolved independently in different groups of arthropods over several 100 million years – resulting in astonishingly similar biomechanical solutions for using liquid food.
Like insects, crustaceans and arachnids, millipedes belong to the megadiverse group of arthropods. While liquid-based diets have been described for insects and arachnids, it was previously only suspected that some millipedes also feed on liquid food. A German-Swiss team led by scientists Leif Moritz (Leibniz Institute for the Analysis of Biodiversity Change, University of Bonn), Dr. Thomas Wesener (Leibniz Institute for the Analysis of Biodiversity Change) and Prof. Dr. Alexander Blanke (University of Bonn) now studied the heads of representatives of the species-poor and exotic Colobognatha and published their results in the renowned journal Science Advances.
The researchers discovered a sucking pump in all nine millipede species studied, which is strikingly similar to those of insects. It consists of a chamber that is widened by strong muscles to suck in liquid food. “Together with the protractible mouthparts the sucking pump enables these millipedes to ingest more or less liquid food,” explains Leif Moritz, a doctoral student at the University of Bonn and the LIB.
The research team was thus able to show that the functional tools for a diet with liquid nutrients have evolved several times independently in all major subgroups of arthropods. “The biomechanical-morphological similarities between the groups of organisms indicate the strength of selection as soon as a food source provides even a slight evolutionary advantage,” elaborates Alexander Blanke, head of the Evolutionary Morphology Group at the University of Bonn.
The study also provides insights to better understand the origin of species diversity. This is because, in contrast to the very species-rich sucking insects with more than 400,000 species, the group of Colobognatha millipedes comprises only about 250 species. “Consequently, the liquid-based diet alone is not a general driver of species richness,” adds Thomas Wesener, head of the Myriapoda section at LIB. Because these millipedes mostly rely on moist habitats and cannot fly, their dispersal options appear limited, and they are more vulnerable to environmental change. “Today’s sucking millipedes are probably a relict group and the remnant of a once much larger diversity,” Alexander Blanke assumes.
Contact
Leif Moritz
Section Myriapoda
Leibniz Institute for the Analysis of Biodiversity Change, Bonn
Tel. +49 228 9122-423
moritz.leif@gmail.com
