Zoology: Bug research shows that liquid nutrition diminishes the sense of taste
18 Apr 2019 | Source: University of Cologne
Animal blood or plant fibre: the type of feeding influences the diversity of enzymes in different species of bugs
The diet of an insect strongly influences its physical properties, including the colour of its shell and wings, or its senses of taste and smell. That is the result of a major comparative study conducted by biologist Dr Kristen Panfilio at the University of Cologne and the University of Warwick. Panfilio’s article ‘Molecular evolutionary trends and feeding ecology diversification in the hemipteran, anchored by the milkweed bug genome’ has now appeared in Genome Biology.
The genetic make-up (genome) of the milkweed bug is an important resource to be able to compare the species’ genes and proteins with those of other insects. Panfilio led a team of 83 international scientists (in 27 work groups across ten different countries) in the genome sequencing of the milkweed bug. For decades, the milkweed bug has served as a biological model organism in genetics, ecology, developmental biology and physiology. In contrast to the fruit fly, which is an established model organism in science, the milkweed bug often contains a genome five times as big as the fruit fly’s, which makes it more complex to sequence.
Analyses confirm that bug species that rely on liquid nutrition, for example bedbugs (which feed on blood) or plant lice (which feed on plant juice), change the number of their genes in a way that reduces their ability to smell or taste. In comparison, the milkweed bug has a much broader repertoire of sensory abilities. To further study the animal’s feeding behaviour, the scientists created a bio-database in the course of the genome project containing all enzymes that play a role in its metabolism – including digestive enzymes.
Mostly feeding on poisonous milkweed, the bug’s bright red-orange shell is an aposematism. ‘It is their signal to ward off potential predators. The milkweed is poisonous, so the bug might be poisonous as well’, explains Panfilio. ‘ However, the bugs can produce special enzymes that break down and digest the poisonous weed structure. We were surprised because even though the milkweed butterfly feeds on the same plant, the two species produce different enzymes.’
The scientists also discovered that the bug has stolen an enzyme from particular bacteria and incorporated it into its own genome. Currently, they are investigating how this ‘theft’ actually occurred. ‘It is important to understand these connections at the level of molecular genetics. Among other things, that will allow us to develop new, sustainable pest control strategies’, says Panfilio. Co-author Robert Waterhouse from the University of Lausanne in Switzerland adds: ‘Genome sequencing projects also enhance our understanding of zoological biodiversity.’
Panfilio and her team cooperated with scientists from the University of Cologne’s Cluster of Excellence in Aging Research CECAD and Collaborative Research Centre 680 ‘Molecular Basis of Evolutionary Innovations’, which was completed in 2017.
Dr Kristen Panfilio
Insect Extraembryonic Development (EED) Lab, Zoological Institute,
Department of Developmental Biology, University of Cologne
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