Max Planck scientists have found out that the olfactory system in hermit crabs is still underdeveloped in comparison to that of vinegar flies. While flies have a very sensitive sense of smell and are able to identify various odor molecules in the air, crabs recognize only a few odors, such as the smell of organic acids, amines, aldehydes, or seawater. Humidity significantly enhanced electrical signals induced in their antennal neurons as well as the corresponding behavioral responses to the odorants. The olfactory sense of vinegar flies, on the other hand, was not influenced by the level of air moisture at all. Exploring the molecular biology of olfaction in land crabs and flies thus allows insights into the evolution of the olfactory sense during the transition from life in water to life on land. (Proc. R. Soc. B, June 2012)
Crabs and flies
Crabs and flies are arthropods. Like many other life forms, they made a transition from water to land life in ancient times. The ancestors of the family of terrestrial hermit crabs (Coenobitidae) probably took this step about 20 million years ago. Today, hermit crabs live their entire lives on land, except for the larval stage. Odor signals are important cues for the crabs' search for food. In order to detect odor molecules outside the water on land, the sensory organs of arthropods had to adapt to the new, terrestrial environment. How did sensory perception evolve during the transition from sea to land?
"The land hermit crab Coenobita clypeatus is an ideal study object to answer this question," says Bill Hansson, director of the Department of Evolutionary Neuroethology at the Max Planck Institute for Chemical Ecology in Jena, Germany. The animals live in humid regions close to the sea and regularly visit water sources. Females release the larvae into the sea, where they grow into young crabs. These young crabs look for empty snail shells and live on land. They eat fruits and plants. Th
|Contact: Bill S. Hansson|
Max Planck Institute for Chemical Ecology