| Title: | "Effect of juvenoids on predator-induced polyphenism in the water flea, Daphnia pulex" |
| Author(s): | Miyakawa H; Gotoh H; Sugimoto N; Miura T; |
| Address: | "Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido, Japan; Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, Myodaiji, Okazaki, Aichi, Japan" |
| Journal Title: | J Exp Zool A Ecol Genet Physiol |
| ISSN/ISBN: | 1932-5231 (Electronic) 1932-5223 (Linking) |
| Abstract: | "In Daphnia pulex, juveniles form 'neckteeth' a defensive structure on their heads, in response to predatory kairomones released by Chaoborus larvae. This phenomenon provides a model experimental system for the study of developmental mechanisms and evolutionary processes in predator-induced polyphenisms. Although it is thought that kairomone signals are sensed and converted into physiological signals resulting in morphological changes, little is known about the endocrine and physiological mechanisms of this process. Juvenile hormones and related chemicals, that is, juvenoids, are key hormones responsible for various physiological events in insects, including polyphenisms. In some crustaceans, methyl farnesoate (MF) is known to act as a juvenoid. In order to investigate the functions of juvenoids in defense morph formation, we treated daphnids with MF as well as JHIII (Juvenile Hormone III, an insect juvenoid) and fenoxycarb (a synthetic juvenile hormone analog) during their developmental stages. Strikingly, in the first-instar juveniles, all examined juvenoids stimulated the formation of neckteeth only in the presence of kairomones, not by themselves. This juvenoid effect on the neckteeth formation might be due to disturbance of the JH pathway. Juvenoid treatments reduced tail-spine length, whereas predatory kairomones are known to elongate tail spine. These results suggest that other physiological factors are responsible for the tail-spine elongation" |
| Keywords: | Animals *Biological Evolution Daphnia/genetics/*physiology Diptera/physiology Endocrine System/metabolism Juvenile Hormones Larva/physiology Pheromones/metabolism *Predatory Behavior; |
| Notes: | "MedlineMiyakawa, Hitoshi Gotoh, Hiroki Sugimoto, Naoki Miura, Toru eng Research Support, Non-U.S. Gov't 2013/06/13 J Exp Zool A Ecol Genet Physiol. 2013 Oct; 319(8):440-50. doi: 10.1002/jez.1807. Epub 2013 Jun 11" |
