Fast development is often perceived as an advantage, as it enables better harmony with one's environment and readiness to cope with the challenges that it poses. However, research conducted at the University of Haifa, Israel, and University of California, Santa Cruz, and published in the scientific journal PLoS ONE*, found that the acceleration of developmental rate incurs potentially lethal physiological costs for the developing individual. "Our findings are consistent with research findings on other animals and call for further research on rates of development in humans," said Asaf Sadeh who led the study.
This study, part of Sadeh's PhD research, was conducted on the fire salamander (Salamandra infraimmaculata) in conjunction with Prof. Leon Blaustein and Noa Truskanov from the University of Haifa, and with Prof. Marc Mangel from the University of California. The fire salamander in Israel breeds in temporary pools that fill during the winter rains and usually dry up in the spring. The larvae that are born into these pools must complete their development and metamorphose into terrestrial life before their pools dry. Larvae failing in this developmental race are destined to die from desiccation.
In the first part of the study, the scientists examined whether salamander larvae employ some early warning mechanism that alerts them to step up their rates of development to avoid drying. They reared an experimental group of larvae in water, to which they added a minute quantity of powder of ground larvae that had desiccated in natural temporary ponds. The development of these larvae was compared to a control group that was not exposed to the powder. They found that immediately after their birth into the pond, the larvae detected the presence of the dried remains and developed more quickly than the control group. Sadeh and colleagues propose that the chemical composition of the flesh of the dead larvae changes as they toast in the sun, producing a
|Contact: Rachel Feldman|
University of Haifa