Paris, September 15, 2008
Thomas Tully and Régis Ferrière, researchers in the Laboratoire Écologie & Évolution(1), studied populations of Collembola, one of the most ancient and abundant groups of arthropods on Earth. They showed that over the course of evolution, some Collembola populations have acquired an extraordinary ability to adjust their reproductive behavior when faced with abrupt environmental or social change. From one laying to another, a female can adapt not only the number but the size of her eggs, so that the young will be more capable of surviving in their new environmental conditions. In a food-rich environment, females will tend to lay a larger number of smaller eggs. In a highly competitive environment, where individuals are numerous but food is less abundant, the eggs will be fewer in number but larger, thus allowing larger newborns to survive better under these difficult conditions.
Such flexibility constitutes a major adaptation, but the scientists also noted that the most plastic lines of Collembola were also those that experienced the earliest mortality. In this species, two strategies coexist in nature: plastic reproduction at the cost of reduced longevity, or a longer life without any great capacity for reproductive adjustment. Comparison of these two strategies, which diverged at an early stage in the evolutionary history of this species, suggests that accelerated aging could result not simply from more intense reproduction but also from a high level of plasticity and genetic potential for reproduction. © T. Tully Figure 1 – Female of the Collembola Folsomia candida during laying. © T. Tully Figure 2 – Newborn Folsomia candida (0.35mm long) near some eggs.
© T. Tully
Figure 1 – Female of the Collembola Folsomia candida during laying.
© T. Tully
Figure 2 – Newborn Folsomia candida (0.35mm long) near some eggs.
1]CNRS/Université Pierre et Marie Curie/École normale supérieure de Paris
Reproductive Flexibility: Genetic Variation, Genetic Costs and Long-Term Evolution in a Collembola Thomas Tully & Régis Ferrière, PLoS One, 15 September 2008
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