Extended lifespan and sex-specific fertility loss in cold-acclimated flies of the sibling species Drosophila buzzatii and Drosophila koepferae.

Survival and reproduction are the core elements of Darwinian fitness. In the context of a fixed energy budget, organisms tend to allocate resources in order to maximize one at the expense of the other, in what has been called the lifespan-reproduction trade-off. Reproductive arrest and extended lifespan are common responses to low temperatures in many insects including fruit flies.

Testing the metabolic homeostasis hypothesis in amphibians.

A number of hypotheses about compensatory mechanisms that allow ectothermic animals to cope with the latitudinal decrease in ambient temperature ( T) have been proposed during the last century. One of these hypotheses, the 'metabolic homeostasis' hypothesis (MHH), states that species should show the highest thermal sensitivity of the metabolic rate ( Q) at the colder end of the range of Ts they usually experience in nature. This way, species should be able to minimize maintenance costs during the colder hours of the day, but quickly take advantage of increases in T during the warmer parts of the day.

Contrasting Plasticity in Ovariole Number Induced by A Dietary Effect of the Host Plants between Cactophilic Drosophila Species.

Under the preference-performance hypothesis, natural selection will favor females that choose oviposition sites that optimize the fitness of their offspring. Such a preference-performance relationship may entail important consequences mainly on fitness-related traits. We used the well-characterized cactus-Drosophila system to investigate the reproductive capacity in the pair of sibling species D.