Allen G. Gibbs

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We investigated physiological characters associated with water balance in laboratory populations of Drosophila melanogaster selected for resistance to desiccating conditions for over 100 generations. Five replicate, outbred, desiccation-selected (D) populations were compared with their control (C) populations. Water loss rates of female D flies were(More)
Energy availability can limit the ability of organisms to survive under stressful conditions. In Drosophila, laboratory experiments have revealed that energy storage patterns differ between populations selected for desiccation and starvation. This suggests that flies may use different sources of energy when exposed to these stresses, but the actual(More)
Fruit flies of the genus Drosophila have independently invaded deserts around the world on numerous occasions. To understand the physiological mechanisms allowing these small organisms to survive and thrive in arid environments, we performed a phylogenetic analysis of water balance in Drosophila species from different habitats. Desert (cactophilic) species(More)
Flies of the genus Drosophila inhabit a wide range of habitats, from the tropics to deserts to boreal forests. The primary physiological mechanism allowing Drosophila and other insects to survive in arid habitats is a reduction in rates of water loss. To understand mechanisms of water retention in greater detail, we investigated the three main routes by(More)
Insects breathe through valved openings (spiracles) in their cuticle. Many insects open and close their spiracles in a cyclic pattern (discontinuous gas-exchange cycles, or DGC). These cycles were observed over half a century ago, their hypothesized function being to minimize loss of water from the tracheal system. However, numerous recent studies have(More)
We exposed adult male Drosophila melanogaster to cold, desiccation or starvation, and examined expression of several genes during exposure and recovery. Frost was expressed during recovery from cold, and was up-regulated during desiccation. Desiccation and starvation (but not cold) elicited increased expression of the senescence-related gene smp-30. Desat2(More)
SYNOPSIS. Epicuticular lipids play a critical role in allowing arthropods to thrive in terrestrial environments, by reducing transpiration of water through the cuticle. These lipids consist of a diverse array of compounds, especiaUy long-chain hydrocarbons. Rates of water loss are correlated with hydrocarbon structural features, including chain length,(More)
Environments that are crowded with larvae of the fruit fly, Drosophila melanogaster, exhibit a temporal deterioration in quality as waste products accumulate and food is depleted. We show that natural selection in these environments can maintain a genetic polymorphism with one group of genotypes specializing on the early part of the environment and a second(More)
Many adult and diapausing pupal insects exchange respiratory gases discontinuously in a three-phase discontinuous gas exchange cycle (DGC). We summarize the known biophysical characteristics of the DGC and describe current research on the role of convection and diffusion in the DGC, emphasizing control of respiratory water loss. We summarize the main(More)