Exposure to mild hot stress or to chill coma stress correlate with changes in lipid profiles, physiological performance and longevity in the Medfly, Ceratitis capitata.

PUJOL LEREIS, LUCIANA M.; BOCHICCHIO, PABLO A.; RABOSSI, ALEJANDRO; QUESADA ALLUÉ, LUIS A.

Amsterdam

Simposio; The Seventh International Symposium on Molecular Insect Science; 2014

Elsevier

Ageing is a combination of internal and external factors acting upon the microheterogeneous genetic background of an individual within a population, thus contributing to senescence parameters of that population. Stress experiments are useful to analyse physiological changes in dipterans like Ceratitis capitata, the Medfly pest. Indicators of functional senescence can be correlated with different kinds of stress, eventually induced at different ages of adult medflies. We compared the survival curves and demographic parameters of single-sex laboratory populations at 23 0C with those of equivalent ones subjected to a permanent mild thermal stress (280C) or to an acute chill coma (00C, 3 hours). The behavioural status of the stressed flies was estimated using motility tests, in particular rapid iterative negative geotaxis (RING) assays. The RING results correlated with age and also showed performance declines due to both kinds of stress. The internal physiological status of different tissues was analysed using different parameters, in particular quantification of neutral and polar lipids. Using a multivariate principal component analysis approach we demonstrated that lipid-dependent principal components correlated with age and mortality parameters and that the same components were able to discriminate stressed populations showing a behavioural decline. Strikingly, young populations at 280C showed similar lipid profiles and derived components than old populations at 23 0C, thus establishing a proof of concept. Sub-population of flies that recovered faster from chill coma showed higher life expectancies, better performance in RING assays and different lipid profiles. Neutral and polar lipids as well as fatty acid composition correlated with the ability to recover from chill coma. Moreover, an analysis of stress response at gene expression level showed that the superoxide dismutase (SOD) RT-PCR results correlated well with life expectancy and RING performance whereas the expression of heat shock proteins (hsp70 and hsp83) was not associated with these parameters.