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Evaluation of biochemical and metabolomics changes in Mediterranean fruit fly Ceratitis capitata on different fruits, diet and life stages to understand the biological and physiological changes

Al-Khshemawee, Hasan (2018) Evaluation of biochemical and metabolomics changes in Mediterranean fruit fly Ceratitis capitata on different fruits, diet and life stages to understand the biological and physiological changes. PhD thesis, Murdoch University.

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Abstract

The Mediterranean fruit fly (medfly) Ceratitis capitata, is a multivoltine pest species present throughout large parts of Western Australia. Medfly is a polyphagous species and has been breed from 250 different species of native and commercially produced fruits and fleshy vegetables. This thesis has developed and optimised the Headspace solid-phase microextraction (HS-SPME) and direct immersion solid-phase microextraction (DI-SPME) methods for analysis of the volatile and non-volatile compounds, sugars and amino acids of C. capitata using multiple scales from individuals through to populations at different stages. The results showed that optimal number of insects required for volatile organic compounds (VOC) extraction at each life stage was 20 at 4 hours of extraction. The VOCs in five different fruit types infested by C. capitata have been investigated. The results indicated that for a few chemicals no significant differences between infested and non-infested fruit could be seen, especially in the fruits with the first instar. However, in the case of third instar larvae infested fruit, significant differences in the chemicals could be seen when compared with the non-infested fruits and other instar infestations. Twenty-seven compounds from larvae, 23 compounds from pupae and 29 compounds from adults were detected. While DI-SPME detected ethyl glycolate, oxime-, methoxy-phenyl-, α-farnesene, dodecanoic acid, decanoic acid, octyl ester, heptadecane, hexadecanoic acid, pyrrolidide, 11-tricosene, 9,12-octadecadienoic acid (Z,Z)-, methyl ester, 9-tricosene, (Z)-, 9,11-didehydrolumisterol acetate, tetrapentacontane, 1,54-dibromo-, campesterol, 9-hexadecenoic acid, hexadecyl ester, (Z)-, 9-octadecenoic acid, (E)- and 9-hexadecenoic acid, octadecyl ester (Z).

Stable isotopes are atoms with an equal number of protons and electrons, but different numbers of neutrons. The most current isotope of carbon is 12C6, where 12 is the atomic mass or the total of neutrons and protons, and 6 is the atomic number. A stable isotope is defined as one that is energetically stable and does not decay. There are about 300 stable isotopes, and over 1200 radioactive isotopes. The possible use of stable isotopes to study medfly mating and life history was also investigated. Results showed that stable isotopes were used successfully for labelling medfly in laboratory conditions, and there were significant differences between labelled and unlabelled treatments in eggs hatching, larval development, pupae emergence, the survival of adults and mating behaviour. Further studies were conducted to investigate the sugars, and amino acids of the C. capitata extracted samples in different labelled treatments. Glucose, fructose, and sucrose were identified as the major sugars. Fifteen amino acids were identified from extracts including l-alanine, ammonium chloride, l-aspartic acid, l-cysteine, l-glutamic acid, l-glycine, l-isoleucine, l-leucine, l-methionine, l-proline, l-phenylalanine, l-serine, l-threonine, l-tyrosine, and l-valine.

This study concludes that C. capitata shows that different compounds with different are released at all stages of insect development. The labelling of medfly with 13C6-glucose plays a major role in this study. Overall, this information details an excellent base of knowledge for studying insect biochemical and metabolomics on different fruits, diet and life stages to understand the biological and physiological of medfly.

Item Type: Thesis (PhD)
Murdoch Affiliation: School of Veterinary and Life Sciences
United Nations SDGs: Goal 12: Responsible Consumption and Production
Supervisor(s): Ren, YongLin
URI: http://researchrepository.murdoch.edu.au/id/eprint/45970
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