Evaluation of the attractant effect and lipid profile modulation of natural fixed oils on the medfly Ceratitis capitata (Wiedemann)

Abstract

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824; Diptera: Tephritidae), is a polyphagous pest in horticulture, mainly targeting Citrus fruits. Natural essential and fixed oils are currently under investigation for their broad-spectrum in pest control. To gain better knowledge about medfly behavior and biochemistry, we examined with behavioral and biochemical assays, the effects on C. capitata from six natural fixed oils obtained from vegetable (five) or animal (one) matrices using the ecofriendly supercritical CO 2 extraction. Oils were obtained at 250/300 bar and 40°C from the seeds of Laurus nobilis and Citrus paradisi, the fruits of Myristica fragrans and Pistacia terebinthus, wheat germ, and mullet roes (marine oil). Behavioral experiments were performed by means of twochoice tests to analyze the oil attractant effect compared with control (water or standard diet). The fatty acid composition of oils and the total lipid and fatty acid profile of medflies were characterized by chromatographic techniques. Behavioral bioassays showed that fixed oil obtained from M. fragrans (nutmeg butter) was more attractive than other oils. Medflies fed (24 hr) on marine oil showed significant changes in the total lipid and fatty acid profile induced by oil ingestion without toxic effects. However, 56% mortality was observed in insects fed on M. fragrans oil and no biochemical changes ascribable to oil ingestion were detected in the medflies that survived. Our results advance Arch. Insect Biochem. Physiol. 2018;99:e21508. wileyonlinelibrary.com/journal/arch

Supercritical CO2 Extraction of Waste Citrus Seeds: Chemical Composition, Nutritional and Biological Properties of Edible Fixed Oils

“…The SFE extraction rate gradually decreased with the extraction of oil from the seed matrix, and the total yield slowly tends toward an asymptotic value, the maximum yield obtainable at those conditions. We have previously observed that 8 h correspond to the complete exhaustion of oil from the matrix . Total yields obtained by SFE extraction were 15, 11, and 28%, while the yields by Soxhlet extraction were 28, 19, and 34% for CLO, CRO, and CPO, respectively (Figure E).…”

“…Fixed oils of lemon, mandarin and grapefruit seeds (CLO, CRO, CPO) were obtained by CO 2 ‐SFE extraction at higher pressure (250 bar) and 40 °C (ρCO 2 = 0.886 g cm −3 ) for 8 h (Figure C). We have previously used these CO 2 ‐SFE operating parameters for the extraction of fixed oils from different vegetable and marine matrices with yields comparable to those obtained with conventional organic solvents . Citrus oils extracted using the SFE technique were compared with the oils extracted by n ‐hexane in a Soxhlet apparatus (SoxE oils) at 60 °C (as control method) performed on the same starting material (Figure C).…”

“…In the double‐choice behavioral tests versus standard diet (control) (Figure C), the number of insects that entered in contact with CLS (51% of attractiveness) or CRS (48%) de‐coated seeds and diet was similar, whereas CPS (37%) was less attractant than standard diet. Natural vegetable fixed oils are currently under investigation for their broad‐spectrum in pest control . Moreover, several studies have explored the insecticidal activity of extracts and compounds obtained from Citrus fruits .…”

“…Experiments were performed on sexually adult medflies, C. capitata , 3–5 days old, obtained from a colony reared in the Department of Biomedical Sciences, University of Cagliari (Italy) at 22 ± 1 °C and relative humidity of 70–80%; these conditions were kept constant throughout the experiments. Adults of both sexes (≈100, 1:1 males and females) were kept in cages provided with water and standard diet (solid mixture of sucrose and yeast 4:1) ad libitum as previously reported . Before behavioral tests, flies were food deprived for 24 h, but had free access to water.…”

“…In the first set of experiments, medfly adults of both sexes (≈60 in each cage) had simultaneously free access to CLO, CRO, CPO oils compared to water. Oils and water (≈3 mL) were presented on a filter paper disk positioned on a Petri dish . In the second set of experiments, medflies had free access to each type of wet seeds (CLS, CRS, and CPS), presented on a filter paper disk positioned on a Petri dish, compared to water or standard diet (control).…”