Extract of olive fruit fly males (Diptera: Tephritidae) attract virgin females

Τα αποτελέσματα ερευνών που διεξάγονται τις τελευταίες δεκαετίες δείχνουν ότι, σε αντίθεση με άλλα έντομα της οικογένειας Tephritidae, η σεξουαλική επικοινωνία του δάκου της ελιάς, Bactrocera oleae (Rossi), βασίζεται κυρίως στη φερομόνη που απελευθερώνεται από τα ενήλικα θηλυκά. Η παρούσα μελέτη ωστόσο δείχνει ότι και τα ενήλικα αρσενικά του δάκου ελκύουν παρθένα θηλυκά. Σε πειράματα εργαστηρίου, με ολφακτόμετρο, μελετήθηκε η ανταπόκριση θηλυκών του δάκου της ελιάς σε εκχυλίσματα αναπαραγωγικά ώριμων αρσενικών. Τα αποτελέσματα έδειξαν ότι εκχυλίσματα των αρσενικών με διχλωρομεθάνιο/μεθανόλη και λιγότερο με διαιθυλαιθέρα, ήταν ιδιαιτέρα ελκυστικά για τα παρθένα θηλυκά κατά τις τελευταίες ώρες της φωτοπεριόδου, οπότε αυτά είναι σεξουαλικά δραστήρια. Η ανταπόκριση των παρθένων θηλυκών στα παραπάνω εκχυλίσματα ήταν αμελητέα όταν αυτά ήταν συζευγμένα. Επιπλέον, παρθένα θηλυκά δεν ανταποκρίνονταν στα παραπάνω εκχυλίσματα τις πρώτες ώρες της φωτοπεριόδου. Τα αποτελέσματα αυτά δείχνουν ότι, εκτός από την ύπαρξη της σεξουαλικής φερομόνης των θηλυκών στο δάκο της ελιάς, υπάρχουν οσμηρές ουσίες στα αρσενικά που προσελκύουν παρθένα θηλυκά. Περισσότερη έρευνα απαιτείται για να διευκρινιστεί σε βάθος ο ρόλος των οσμηρών ουσιών των αρσενικών. Τα παραπάνω ευρήματα συμβάλλουν στην πληρέστερη κατανόηση της σεξουαλικής συμπεριφοράς του δάκου της ελιάς και μπορούν να αξιοποιηθούν για την αποτελεσματικότερη αντιμετώπισή του με φιλικά προς το περιβάλλον μέσα.Research conducted during the past three decades suggests that in contrast to most other tephritid fruit flies, in which sexual pheromones are produced by males, the olive fruit fly Bactrocera oleae (Rossi) relies for its sexual communication on a pheromone that is produced by females. However, our present study suggests that virgin, mature females are attracted to male odors. In olfactometer assays extracts of male bodies obtained with a two-solvent system of methanol and dichloromethane were highly attractive to virgin females. This was observed during the last two hours of the photophase, when males are sexually active, but not during the first hours of the photophase, or when mated females were tested. Extracts of male bodies obtained with diethyl ether were also attractive to virgin females, albeit not as strongly as the two-solvent extracts. These results strongly indicate that males of the olive fruit fly elicit attraction to virgin females based on olfactory stimuli. The importance of these findings for understanding the sexual behavior of the olive fruit fly is discussed

Towards improving sterile insect technique: Exposure to orange oil compounds increases sexual signalling and longevity in Ceratitis capitata males of the Vienna 8 GSS

The Mediterranean fruit fly (medfly), Ceratitis capitata, is a notorious insect pest causing huge economic losses worldwide. The sterile insect technique (SIT) is widely used for its control. Using sexually mature sterilized males of the Vienna 8 (tsl) strain in the laboratory, we explored whether exposure of males to citrus compounds (separately or in a mixture) affects their sexual behaviour and if nutritional conditions and age modulate those effects. Exposed males exhibited increased sexual signalling compared to unexposed ones, particularly when fed a rich adult diet. Interestingly, and for the first time reported in medfly, exposure of Vienna 8 males to a mixture of citrus compounds increases longevity under poor adult diet conditions. We discuss the possible associated mechanisms and provide some practical implications of our results towards improving the effectiveness of SIT. © 2017 Kouloussis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Age related assessment of sugar and protein intake of Ceratitis capitata in ad libitum conditions and modeling its relation to reproduction

In the inquiry on the age related dietary assessment of an organism, knowledge of the distributional patterns of food intake throughout the entire life span is very important, however, age related nutritional studies often lack robust feeding quantification methods due to their limitations in obtaining short-term food-intake measurements. In this study, we developed and standardized a capillary method allowing precise life-time measurements of food consumption by individual adult medflies, Ceratitis capitata (Diptera: Tephritidae), under laboratory conditions. Protein or sugar solutions were offered via capillaries to individual adults for a 5 h interval daily and their consumption was measured, while individuals had lifetime ad libitum access to sugar or protein, respectively, in solid form. Daily egg production was also measured. The multivariate data-set (i.e., the age-dependent variations in the amount of sugar and protein ingestion and their relation to egg production) was analyzed using event history charts and 3D interpolation models. Maximum sugar intake was recorded early in adult life; afterwards, ingestion progressively dropped. On the other hand, maximum levels of protein intake were observed at mid-ages; consumption during early and late adult ages was kept at constant levels. During the first 30 days of age, type of diet and sex significantly contributed to the observed difference in diet intake while number of laid eggs varied independently. Male and female adult longevity was differentially affected by diet: protein ingestion extended the lifespan, especially, of males. Smooth surface models revealed a significant relationship between the age dependent dietary intake and reproduction. Both sugar and protein related egg-production have a bell-shaped relationship, and the association between protein and egg-production is better described by a 3D Lorenzian function. Additionally, the proposed 3D interpolation models produced good estimates of egg production and diet intake as affected by age, providing us with a reliable multivariate analytical tool to model nutritional trends in insects, and other organisms, and their effect upon life history traits. The modeling also strengthened the knowledge that egg production is closely related to protein consumption, as suggested by the shape of the medfly reproduction-response function and its functional relationship to diet intake and age. © 2017 Kouloussis, Damos, Ioannou, Tsitsoulas, Papadopoulos, Nestel and Koveos

Age, sex, adult and larval diet shape starvation resistance in the Mediterranean fruit fly: an ecological and gerontological perspective

The ability of an animal to withstand periods of food deprivation is a key driver of invasion success (biodiversity), adaptation to new conditions, and a crucial determinant of senescence in populations. Starvation resistance (SR) is a highly plastic trait and varies in relation to environmental and genetic variables. However, beyond Drosophila, SR has been studied poorly. Exploiting an interesting model species in invasion and ageing studies-the Mediterranean fruit fly (Ceratitis capitata)- we investigated how age, food and gender, shape SR in this species. We measured SR in adults feeding in rich and poor dietary conditions, which had been reared either on natural hosts or artificial larval diet, for every single day across their lifespan. We defined which factor is the most significant determinant of SR and we explored potential links between SR and ageing. We found that SR declines with age, and that age-specific patterns are shaped in relation to adult and larval diet. Females exhibited higher SR than males. Age and adult diet were the most significant determinants of SR, followed by gender and the larval diet. Starvation resistance proved to be a weak predictor of functional ageing. Possible underlying mechanisms, ecological and gerontological significance and potential applied benefits are discussed. © 2019, The Author(s)

Trapping of Ceratitis capitata Using the Low-Cost and Non-Toxic Attractant Biodelear

Trapping is considered a powerful tool in the monitoring and control of fruit flies of high economic importance such as the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae). However, the cost of trapping and, in some cases, the safety of the chemicals used as baits are concerning for growers and the environment. Here we present a novel, low cost, environmentally friendly, female-specific bait for C. capitata, called Biodelear, that consists of a mixture of attracting compounds such us pyrazines, pyranones and amorphous nitrogen-based polymers. The new bait was compared to the commercially available attractant Biolure® (Suterra LLC, Bend, OR, USA) in Greece. McPhail-type traps were deployed in an orange orchard located in Athens. Five traps per treatment were used for several weeks during 2009 and four traps per treatment in 2010. Traps contained either 17 g of Biodelear or one Biolure Unipack dispenser. The results showed that both baits were highly efficient in attracting C. capitata females, and to a lesser extent, males. Although Biolure initially appeared to outperform Biodelear, later in the season the two attractants converged in efficacy. In both years, female captures were similar in traps baited with Biolure and Biodelear. However, male captures were higher in Biodelear-baited traps in 2010. In addition, Biodelear seemed to be longer lasting than Biolure, despite not being formulated into a slow-release dispersion system. The low cost of Biodelear and its strong, long-lasting effects render it suitable for mass trapping of the Mediterranean fruit fly. © 2022 by the authors. Licensee MDPI, Basel, Switzerland