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

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

Plant chemicals and the sexual behavior of male tephritid fruit flies

Plant compounds affect insects in many different ways. In addition to being a food source, plants also contain secondary metabolites that may have positive and negative impacts on insects. The influence of these compounds on sexual behavior, in particular, has been the focus of many recent studies. Here, we review the existing literature on the effects of plant compounds on the sexual behavior of tephritid fruit fly males. We put special focus on polyphagous species whose males congregate in leks, where females exert strong mate selection. We first summarize the main findings related to plant compounds that increase male signaling behavior and attraction of females and consequently increase mating frequency, a phenomenon that has been recorded mainly for species of Anastrepha and Ceratitis. In other tephritid species, males are attracted to phenylpropanoids produced by plants (such as methyl eugenol or raspberry ketone) that, upon encounter, are consumed and sequestered by males. These compounds, or metabolic derivatives, which normally have negligible nutritional value, are included in the pheromone and also confer advantages in a sexual context: enhanced female attraction and improved male mating success. These phenomena have been reported for several Bactrocera species as well as for Zeugodacus cucurbitae. Because many tephritid species are serious pests, the effect of plant compounds on male behavior has been explored for potential incorporation into control strategies such as the sterile insect technique (SIT). We conclude noting several factors, such as age and nutrition during larval and adult stage, that modulate the effect of plant compounds on male mating behavior as well as some prominent gaps that preclude a thorough understanding of the plant-mediated enhancement of male sexual performance and hence limit our ability to effectively utilize phytochemicals in pest control strategies.Instituto de GenéticaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Belliard, Silvina A. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Bachmann, Guillermo Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ruiz, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Jofre-Barud, Flavia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández, Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lopez, M. Liza. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Shelly, Todd E. United States Department of Agriculture. Animal and Plant Health Inspection Service; Estados Unido

HOST-PLANT SELECTION IN THE INSECT EURYTOMA AMYGDALI ENDERLEIN (HYMENOPTERA : EURYTOMIDAE)

THE RESULTS OF THE PRESENT DISSERTATION SHOWED THAT EURYTOMA AMYGDALI FEMALES ARE ATTRACTED TO ODOURS FROM ALMOND FLOWERS, LEAVES AND FRUIT, WHEREAS MALES ARE NOT. THE SELECTION OF FRUITS FOR OVIPOSITION IS INFLUENCED BY CHEMICAL FACTORS ASSOCIATED WITH THEM, AS WELL AS BY THE THICKNESS OF THE PERICARP AND THE HARDNESS OF THE ENDOCARP. FOLLOWING OVIPOSITION FEMALES DEPOSIT A HOST-MARKING PHEROMONE ON THE FRUIT SURFACE. THIS PHEROMONE ENABLES FEMALES TO DISCRIMINATED BETWEEN THE INFESTED AND THE UNINFESTED FRUITS AND TO SELECT THE LATTER FOR OVIPOSITION. THE PHEROMONE CONTRIBUTES IN THE DEPOSITION OF ONE EGG PER FRUIT AND IN THE UNIFORMITY OF EGG DISPERSION AMONG FRUITS. WHEN THE POPULATION OF THE WASP IS HIGH AND THE NUMBER OF AVAILABLE FOR OVIPOSITION FRUITS LOW, MORE THAN ONE EGGS ARE OFTEN DEPOSITED PER FRUIT, DESPITE THE EXISTENCE OF THE PHEROMONE. IN THAT CASE ONLY ONE LARVA DEVELOPS PER FRUIT, AS A RESULTOF CANNIBALISM BETWEEN THE LARVAE WITHIN THE SAME FRUIT.ΒΡΕΘΗΚΕ ΟΤΙ ΤΑ ΘΗΛΥΚΑ ΤΟΥ ΕΝΤΟΜΟΥ EURYTOMA AMYGDALI ΠΡΟΣΕΛΚΥΟΝΤΑΙ ΑΠΟ ΤΙΣ ΟΣΜΕΣ ΤΩΝ ΑΝΘΕΩΝ, ΤΩΝ ΦΥΛΛΩΝ ΚΑΙ ΤΩΝ ΚΑΡΠΩΝ ΤΗΣ ΑΜΥΓΔΑΛΙΑΣ, ΑΛΛΑ ΟΧΙ ΚΑΙ ΤΑ ΑΡΣΕΝΙΚΑ. ΚΑΤΑ ΤΗΝ ΕΠΙΛΟΓΗ ΤΩΝ ΚΑΡΠΩΝ ΓΙΑ ΩΟΤΟΚΙΑ ΣΗΜΑΝΤΙΚΟ ΡΟΛΟ ΠΑΙΖΟΥΝ ΤΑ ΧΗΜΙΚΑΕΡΕΘΙΣΜΑΤΑ ΠΟΥ ΠΡΟΕΡΧΟΝΤΑΙ ΑΠΟ ΑΥΤΟΥΣ, ΚΑΘΩΣ ΕΠΙΣΗΣ ΚΑΙ ΤΟ ΠΑΧΟΣ ΤΟΥ ΠΕΡΙΚΑΡΠΙΟΥ ΚΑΙ Η ΣΚΛΗΡΟΤΗΤΑ ΤΟΥ ΕΝΔΟΚΑΡΠΙΟΥ ΤΩΝ ΚΑΡΠΩΝ. ΜΕΤΑ ΤΗΝ ΩΟΤΟΚΙΑ ΤΑ ΘΗΛΥΚΑ ΑΠΟΘΕΤΟΥΝ ΣΤΗΝ ΕΠΙΦΑΝΕΙΑ ΤΩΝ ΚΑΡΠΩΝ ΜΙΑ ΦΕΡΟΜΟΝΗ ΑΠΟΤΡΟΠΗΣ ΩΟΤΟΚΙΑΣ, ΜΕ ΤΗ ΒΟΗΘΕΙΑ ΤΗΣ ΟΠΟΙΑΣ ΑΝΑΓΝΩΡΙΖΟΥΝ ΤΟΥΣ ΑΠΡΟΣΒΛΗΤΟΥΣ ΚΑΡΠΟΥΣ ΑΠΟ ΤΟΥΣ ΠΡΟΣΒΕΒΛΗΜΕΝΟΥΣ ΚΑΙ ΕΠΙΛΕΓΟΥΝ ΓΙΑ ΩΟΤΟΚΙΑ ΤΟΥΣ ΠΡΩΤΟΥΣ. Η ΦΕΡΟΜΟΝΗ ΣΥΜΒΑΛΛΕΙ ΣΤΗΝ ΑΠΟΘΕΣΗ ΕΝΟΣ ΑΥΓΟΥ ΑΝΑ ΚΑΡΠΟ ΚΑΙ ΣΤΗΝ ΟΜΟΙΟΜΟΡΦΗ ΚΑΤΑΝΟΜΗ ΤΩΝ ΑΥΓΩΝ ΣΤΟΥΣ ΚΑΡΠΟΥΣ. ΟΤΑΝ Ο ΠΛΗΘΥΣΜΟΣ ΤΟΥ ΕΝΤΟΜΟΥ ΕΙΝΑΙ ΜΕΓΑΛΟΣ ΚΑΙ ΟΙ ΔΙΑΘΕΣΙΜΟΙ ΓΙΑ ΩΟΤΟΚΙΑΣ ΚΑΡΠΟΙ ΛΙΓΟΙ, ΣΥΧΝΑ ΑΠΟΤΙΘΕΝΤΑΙ ΠΟΛΛΑ ΑΥΓΑ ΣΕ ΚΑΘΕ ΚΑΡΠΟ, ΠΑΡΑ ΤΗΝ ΥΠΑΡΞΗ ΤΗΣ ΦΕΡΟΜΟΝΗΣ. ΣΤΗΝ ΠΕΡΙΠΤΩΣΗ ΑΥΤΗ ΑΝΑΠΤΥΣΣΕΤΑΙ ΜΟΝΟ ΜΙΑ ΠΡΟΝΥΜΦΗ ΣΕ ΚΑΘΕ ΚΑΡΠΟ, ΛΟΓΩ ΚΑΝΝΙΒΑΛΙΣΜΟΥ ΜΕΤΑΞΥ ΤΩΝ ΠΡΟΝΥΜΦΩΝ ΠΟΥ ΒΡΙΣΚΟΝΤΑΙ ΜΕΣΑ ΣΤΟΝ ΙΔΙΟ ΚΑΡΠΟ

Mating Competition between Wild and Artificially Reared Olive Fruit Flies

Mating success of artificially reared males of the olive fruit fly is essential for genetic control techniques for this pest. We studied the mating competition between males from a laboratory-adapted population reared with an artificial diet and wild males emerged from field-infested olives and grown in olives in the laboratory. We maintained virgin wild females or artificially reared females in cages together with virgin wild and artificially reared males and scored the percentages of different males in the mated pairs, mating latency, and mating duration. After mating, we determined the egg production and the size of spermathecae of females mated with different males. Our results indicate that artificially reared males are competitive to the wild males, and they mated in similar percentages with wild and artificially reared females. Mean mating latencies (SE) of wild females that mated with wild and artificially reared males were 69.8 (4.8) min (n = 39) and 114.6 (8.1) (n = 43) min, respectively. No difference was discovered in the mating duration or egg production between females that mated with a wild or artificially reared male. Wild females had higher spermathecae volume when they mated with wild males compared to artificially reared males (two-tailed t-test = −2.079, df = 54, p = 0.0423)

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

ABSTRACT 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

Females of <i>Halyomorpha halys</i> (Hemiptera: Pentatomidae) Experience a Facultative Reproductive Diapause in Northern Greece

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is a native pest of East Asia that overwinters as an adult in natural and human-made structures. Adult emergence from overwintering sites starts in spring, whereas females produce offspring in early summer on host plants, where most feeding occurs. In this study, we investigated the reproductive physiology of overwintering females of H. halys in Northern Greece, by determining the duration of the preoviposition period and fecundity of individuals that were left to overwinter in natural conditions and were subsequently transferred to chambers with standard conditions monthly, from December 2020 to March 2021. According to our results, overwintering H. halys females do not initiate egg laying once they emerge from overwintering sites, but rather need some additional time to exit diapause and mature reproductively. The mean preoviposition period of overwintering females that were transferred from their overwintering sites to the chambers in December 2020 was 29.0 days, which was significantly longer by 8.3 days than that of females that overwintered until March 2021, and by 13.2 days than the control (26 °C, 60% RH and a 16:8 h light: dark photoperiod). No significant difference among the average number of eggs per egg mass laid by overwintering individuals brought in the chambers in different time intervals and the laboratory colony was observed. However, females that were left to overwinter until March laid a significantly higher number of eggs in total, compared to the ones whose overwintering was disrupted in February. Based on our findings, overwintering females of H. halys experience a facultative reproductive diapause in Northern Greece. Our study was the first to determine the occurrence of diapause of H. halys in N. Greece and our findings could be very valuable for assessing the damage of this pest to early-season crops and designing successful management practices

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

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

The Roles of Mating, Age, and Diet in Starvation Resistance in <i>Bactrocera oleae</i> (Olive Fruit Fly)

The olive fruit fly (Bactrocera oleae (Rossi) (Diptera: Tephritidae)), although a pest of major economic importance for the olive industry, has not been sufficiently studied with respect to the factors affecting its survival resistance to food deprivation. In the present study, we examined the effect of the interaction between mating status (virgin/mated), age class (11–20/21–30/31–40/41–50), and diet quality (protein plus sugar or only sugar) on starvation resistance in B. oleae under constant laboratory conditions. We conducted a total of 16 treatments (2 × 4 × 2 = 16) for each gender. Our results showed that starvation resistance in B. oleae did not differ significantly between females and males. The main conclusions of our study regarding mating status, age, and diet indicated that mated adults showed much less starvation resistance compared to virgins, younger adults endured longer, and the adults fed a restricted diet endured longer than those fed a full diet. A three-way interaction between mating status, diet, and age class was also identified and was the same for both genders. The interaction between mating status, age class, and diet also had a significant influence on starvation resistance in both sexes