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

Reproductive behaviour of olive fruit fly (Bactrocera oelae) with emphasis on the sexual behaviour of the fly

The olive fruit fly (Bactrocera oleae) is a monophagous, multivoltine species that following its recent invasion in North America (California, NorthMexico) now threatens almost the entire olive producing industry of the worldand causes enormous economic losses for olive growers each year. Despitedecades of intensive research the mating system of the olive fly has not yet been resolved in detail. Besides that -in contrast to other tephritids- bothsexes seem to release a sexual pheromone in this species. The aim of the current dissertation was two fold. Firstly to elucidate aspects of mating and especially of the sexual behavior of this species, with emphasis on male polygyny behavior, and how these behaviors affect adult life history traits. Secondly to study the effect (independently or combined) of major ecological factors -such as host availability, host volatiles (α-pinene) and food (hydrolysate yeast availability) on mating behavior and fitness of olive fruit flies. Experiments were conducted under constant laboratory conditions (25 ±1°C), in the laboratory of Entomology and Agricultural Zoology, University of Thessaly, Greece during autumn - spring 2010 -2014. In all experiments, theflies used originated from field-infested olives, collected in Volos in August 2010, and were reared for 1 to 3 generations on olive fruit. General introductory information regarding olive fruit fly biology, reproductive ecology, mating and sexual behavior of olive fruit fly and its management are elaborated in Chapter 1. The utilization and application of materials and methods during the experiments are presented in Chapter 2. Conclusionsdrawn by this thesis, theoretical and practical applications and future researc hopportunities are discussed in Chapter 7.In Chapter 3 we studied the male polygyny behavior and its effects on male and female fitness. Allowing males to copulate with virgin females on successive days, we investigated (a) how male olive flies budget sperm to successive copulations, (b) what costs successive copulations in cur to males and (c) how male mating history affects female fecundity, fertility and longevity. We found that as males gained sexual experience, latency to mate declined significantly, while copula duration increased. The number of spermstored by females declined according to the sexual history of her mate – asmales gained experience, significantly fewer of their sperm was stored. Mated males suffered a significant longevity cost compared to virgin males; however multiple mating did not compound this cost. Male sexual experience affected female fecundity but not fertility. Furthermore, mating with an experienced male incurred a longevity cost to females. We conclude that non-sperm components of the male ejaculate are responsible for reducing female fecundity and longevity, and predict that females should prefer to mate with virgin males. In Chapter 4 we studied the effect of host and food -independently or combined- on mating performance and mating competitiveness of both sexes of olive fruit flies. Female mating receptivity was significantly influenced by hydrolysate yeast availability, olive fruit presence and their interaction. Female adults that were fed with protein were more willing to mate than those fed only with sugar. Similarly, host presence increased significantly female readiness to mate. Interestingly, in sugar fed females, adults that had access to olive fruits managed to achieve similar number of copulations with females that were maintained in protein. Latency to mate was significantly shorter for females fed with protein compared to those fed only with sugar. Inperformance tests -two choice tests- the nutritional status of females influenced their sexual competitiveness. On the contrary, females that were fed with protein achieved significantly longer copulations than those fed only with sugar, regardless of fruit presence. Protein fed females were significantly more competitive than individuals fed only with sugar, gaining the majority of copulations when competing for well-fed males. Olive fruit presence had apositive effect on female mating competitiveness though not significant. On the other hand, male mating success (number of copulations obtained by each treatment) was not influenced either by protein availability and host presence. Male mating and remating success ranged in high levels among all treatments (88-95%). Latency to mate was shorter for males that had access to olive fruits, irrespectively of their nutrition. However, copula duration was not affected by protein availability and host presence. In two choice tests, the nutritional status of males influenced their sexual competitiveness. Protein availability increased significantly the sexual competitiveness of males compared to only sugar fed ones. However, host presence did not have a significant effect on male sexual competitiveness. Additionally, based on results pooled from all subsets of experiments, we observe that females are more reluctant to mate when they are given the opportunity of choice inrelation to non-choice conditions. In Chapter 5, we tested the effect of a host volatile- specifically α-pinene- on the mating competitiveness of adult olive flies by counting the mating success of exposed to α-pinene aroma against non-exposed rivals. Moreover, copula characteristics were recorded and different dosages of α-pinene -5, 10, 20, 40 and 80 μl- were tested for both sexes. Exposure of sexually mature adult olive flies to the aroma of α-pinene significantly increased the mating performance over non-exposed individuals. Reproductively mature males of the olive fly that were exposed to pure α-pinene gained a significant, dose-dependent mating advantage over no nexposedmales. Significant differences between treated and control males were observed for the doses of 10 and 20 μl, respectively, with peak advantage reported at 20 μl. At this dose, exposed males achieved 82% of all matings. Higher doses seemed to induce some negative effects- though not significant- while lower ones failed to reach significance. Over all it seems that latency to mate and copula duration was similar for exposed and non-exposed males. Likewise, exposure of reproductively mature, non-mated females to doses of 20 and 80 μl of α-pinene significantly boosted their mating successto 62% and 65% respectively. Differences in copula characteristics were not observed in general between exposed and non-exposed females. This is the first report of such an effect on the olive fly, and the first time that a single plant volatile has been reported to induce such a phenomenon on both sexes of a single species. In Chapter 6, we investigated whether exposure of adults to the aroma of α-pinene modulates (a) longevity of males and females, (b) reproductive traits of females and (c) life-history traits in similar manner in a stressful –dietary (protein) restricted (DR) and in a relaxed- full diet (FD) feeding environment. Accordingly, we exposed males and females to the aroma of α-pinene and measured longevity and fecundity in the above two dietary contexts. Our results demonstrate that exposure to the odour of α-pinene -most possibly through sensing- increased longevity in males and fecundity in females only under dietary restricted conditions, where as in relaxed food conditions a shift of intense egg laying to younger ages has been reported. This is the first report demonstrating that a plant compound affects key life history traits of adult olive flies, such as longevity and reproduction, throughol faction. These effects are sex-specific and more pronounced in dietary restricted adults. The results of the current thesis contribute to a better understanding of the sexual behavior of the olive fruit fly, an organism with complex mating system and several specificities from ot her Tephritid species. Moreover, the effects of factors of major ecological significance like host presence, hostvolatile and adult diet on mating behavior and fitness traits of olive fruit fly were also explored. The results demonstrate that important aspects of mating behavior -mating success, mating competiveness and copula characteristics as well as biological key parameters -lifespan and reproduction- of adult olive flies can be influenced by the above factors and indicate the close relationships between a monophagous species with its host. The contributionof these findings towards understanding the sexual behavior and mate choice of olive fruit fly, as well as how ecological factors can shape behavior arebeing discussed and possibilities for future research are being proposed.Στην παρούσα διατριβή μελετήθηκε η αναπαραγωγική συμπεριφορά του δάκου της ελιάς (Bactrocera oleae) (Diptera:Tephritidae) σε συνθήκες εργαστηρίου (25±1°C) με έμφαση στη σεξουαλική συμπεριφορά του είδους. Χρησιμοποιήθηκαν έντομα που προήλθαν από προσβεβλημένους καρπούς που συλλέχτηκαν στην ευρύτερη περιοχή της Θεσσαλίας και εξετράφησαν στο εργαστήριο σε ελαιόκαρπους για 1 έως 3 γενεές. Στην πρώτη ενότητα πειραμάτων (Κεφάλαιο 3) μελετήθηκε το φαινόμενο της πολυγαμίας των αρσενικών. Ειδικότερα, προσδιορίστηκε η μεταφορά σπέρματος σε θηλυκά που τρέφονταν με μίγμα ζάχαρης και πρωτεΐνης και που συζεύχτηκαν με αρσενικά που είτε δεν είχαν συζευχτεί καθόλου, είτε είχαν προηγουμένως συζευχτεί μία, δύο, και τρεις φορές. Σε μια δεύτερη σειρά πειραμάτων μελετήθηκε η επίδραση του (α) αριθμού των διαδοχικών συζεύξεων των αρσενικών στη μακροβιότητά τους και (β) της συχνότητας επανασύζευξης του αρσενικού στη μακροβιότητα, ωοπαραγωγή και γονιμότητα των θηλυκών τα οποία συζεύχτηκαν με τα παραπάνω αρσενικά. Τα ευρήματά μας δείχνουν πως καθώς αυξάνεται ο αριθμός των προηγούμενων συζεύξεων των αρσενικών, μειώνεται ο χρόνος που απαιτείται έως την έναρξη της σύζευξης ενώ αυξάνεται η διάρκειά της. Ο αριθμός σπερματοζωαρίων που μεταφέρεται στα αναπαραγωγικά όργανα του θηλυκού μειώνεται σημαντικά καθώς αυξάνεται ο αριθμός των προηγούμενων συζεύξεων των αρσενικών. Η διάρκεια ζωής των συζευγμένων αρσενικών ήταν μικρότερη σε σχέση με των μη συζευγμένων ως αποτέλεσμα του κόστος της σύζευξης. Εντούτοις, το κόστος στη διάρκεια ζωής των συζευγμένων αρσενικών ήταν ανεξάρτητο του συνολικού αριθμού των συζεύξεών τους. Ο αριθμός των προηγούμενων συζεύξεων των αρσενικών επηρέασε την ωοπαραγωγή και τη γονιμότητα των θηλυκών και επέφερε κόστος στη διάρκεια της ζωής τους. Ειδικότερα, τα θηλυκά που συζεύχτηκαν με παρθένα αρσενικά επιβίωσαν για μεγαλύτερο χρονικό διάστημα και ταυτόχρονα απέθεσαν περισσότερα αυγά από τα θηλυκά τα οποία είχαν προηγουμένως συζευχτεί με πολλαπλά συζευγμένα αρσενικά. Η επιβίωση των θηλυκών που συζεύχτηκαν με ήδη συζευγμένα αρσενικά ήταν μειωμένη, καθώς επίσης και η αναπαραγωγή τους. Στο Κεφάλαιο 4 μελετήθηκε η επίδραση της τροφής και της παρουσίας ελαιοκάρπου στη συμπεριφορά σύζευξης θηλυκών και αρσενικών του δάκου της ελιάς. Ειδικότερα, μελετήθηκε η επίδραση των παραπάνω παραγόντων, μεμονωμένα αλλά και συνδυαστικά, στην επιτυχία και στην ανταγωνιστικότητα σύζευξης. Πραγματοποιήθηκαν δοκιμές σύζευξης μη-επιλογής και επιλογής τόσο σε αρσενικά όσο και σε θηλυκά. Η δεκτικότητα σύζευξης των θηλυκών επηρεάστηκε τόσο από τη διαθεσιμότητα της πρωτεΐνης στην τροφή των ενηλίκων όσο και από την παρουσία του ελαιοκάρπου και της αλληλεπίδρασης των δυο παραγόντων. Τα θηλυκά που τρέφονταν με πρωτεΐνη και ζάχαρη ήταν πιο δεκτικά απ’ ότι τα θηλυκά που τρέφονταν μόνο με ζάχαρη, ανεξάρτητα από την παρουσία ελαιοκάρπου. Ο ελαιόκαρπος αύξησε τη δεκτικότητα των θηλυκών, ιδιαίτερα εκείνων που είχαν ως τροφή μόνο ζάχαρη. Σε ότι αφορά τα χαρακτηριστικά της σύζευξης παρατηρείται ότι ο χρόνος έως την έναρξη της σύζευξης ήταν μικρότερος για τα θηλυκά που τρέφονταν με πρωτεΐνη έναντι εκείνων που τρέφονταν με ζάχαρη, με σημαντικές διαφορές να παρατηρούνται μόνο μεταξύ θηλυκών που είχαν πρόσβαση σε ελαιόκαρπους. Αντίθετα, τα θηλυκά που τρέφονταν με πρωτεΐνη συζεύχτηκαν για μεγαλύτερο χρονικό διάστημα απ’ ότι θηλυκά που τρέφονταν μόνο με ζάχαρη, ανεξάρτητα από το εάν είχαν πρόσβαση ή όχι σε ελαιόκαρπο. Τα πειράματα ανταγωνιστικότητας των θηλυκών κατέδειξαν τη σημαντική επίδραση της πρωτεΐνης στην αύξηση της ανταγωνιστικότητας σύζευξης των θηλυκών. Η επίδραση του ελαιοκάρπου αύξησε την ανταγωνιστικότητα σύζευξης, χωρίς ωστόσο οι επιδράσεις να είναι σημαντικές. Στο Κεφάλαιο 5 μελετήθηκε η επίδραση του α-πινενίου στη σεξουαλική συμπεριφορά αρσενικών και θηλυκών του δάκου της ελιάς. Ειδικότερα, μελετήθηκε η ανταγωνιστικότητα σύζευξης αρσενικών του δάκου της ελιάς που εκτέθηκαν στο α-πινένιο σε σχέση με αρσενικά που δεν εκτέθηκαν. Πραγματοποιήθηκαν πειράματα σύζευξης (mating tests) επιλογής (choicetests). Σε άλλη σειρά πειραμάτων με παραπλήσια μεθοδολογία μελετήσαμε την επίδραση του α-πινενίου στην ανταγωνιστικότητα σύζευξης των θηλυκών του δάκου της ελιάς. Θηλυκά που είχαν εκτεθεί σε α-πινένιο και θηλυκά που δεν είχαν εκτεθεί «ανταγωνίζονταν» να συζευχθούν με αρσενικά που δεν είχαν εκτεθεί στην παραπάνω ουσία. Χρησιμοποιήθηκαν 5 διαφορετικές δόσεις της καθαρής ουσίας α-πινένιο τόσο για τα αρσενικά όσο και τα θηλυκά. Τα αποτελέσματα των πειραμάτων επιλογής έδειξαν ότι αρσενικά και θηλυκά που είχαν εκτεθεί σε α-πινένιο απέκτησαν πλεονέκτημα στη σύζευξη σε σχέση με αντίστοιχα άτομα που δεν είχαν εκτεθεί σε αυτή την ουσία. Στο Κεφάλαιο 6 μελετήθηκε η επίδραση της έκθεσης στο α-πινένιο σε βιολογικά χαρακτηριστικά του δάκου της ελιάς. Ειδικότερα, διερευνήσαμε εάν η έκθεση στο α-πινένιο μπορεί να επηρεάσει τη διάρκεια ζωής και την αναπαραγωγή ενηλίκων του δάκου της ελιάς και αν οι επιδράσεις που προκύπτουν επηρεάζονται από την τροφή των ενηλίκων. Τα αποτελέσματά μας δείχνουν ότι η έκθεση στο α-πινένιο αύξησε τη διάρκεια ζωής των αρσενικών που τρέφονταν μόνο με ζάχαρη καθώς επίσης και την ωοπαραγωγή των θηλυκών που είχαν πρόσβαση στην ίδια τροφή. Στην περίπτωση που τα ενήλικα είχαν πρόσβαση σε διάλυμα πρωτεΐνης και ζάχαρης, η έκθεση στο α-πινένιο δεν επηρέασε τη συνολική ωοπαραγωγή των θηλυκών. Ωστόσο σε αυτή την περίπτωση παρατηρήθηκε διαφορά στην κατανομή της ωοπαραγωγής με τα εκτεθειμένα θηλυκά να έχουν αποθέσει το μεγαλύτερο μέρος των αυγών τους σε νεαρές ηλικίες. Τα παραπάνω αποτελέσματα συμβάλλουν στην καλύτερη κατανόηση της σεξουαλικής συμπεριφοράς του δάκου της ελιάς, ο οποίος εκδηλώνει ένα σαφές διαφορετικό σύστημα σύζευξης σε σχέση με τα υπόλοιπα είδη της οικογένειας Tephritidae. Επιπλέον, μελετήθηκε η επίδραση σημαντικών οικολογικών παραγόντων-παρουσία ξενιστή, οσμές ξενιστή, τροφή ενηλίκων-στη συμπεριφορά σύζευξης και την αρμοστικότητα των ενηλίκων του δάκου της ελιάς. Τα αποτελέσματα των πειραμάτων έδειξαν πως σημαντικές πτυχές της σεξουαλικής συμπεριφοράς, όπως η ικανότητα σύζευξης και η ανταγωνιστικότητα σύζευξης, καθώς επίσης και βασικά βιολογικά χαρακτηριστικά των ενηλίκων όπως η επιβίωση και η αναπαραγωγή,επηρεάστηκαν από τους παραπάνω διατροφικούς, χημικούς (σχετικούς με το φυτό ξενιστή) και «κοινωνικούς» (επιλογή αναπαραγωγικού συντρόφου) παράγοντες και καταδεικνύουν τη στενή σχέση μεταξύ ενός μονοφάγου είδους και του ξενιστή του. Αναλύθηκε η συνεισφορά των ευρημάτων στην κατανόηση της σεξουαλικής συμπεριφοράς και της σεξουαλικής επιλογής και πώς αυτή διαμορφώνεται από ποικίλους οικολογικούς παράγοντες. Τέλος,σχολιάστηκαν οι δυνατότητες πρακτικής εφαρμογής των αποτελεσμάτων και οι προοπτικές για μελλοντικές συναφείς έρευνες

The odor of a plant metabolite affects life history traits in dietary restricted adult olive flies

Food quality shapes life history traits either directly or through response of individuals to additional environmental factors, such as chemical cues. Plant extracts used as food additives modulate key life history traits; however little is known regarding such effects for olfactory chemical cues. Exploiting an interesting experimental system that involves the olive fly (Bactrocera oleae) and the plant metabolite α-pinene we asked whether exposure of adults to this compound modulates adult longevity and female reproduction in similar manner in a stressful-dietary (protein) restricted (DR) and in a relaxed-full diet (FD) feeding environment. Accordingly, we exposed males and females to the aroma of α-pinene and measured lifespan and age-specific fecundity in the above two dietary contexts. Our results demonstrate that exposure to α-pinene increased longevity in males and fecundity in females only under dietary restricted conditions. In relaxed food conditions, females exposed to α-pinene shifted high egg-laying towards younger ages compared to non-exposed ones. This is the first report demonstrating that a plant compound affects key life history traits of adult olive flies through olfaction. These effects are sex-specific and more pronounced in dietary restricted adults. Possible underlying mechanisms and the ecological significance are 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. © 2019, The Author(s)

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 odor of a plant metabolite affects life history traits in dietary restricted adult olive flies.

Food quality shapes life history traits either directly or through response of individuals to additional environmental factors, such as chemical cues. Plant extracts used as food additives modulate key life history traits; however little is known regarding such effects for olfactory chemical cues. Exploiting an interesting experimental system that involves the olive fly (Bactrocera oleae) and the plant metabolite α-pinene we asked whether exposure of adults to this compound modulates adult longevity and female reproduction in similar manner in a stressful - dietary (protein) restricted (DR) and in a relaxed- full diet (FD) feeding environment. Accordingly, we exposed males and females to the aroma of α-pinene and measured lifespan and age-specific fecundity in the above two dietary contexts. Our results demonstrate that exposure to α-pinene increased longevity in males and fecundity in females only under dietary restricted conditions. In relaxed food conditions, females exposed to α-pinene shifted high egg-laying towards younger ages compared to non-exposed ones. This is the first report demonstrating that a plant compound affects key life history traits of adult olive flies through olfaction. These effects are sex-specific and more pronounced in dietary restricted adults. Possible underlying mechanisms and the ecological significance are discussed

Female olive fly.

<p>Female olive fly.</p

Sudden Bilateral Sensorineural Hearing Loss Associated with HLA A1-B8-DR3 Haplotype

Sudden sensorineural hearing loss may be present as a symptom in systemic autoimmune diseases or may occur as a primary disorder without another organ involvement (autoimmune inner ear disease). The diagnosis of autoimmune inner ear disease is still predicated on clinical features, and to date specific diagnostic tests are not available. We report a case of bilateral sudden hearing loss, tinnitus, intense rotatory vertigo, and nausea in a female patient in which the clinical manifestations, in addition to raised levels of circulating immune complexes, antithyroglobulin antibodies, and the presence of the HLA A1-B8-DR3 haplotype, allowed us to hypothesize an autoimmune inner ear disease. Cyclosporine-A immunosuppressive treatment in addition to steroids helped in hearing recovery that occurred progressively with normalization of the hearing function after a five-month treatment. Cyclosporine-A could be proposed as a therapeutic option in case of autoimmune inner ear disease allowing the suspension of corticosteroids that, at high dose, expose patients to potentially serious adverse events