Cryopreservation of the Mediterranean fruit fly (Diptera: Tephritidae) VIENNA 8 genetic sexing strain: No effect on large scale production of high quality sterile males for SIT applications.

The sterile insect technique (SIT) integrated in area-wide integrated pest management (AW-IPM) programmes is being used for the successful management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) which is a horticultural pest of economic importance in tropical and subtropical countries. All programmes with an SIT component are using the VIENNA genetic sexing strains (GSS), mainly the VIENNA 8 GSS, which have been developed by applying classical genetic approaches. The VIENNA 8 GSS carries two selectable markers, the white pupae and the temperature sensitive lethal genes, which allows the production and release of only males thus increasing the biological efficiency and cost effectiveness of SIT applications. However, mass rearing may affect quality traits of the GSS, in which case replenishment of the colony with wild flies is recommended, a process which is tedious and time consuming. We previously reported the development of a cryopreservation protocol for the VIENNA 8D53+ strain. In the present study, we report on the evaluation of the cryopreserved strain VIENNA 8D53+/Cryo-228L, reared under semi mass rearing conditions, for production parameters, quality control indices and mating competitiveness of males, in a comparative way with the non-cryopreserved VIENNA 8D53+ strain, against wild type males. The VIENNA 8D53+ and VIENNA 8D53+/Cryo-228L strains were similar for production parameters viz. egg production, pupal production, pupal recovery, and quality control indices like fly emergence, sex ratio and flight ability. Males from both strains were equally competitive with males of the wild type strain in achieving mating with wild type females under field cage conditions. Results are discussed in the context of cryopreservation as a potential backup strategy for refreshing the mass rearing colony with biological material from a cryopreserved stock

One for all: Mating compatibility among various populations of olive fruit fly (Diptera: Tephritidae) for application of the sterile insect technique.

The olive fruit fly, Bactrocera oleae (Rossi), is the most important insect pest for the cultivation of olives worldwide. Considerable research efforts have been invested in the past decades to develop eradication or suppression tactics for use within an area-wide integrated pest management (AW-IPM) approach that includes a sterile insect technique (SIT) component. One of the major obstacles encountered in the development of SIT for olive fruit fly was the inferior quality of the mass-reared flies, expressed among others evident primarily by sterile males having a different timing of peak mating and a lower mating propensity in comparison with their wild counterparts. In this study we assessed the mating behaviour and mating compatibility of olive fruit flies originating from four countries of the Mediterranean region (Croatia, France, Italy, Spain) in walk-in field cages and post zygotic compatibility (expressed as % egg hatch) under laboratory conditions. Furthermore, we tested the hypothesis whether a hybrid strain (Greece (domesticated)/Israel (wild)) adapted to laboratory rearing conditions showed any mating barriers with all the four "wild" populations. Finally, we examined the effect of colonization on the mating compatibility of the four newly established populations over three consecutive generations. The results showed no pre-zygotic (mating barriers) or post-zygotic isolations (measured by egg hatch%) among the olive fruit fly populations from the four countries tested. Also, there was no evidence of mating barriers between the hybrid strain and the wild populations of the Mediterranean region

Evaluation of quality production parameters and mating behavior of novel genetic sexing strains of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera : Tephritidae)

The Mediterranean fruit fly Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is one of the most important pest of fruits and vegetables in tropical and subtropical countries. The sterile insect technique (SIT) as a component of area-wide integrated pest management (AW-IPM) approaches is being used for the successful management of this pest. VIENNA 8 is a genetic sexing strain (GSS) that has a white pupae (wp) and temperature sensitive lethal (tsl) mutation, the latter killing all female embryos when eggs are exposed to high temperatures (34°C). The use of this GSS permits production and the release of only males which has increased the cost effectiveness of the SIT several fold for this pest. An efficient method of identification of recaptured sterile males can further increase the cost effectiveness of the SIT for this pest. Therefore, VIENNA 8-Sergeant2 (Sr²) strain and the transgenic strain VIENNA 8–1260 having visible markers were constructed. All three strains were evaluated for egg production, egg hatch, and egg sterility parameters under semi mass-rearing conditions and mating competitiveness in field cages. VIENNA 8–1260 females produced significantly fewer eggs as compared with the two other strains, which produced similar numbers of eggs. However, egg hatch of all strains was similar. Egg hatch of eggs produced by untreated females that had mated with adult males that had been irradiated with 100 Gy as pupae 2 days before emergence, was different for the three strains, i.e., egg hatch of 0.63%, 0.77%, 0.89% for VIENNA 8, VIENNA 8–1260, and VIENNA 8-Sr², respectively. Differences in male mating competitiveness of the three strains against wild-type males were gradually reduced with successive generations under semi mass-rearing conditions. However, VIENNA 8 males adapted faster to laboratory conditions as compared with VIENNA 8-Sr² and VIENNA 8–1260 males with respect to mating competitiveness. VIENNA 8 males of the F10 generation were equally competitive with wild-type males, whereas the mating competitiveness of VIENNA 8-Sr² and VIENNA 8–1260 males was similar but lower as compared with wild-type males. Males from all three strains copulated earlier than wild-type males. Results are discussed in relation with the potential benefits of incorporating novel strains for more effective SIT application.14 page(s

Conserved metallomics in two insect families evolving separately for a hundred million years

Μetal cofactors are required for enzymatic catalysis and structural stability of many proteins. Physiological metal requirements underpin the evolution of cellular and systemic regulatory mechanisms for metal uptake, storage and excretion. Considering the role of metal biology in animal evolution, this paper asks whether metal content is conserved between different fruit flies. A similar metal homeostasis was previously observed in Drosophilidae flies cultivated on the same larval medium. Each species accumulated in the order of 200 µg iron and zinc and approximately ten-fold less manganese and copper per gram dry weight of the adult insect. In this paper, data on the metal content in fourteen species of Tephritidae, which are major agricultural pests worldwide, are presented. These fruit flies can be polyphagous (e.g., Ceratitis capitata) or strictly monophagous (e.g., Bactrocera oleae) or oligophagous (e.g., Anastrepha grandis) and were maintained in the laboratory on five distinct diets based on olive oil, carrot, wheat bran, zucchini and molasses, respectively. The data indicate that overall metal content and distribution between the Tephritidae and Drosophilidae species was similar. Reduced metal concentration was observed in B. oleae. Feeding the polyphagous C. capitata with the diet of B. oleae resulted in a significant quantitative reduction of all metals. Thus, dietary components affect metal content in some Tephritidae. Nevertheless, although the evidence suggests some fruit fly species evolved preferences in the use or storage of particular metals, no metal concentration varied in order of magnitude between these two families of Diptera that evolved independently for over 100 million years.13 page(s

Number of eggs (± SD) produced per female per day by the Mediterranean fruit fly genetic sexing strains VIENNA 8, VIENNA 8-Sr² and VIENNA 8–1260 under semi mass-rearing conditions.

<p>Means followed by the same letter do no differ significantly (Tukey-Kramer HSD, α = 0.05).</p

Mediterranean fruit fly genetic sexing strains VIENNA 8, VIENNA 8-Sr² and VIENNA 8–1260 egg hatch (% ± SD) data during the course of eight generations under semi mass-rearing conditions.

<p>Mediterranean fruit fly genetic sexing strains VIENNA 8, VIENNA 8-Sr² and VIENNA 8–1260 egg hatch (% ± SD) data during the course of eight generations under semi mass-rearing conditions.</p

Mating latency (min) and mating duration (min) among three laboratory strains of Mediterranean fruit fly and a wild-type Argentina strain.

<p>Average mating latency or duration ± standard deviation is presented, couples observed are presented in parenthesis. First column for each parameter presents results collected from competitiveness study cages, second column presents results collected from control cages. Within the columns, numbers followed by the same letter do no differ significantly (Tukey-Kramer HSD, α = 0.05).</p

RSI indices from mating competitiveness experiments with three laboratory strains of the Mediterranean fruit fly tested against a wild-type Argentina population in field cages.

<p>Couples observed for each type of mating, RSI values± SD with chi-square results (<i>p</i> > 0.05) showed equal mating propensity. Number of couples from each strain followed by same letter are not significantly different from each other (Tukey-Kramer HSD, α = 0.05) and numbers of cages that have been taken into account (>50% of total expected) in parenthesis.</p

Egg hatch (%) of three strains of Mediterranean fruit fly, presenting the effect of irradiation on males and females at different generations under mass-rearing conditions (10 days of egg collection for each generation were tested for successful hatching).

<p>For the sterile sex of each one of the following combinations, the sterilizing dose was 100 Gy delivered from Co⁶⁰ source. Average and standard deviation of egg hatch percentage are presented, total number of eggs examined are presented in parenthesis.</p