Release-Recapture Test of Dispersal and Survival of Sterile Males of Ceratitis capitata (Diptera: Tephritidae)

The sterile insect technique is used around the world to suppress or eradicate populations of Ceratitis capitata (Wiedemann) with successful results. It consists of inundative releases of sterile insects into a wide area to reduce reproduction in a field population of the same species. It is necessary to know the dispersion of the sterile males in the field in order to define the maximum distance between the release points that ensures the distribution of the sterile flies in the entire target area. The release methods may vary depending on the area to be covered and the resources available. Manual ground release requires less technology. The aim of this research was to estimate the ability of sterile males to survive and disperse in the field, in the two main areas of citrus production in Uruguay. A release of 20,000 sterile males of C. capitata TslV8 (-inv D53) was performed at the central point of each area defined for the trials. Around these points, a network of 54 Jackson traps baited with trimedlure was installed forming five concentric rings, which were placed on days 1, 3, 5, and 7 after the release and were removed at 24 h in all cases. The emergence rate, flight ability, dispersion, and longevity were estimated. The standard distances obtained by the regression models were 127 m and 131 m for Salto and San José respectively. In Salto, the traps had catches until the eighth day, and in San José, there were no catches after the sixth day.

The genome sequence of the grape phylloxera provides insights into the evolution, adaptation, and invasion routes of an iconic pest

BACKGROUND

Although native to North America, the invasion of the aphid-like grape phylloxera Daktulosphaira vitifoliae across the globe altered the course of grape cultivation. For the past 150 years, viticulture relied on grafting-resistant North American Vitis species as rootstocks, thereby limiting genetic stocks tolerant to other stressors such as pathogens and climate change. Limited understanding of the insect genetics resulted in successive outbreaks across the globe when rootstocks failed. Here we report the 294-Mb genome of D. vitifoliae as a basic tool to understand host plant manipulation, nutritional endosymbiosis, and enhance global viticulture.

RESULTS

Using a combination of genome, RNA, and population resequencing, we found grape phylloxera showed high duplication rates since its common ancestor with aphids, but similarity in most metabolic genes, despite lacking obligate nutritional symbioses and feeding from parenchyma. Similarly, no enrichment occurred in development genes in relation to viviparity. However, phylloxera evolved > 2700 unique genes that resemble putative effectors and are active during feeding. Population sequencing revealed the global invasion began from the upper Mississippi River in North America, spread to Europe and from there to the rest of the world.

CONCLUSIONS

The grape phylloxera genome reveals genetic architecture relative to the evolution of nutritional endosymbiosis, viviparity, and herbivory. The extraordinary expansion in effector genes also suggests novel adaptations to plant feeding and how insects induce complex plant phenotypes, for instance galls. Finally, our understanding of the origin of this invasive species and its genome provide genetics resources to alleviate rootstock bottlenecks restricting the advancement of viticulture.

The curvicauda species group of Anastrepha Schiner, 1868 (Diptera, Tephritidae, Trypetinae) in Uruguay: new records of species and host plant

We report for the first time the occurrence in Uruguay of three species of Anastrepha, which belong to the curvicauda species group. Specimens of Anastrepha australis (Blanchard, 1959), Anastrepha littoralis (Blanchard, 1959), and Anastrepha nigra (Blanchard, 1959) were collected with McPhail traps baited with PBX® yeast/borax placed in fruit orchards. These records represent the most southern distribution known for A. littoralis and A. nigra, in addition to the first host plant records for A. nigra, which were reared from larvae on fruits of Araujia hortorum E. Fourn. (Apocynaceae).

Sex pheromone of South American tortricid moth Argyrotaenia sphaleropa

By means of electroantennographic detection and gas chromatography-mass spectrometry, the sex pheromone of Argyrotaenia sphaleropa was identified as a mixture of (Z)-11-tetradecenal, (Z)-11,13-tetradecadienal, (Z)-11-tetradecenyl acetate, and (Z)-11,13-tetradecadienyl acetate in the ratio of 1:4:10:40. Best trap catches were obtained with mixtures of (Z)-11-tetradecenal and (Z)-11,13-tetradecadienal in the ratio of 1:4 to 1:9.