Development of assays for the characterization of sperm motility parameters, viability, and membrane integrity in the epididymis and vas deferens of the greater rhea (Rhea americana)

The objectives of the study were to (1) describe the kinematic parameters of spermatozoa (2) compare methods of evaluating sperm viability (3) validate assays of functionality and integrity of the sperm membrane and (4) evaluate possible changes between spermatozoa from the epididymis and the vas deferens of the greater rhea. Semen samples were recovered from 7 adult individuals. Sperm motility was characterized by adjusting the set-up for Computer-assisted semen analysis (CASA) to that new species. For sperm viability evaluation, smears of bromophenol blue and eosin-nigrosine dyes were used. Five solutions of different osmolarities were then tested for the hypoosmotic swelling test (HOST). The combination of fluorescent probes (propidium iodide - IP and Hoechst 33342) was also used to assess plasma membrane integrity. Data were presented as mean ± SEM. Rhea spermatozoa from the vas deferens had an overall motility of 14.6 ± 2.5%. The bromophenol blue staining technique revealed that 64.6 ± 5.2% sperm were viable, while that proportion was 72.1 ± 2.5% using eosin-nigrosine. An average of 77.6 ± 4.8% of spermatozoa reacted to the HOST with distilled water at 0 mOsm/l. Fluorescent probes indicated that 65.3 ± 2.6% of spermatozoa had intact membranes. Interestingly, no statistical differences were observed between the parameters analyzed in the epididymal spermatozoa and the vas deferens. These new assays set reference values that can now be used to further exploration of sperm handling conditions and freezing protocols in rheas.

The Past and Current Potential Distribution of the Fruit Fly Anastrepha obliqua (Diptera: Tephritidae) in South America

Anastrepha obliqua (Macquart) is an agricultural pest of wide geographic distribution infesting a vast list of host species in America. However, little is known about the past geographic distribution of this species. In this study, we investigated the potential past and current distribution of species in South America. In this sense, the MaxEnt algorithm was used to model the ecological niche of the species in the past (Last Interglcial Maximum; Last Glacial Maximum) and current periods. The results suggested that under the current climatic conditions, A. obliqua showed high environmental suitability to become established in most South American countries, especially in Brazil. The lowest suitability indices were observed in Chile, Argentina, and Uruguay. The past analysis for Last Glacial Maximum revealed that there was no significant change in the distribution potential of the species when compared to the current model; however, in the Last Interglacial Maximum period, there was a large reduction in the areas of suitability for the species when compared to the current and Last Glacial Maximum distribution models. The analysis also revealed vast areas of refuges for the species mainly on the coast of Brazil, as well as Venezuela, Bolivia, Guyana, and Surinam. The results presented here may be useful for future phylogeographical studies in order to test if the refuge areas concentrate greater genetic diversity for this species. In addition, our study provides important information for understanding the current dynamics of A. obliqua, which may be useful for control programs in places where this species can become a pest.