Origin and Evolution of Saturn's Ring System

The origin and long-term evolution of Saturn's rings is still an unsolved problem in modern planetary science. In this chapter we review the current state of our knowledge on this long-standing question for the main rings (A, Cassini Division, B, C), the F Ring, and the diffuse rings (E and G). During the Voyager era, models of evolutionary processes affecting the rings on long time scales (erosion, viscous spreading, accretion, ballistic transport, etc.) had suggested that Saturn's rings are not older than 100 My. In addition, Saturn's large system of diffuse rings has been thought to be the result of material loss from one or more of Saturn's satellites. In the Cassini era, high spatial and spectral resolution data have allowed progress to be made on some of these questions. Discoveries such as the ''propellers'' in the A ring, the shape of ring-embedded moonlets, the clumps in the F Ring, and Enceladus' plume provide new constraints on evolutionary processes in Saturn's rings. At the same time, advances in numerical simulations over the last 20 years have opened the way to realistic models of the rings's fine scale structure, and progress in our understanding of the formation of the Solar System provides a better-defined historical context in which to understand ring formation. All these elements have important implications for the origin and long-term evolution of Saturn's rings. They strengthen the idea that Saturn's rings are very dynamical and rapidly evolving, while new arguments suggest that the rings could be older than previously believed, provided that they are regularly renewed. Key evolutionary processes, timescales and possible scenarios for the rings's origin are reviewed in the light of tComment: Chapter 17 of the book ''Saturn After Cassini-Huygens'' Saturn from Cassini-Huygens, Dougherty, M.K.; Esposito, L.W.; Krimigis, S.M. (Ed.) (2009) 537-57

Biodiversity and extinction

Oestrid larvae causing myiasis display a wide degree of biodiversity, in terms of species of domestic and wild mammals infected and anatomical sites. The presence in some regions of southern Europe of a high number of different species of oestrids in domestic animals stimulated interest in exploring the basis of such degree of parasitic biodiversity in the Mediterranean region. However, broad spectrum anti-parasitic treatments (e.g. macrocyclic lactones) constitute a critical factor for the selection of species of Oestrids and for the maintenance of their biodiversity in a given area. The dynamic equilibrium that oestrid larvae have established with the host and the environment as well as the span of biodiversity they represent may be considered to be at odds with maintaining animal welfare and reducing animal production losses

Biodiversity and extinction versus control of Oestrid causing myiasis in Mediterranean area

Oestrid larvae causing myiasis display a wide degree of biodiversity, in terms of species of domestic and wild mammals infected and anatomical sites. The presence in some regions of southern Europe of a high number of different species of oestrids in domestic animals stimulated interest in exploring the basis of such degree of parasitic biodiversity in the Mediterranean region. However, broad spectrum anti-parasitic treatments (e.g. macrocyclic lactones) constitute a critical factor for the selection of species of Oestrids and for the maintenance of their biodiversity in a given area. The dynamic equilibrium that oestrid larvae have established with the host and the environment as well as the span of biodiversity they represent may be considered to be at odds with maintaining animal welfare and reducing animal production losses