Inhabiting warm microhabitats and risk-spreading as strategies for survival of a phytophagous insect living in common pastures in the Pyrenees

[EN] The breakdown of the transhumant grazing system in the Spanish Pyrenees has led to a severe decline in the area of pastures. However, in the high mountain zone there are still large areas of species-rich grasslands. The aim of this study was to assess the oviposition preferences of the shrub-feeding Blue-spot hairstreak, Satyrium spini (Denis & SchiffermÃller, 1775), in montane common pastures in the Spanish Pyrenees and recommend a way of managing these grasslands that favours this species. Our study showed that females of S. spini laid their eggs on Dwarf buckthorn (Rhamnus pumila Turra) and Alpine buckthorn (R. alpina L.), which are novel host plant records for Spain. A warm microclimate was of crucial importance for egg-laying. Occupied plants grew mostly at sparsely vegetated grassland sites where there were large patches of bare rocks, stones or gravel. Most egg batches were laid close to the ground and 75% consisted of only one egg. The number of batches per R. pumila plant was higher on east-, southand west-facing slopes than on north-facing slopes. Presence of eggs and the number of egg batches per R. pumila plant were best explained by a long sunshine duration. At high altitudes particularly warm microhabitats seem to be more important for S. spini than at lower altitudes in Central Europe. We assume that the preference for unusually warm microhabitats is explained by the cold climatic conditions near the altitudinal range limit of the species. That most of the eggs were laid singly and not in small batches as in Central Europe might be a risk-spreading strategy to cope with the harsh climatic conditions and the high inter-annual variation in weather conditions in the high mountain zone in the Pyrenees. The best way to maintain open grasslands for S. spini and other thermophilous grassland species in the high mountain zone of the Pyrenees is to use the traditional combination of sheep and cattle grazing.Peer Reviewe

New approaches to almond breeding at the University of California-Davis program

4 pages.-- En: ISHS Acta Horticulturae 591: III International Symposium on Pistachios and Almonds.The breeding program in the Department of Pomology at the University of California at Davis is one of the largest and oldest continually active almond improvement programs in the world. In this study, current strategies for almond improvement, including germplasm improvement, propagation techniques and use of molecular markers, are described. In germplasm improvement, the introduction of genes from related Prunus species conferring several potentially useful traits (including self-compatibility, improved growth habit, drought resistance, kernel quality) is being pursued. Twin seeds (two embryos within the same seedcoat that occur spontaneously in certain almond cultivars) produce seedlings with unusual growth and development. Plants appear to be aneuploid, which, if confirmed, would be very useful for genetic studies (isolation and sequencing of genes, genetic transformation, etc.). Propagation methods employed include in-vivo micrograft techniques that allow the early propagation and invigoration of weak material. In addition, the growth of seedlings in controlled environments, including the induction of an artificial rest period (in cold chambers), provides a strategy for obtaining vigorously growing plant tissue throughout year. Molecular markers have become a essential tool in breeding. In our assays, different types of molecular markers (isozymes, PCR, SSRs and AFLPs) have been employed for the genetic characterization of plant material and the linkage of traits with agronomic interest, and the establishment of genetic relationships between cultivars and species.Peer reviewe