New publication: Sperm competition in frogs differs among populations with different breeding systems
In species with simultaneous
polyandry, male-biased operational sex-ratio is expected to increase the risk
of sperm competition and thus sperm traits affecting siring success can differ
amongst populations. Here we test the hypothesis that high male-female ratios
will enhance sperm competitiveness of Rana temporaria males. In this
species, local populations can show either prolonged or explosive breeding. In
a context of sperm competition and in controlled laboratory conditions,
prolonged-breeding males sired a higher proportion of eggs than
explosive-breeding males, regardless of female origin. This study demonstrates intrapopulation
variation in siring success under a situation of sperm competition, consistent
with the prolonged-explosive dichotomy of breeding strategies.Alvarez D, Viesca L & Nicieza AG (2013) Sperm competitiveness ...
Posted Nov 28, 2013, 3:33 AM by David Alvarez
New publication: Climate Influences Fledgling Sex Ratio and Sex-Specific Dispersal in a SeabirdClimate influences the dynamics of natural populations by direct effects over habitat quality but also modulating the phenotypic responses of organisms’ life-history traits. These responses may be different in males and females, particularly in dimorphic species, due to sex-specific requirements or constraints. Here, in a coastal seabird, the European shag (Phalacrocorax aristotelis), we studied the influence of climate (North Atlantic Oscillation, NAO; Sea Surface Temperature, SST) on two sex-related population parameters: fledgling sex ratio and sex-specific dispersal. We found that fledgling sex ratio was female skewed in NAO-positive years and male skewed in NAO-negative years. Accordingly, females dispersed a longer distance in NAO-positive years when females were overproduced, and on the contrary, males ...
Posted Nov 28, 2013, 1:44 AM by David Alvarez
New publication: Urban fire salamanders (in Spanish)In the last issue of the Quercus journal (november 2012) I have published an article about the urban population of Fire salamander (Salamandra salamandra bernardezi) living in the city of Oviedo. The study was conducted during the last four years on a plot located on the University campus, behind the building of the Faculty of Biology.By the use of microchips, we were able to identify individually more than 200 different salamanders and thus ensure that the population density in that plot was higher than one individual per square meter. Furthermore, we also found that the vital domain of salamanders was very small, and rarely moved away more than 4 or 5 meters from where they had been located for ...
Posted Oct 24, 2012, 2:32 AM by David Alvarez
Atlantic salmon restocking (in Spanish)In the Spanish journal Quercus, I have published an article about the problems of restocking on for Atlantic salmon conservation. This species has suffered a major decline in recent decades, despite which, the last angling normatives in Asturias has eliminated any protectionist measures, increasing recreational catch quotas and pressure on the species. According to regional administration, the solution to reverse this decline is to increase the restocking practises, but these measures do not only serve to help the species, but may represent an additional problem. Álvarez D (2012) Repoblaciones de salmón: cuando el remedio es peor que la enfermedad. Quercus 316: 80-82.
Posted Nov 28, 2013, 1:45 AM by David Alvarez
14th International Behavioral Ecology CongressThe 14th International Behavioral Ecology Congress will be hosted by the Department of Biology at Lund University, Sweden, in 2012. The congress is scheduled from Sunday August 12 to Friday August 17. More information in this LINK
Posted Jul 11, 2012, 8:35 AM by David Alvarez
XII Congreso Luso-Español de HerpetologíaEntre el 3 y el 5 de octubre de 2012 se celebrará en el CEMACAM de Murcia el XII CONGRESO LUSO-ESPAÑOL DE HERPETOLOGÍA / XVI CONGRESO ESPAÑOL DE HERPETOLOGÍA bajo el lema “Fragmentación del territorio y conservación de herpetofauna”.
Posted Jul 11, 2012, 8:32 AM by David Alvarez