Barbosa, A.M., Fernández-García, J.L., Carranza, J. (2009). A new marker for rapid sex identification of red deer (Cervus elaphus). Hystrix It. J. Mamm. 20(2), 169-172

Un nuovo marcatore per l’identificazione rapida del sesso del cervo (Cervus elaphus ) Il cervo ( Cervus elaphus ) è una specie cacciabile economicamente importante che risente di alcuni problemi di conservazione. La conoscenza di parametri di popolazione come il rapporto sessi è importante per la sua gestione e conservazione. In questo studio, utilizzando condizioni poco specifiche per l’amplificazione di un frammento del cromosoma Y già descritto in precedenza, descriviamo un metodo che permette una rapida e corretta identificazione del sesso in questa specie, producendo due amplicons diversi nei maschi e uno nelle femmine. I due frammenti, diversi per il peso molecolare, sono facilmente separabili mediante elettroforesi in gel di agarosio, permettendo l’identificazione del sesso con un unico test in campioni biologici come carcasse, embrioni recuperati da femmine abbattute e, forse, peli o escrementi (se la qualità del DNA è accettabile). Questo metodo può essere di aiuto in studi sul rapporto sessi degli embrioni, sulla mortalità associata al sesso o sul rapporto sessi in popolazioni selvatiche o semi-selvatiche, con ricadute applicative per le analisi demografiche, la gestione venatoria e la conservazione

https://www.researchgate.net/publication/50889716_A_new_marker_for_rapid_sex_identification_of_red_deer_Cervus_elaphus

Carranza , J., Pérez-González, J., Mateos, C., Fernández-García, J. L. (2009). Parents’ genetic dissimilarity and offspring sex in a polygynous mammal. Molecular Ecology 18, 4964-4973.

Offspring quality may benefit from genetic dissimilarity between parents. However, genetic dissimilarity may trade‐off with additive genetic benefits. We hypothesized that when sexual selection produces sex‐specific selective scenarios, the relative benefits of additive genetic vs. dissimilarity may differ for sons and daughters. Here we study a sample of 666 red deer (Cervus elaphus) microsatellite genotypes, including males, females and their foetuses, from 20 wild populations in Spain (the main analyses are based on 241 different foetuses and 190 mother‐foetus pairs). We found that parental lineages were more dissimilar in daughters than in sons. On average, every mother was less related to her mate than to the sample of fathers in the population when producing daughters not sons. Male foetuses conceived early in the rutting season were much more inbred than any other foetuses. These differences maintained through gestation length, ruling out intrauterine mortality as a cause for the results, and indicating that the potential mechanism producing the association between parents’ dissimilarity and offspring sex should operate close to mating or conception time. Our findings highlight the relevance of considering the sex of offspring when studying genetic similarity between parents.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-294X.2009.04401.x

Pérez-González, J. & Carranza, J. (2009). Female-biased dispersal under conditions of low male competition in a polygynous mammal. Molecular Ecology 18(22), 4617-4630.

Sex‐biased dispersal is a common phenomenon in birds and mammals. Competition for mates has been argued to be an important selective pressure favouring dispersal. Sexual differences in the level of intrasexual competition may produce asymmetries in the costs‐benefits balance of dispersal and philopatry for males and females, which may favour male‐biased dispersal in polygynous species such as most mammals. This being the case, condition‐dependent dispersal predicts that male‐bias should decrease if mating competition relaxes. We test this expectation for red deer, where male‐biased dispersal is the norm. In southwestern Spain, red deer populations located in nonfenced hunting estates presented altered structures with sex ratio strongly biased to females and high proportion of young males. As a consequence, mate competition in these populations was lower than in other, most typical red deer populations. We found that, under such conditions of altered population structure, dispersal was female‐biased rather than male‐biased. Additionally, mate competition positively related to male dispersal but negatively to female dispersal. Other factors such as resource competition, age of individuals and sex ratio were not related to male or female dispersal. Males may not disperse if intrasexual competition is low and then females may disperse as a response to male philopatry. We propose hypotheses related to female mate choice to explain female dispersal under male philopatry. The shift of the sex‐biased dispersal pattern along the gradient of mate competition highlights its condition‐dependence as well as the interaction between male and female dispersal in the evolution of sex‐biased dispersal.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-294X.2009.04386.x

Torres-Porras, J., Carranza, J. & Pérez-González, J. (2009). Combined effects of drought and density on body and antler size of male Iberian red deer (Cervus elaphus hispanicus): implications for climate change prospects. Wildlife Biology 15, 213-221.

Hunting management of red deer Cervus elaphus populations may tend to increase population densities to maximise annual yield. Some studies have shown that density and low winter temperatures affect red deer populations in central and northern Europe, but these results cannot be extrapolated to red deer populations in the Mediterranean region where the limiting season is summer instead of winter. The two regions are predicted to experience different climate change effects: while rainfall may increase in northern latitudes, heavier droughts are expected in the Mediterranean region. We studied red deer populations of different densities on 19 hunting estates in southern Spain during two years with contrasting precipitation levels. Our aim was to quantify the combined effects of drought and population density on the development of stags, which is the main economic objective of hunting management in these areas. We found that drought affected body and antler size negatively, and that the effects were more severe in populations of high density. On the basis of our results, we recommend reducing the current densities of red deer in southern Spain to maintain the economic and environmental sustainability of hunting exploitation in the context of global climate change.

https://doi.org/10.2981/08-059

Pérez-González, J., Mateos, C., Carranza, J. (2009). Polygyny can increase rather than decrease genetic diversity contributed by males relative to females: evidence from red deer. Molecular Ecology 18: 1591-1600.

Polygyny is expected to erode genetic variability by reducing the diversity of geneticcontribution of males to the next generation, although empirical evidence shows thatgenetic variability in polygynous populations is not lost as rapidly as expected. We usedmicrosatellite markers to study the genetic variability transmitted by mothers and fathersto offspring during a reproductive season in wild populations of a polygynous mammal,the red deer. Contrary to expectations, we found that males contributed more genetic diversitythan females. Also, we compared study populations with different degrees of polygyny tofind that polygyny was not related to a decrease in genetic diversity contributed by males.On the contrary, when population genetic diversity was relatively low, polygyny associatedwith higher genetic diversity of paternal lineage. Our results show that sexual selection, byfavouring heterozygote individuals, may compensate the potential reduction of effectivepopulation size caused by polygyny, thus contributing to explain why genetic diversity isnot depleted in polygynous systems.

https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1365-294X.2009.04150.x

Redondo, A., Carranza, J., Trigo, P. (2009). Fat diet reduces stress and intensity of startle reaction in horses. Applied Animal Behaviour Science 118, 69-75.

Intense startle reaction by horses is a common cause of injuries for both riders and horses. Some studies suggest that diet composition, in particular the percentage of fat, may have an effect in stress and behavioural response to novel stimuli. Here we use 28 individual horses to perform an experiment on the influence of diet treatment on physiological parameters and behaviour. We compared a control starch–sugar diet with a diet with higher proportion of fat but the same total energetic content. Physiological and behavioural responses were measured for diet types, both at rest and when exposed to a startling visual stimulus. Our results demonstrate that the increment of fat proportion in the diet reduces the level of stress at resting and the intensity of response to startling stimuli, as denoted both in physiological parameters and in behavioural variables. We conclude that increasing the fat content in diet may be a valuable tool to reduce horse stress and the risk of accidents.

https://www.sciencedirect.com/science/article/pii/S0168159109000355?via%3Dihub

Torres-Porras, J., Carranza, J., Pérez-González, J. (2009). Selective culling of Iberian red deer stags (Cervus elaphus hispanicus) by selective montería in Spain. European Journal of Wildlife Research 55, 117-123

Hunting can affect animal populations not only by increasing mortality but also by introducing selection components associated with particular features of individuals. In addition to the most widespread hunting system in Spain for Iberian red deer stags (Cervus elaphus hispanicus) called montería, there are also selective monterías aimed at culling poor-trophy males in order to improve the average quality of the trophies for commercial hunt. This way of removing poor-trophy males contrasts with the most common procedure of shooting individual males by selective stalking that is used in other areas of Europe. Also, due to the hunting procedure by which most deer are shot while running chased by dogs, it is doubtful whether hunters are actually producing a selective impact on deer populations. In this paper, we compare data of males shot in commercial montería and in selective montería in Southern Spain. We found that males in selective montería were smaller in body size and in antler size than in commercial hunts, even correcting by age, although the selective effect was stronger at some ages. We discuss the implications of this practice for sustainable use and conservation.

https://link.springer.com/content/pdf/10.1007/s10344-008-0225-4.pdf

CARRANZA, J. (2009). Defining sexual selection as sex-dependent selection. Animal Behaviour 77, 749-751.

https://doi.org/10.1016/j.anbehav.2008.11.001