Feromones: el paper de l'olor en la comunicació animal

Chemical perception is considered one of the first senses used as a communication system between living organisms. Such communication is based on the emission of signals between a sender and a receiver; if the communication is chemical, these signals are called pheromones. These signals have evolved via natural selection through a mechanism known as ritualization, which converts cues (which are not adapted to communication and which the receiver picks up regardless of the interests of the sender) into signals (information that the sender transmits as an adaptative response to its previously developed perception of the receiver). When communication has evolved between actors (sender and receiver) with common interests, the honesty of the signal is taken for granted, since both want the same thing (i.e., there is no reason to deceive). If the actors have conflicting interests, however, then the possibility of deception seeps into the possible array of adaptations. This can be observed in the case of communicative mimicry. However, in other situations natural selection imposes conditions that screen the possible signals, allowing only those that meet the requirement of honesty to stabilize. These include indices and added-cost signals. The emission of pheromones plays a variety of roles in the life processes of living beings. It facilitates encounters between individuals of the same species and is heavily involved in the mechanisms of recognition of relatives. It also fosters behaviours such as altruism (cooperation between individuals that share a percentage of their genetic inheritance). In many species, including humans, chemical communication works behind the scenes to guide the choice of a sexual partner

Does restocking with Japanese quail or hybrids affect native populations of common quail Coturnix coturnix?

Natural populations of the common quail Coturnix coturnix may hybridize in the wild with non-native individuals (Japanese quail Coturnix japonica or hybrids) as a result of restocking for hunting purposes. Several laboratory studies suggest that this could lead to a decline in the impulse to migrate in the common quail, and a drop in the frequency of phenotypes showing this tendency. This could lead to an increase in common quail populations in North Africa and a decrease in Europe. This paper provides new data on the proportion of hybrids in Catalonia (Northeast Spain) over 24 years (1983-2006) showing how restocking with Japanese quail or hybrids affects native populations of common quail. The first hybrids were detected in 1990 with an estimate of 4.65% of non-native individuals during the breeding season of wild common quail populations. No increase in non-native or hybrid numbers was detected during the study period, indicating that restocking poses no serious conservation problems at present. However, this may change in the near future, either with or without changes in the current scenario. A prudent policy with regard to restocking with non-native individuals is suggested. Moreover, further studies are needed to clarify the extent of this conservation problem

Post–breeding movements and migration patterns of western populations of common quail (Coturnix coturnix): from knowledge to hunting management

Hemos investigado los patrones de los movimientos postcría de la codorniz común (Coturnix coturnix) en la península ibérica con el fin de describir su fenología de paso migratorio y algunas características fisiológicas de los individuos. Esta información es necesaria para un ajuste óptimo de los períodos de caza. Hemos trabajado a partir de dos conjuntos de datos: a) capturas efectuadas en una zona que no es de cría (Garraf) de agosto a octubre en 2009 y 2010; b) recuperaciones, posteriores a la presunta época de cría, de individuos anillados en Europa y recapturados en España durante el período 1933-2005. Los resultados obtenidos muestran que los movimientos postcría en Garraf están formados por dos oleadas: una primera, que se produce sobre el 10 VIII, formada principalmente por jóvenes del año inactivos sexualmente que no son fisiológicamente migrantes; y una segunda, mucho más intensa, que se produce sobre el 17 IX, formada principalmente por migrantes jóvenes del año inactivos sexualmente. La época de caza en España tiene lugar principalmente durante la primera oleada, preservando el paso de los migrantes provenientes de España y de otros países europeos. La información de los movimientos postcría en otras regiones españolas y en otros países europeos en los que la codorniz común es una especie cinegética popular, permitiría mejorar el ajuste entre el período de caza y la migración, proporcionando recomendaciones de gestión cinegética más precisas para esta especie

Determining population trends and conservation status of the common quail (Coturnix coturnix) in Western Europe

En el presente estudio hacemos una revisión del estado de conservación y las tendencias poblacionales de la codorniz común (Coturnix coturnix) desde 1900 hasta nuestros días. Algunos de los datos de los que disponemos son contradictorios con respecto al estado de la especie, que presenta ciertas características que dificultan el poder proporcionar estimas poblacionales fiables. Datos recientes sugieren claramente, tanto a escala local como a escala transnacional, que las poblaciones atlánticas de codorniz común han permanecido estables en las dos últimas décadas y que la práctica de liberar codornices criadas en granjas (híbridas con la codorniz japonesa, Coturnix japonica) con finalidades cinegéticas, no afectan significativamente a nuestras estimas. Por otra parte, los complejos patrones de desplazamiento de esta especie requieren especial atención. En este sentido, el análisis de recuperaciones de anillas puede aportar información relevante, especialmente de los movimientos nomádicos de codornices a la búsqueda de hábitats adecuados, tras la destrucción de los cultivos invernales de cereales debido a la siega. Así, al desarrollar un modelo de distribución de cría para esta especie, se debe incorporar continuamente información actualizada de los cambios estacionales de hábitat y clima, con el fin de obtener unas predicciones óptimas. En este sentido, por ejemplo, la inclusión de datos quincenales de índices de vegetación en los modelos de distribución ha dado muy buenos resultados. La obtención de predicciones fiables de los cambios de la distribución de la especie y de sus desplazamientos durante la estación de cría puede ser muy útil para un mejor conocimiento del estado de conservación y las tendencias poblacionales de la especie, así como para el diseño de futuras medidas de gestión

Females of the cellar spider discriminate against previous mates

Mate choice for novel partners should evolve when remating with males of varying genetic quality provides females with fitness enhancing benefits. We investigated sequential mate choice for same or novel mating partners in females of the cellar spider Pholcus phalangioides (Pholcidae) to understand what drives female remating in this system. Pholcus phalan- gioides females are moderately polyandrous and show reluctance to remating, but double-mated females benefit from a higher oviposition probability compared to single-mated females. We exposed mated females to either their former (same male) or a novel mating partner and assessed mating success together with courtship and copulatory behaviours in both sexes. We found clear evidence for mate discrimination: females experienced three fold higher remating probabilities with novel males, being more often aggressive towards former males and accepting novel males faster in the second than in the first mating trial. The preference for novel males suggests that remating is driven by benefits derived from multiple partners. The low remating rates and the strong last male sperm precedence in this system suggest that mating with novel partners that represent alternative genotypes may be a means for selecting against a former mate of lower quality

Exploring male and female preferences, male body condition and pair bonds in the evolution of sexual male aggregation: the case of the Common Quail (Coturnix coturnix)

One of the unresolved problems of male sexual aggregations is that a small number of males monopolize most matings. The Common Quail (Coturnix coturnix (L., 1758)), is a bird species that has a short life span and a reproductive strategy that involves male aggregations, which females visit for the purpose of mating. Once a mate has been chosen, birds leave the aggregation and form pair-bonds until incubation begins. This remarkable mating system might represent an intermediate step between lekking and pair-bond mating systems in which males provide some parental care. We designed a field experiment with funnel traps simulating male groups and single females to observe male and female preferences, and to examine the possible evolutionary process that drives males to aggregate. Radio-tagged individuals were also monitored to study pair-bonding behaviour in the field. Our results suggest that body condition is an important factor in male group formation, and that males with better body condition tend to aggregate, while males in poorer condition wait for extra-pair copulation opportunities. Moreover, this mating system creates a situation in which a queuing strategy might occur

Terrestrial Megafauna Response to Drone Noise Levels in Ex Situ Areas

Drone use has significantly grown in recent years, and there is a knowledge gap on how the noise produced by these systems may affect animals. We investigated how 18 species of megafauna reacted to drone sound pressure levels at different frequencies. The sound pressure level on the low frequency generated by the drone did not change the studied species’ behavior, except for the Asian elephant. All other studied species showed higher noise sensitivity at medium and high frequencies. The Asian elephant was the most sensitive species to drone noise, mainly at low frequencies. Felines supported the highest sound pressure level before showing behavioral reactions. Our results suggest that drone sound pressure levels in different frequencies cause behavioral changes that differ among species, which is relevant to assessing drone disturbances in ex situ environments. The findings presented here can help to reduce drone impact for target species and serve as an experimental study for future drone use guidelines.M.M.P. contract is funded by the European Union “NextGenerationEU” Programa María Zambrano, Ministerio de Universidades, Spain. Fundación Barcelona Zoo, 310557 Project (Ayuntamiento de Barcelona)

Steps to build a DIY low-cost fixed-wing drone for biodiversity conservation

Despite the proved usefulness of drones in biodiversity studies, acquisition costs and difficulties in operating, maintaining and repairing these systems constrain their integration in conservation projects, particularly for low-income countries. Here we present the steps necessary to build a low-cost fixed-wing drone for environmental applications in large areas, along with instructions to increase the reliability of the system and testing its performance. Inspired by DIY (Do It Yourself) and open source models, this work prioritizes simplicity and accounts for cost-benefit for the researcher. The DIY fixed-wing drone developed has electric propulsion, can perform pre-programmed flight, can carry up to 500 g payload capacity with 65 minutes flight duration and flies at a maximum distance of 20 km. It is equipped with a RGB (Red, Green and Blue) sensor capable of obtaining 2.8 cm per pixel Ground Sample Distance (GSD) resolution at a constant altitude of 100 m above ground level (AGL). The total cost was $995 which is substantially less than the average value of similar commercial drones used in biodiversity studies. We performed 12 flight tests in auto mode using the developed model in protected areas in Brazil, obtaining RGB images that allowed us to identify deforestation spots smaller than 5 m2 and medium-sized animals. Building DIY drones requires some technical knowledge and demands more time than buying a commercial ready-to-fly system, but as proved here, it can be less expensive, which is often crucial in conservation project

Postcopulatory sexual selection favors fertilization success of restocking hybrid quails over native Common quails (Coturnix coturnix)

Postcopulatory sexual selection plays an important role in the reproductive success of males in many species. Differences in fertilization success could affect rates of admixture and genetic introgression between divergent lineages. We investigated sperm precedence in matings in captivity involving Common quails (Coturnix coturnix) and farm quails of hybrid origin (C. coturnix × domestic Japanese quail, C. japonica), the last used in restocking practices to increase hunting bags. These inter-specific matings in natural conditions are claimed to represent an important threat to the conservation of native Common quail populations. Results showed that fertilization success of each male depended on (1) the time it spent with the female, (2) the presence of sperm from a previous male in the female oviduct, (3) the time that the previous partner had been copulating with the female, and, most importantly, (4) the genetic origin of the male (wild or farm). Farm hybrid males showed higher fertilization success than wild Common males, and they required less time with the female to fertilize the same proportion of eggs. The presence of sperm from another male in the female oviduct reduced the percentage of fertilized eggs by a male. However, this reduction was higher for wild males when the precedent mate was a farm male. In summary, the sperm of farm hybrid males may outcompete the sperm of native males and this could be favoring the introgression of domestic Japanese alleles into the Common quail population, thus constituting a severe conservation threat to wild Common quail populations

African climate warming advances spring arrival of the Common Quail Coturnix coturnix

La fecha de la primera llegada de la Codorniz se ha avanzado bruscamente entre 1983 y 2004 en el noreste de España. Estos cambios fenológicos se correlacionaron significativamente con las temperaturas registradas durante los meses previos en la franja subsahariana pero sólo en su parte más occidental. Esto indica que ésta podría ser el área de invernada para algunas poblaciones ibéricas. El fuerte efecto del tiempo atmosférico sobre la fenología de los movimientos migratorios en esta especie beneficia su conservación, ya que la respuesta encontrada es adecuada y coherente con el avance del ciclo de la vegetación en la Península Ibérica