Sex differences in the use of spatial cues in two avian brood parasites

Shiny and screaming cowbirds are avian interspecific brood parasites that locate and prospect host nests in daylight and return from one to several days later to lay an egg during the pre-dawn twilight. Thus, during nest location and prospecting, both location information and visual features are available, but the latter become less salient in the low-light conditions when the nests are visited for laying. This raises the question of how these different sources of information interact, and whether this reflects different behavioural specializations across sexes. Differences are expected, because in shiny cowbirds, females act alone, but in screaming cowbirds, both sexes make exploratory and laying nest visits together. We trained females and males of shiny and screaming cowbird to locate a food source signalled by both colour and position (cues associated), and evaluated performance after displacing the colour cue to make it misleading (cues dissociated). There were no sex or species differences in acquisition performance while the cues were associated. When the colour cue was relocated, individuals of both sexes and species located the food source making fewer visits to non-baited wells than expected by chance, indicating that they all retained the position as an informative cue. In this phase, however, shiny cowbird females, but not screaming, outperformed conspecific males, visiting fewer non-baited wells before finding the food location and making straighter paths in the search. These results are consistent with a greater reliance on spatial memory, as expected from the shiny cowbird female’s specialization on nest location behaviour.Fil: Lois Milevicich, Jimena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Kacelnik, Alex. University of Oxford; Reino UnidoFil: Reboreda, Juan Carlos. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Phylogenetic signal in the skull of cowbirds (Icteridae) assessed by multivariate and cladistic approaches

Closely related species are expected to resemble each other because of inheritance of features from their common ancestors, which are therefore said to carry phylogenetic signal. Cowbirds (Molothrus) are icterids well known from being interspecific brood parasites, but their taxonomy and evolutionary relationships have varied considerably based on morphology alone. In turn, these relationships became unsupported by molecular phylogenies, lending lower value to morphological data in general. However, the osteology of cowbirds has not yet been studied under a quantitative phylogenetic framework and it is uncertain whether their skulls carry phylogenetic signal. In order to test this, we assembled a data matrix, including continuous and discrete characters of the skull of cowbirds and allies, and analyzed it with two complementary approaches under the evolutionary framework provided by molecular phylogenies. We first took a multivariate approach, exploring the occupation of a phylomorphospace based on skull data and estimating the amount and significance of phylogenetic signal by calculation of the Kmult statistic. The second approach relied on a Maximum Parsimony optimization of characters on a scaffold tree. Our results indicate that, although some homoplasy exists, the skull of cowbirds and allies carries significant phylogenetic signal and provides useful characters to diagnose Molothrus and other still poorly diagnosed clades. This first comparative approach is promising and opens the possibility of integrating data from fossils, while encouraging further osteological analyses in cowbirds and other icterids.Fil: Gómez, Raúl O.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Lois Milevicich, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Viscosity as a key factor in decision making of nectar feeding ants

It is well known that viscosity reduces the intake rates in nectar-feeding insects, such as nectivorous ants, though it remains unclear whether viscosity imposes a higher energy investment in these insects, and how this affects their feeding motivation. To address this issue, we studied feeding behavior, metabolism, and pharyngeal pump activity in the carpenter ant Camponotus mus during ingestion of ad libitum sucrose solutions. In some solutions tylose was added to modify viscosity without changing its sucrose concentration, in a way that allowed comparing: (1) two solutions with the same viscosity and different sucrose concentration (10 T and 50), and (2) two solutions with different viscosity and the same sucrose concentration (50 and 50 T). The viscosity increase was detrimental to the metabolic rate and energy balance. Ants feeding on a solution with high sucrose concentration and increased viscosity (50 T) spent extra-time until reaching a crop load similar to that reached by ingesting the solution without tylose (50). For all solutions offered, ants started feeding with the same pharyngeal pump frequencies, reflecting a similar motivation. Interesting, when ants fed on a low sucrose concentration and increased viscosity solution (10 T), their pump frequencies dropped rapidly respect to the pure-sucrose solution (50). On the contrary, pump frequencies for 50 and 50 T remained similar until the end of the intake. Since the pump frequency is strongly modulated by the ant motivation, an increase in viscosity with low sucrose content, demotivates the ants rapidly, suggesting a rapid integration of different kinds of information about the food value. Our results helped to understand how nectivorous ants could modulate their foraging decision-making.Fil: Lois Milevicich, Jimena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schilman, Pablo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Josens, Roxana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin

Food information acquired socially overrides individual food assessment in ants

Abstract: Social insects rely on sophisticated communication channels and on individual decision making to achieve efficient foraging behavior. Through social interactions, individuals can acquire information inadvertently provided by a nestmate such as in trophallaxis. During this mouth-to-mouth food exchange, food receivers can perceive the odor of the food delivered by the donor and thus associate this odor with a food reward. Through individual experience, workers are able to perceive characteristic information of the food they have found and to evaluate food quality. Here, we determined which information, social or individual, is prioritized by the carpenter ants Camponotus mus in a foraging context. We exposed receiver ants to a deterrent and harmful food with the same odor they had previously learned in the social context of trophallaxis. We determined on which information individual ants based their decision to forage, whether on their individual evaluation of food quality or on the previously acquired social information. We show that the odor experienced in a trophallactic contact overrides individual food assessment to the extent that ants collect the deterrent food when the odor coincided with that experienced in a social context. If ants were exposed individually during a similar time to a food with the odor and afterwards, they were confronted with the same odor paired with the deterrent substance, and they rejected the deterrent food, contrary to what occurred when the odor was experienced in a social context. These results show that olfactory appetitive experiences in the social context play a fundamental role for subsequent individual foraging decisions. Individuals can acquire information by interacting directly with the environment or through social interactions with other individuals. Individual and social information may induce informational conflicts so that it is crucial to determine when it is worth ignoring one sort of information in favor of the other. Social insects are useful models to address this question: individuals evaluate and learn about their environment and rely on sophisticated communication systems. Here, we show that carpenter ants receiving social instructions, leading them to forage on a toxic food, overcome their natural rejection of this food, despite its noxious effects. Social instructions are, therefore, powerful enough to induce the consumption of food that would be otherwise rejected on the basis of the ants’ individual evaluation. Thus, although eusociality seems to favor sacrificing individual assessments in favor of social information, the resulting ‘social obedience’ may not always be adaptive. Significance Statement: Individuals can acquire information by interacting directly with the environment, or through social interactions with other individuals. Individual and social information may induce informational conflicts so that it is crucial to determine when it is worth ignoring one sort of information in favor of the other. Social insects are useful models to address this question: individuals evaluate and learn about their environment and rely on sophisticated communication systems. Here we show that carpenter ants receiving social instructions leading them to forage on a toxic food, overcome their natural rejection of this food, despite its noxious effects. Social instructions are, therefore, powerful enough to induce the consumption of food that would be otherwise rejected on the basis of the ants‘ individual evaluation. Thus, although eusociality seems to favor sacrificing individual assessments in favor of social information, the resulting ‘social obedience’ may not always be adaptive.Fil: Josens, Roxana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Mattiacci, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Lois Milevicich, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Giacometti, Alina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; Argentin

Urban ants of the city of Buenos Aires, Argentina: species survey and practical control

Ants are among the most diverse, abundant and ecologically significant organisms on earth. They have colonized almost all existing habitats, including urban areas, where they may pose serious problems for human activities. Here, we present different aspects of our studies on urban ants in the city of Buenos Aires aimed at collecting information on the species present in the city and at improving bait control strategies via laboratory assays. The use of these baits represents a control strategy that is environment-friendly as it avoids indiscriminate pesticide release. Moreover, we show that our baits exhibit higher efficiency when compared to a commercial bait, as it is optimized in terms of the ants’ feeding behavior even when both have the same active compound and at the same concentration. This work represents the first integrative study on urban ants in the city of Buenos Aires and indicates that the control of invasive species in urban settings may be improved by increasing the scientific knowledge of the biology of the target species.Fil: Josens, Roxana Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Sola, Francisco Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Lois Milevicich, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Fisiología, Biología Molecular y Neurociencias. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Fisiología, Biología Molecular y Neurociencias; ArgentinaFil: Mackay, William. University of Texas at El Paso; Estados Unido

Sexado molecular rápido y económico para un córvido, utilizando un mismo protocolo con dos pares de cebadores universales

The absence of sex dimorphism in many bird species complicates sex determination by direct observation, hindering sex-specific studies. Standard protocols for molecular sexing include polymerase chain reaction (PCR) amplification of intron regions of the Chromodomain-Helicase DNA-binding protein 1 (CHD1) gene. While several methods have been studied, their usefulness for songbirds (Passeriformes) has not been consistent and has largely depended on target species and on time-consuming primer-set specific optimisation of available protocols. We tested a molecular sexing protocol with two universal primer sets (P2/P8 and 2550F/2718R) in a corvid songbird: the Plush-crested Jay Cyanocorax chrysops. The protocol was rapid and inexpensive as well as highly effective. Using 2550F/2718R, females were revealed by two bands separated for some 200 base pairs (bp) that resolved easily on 0.8% agarose gel. Conversely, P2/P8 female amplicons differed in roughly 30 bp and a more expensive 3% agarose gel was necessary to reveal them. Our results are contextualised with an up-to-date literature survey of molecular sexing in other corvids. The primer set 2550F/2718R is found to be effective, providing a reliable and low-cost method for sexing jays and other corvids.La ausencia de dimorfismo sexual en muchas especies de aves dificulta la determinación del sexo a simple vista, lo cual complejiza los estudios sexo-específicos que dependen de esta determinación. Los protocolos estándar para sexado molecular incluyen una amplificación por reacción en cadena de la polimerasa (PCR) de intrones del gen de la helicasa con cromodominio de unión a ADN 1 (ChD1). Pese a que muchos métodos han sido estudiados, su utilidad en aves cantoras (Passeriformes) no ha sido consistente y su optimización ha dependido de combinar protocolos disponibles y cebadores determinados de manera específica para cada especie. En este trabajo testamos un protocolo para sexado molecular en urracas (chara moñuda Cyanocorax chrysops) usando dos pares de cebadores universales (P2/P8 y 2550F/2718R). El protocolo resultó rápido, económico y altamente efectivo. Las hembras fueron diferenciadas de los machos a través de la visualización de dos bandas separadas por 200 pares de bases (pb) aproximadamente usando el par 2550F/2718R, las cuales fueron fácilmente reveladas en un gel de agarosa al 0,8%. En cambio, los fragmentos obtenidos para las hembras usando el par P2/P8 difirieron en apenas 30 pb y necesitaron un gel de agarosa más concentrado (3%) para diferenciarse. Nuestros resultados se contextualizan con una revisión de la literatura actualizada sobre el sexado molecular en córvidos. El par de cebadores 2550F/2718R resulta efectivo, proporcionando un método confiable y de bajo costo para determinar el sexo de urracas y otros córvidos.Fil: Lois Milevicich, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Gomez, Raul Orencio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Ursino, Cynthia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. University of Princeton; Estados UnidosFil: Lois, Nicolás Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: de la Colina, María Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación Temaikèn; Argentin

Improving skills to teach statistics in secondary school through activity based workshops

Though statistics is covered in secondary-school curricula, it is usually limited to few lessons and mainly taught in a procedural approach. There seems to be a gap between the education of mathematics teachers and the demands on their practice. Learning statistics from a mathematical perspective does not qualify to teach the subject properly. Therefore, we developed a pedagogical intervention that consists in a training program for teaching aimed at mathematics pre-service teachers and focused on activity-based learning. Two workshops and a web-site were designed: first, to improve competencies in teaching statistics at secondary level, and second, to positively influence attitudes towards statistics. Workshops about descriptive statistics and probability were focused on real-data analysis from media, games, and simulations. Over several years, more than 500 teachers attended these workshops, which were positively evaluated in terms of content, relevance, and applicability. A follow-up survey 2–5 years later showed that most teachers are teaching statistics in their classes, which can be seen as great step forward to bring statistics into the classroom.Fil: Fernández, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Pomillo, Carlos. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Cueto, Gerardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Filloy, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: González Arzac, Adelia. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lois Milevicich, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Pérez, Adriana Alicia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentin