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Hummingbird song evolution
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Cultural evolution
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Visual dialects
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Lek habitat
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Since the Modern Synthesis, it has been clear that the transmission of biological information across generations determines the tempo and mode of organic evolution in fundamental ways. To date DNA has been regarded as the single relevant vehicle for the trans-generational transmission of information. There is increasing awareness, however, that information passed across generations through non-genetic means can also contribute to phenotypes . These means of alternative inheritance are found across all taxa and occur in a variety of forms, including epigenetic effects, cumulated environmental changes and cultural transmission. Given its ubiquitous presence and significant effect on phenotypes, non-genetic inheritance could potentially play a major role in shaping biological diversity. However, empirical evidence is still scarce.
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The most well-known example of non-genetically transmitted behavior are learned songs in birds, which show a unparalleled level of plasticity. This project evaluates the macroevolutionary significance of song learning in hummingbirds from a phylogenetic comparative perspective. The project aim to compare several aspects of vocal evolution between hummingbirds and their non-vocal learning sister group (Apodidae) in order to isolate evolutionary dynamics related to cultural transmission.
Check out my poster at the Behaviour Conference 2019 (first prize Founders award for overall outstanding poster):
Long-billed hermit visual displays at the lek
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It has been proposed that visual learning is an important evolutionary precursor to vocal learning. This hypothesis predicts that species that exhibit geographic variation in learned vocal signals (e.g. song dialects) will also exhibit geographic variation in visual displays. This project attempts to evaluate the role of social learning in the development of visual displays. A total of 1014 videos of display perches were taken during jan-jun 2013. Videos were taken at 6 leks from 3 sites across the Caribbean slope of Costa Rica. We sampled 5-6 individuals for a minimum of 36 hours. Videos are currently under analysis for variation in display
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repertoire, syntax and form of single display elements. We will then test for variation at the level of song-type group, lek and population. The results will provide a unique test for the co-occurrence of vocal and motor learning modalities in an animal species.
Leks are usually found in traditional sites despite turnover of lekking males. The continuous use of the same areas suggests that there are limitations in the habitats that can be used for lekking. However the ecological factors that influence the location and composition of leks are not fully understood. In this research I will use ecological niche modeling (MaxEnt) to determine the structural (habitat type, understory vegetation density, total vegetation density and canopy height) and geoclimatic parameters (distance to streams, slope and soil type) that better predict the location of lekking sites. To evaluate the effect of food resources in lek size I will calculate the availability of nectar calories in a 1 km buffer around the leks. This will be accomplished using the estimations of flowering plants per habitat type, the number of flowers per plant, the volume of nectar produce per flower and the calories per nectar volume for the species visited by long billed hermits at La Selva from a previous study. Results from this study will provide insight into the ecological factors modulating lekking behavior.