Our research focuses on the interplay between the environment and the processes that link genotype, phenotype, and fitness. To understand these dynamics, we take an integrative approach combining laboratory and field research; from surveys, manipulative common garden- and mesocosm experiments up to cutting-edge molecular tools. The emphasis of the lab is on the evolution of life history traits and color vision in fish. Fish have a diverse ecology and evolutionary history and are relatively easy to keep under controlled conditions providing a good study system. The strong theory behind the evolution of life history traits and the tractable genotype-phenotype-performance relationship of color vision make these traits excellent to study adaptation in natural populations.
Molecular evolution of visual sensitivity in cichlid fishes
Vision plays a fundamental role in the life of many organisms influencing their capabilities to avoid predators and to find food, shelter, and mates. However, performing these activities highly depends on the visual properties of the environment –as anyone who ever drove in fog can attest. The visual conditions of aquatic environments are highly variable, both across space and time, providing a great opportunity to study adaptive variation of the visual system of aquatic organisms. As a consequence, there is high variation in the visual system across fish species. This combined with a good understanding of the adaptive value of such variation makes vision in fishes a tractable system to study the molecular mechanisms underlying adaptive divergence in the wild. My research on vision focuses on three different topics: (i) identifying the molecular and developmental mechanisms that underlie phenotypic variation in Nicaraguan cichlid fishes, (ii) understanding the contribution of genetic parallelisms to convergent evolution across Neotropical cichlids, and (iii) comparing the molecular signal of past selection across different cichlid radiations.
​Funding
DFG Research Grant: “Ontogeny and evolution: parallel cooption of developmental pathways in the adaptive evolution of the visual system of Neotropical cichlid fish in recently colonized crater lakes.” (2019-2022) 
Young Scholar Fund: "The Why and How of the complex retina of the Amazonian dwarf cichlid fish Dicrossus filamentosus" (2018)
Young Scholar Fund: "Molecular evolution of color vision in Neotropical cichlid fishes" (2016)
Does side matter? The evolution of asymmetric genitalia in livebearing fish
Asymmetry in otherwise bilateral animals has attracted the attention of biologists for a long time. Whereas most departures from bilateral symmetry are a result of developmental instability, morphological bilateral asymmetry can also be adaptive. Yet, adaptive asymmetry is a relatively rare evolutionary phenomenon and remains poorly understood. Investigating those rare cases of adaptive asymmetry have the potential to further our understanding of how selection acts on developmental processes and how adaptive traits are shaped by natural and/or sexual selection.
One particular case of adaptive asymmetry is represented when asymmetry affects the genitalia of organisms, which has evolved multiple timed in independent groups. However, as most species with asymmetric genitalia are not polymorphic (within species, either only a left- or a right-sided morph is present) the understanding of the evolution of genital asymmetry is still limited. An exception is presented by one-sided livebearer fish and four-eyed fish of the family Anablepidae. Here, both left- and right-sided individuals can be found within populations. This provides a great opportunity to explore causes and consequences of the evolution of genital asymmetry.
My research in this system revolves around determining if sidedness of genital asymmetry is heritable and if it affects mating success of these fishes. Further, I attempted to make predictions and test for the potential of genetic divergence within populations and trait evolution at a phylogenetic scale.​
  • Torres-Dowdall J., Rometsch S.J., Kautt A.F., Aguilera G., and Meyer A. (2020) The direction of genital asymmetry is expressed stochastically in internally fertilizing anablepid fishes. Proceedings of the Royal Society B 287:20200969.
  • Torres-Dowdall J., Rometsch S.J., Aguilera G., Goyenola G., Meyer A. (2020) Asymmetry in genitalia is in sync with lateralized mating behavior but not with the lateralization of other behaviors. Current Zoology. 66: 71-81.
Funding
DFG Research Grant: “Does side matter? The evolution of asymmetric genitalia in livebearing fish" (2015-2019) 
​Marie Curie ZK Incoming Fellowship (2013–2015)
Adaptive phenotypic variation along environmental gradients
​Environments often vary gradually, and organisms have to adapt to these changes, or they might not persist along these gradients reaching their distribution limits. Interesting eco-evolutionary questions emerge in this context: how closely do organisms track environmental changes? Is phenotypic variation along gradients the result of plastic responses or genetic differences? Which factors influence species range limits along these gradients? In other words, which factors limit adaptations to conditions outside the species range limit? During my PhD, I addressed these issues in Trinidadian guppies combining observational fieldwork with common garden experiments. I found (i) a genetic bases for phenotypic variation in life history traits at finer geographic scales than previously considered. However, I also found that plasticity can both, (ii) shield phenotypes from selection along environmental gradients and (iii) that it can evolve as a byproduct of local. (iv) Abiotic factors and asymmetric biotic interactions combined constrain adaptation along gradients and influence the range limits of parapatrically distributed species.
Picture
With Felipe Dargent, preparing field enclosures for Trinidadian guppies
  • Mauro A*, Torres-Dowdall J*, Marshall CA, Ghalambor CK (2021) A genetically based ecological trade- off contributes to setting a geographic range limit. Ecology Letters 24: 2739-2749.
  • Fitzpatrick SW, Torres-Dowdall J, Reznick DN, Ghalambor CK, Funk C (2014) Parallelism isn't perfect: Could disease and flooding drive a life history anomaly in Trinidadian guppies? The American Naturalist 183: 290-300.
  • Torres-Dowdall J, Dargent F, Handelsman CA, Ramnarine I, Ghalambor CK (2013). Ecological correlates of the distribution limits of two poeciliid species across a salinity gradient. Biological Journal of the Linnean Society 108: 790-805.
  • Dargent F, Torres-Dowdall J, Scott ME, Ramnarine IW, Fussmann GF (2013) Can mixed-species groups reduce individual parasite load? A field test with two closely related Poeciliid fishes (Poecilia reticulata and Poecilia picta). PLoS one 8(2):e56789.
  • Torres-Dowdall J, Handelsman CA, Reznick DN, Ghalambor CK (2012). Local adaptation and the evolution of phenotypic plasticity in Trinidadian guppies (Poecilia reticulata). Evolution 66: 3432-3443.
  • Torres-Dowdall J, Handelsman CA, Ruell E, Auer SK, Reznick DN, Ghalambor CK (2012). Fine scale local adaptation in life histories along a continuous environmental gradient in Trinidadian guppies. Functional Ecology 26: 616-627.
​Funding
NSF-DDIG: Ecological aspects of species distribution limits: interaction of biotic and abiotic factors. (2010-2012)
U.S. Fulbright Commission - Organization of American States Doctorate Fellowship in Ecology. (2005-2007)
Tracking migratory connectivity in nearctic shorebirds
My master studies aimed to develop tools to study connectivity of migratory shorebirds. We tested the role of stable isotopes and trace elements as intrinsic biomarkers to connect their breeding and wintering grounds. The idea was that shorebirds molt their feathers in their winter grounds once a year. If each location had its specific isotopic and trace elements signature, birds caught in their breeding areas could be caught and the chemical signature of their feathers measured to determine where did it molt and therefore connect the locations in their migratory cycle. Our work showed that it is possible to make such connections but the accuracy at which this could be done is low. This was mainly due to the environmental gradient on stable isotopes was shallow in the molting grounds of shorebirds and because ageing of feathers affected the stable isotope signature.
  • Torres-Dowdall J, Farmer AH, Abril M, Bucher EH, Ridley I (2010). Trace elements have limited utility for studying migratory connectivity in shorebirds that winter in Argentina. Condor 112: 490-498​
  • Torres-Dowdall J, Farmer AH, Bucher EH, Rye RO, Landis G (2009). Population variation in the isotopic composition of shorebirds feathers: implications for determine molting grounds. Waterbirds 32: 300-310.
  • Farmer AH, Cade BS, Torres-Dowdall J (2008). Fundamental limits to the accuracy of deuterium basemaps for identifying the spatial origin of birds. Oecologia 158: 183-192.
  • Farmer A, Abril M, Fernandez M, Torres-Dowdall J, Kester C, Bern C (2004). Using stable isotopes to associate migratory shorebirds with their wintering locations in Argentina. Ornitología Neotropical 15: 377-384.
  • Torres-Dowdall J, A Farmer, Bucher EH (2006). Using stable isotopes to determine migratory connectivity in birds: possibilities and limitations. El Hornero 21(2): 73-84, Argentina. (in Spanish)
Avian diversity in urban areas
As an undergraduate student in my hometown in Argentina, I was lucky to be involved in one of the earliest urban ecology projects in the area. Some of the data we collected is awaiting to be publish. However, we put together an amazing field guide to the birds of the Miguel Lillo botanical garden. My partner and I did all the illustrations! 
  • Echevarria AL, Lobo Allende IR, Juri MD, Chani JM, Torres-Dowdall J, Martín E (2011). Composition, structure, and seasonal variation in the bird community of the Botanical Garden of the Miguel Lillo Foundation. Acta Zool. Lilloana 55: 123-136. Argentina (in Spanish)
  • Echevarria A, Chani J, Lobo I, Juri MD, Torres-Dowdall J, Martin E, Tribulo E (2007). Birds of the Botanical Garden of Miguel Lillo Fundation.  Fundación Miguel Lillo, Tucumán, Argentina. (in Spanish)