It is now well documented that androgen and estrogen signaling dur- ing early development cause a sexual dimorphism in second-to-fourth digit length ratio (2D:4D). It is also well documented that males of mam- malian ...

The Palo Verde wetland, one of the most important places for aquatic organisms in Costa Rica, is currently recovering from an invasive expansion of Typha domingensis (cattail). A monitoring program was designed to understand ...

Offspring discrimination, the differential treatment of offspring and unrelated young, functions in numerous animal taxa to ensure that vital and costly parental care behaviours are appropriately directed. Discrimination ...

Aposematic coloration allows predators to use visual cues to avoid eating potentially toxic or distasteful prey. Predators across many animal taxa actively avoid aposematically colored prey and remember distasteful brightly ...

In June 2014, we captured approximately 100 R. dorsalis tadpoles in a net from a seasonal wetland in Palo Verde National Park (10.3428 N, 85.3375 W) in N, 85.3375 W) in northwestern Costa Rica. While rearing the tadpoles ...

Rhinella yunga, a recently described toad species of the Rhinella margaritifera group (Moravec et al. 2014. Zookeys 37:35–56), is known from the tropical mountains of the Cordillera Yanachaga, Junin Province, Peru. Rhinella ...

In recent decades, theoretical and empirical work has investigated the relative roles of costs and benefits in inhibiting excessive displays of begging to parents. Whether costs are important in maintaining reliability of ...

Parents can benefit from allocating limited resources non randomly among offspring, and offspring solicitation (i.e. begging) is often hypothesized to evolve because it contains information valuable to choosy parents. We ...

Parents in many taxa, including insects, mol- luscs, fish, snakes, and amphibians provision chemical defences, such as peptides, steroids, or alkaloids to their offspring to reduce the risk of predation. In most cases, ...

The second-to-fourth digit ratio (2D : 4D) is a well-studied sexual dimorphism that likely arises as a result of prenatal androgenic effects on homeobox gene expression. This dimorphism has been found to exhibit interesting ...