Sebastian Echeverri | PhD student


I am interested in how animals perceive the world around them, and how this shapes their behavior. How do animals’ senses and their environment interact to determine how they communicate with each other?

Attention-Grabbing Courtship in Jumping Spiders
In some species of jumping spiders, males perform elaborate courtship dances to impress prospective mates, and I want to understand how and why these displays have evolved. In particular, I am interested in how females’ visual system (the way their eyes work) has influenced the evolution of male displays. I am working with Dr. Nathan Morehouse (now at the University of Cincinnati) to study this question in the Habronattus genus, a very diverse group of jumping spiders found throughout the Americas.

Jumping spiders have excellent eyes for detail – their vision is some of the sharpest of any invertebrate on land. In daylight, they can see about as clearly as a housecat can – doubly impressive when you remember that these animals are smaller than the entire eyeball of a cat. With all of their eyes put together, these spiders have an almost 360-degree field of view; they can see all around themselves. However, some of a jumping spider’s eight eyes are better than others – the two biggest foward-facing eyes (“primary eyes”) see the sharpest image, while the others are blurrier. These primary eyes are also the only ones that can see in color – so how female perceives a courting male actually depends on whether or not she is facing him!

How does limited field of color vision affect communication? We studied how males and females were positioned during courtship, and found that while males always directed their displays towards females, females often looked away from his dancing. In fact, females can see a male’s colors only 30% of the time! Since females are often looking elsewhere (perhaps watching for predators, or prey), males wait until females are watching intently before showing off their more impressive dance moves. This work was recently published in Behavioral Ecology (Echeverri et al. 2017) and covered by Popular Science.

Attracting a female’s gaze – so that she can see his colors – may be important for a male to effectively communicate his quality. We suspect that males may have evolved ways to get her attention. In particular, many Habronattus males do a waving display with their palps and/or first pair of legs. Since jumping spiders are very sensitive to motion, we studied how this waving display might catch a female’s eye using an animated male spider. Females do indeed turn to look at waving males, even when there is other movement (plants blowing in the wind) in the background. We are also investigating whether males change their waving dance to compensate for these types of background distractions.

Color Vision in a Polymorphic Frog
How does what we see determine the choices we make? Differences in how animals’ eyes work can make certain colors more (or less) appealing, and even influence how they choose their mates. I am interested how changes in vision affect the evolution of diverse color signals. Since joining the RZ Lab in 2017, I have become very curious about the evolution of numerous different color varieties within a single species of poison dart frog (Oophaga pumilio). While these small frogs are normally bright red, in the Bocas del Toro region of Panama, there are several recently isolated populations, each with their own different coloration. O. pumilio uses color to choose their mates, and appear to prefer frogs of their own color variety. In other cases, the evolution of such color preferences often happens alongside the evolution of differences in color vision. Animals evolve the ability to see a certain color more easily, and in turn, begin to prefer that color. However, we dont know very much about how color vision works in O. pumilio. I plan to study how individuals of different colors might see color differently, and if these differences explain their mate preferences. You can learn more about the RZ Lab’s work on this species here.

Science Education & Outreach
I am also passionate about engaging the public in science and nature. Two of my main goals as an educator are to (1) show that science is for anyone, regardless of background or skin color, and (2) teach that insects and spiders, while sometimes scary, are beautiful animals worthy of our attention and respect. I brought my outreach spiders to the Carnegie Museum of Natural History, Phipps Conservatory & Botanical Gardens, local schools, and even helped put on a spider dance show at the Wood Street Art Gallery. In addition, I have designed and run several after-school events with Assemble PGH, a non-profit aimed at serving students from underprivileged neighborhoods, including a four-part series on animal and human senses. If you are in the Pittsburgh area and are interested in having me visit your institution to talk about spiders, vision, and/or science at large, please get in touch! My email is echeverri.sa@gmail.com

Background
Prior to all of this, I completed my dual Bachelor’s degree in Biology and Applied Physics at the University of Miami in 2013. There, I worked as a research assistant with Dr. Gavin Leighton (now at the Cornell Lab of Ornithology) studying the maintenance of social nest construction in sociable weavers (Philetarius socius).

In my free time, I like to go hiking and practice wildlife photography.

Download Sebastian’s CV.

Follow Sebastian on Twitter: @SA_Echeverri