Calling differences between túngara frogs (Engystomops pustulosus) and house crickets (Acheta domesticus)

Vertebrates and invertebrates have diverged from an evolutionary standpoint almost a billion years ago. Males in both frogs (vertebrates) and crickets (invertebrates) invest energy and time calling to attract females and potentially reproduce. They perform the same task but with independently evolved neural circuitry. Calling is limited and shaped by the variability of energy, the neural circuitry of the animal, and the risk of being eaten or parasitized. We placed túngara frogs (Engystomops pustulosus) and house crickets (Acheta domesticus) in almost identical micro-environments for side-by-side comparisons. We had eight containers set up for frogs and eight for crickets. Each container was acoustically insulated and contained a microphone that recorded every call produced daily. Preliminary analyses of the results indicated that when signaling from the same microenvironment, frogs concentrated their calling around 2 h after sunset, whereas crickets chirped the most 2 h later and had their calling activity more broadly distributed over the night. Chirping in crickets was also more variable in amplitude than calling in frogs, but the variability in duration and frequency was similar in the two types of animals. Since the experimental animals called from the same environment, the differences that we found in timing and intensity of calling were not derived from external factors, but they were caused by intrinsic mechanisms. We are currently refining the analysis to precisely describe these differences in signaling activity within three time scales: a bout of calling, a night and across nights. This will allow us generate testable hypothesis about the physiological bases of the differences and start testing them through experimentation