Polarization vision in Neohelice granulata

LUCCA SALOMON; JULIANA REVES SZEMERE; VERONICA PEREZ SCHUSTER; FEDERICO SEVLEVER; MARTIN BERÓN DE ASTRADA; MELANIE BASNAK; GABRIELA HERMITTE

LUND

Workshop; Sensory ecology Course; 2018

Lund University

Many animal species take advantage of polarization vision for vital tasks such as orientation,communication, and contrast enhancement. Neohelice granulata , like other crabs, lives in anenvironment rich in polarization information. In a previous work we have characterized thepolarization contrast sensitivity in a grapsid crab. Giving strong evidential support for thetheoretical model of polarized object detection where object-based polarization vision rely on atwo-channel detection system analogous to that of color processing in dichromats.Another question that arises is how Neohelice combines intensity with polarization information. Toaddress this we confronted animals with edge moving stimuli with different combinations ofintensity and polarization contrast. By monitoring crab?s cardiac frequency as an index of sensoryperception we have identified two different phases in crab?s cardiac response(fig 1 A and B). A firstphase, fast and stable, and a second one that follows stimuli dynamics and intensity contrast.Overall, ours results are consistent with the idea that polarization information is mainly associatedto the first component, reminiscent to an alert phenomena (fig 1C); while intensity contrastinformation feeds both the first and second phase response (fig 1D), the latter probably subservedby more more classical motion detection process.