Characterization and comparison of visually induced defensive behavior in Peromyscus

Samenvatting

Avoidance of avian predators is an essential task in many animals that is predominantly
guided by the visual system. Different species may rely on different behaviors based on their
habitat and life history. This study aims to characterize visually induced innate defensive
behaviors of two closely related rodent species of Peromyscus. To accomplish this, a
controlled open field environment was designed where different overhead threat stimuli were
presented. It was found that these stimuli reliably induce defensive responses. Different
types of stimuli that imitate either an overflying or attacking predator induced different
defensive strategies in both species. While an immobility response was measured for an
overflying predator in both species, an attacking predator induced different behaviors, i.e.
immobility or flight, in each species. These response differences did not change when
modulating stimulus parameters and the open field environment. The observed difference in
response strategies between the species most likely results from neurological differences in
vision-associated circuits that drive defensive behaviors. Chemical inactivation experiments
support a role for a conserved midbrain structure, the superior colliculus, for mediating these
behaviors in both species. In summary, the data obtained in this study show distinct
response behaviors of two close Peromyscus relatives to identical visual threat, which
suggests that the neural circuits underlying visually induced defensive behaviors are wired
differently in the two species. This work thus forms a basis to study evolution of such
essential circuitry.

Datum prijs	2019
Originele taal	English
Prijsuitreikende instantie	KU Leuven