These light intensities are consistent with those previously reported for inducing a photophobic response in larvae (Xiang et al, 2010) and are at levels consistent with full daylight sun on a clear day as measured on a luxmeter.
The light intensities measured were the same as described above and, to control for the photophobic response, are consistent with levels previously demonstrated to induce light avoidance by larvae (Xiang et at, 2010).
This behavior does not appear to represent a photophobic response to light-induced activation of class IV neurons, given that control animals fail to display any consistent aversive behavior in response to either white or blue light, whereas experimental animals specifically avoid the blue-light-illuminated side of the plate, a behavior that is more consistent with a nocifensive avoidance response to activation of these neurons.
Photophobic responses of copepods are thought to play a role in planktonic predator-prey interactions--both in terms of a predator-deterrent role of bioluminescence in dark-adapted copepods (Buskey and Swift, 1983, 1985) and in terms of a predator-avoidance role for copepods exposed to shadows in light-adapted copepods (Buskey et al.
Calanoid copepods may use photoreception to avoid direct attacks by predators through photophobic responses to rapid increases or decreases in light intensity (Buskey et at.
Photophobic responses of calanoid copepods: possible adaptive value.