PHOTOMOVEMENT, PIGMENTATION AND UV-B SENSITIVITY IN PLANARIA

Four differently pigmented species of planarians were examined for UV-B (Λ= 320 280 nm) tolerance and ability to delect and avoid UV-B-exposed areas. It was found that lighter-pigmented species are more UV sensitive and that movement out of the UV-B is directly related to UV sensitivity. Three species showed positioning preference corresponding to their pigmentation; the darker the species, the less avoidance of UV-B. The white (unpigmented) species showed exceptional and very sensitive behavior.