Phototactic Responses to Ultraviolet and White Light in Various Species of Collembola, Including the Eyeless Species,Folsomia candida

Abstract

Previous observations have indicated homology in the cellular components between collembolan eyes and the compound eyes of insects. However, behavioral or physiological studies indicating similarities in function are lacking. Collembolan eyes were examined from three species in the Family Isotomidae using scanning electron microscopy. Collembolan eyes are arranged dorsally and laterally on each side of the head in two species, Proisotoma minuta with eight eyes on each side of the head and Folsomia similis with one eye on each side of the head. In both of these species the eyes were located just posterior to the postantennal organ. In Folsomia candida, no external eye structures were detected. These three species were assayed for a series of behavioral preferences using ultraviolet (UV), white light and dark, and temperature conditions. The tests demonstrated that over 76% of all three species, including the eyeless F. Candida, chose white over UV light, over 69% preferred dark over UV, and over 77% favored dark over white light. The results demonstrated that all three species detect both UV and white light and avoid it, preferring cool, dark habitats. From the results of this study, it is hypothesized that F. candida may, in fact, be only “lensless” and may be able to detect light by having internal, non-ocular photoreceptors. Further histological studies are needed to investigate this possibility.

Locomotor Response ofFolsomia candida(Collembola: Isotomidae) to Cooling Temperatures

“…The species is blind but sensitive to light (Fox et al 2007). It disperses by walking and by jumping using six clawed legs and a short furcula arising from the abdomen, respectively.…”

The molecular characterization of antioxidant enzyme genes in Helicoverpa armigera adults and their involvement in response to ultraviolet-A stress

“…Of the three components of solar UV radiation, only UV-A and UV-B can reach the surface of the Earth, whereas UV-C (200-280 nm) is blocked completely by the ozone layer (Karentz, 1994;Cockell, 2001;Franco et al, 2009;Dahms and Lee, 2010). UV-A radiation can cause the massive production of ROS as a result of photooxidation reactions caused by endogenous photosensitizers, as nucleic acid bases absorb UV radiation weakly above 320 nm (Ravanat et al, 2001;Cadet et al, 2005).…”

“…The UV-A (320-400 nm) light, also referred to as the blacklight, is widely used in integrated pest management to monitor and control H. armigera (Antignus, 2000;Steinbauer, 2003;Kojima et al, 2005). Direct effects of UV upon insect behavior, developmental physiology and biochemistry have been reported, with a particular focus on UV-B (280-320 nm), as it causes a variety of harmful effects (Mazza et al, 2002;Fox et al, 2007;Suzuki et al, 2008;An Nguyen et al, 2009;Kim et al, 2010a,b;Jung et al, 2011). Contrarily, the information about the effects of UV-A radiation is limited.…”

Arthropod Phototaxis and Its Possible Effect on Bird Strike Risk at Two Namibian Airports

“…Light Emitting Diodes (LED lights) were used as it does not produce heat, a factor which can influence the attraction of arthropods (Fox et al, 2006). The lights were switched on at dusk and switched off at dawn the following morning.…”