positive phototaxis

positive phototaxis

[¦päz·əd·iv ‚fōd·ō′tak·səs]
(physiology)
The orientation and movement of an organism toward the source of a light stimulus.
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The 2nd, 3rd, 4th, and 5th instar nymphs did not respond differently to the light source and appeared not to show any positive phototaxis throughout the trials (Fig.
Abalone larvae generally exhibit positive phototaxis during trocophore stage (Ino 1952, Yano & Ogawa 1977, Tanaka 1978) (but see Leighton 1989), indicating upward swimming behavior.
In laboratory conditions, many decapod larvae display positive phototaxis (Forward Jr., 1989; Queiroga & Blanton.
Furthermore, queen conch larvae exhibit positive phototaxis and are thus associated with surface layers (Barile et al., 1994; Stoner and Davis, 1997), where many contaminants, including pesticides, accumulate (Rumbold and Snedaker, 1997).
Species can be attracted to, or disoriented by, sources of artificial light through positive phototaxis (Verheijen 1985; Longcore and Rich 2004).
The neural wiring thus appears to be more complicated than if each behavior were driven by a single spectral type of receptor." When perceived by an insect, UVA radiation could trigger a wavelength-dependent response to light attraction similar to what has been measured in frogs: "If the tendency of most species of frogs to jump towards a light is measured as in a forced choice experiment, short wavelengths ([A.sub.max] 480 nm) stimulate positive phototaxis and longer wavelengths inhibit [phototaxis]." [Goldsmith 1994:303].
However, a common misunderstanding is that this attraction represents a positive phototaxis. Contrary to this belief, Thompson (1917), Verheijen (1958), Mazokhin-Porshnyakov (1969), Janzen (1983), and more recently Nowinszky (2003) observed that insect attraction to lights is the result of navigational confusion.
Based on the premise that in the absence of moonlight, sandflies would exhibit positive phototaxis and be attracted to light traps, a maximum catch would be expected during a new moon.
Flies stayed at the top because of positive phototaxis and negative geotaxis until they succumbed to heat and rolled down a series of baffles reaching a collecting vial.
Positive phototaxis, manifest as an increase in OD, was observed for wavelengths between 440 nm and 538 nm with a maximum phototactic response at 503 nm.
Key Words: western cherry fruit fly; positive phototaxis; halogen bulb; light intensity; ammonium carbonate
It has been suggested that this behavior is caused by positive phototaxis, yet some other studies proposed negative geotaxis (Yano & Ogawa 1977, Sasaki & Shepherd 1995, Leighton 1989).