Culex tarsaris

The high fluorescence of a-terthienyl facilitates its visual localization in insect tissues. Pictures have shown the ffuorescence of the abdominal region, midgut wall, and Malpighian tubules of 4th instar larvae of Culex tarsaris treated with a-terthienyl (120). Differences in recorded ffuorescence intensities in different areas are likely related to differences in the concentration of sensitizer in these tissues but not necessarily proportional to them. However, one does not know the extent to which differential transmission of light (either excitation or ffuorescence) through different tissues or the presence of endogenous quenchers must be taken into account. 

Tritiated a-terthienyl was used to examine its rate of elimination from Aedes aegypti and from Culex tarsaris (120). Despite the conclusion that an inverse relationship existed between a-terthienyl sensitivity and elimination rate constants, the small differences involved could have resulted from many different factors. Much more useful information will probably be gained by carefully studying the metabolism in a single organism and by analyzing the time dependence and chemical structure of the radioactive molecules released. 

---