MadSci Network: Zoology

Re: Why insecticide instead of insect repelent?

Date: Mon Nov 29 13:58:28 2010
Posted By: Uncle Al Schwartz, Organic synthetic chemist
Area of science: Zoology
ID: 1290875308.Zo

A dead insect cannot reproduce. Dead insects are physical evidence that the treatment worked. Dead insects do not infest neighbors who do not use the treatment. It is easy to attract male insects. Repelling male plus female insects is very rare. One inexpensive molecule can be lethal across a broad selection of insects. Insecticides can be designed to resist sunlight, hydrolysis, and oxidation.

R is right-handed geometry (Latin, rectus) "right")
S is left-handed geometry (Latin, sinister "left")
(-) is laevorotatory for plane-polarized light (counterclockwise)
(+) is dextrorotatory for plane-polarized light (clockwise)
E is a trans-double bond (zig-zag)
Z is a cis-double bond (same side) (from German entgegen "opposite" and zusammen "together." Horrible choices).

Insect pheromones are extremely selective (one species of insect) and expensive as materials - including chirality. Chirality, molecular handedness, is important. R-(-)carvone is the smell of spearmint. S-(+)carvone is the smell of caraway. Big difference!

Disparlure (2-methyl-7R,8S-epoxy-octadecane) is specific to the male gypsy moth. Boll weevil aggregation pheromone is an exact ratio mixture of four chemicals,

(1R-Z)-1-methyl-2-(1-methylethenyl)cyclobutane ethanol

Calvin Klein's "Obsession for Men" is a powerful attractant for big cats: tigers, cheetas, mountain lions, jaguars, lions...

Poisons are economically and emotionally more effective than repellents.

Current Queue | Current Queue for Zoology | Zoology archives

Try the links in the MadSci Library for more information on Zoology.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2006. All rights reserved.