NOVEMBER
2003

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

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Check out these books by Tom Turpin:

Flies in the face of fashion

What's Buggin You Now?

 

 

 

11-26-03

Download the audio of On Six Legs: MP3, WMV.

Metrosexuals Abound in the Insect World


There is a difference in the physical appearance of men and women. In biology, when males and females of a species vary in visible structure, it is called sexual dimorphism. So we humans exhibit sexual dimorphism!

The obvious differences in sex organs don't count in this discussion. But secondary sexual characteristics of body size and hair cover do. Men are generally larger and possess more body hair than women. The latter difference prompted Cole Porter to write in "Kiss Me Kate" 'I Hate Men': "He may have hair upon his chest but, sister, so has Lassie."

Humans can't do much about the inherent size difference between the sexes. But, for centuries, women have modified their body hair. They shave and pluck the offending follicles. Men, on the other hand, have either ignored hair or limited the battle to head and facial hair.

But now, with the emergence of the metrosexual male, some men are shaving and plucking with the aplomb of the most finicky women. In addition, men are using makeup to improve their looks. A process perfected by women, in general, and male actors and TV personalities.

Sexual dimorphism also exists in the rest of the animal world. In general, all mammals share the human difference with the males being larger and hairier than the females. That trend does not hold in the insect world, however.

There is a size difference between the sexes among some species of insects. But the difference is that the females are larger! And for a good biological reason -- the larger females are generally more successful at producing a higher number of eggs.

The amount of hair usually is not related to the sex of an insect. Unless, that is, you count the really fuzzy antennae of some male moths. Such antennae allow the males to capture the odor of the female moth.

Generally, insect males could be classified as metrasexuals. In most insect species, it is very difficult to tell males from females. However, in some species, there are some obvious characteristics that can be used to distinguish a male from a female.

One such characteristic would be the presence or absence of wings. In some walking sticks and cockroaches, females are wingless while males have wings. The same is true of those tree pests called a bagworms and gypsy moths. In both cases, the female is wingless and the male has wings. The wings allow the male to move to the female for mating purposes.

Some insects share a secondary sexual difference that is exhibited by some mammals. That characteristic is the presence of large horns on the males, while horns are reduced or absent on the females. Deer are a good example. The large set of horns functions in fighting with other males. The same is true of some insects. In a number of scarab beetles, the males have impressive horns while the females are hornless, or nearly so.

Even the color patterns are different between sexes of some species of insects. This characteristic is also exhibited by many species of birds, including the very familiar cardinal. In both the birds and the insects, the males are brighter colored than the females. So, in the insect world where a difference in look exists, it is, more often than not, the female that needs to become more metro!

 

 

Writer: Tom Turpin
Editor: Olivia Maddox