Biodiversity

Tuesday, May 09, 2006

THE SIGNALS USED BY INSECTS TO ATTRACT A MATE FOR SEXUAL REPRODUCTION

Insects use different signals to attract their mates. These include the use of pheromones, nibbling, waving of abdomen, sound and display of mating behaviour. Insects use odors to attract male from a distance. Majority of insects have contact sex pheromones on their cuticles that allow each sex to clearly identify the other once when they contact each other. Pheromones are usually used by social insects such as ant, termites and honeybees to differentiate nest mates and non nest mates.

In moth, the main determinant of female attractiveness is pheromone tilter. "A virgin female, biosynthesize pheromones and release them to attract males. After mating they cease synthesizing and releasing pheromones" (1). Pheromones biosynthesis in female moth is stimulated by a brain factor called pheromone biosynthesis activating neuropeptide. Male moths often trace a side to side crisscross flight way as they follow the windborne pheromones to its source. When the male arrives where there is a female, the physical contact is made. Mating proceeds almost instantaneously. However, in some moths upon his arrival a male releases his unique courtship pheromones and fans it over female with wings.

American cockroach (Periplanete Americana) begins when a mature female emits pheromones that attract male or many males on the mating ground. When the male accept this enticing signal, he approaches and flaps his wings to show his interest toward her. He will then probe the female with his abdomen as a way of searching for the origin of the omitted pheromones. Finally mating by males backing into the female and exchange sperm (2).

In some insects nibbling, waving of the abdomen and hissing are displays of mating behaviour. Some males will also emit sexual pheromones of their own initiate courtship and assume calling posture by exposing sexual gland of their abdomen called tergites. If the female is next to the male, she will open her genital atrium widely therefore exposing her atrium glands (2).

"Water striders or gerrids attract mates by using legs to create patterns of ripples on the surface of water" (2). Some insects use sound signals to attract mates. They also use the pattern of light flashes from firefly or chirps from a cricket are conspicuous signals used to attract mate. Cricket, grasshoppers as well as cicadas attract mating partners by sounds which produce the process of stridulation. Cicadas make their sound by clicking a taut membrane (4). Among grasshoppers and cricket, stridulation involves rubbing one body part against another to produce sound. Both males and female have a unique ears called tympana, for detecting the calls or songs from others.

"In Drosophila melanogaster, males are also attracted by pheromones of female and female movement. The amount of courtship a female elicit from males is used as a measure of her attractiveness. A virgin female are vigorously courted by whereas mated female elcit less courtship"(3). Some insects use antennae to hear sound made by other species members. For instance male mosquitoes use their featherlike antennae to hear sound of the female wing beats. Female insects become less attractive to male insects after mating.

Some female insects stop releasing pheromones after mating for examples Gypsy moth Lymantria dispar and brown-banded cockroach Supella longipalpa. However they rely on sperm to regulate their attractiveness. In contrast, Helicopverpa zea stop to release pheromones for only one night after mating. The process is accessory gland products that make up the spermatophore and not by sperm. Most of the insects use pheromones to attract mates.

References
1. Millar J (2002) Insect Chemical Ecology [Internet] 2006 May 06, 14:03 UTC [cited 2006 May 08] Avaliable from:
http://www.entomology.ucr.edu/events/winter2002.pdf

2. Randall T.N. Sexual Behavior Mechanisms in Cockroaches: How Have They Managed to Survive? [Internet] 2006 May 06, 13: 04 UTC [cited 2006 May 08] Available from: http://www.colostate.edu/Depts/Entology/courses/en507/papers-2001/ran%20dall.htm

3. Tram T & Wolfner M.F. Seminal fluid regulation of female sexual attractiveness in Drosophila melanogaster 2006 May 06, 09:30 UTC [cited 2006 May 08] Available from: http://www.pnas.org/cgi/content/abstract/95/7/4051
4. Wikepedia contributors. Insects and Behaviour, The free Encyclopedia[Online] 2006 May 07, 08:30 UTC [cited 2006 May 08] Available from:
Masiya Kedibone
CSIR PTA
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Cell No: 073 2519071
Tel No: 012 8412123
Fax: 012 842 3676
E-mail:kmasiya@csir.co.za
Weblog: http://kedibone-kedimasiya.blogspot.com/

1 Comments:

  • Hi there

    Your coverage of the topic is fairly good, and stays on-point. Please be consistent in your formatting (e.g. the double-spacing between some paragraphs). Also, watch your grammar, and remember that species names are written like this: Drosophila melanogaster. As for your references: of the two non-Wiki, one is an abstract (always reference the actual paper, if possible), and the other has anon-functional link. Try to get a better spread next time.

    Nick

    By Blogger NcK, at May 17, 2006 12:26 PM  

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