dianah nangammbi

I have a B.Sc degree in Biochemistry and Biology from the university of Venda.Currntly i have registred an honours degree from the University of Western Cape, and i am really enjoying it.I am based at the csir pretoria.

Tuesday, May 16, 2006

SIGNALS USED BY INSECTS TO ATTRACT A MATE FOR SEXUAL REPRODUCTION

Insects have both male and female species that mate and reproduce sexually. Some insects reproduce by lying eggs while in some the egg hatches inside the female and are born after a short time. During other seasons of the year the males are not available to mate with the female but species like aphids still reproduced.


Different insects use different semiochemicals to attract their mating partners. Semiochemicals are chemicals that mediate interactions between organisms. These chemicals are divided into allelochemicals and pheromones depending on the nature of interactions if it was interspecific or intraspecific. Allelochemicals are those chemicals that important to individuals of a species that are different from the source species. These chemicals are also subdivided into different groups depending on whether the respond of the receiver is comfortable with the emitter not the receiver or the chemical is favourable with the receiver not the emitter or is favourable to both emitter and the receiver. Both allelochemicals and pheromones it is always useful to refer to chemicals as arrestants, attractants, repellents, deterrents, stimulants or other descriptive terms. These terms can indicate what behaviour is involved in the response such as a feeding stimulant or flight arrestant. Pheromones are released by a certain species with the effect of having the attraction to the same kind of species.


Insects have different ways they use to attract each other like in the case of the moths. The female moths have scent glands on the abdomen that secrete pheromones. These chemicals are secreted to attract the male moth. The male moth can detect these chemicals at a distance of four to eleven kilometres. Sometimes the males secrete pheromone just to induce the females so that they mate. Insects like butterflies use colour and movement. The males will be attracted by the coloured imitations of females and in the same time they will be chasing the other male away. Male flies also form a compact swarms that attracts the female.


Sound is also used as a way to attract each other sexually. The male mosquitoes are attracted to the note or sound produced by the wing vibration of the wing. Female grasshoppers, crickets and cicadas are attracted by the sound produced by their males. Crickets use the burrows to resonate the sound, the cicadas use their large empty space in their abdomen and the substrate vibration helps the leafhoppers to communicate. After mating the males have different methods they use to protect their sperm from other males. Some guard the mated female preventing her from mating with other males. Extended copulation is also used which also prevents other male to mate with her for that period. Some produce accessory glands which produce chemicals that plug the vagina after mating thus giving her an opportunity only to mate once. Other males use genital apparatus that push the new arriving sperms back out of the way in the female spermathecae. If the female has already mated, other male have scoops which remove sperms of the previous males from the females systems.

Reference

1. Insects and bugs Information [Internet] [cited 2006 05 08] Available from: http://www.ivyhall.district96.k12.il.us/4th/KKhp/1insects/buginfo.html

2. Neuroendocrine control of reproduction in insects [Internet] [cited 2006 05 08] Available: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7186527&dopt=Abstract

3. How do the sexes find each other [Internet] [cited 2006 05 08] Available: http://bugs.bio.usyd.edu.au/Entomology/InternalAnatomy/reproduction.html

Dianah Nangammbi
CILLA CSIR
P.O BOX 395
PRETORIA
0001
Tel: +27 12 841 2133
Cell: +27 73 121 3589
Email: dnangammbi@csir.co.za
http://wwwdianah.blogspot.com/

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