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The Role of Different Components of the Pheromone Emission of Mature Males of the Desert Locust, Schistocerca gregaria (Forskål) (Orthoptera: Acrididae) in Accelerating Maturation of Immature Adults

  • Hassane Mahamat
  • Ahmed HassanaliEmail author
  • Hezekiel Odongo
Research Article

Abstract

Different blends of five chromatographically prominent components of the pheromone emission of gregarious-phase mature desert locust Schistocerca gregaria (Forskål) (Orthoptera: Acrididae) males were bioassayed for their maturation-accelerating effects on immature counterparts. The blend of all five components, namely anisole, veratrole, benzaldehyde, phenylacetonitrile and 4-vinylveratrole was as effective as the emission from live mature males in accelerating the onset of mating in immature males. Subtraction of anisole had no significant effect but removal of any one of the other four components significantly reduced the acceleration potency of the resulting blends. The maximum reduction occurred in the absence of phenylacetonitrile which appears to be critical to the activity of the blend. The magnitude of reduction in maturation acceleration that resulted from the subtraction of the other three components suggests that, although present in lesser relative amounts, these compounds contribute significantly to the activity of the full blend. Some differences were found between the onset of integumental yellowing and mating which indicate that blends of slightly different compositions are involved in promoting these two physiological processes.

Key Words

desert locust Schistocerca gregaria maturation acceleration phenylacetonitrile benzaldehyde veratrole 4-vinylveratrole anisole 

Résumé

On a essayé différents mélanges de 5 substances les plus importantes obtenues lors de la Chromatographie des sécrétions phéromonales des mâles adultes en phase grégaire du criquet du désert (Schistocerca gregaria) Forskal (Orthoptera: Acrididae), afin de déceler leurs effets biologiques de hâter le début d’accouplement chez les sujets immatures de la même espèce. Le mélange de cinq substances dont l’anisole, le vératrole, le bénzaldéhyde, le phénylacétonitrile et le 4-vinylvératrole accélérait efficacement le début d’accouplement au sein des sujets mâles immatures au même titre que le phéromone dégagé par les mâles adultes vivants. L’exclusion de l’anisole du mélange n’avait pas d’effet significatif mais par contre, la suppression de l’une ou l’autre des quatre substances réduisait significativement la capacité du mélange d’accélérer le début d’accouplement. La réduction maximale avait lieu à l’absence du phénylacétonitrile qui semble être indispensable pour l’activation du mélange. L’importance de la réduction de l’accélération du début d’accouplement résultant de l’exclusion des autres substances suggère que celles-ci contribuent significativement à l’activation du mélange des cinq éléments, quand bien même à des concentrations relativement faibles. Quelques différences ont été notées entre le début du jaunissement du tégument et le début d’accouplement, ce qui indique que les mélanges avec des compositions légèrement différentes participent dans l’activation de ces deux processus physiologiques.

Mots Clés

criquet du désert Schistocerca gregaria accélération de la maturité phénylacétonitrile anisole vératrole bénzaldéhyde 4-vinylvératrole 

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Copyright information

© ICIPE 2000

Authors and Affiliations

  • Hassane Mahamat
    • 1
  • Ahmed Hassanali
    • 1
    Email author
  • Hezekiel Odongo
    • 1
  1. 1.International Centre of Insect Physiology and Ecology (ICIPE)NairobiKenya

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