The pheromone released by the Khapra beetle female is a sex pheromone, specifically attracting males. Maximum response of unmated males to the ether extract of the pheromone was observed with 6–7 day old males. Mated males showed significantly reduced response to the pheromone compared to unmated ones, and physical presence of virgin females considerably reduced attraction of unmated males to the pheromone extract.
ZUSAMMENFASSUNG
WIRKUNG VON ALTER UND VORAUSGEGANGENEN PAARUNGEN AUF DAS VERHALTEN DES MÄNNLICHEN KHAPRAKÄFERS ZUM WEIBLICHEN GESCHLECHTSPHEROMON
Weibliche Khaprakäfer (Trogoderma granarium) scheiden ein in Äther lösliches Sexual‐pheromon ab, das nur auf Männchen anziehend wirkt. Die Anzahl der angelockten Männchen nimmt mit dem Alter der Männchen zu. Männchen im Alter von 6–7 Tagen zeigen maximale Reaktionen. Bei noch älteren Männchen nimmt die Reaktion wieder ab. Bereits gepaarte Männchen zeigten signifikant schwächere Reaktionen auf den Pheromonextrakt als noch ungepaarte. Jedoch wurde die Reaktion unverpaarter Männchen auf den Pheromonextrakt durch die Anwesenheit unbegatteter Weibchen stark herabgesenkt.
Adult red palm weevils (Rhynchophorus ferrugineus Oliv.) were labeled by topical application of cerium chloride (CeC1 3 ) in 90% ethanol. Marked adults were detectable by assay of radiocerium following neutron activation of excised elytra. No significant loss of cerium from marked insects occurred over prolonged periods or after repeated washing with water. This marking technique has potential application in ecological studies, especially those of long duration.
Influence of age, sex pheromone concentration and mating status on the response of Earias vittelta and Earias insulana males to their female sex pheromone was studied using a Tshaped oifactometer. Males of both the species showed age related variation in their response to fern ale sex pheromone and 4-day-oId males were maximally responsive. Response of males of both the species to the female sex pheromone was concentration dependent and the level of response generally increased with an increase in pheromone concentration. In£. vittella, response of mated males was comparable with unmated males. In E. insulana, mating caused some reduction in the response of males.Resume-On a etudie 1'influence de l'age, de la concentration de pheromone sexueiie et le status de l'accouplement sur la reponse des m&ies Earias vittella et Earias insulana a la pheromone sexueiie femelle conspecifique en se servant de I'oifactometre d'une forme T. Les males do toutes les deux especes ont montrl une variation ayant rapport a l'age dans Ieur reponse a la pheromone sexueiie femelle et les males ages de 4 jours etaient les plus reponslfs. La reponse des males de toutes Ies deux especes a la pheromone sexueiie femelle dependait de la concentration et le niveau de la reponse augmentait ge'ne'ralement avec Faugmentation dans la concentration de pheromone. EnE. vittella, la reponse des males accouples etait comparable avec les males non accouples. En E. insulana, l'accouplement a resulte en un peu de reduction dans la reponse des males.
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