Effect of amputating Stylets of Mature Apterous Viviparæ of Myzus persicae

Abstract

WHILE investigating the transmission of viruses by aphids, I observed that amputating the stylets of mature apterous viviparæ of Myzus persicae (Sulz.) caused them to give birth to an unusually large number of larvæ for aphids that could not feed. Indeed, for about a day the aphids produced as many larvæ as if they were feeding. To appreciate the unusualness of this response, it should be understood that, as a rule, keeping M. persicae without food almost completely inhibits the birth of larvæ. For example, when 25 mature adults were kept singly in small vials at about 20° C., the number alive after 1, 2 and 3 days was 25, 22 and 0 respectively; and during this time 14 of the aphids produced no larvæ, 9 produced one each, and 2 produced two each (13 larvæ in all). In comparison, the same number of aphids on a host plant produced more than 100 larvæ each day ; and when 25 aphids were kept in vials after amputation of their stylets, each one produced from two to several larvæ (a total of 133 larvæ the first day) ; the bodies of these aphids became greatly distended, and all of them died on the second day, which was about a day earlier than the controls in vials died. The larvæ born in vials were nearly all alive at the end of the day when they were counted, and those transferred to host plants developed into adults within two weeks. Thus they appeared to be normal.