Medical and Veterinary Entomology (Vol. 12: 30-38, 1998) 

Alary polymorphism in Triatoma spinolai and its possible relationship with demographic strategy

 C.J. Schofield/1, W. Apt/2, H. Sagua/3, F. Panzera/4 and J.P. Dujardin/5

1. London School of Hygiene and Tropical Medicine. U.K.

2. Facultad de Medicina, Universidad de Chile

3. Facultad de Ciencias de la Salud. Universidad de Antofagasta, Chile

4. Facultad de Ciencias. Universidad de la República. Montevideo, Uruguay

5. UMR CNRS-ORSTOM. BP5045, Montpellier, France

Among collections of Triatoma spinolai from various sites in northern Chile, adults from coastal populations are invariably wingless, whereas inland populations show balanced alary polymorphism between wingless females and males that are either winged or wingless. Laboratory crosses showed that male offspring from normal-winged male parents were all long-winged. The male offspring from wingless males always included winged males: 11/33 = 33%, of which 8/11 = 73% were long-winged. An X-linked mutation is proposed to inhibit wing development. Field studies of population demography indicate that male alary polymorphism is advantageous in the desert environment of northern Chile.

 Key words: Triatoma spinolai - Trypanosoma cruzi - polymorphism - Chile