Análisis del Voltinismo y la Diapausa en Poblaciones de Apagomerella versicolor (Coleoptera: Cerambycidae) en el Gradiente Latitudinal de su Distribución en la Argentina

• Published in: Revista de la Sociedad Entomológica Argentina 2005, Vol.64 (3), p.68-71
• Main Authors: Logarzo, Guillermo, Gandolfo, Daniel E
• Format: Article
• Language: eng ; spa
• Subjects: Ambrosia; Apagomerella versicolor; Asteraceae; Barrenador de tallos; Borers; Cerambicid; Cerambycidae; Cerambícido; Coleoptera; Diapause; Geographic races; Host plants; Pluchea; Pluchea sagittalis; Razas geográficas; Stemborer.Asteraceae; Voltinism; Xanthium; Xanthium cavanillesii
• ISSN: 0373-5680; 1851-7471

Apagomerella versicolor (Boheman), a long horn stem-borer beetle of the host genera Pluchea., Xanthium, and Ambrosia (Asteraceae). In Argentina, it occurs between 25 and 39 o S. Studies conducted in Buenos Aires (35 o S) indicated that A. versicolor is univoltine and has a winter diapause, and also indicate that diapuse larvae exposed to low temperatures broke the diapuse. However, some observations suggested that populations from northern Argentina could be bi or multivoltine and did not diapause. The voltinism and the diapause of A. versicolor were studied along its latitudinal distribution, between 25 and 32 o S. We conducted an experiment to identify diapause presence; larvae collected at different latitudes were separate in two groups, one of them were exposed to low temperatures to break the diapause, the other one was control. Those diapausing larvae that received cold treatment should pupate in a shorter time than those that did not receive it. In addition, ten collecting trips were made in January, March, July, August, October and December in different years in the study area to observe the immature stages present in its main hosts, Pluchea sagittalis Cabr. and Xanthium cavanillesii Schouw, at different latitudes. It was found evidence that A. versicolor is at least bivoltine between 25 º and 27 o S, and it does diapause at latitudes over 31 o S. The influence of the biology of the host plants on voltinism and diapause is discussed here. RESUMEN. Apagomerella versicolor es un cerambícido cuyas larvas barrenan los tallos de plantas compuestas de los géneros Xanthium, Ambrosia y Pluchea (Asteraceae). En la Argentina se distribuye entre los 25º y 39º de LS. Estudios sobre la biología de este insecto realizados con poblaciones de los alrededores de Buenos Aires (35º S), indicaban que era una especie univoltina con diapausa larval durante el invierno y que se podía inducir la salida del estado de diapausa exponiendo las larvas a bajas temperaturas. Sin embargo algunas observaciones sugerían que poblaciones del norte del país podían ser bi o multivoltinas sin diapausa larval. En este trabajo estudiamos el voltinismo y la diapausa en una clina latitudinal entre los 25 y los 32º de LS. Se realizó un ensayo para revelar la presencia de diapausa.en las distintas latitudes, para ello, larvas de distintas latitudes fueron separadas en dos grupos, uno fue expuesto a un tratamiento de bajas temperaturas para romper la diapausa y el otro fue utilizado como contr