Relationship between Wolbachia density and sex-ratio in a Trichogramma strain

A controlled thermal cure was applied to a Trichogramma cordubensis strain completely infected by endosymbionts belonging to the Wolbachia genus and which induce the thelytokous mode of reproduction. Varying the conditions of the cure led to the production of a variable number of males among the progeny, and it was possible to examine the correlation between sex-ratio and bacterial density estimated by means of the Dot-blot technique, using the Trichogramma gene 18S and the Wolbachia gene wsp. A slight positive correlation was observed between the two vari.ables. An additional statistical analysis confirmed that a relationship exists between the host sex-ratio and bacterial density but that this relationship is partially concealed by methodological problems. Un tratamiento térmico controlado se aplicó a una linea de Trichogramma cordubensis completamente infes­ tada par endocitobiotos que pertenecen al genera Wolbachia, y que inducen a un modo de reproducci6n de tipo telitoquia. La variacion en la intensidad de! tratamiento condujo a la producci6n de un numero variable de machos en la progenie, lo que permiti6 analizar la correlaci6n entre la razón sexual y la densidad bacteriana estimada por media de la tecnica de Dot-blot, utilizando el gen l 8S de Trichogramma y el gen wsp de Wolbachia. Una baja correlación positiva se constató entre las dos variables. Un analisis estadistico suplementario permiti6 confirmar la relación entre la razon sexual de] huesped y la densidad bacteriana, pero esta relación resultó parcialmente encubierta por problemas metodológicos.