Changes in sex ratio during attempts to establish a laboratory colony of Lutzomyia longipalpis (Diptera: Psychodidae).

After the discovery of "one spot" and "two spot" male Lutzomyia longipalpis in the same dog's kennel, attempts were made to establish laboratory colonies of the two forms. Pure lines of the two forms were not obtained and various "intermediate" males were recorded. Interbreeding between the two populations probably occurs in nature but appears precarious. In one colonization attempt a change in sex ratio was noted from the 7th generation onwards and only females emerged in the 11th generation.