Genetic variation in Bactericera cockerelli (Hemiptera: Triozidae) from Mexico.

Bactericera cockerelli (Sulc) is a significant pest of several solanacious crops in Mexico and the United States since 1970. In 2001 significant outbreaks of outstanding importance were observed for the first time in areas where infestations of this insect were historically rare. Molecular studies revealed that this was because of the development of a new biotype of B. cockerelli that had become adapted to south-western United States, further demonstrating that this genetic differentiation was reflected in the survival, development cycle, fertility, and growth rate of both the native biotype as well as the one recently reported. To determine genetic variation in populations of B. cockerelli from Mexico, inter simple sequence repeat were used. Results showed that populations of B. cockerelli from central and northeastern Mexico (Guanajuato, Morelos, Estado de Mexico, and Nuevo Leon states) are genetically similar, meanwhile B. cockerelli from northwest, southwest, and southeast of the country (Sinaloa, Michoacan, and Oaxaca states) are genetically distinct from each other and from the rest of the populations included in the study.

Molecular phylogenetic analysis of an endangered Mexican sparrow: Spizella wortheni.

The Worthen's Sparrow (Spizella wortheni) is an endemic bird species of the Mexican Plateau that is protected by Mexican law. Considering its limited range (25 km(2)), small population size (100-120 individuals), and declining population, it is one of the most endangered avian species in North America. Although it has been assumed to be the sister taxon of the Field Sparrow (Spizella pusilla), the systematic and evolutionary relationships of Worthen's Sparrow have never been tested using modern molecular phylogenetic methods. We addressed the molecular phylogeny of S. wortheni analyzing six mitochondrial genes (3571 bp) from all of the natural members of the genus Spizella. Our maximum likelihood and Bayeasian analysis indicate that despite the superficial similarity, S. wortheni is not the sister taxon of S. pusilla, but is instead most closely related to the Brewer's Sparrow (Spizella breweri). Also new insights about the phylogenetics relationships of the Spizella genera are presented.