| We studied the seasonal activity of Bombus pennsylvanicus sonorus Say in subtropical conditions of the Mexican Central Plateau. Monthly during 1998, we recorded caste of active individuals (inferred form corporal size measured as wing length), presence and activity of reproductive individuals, and mating activity. Also, we recorded the flower plants used as resources. Subtropical conditions of the Mexican Central Plateau do not seem to modify phenological features of B. pennsylvanicus sonorus since the species presents annual colonies and a clearly defined period of inactivity. The size of individuals progressively increased between the first recorded activity period in middle April and the end of the colonies in November. Reproductive bees were observed... |
