Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 30, 1994
Publication Date: N/A
Interpretive Summary: The pepper weevil, Anthonomus eugenii, is an important pest of peppers (Capsicum spp.) throughout the southern United States, Mexico, and Central America. Research on chemical communication in this species required scientists to be able to separate males from females. Although some methods for sexing pepper weevils are known, they are not always completely reliable. Scientists at the National Center for Agricultural Utilization Research, Peoria, IL, discovered that male pepper weevils possess a curved hook (i.e., mucro) near the base of their hind legs which is not present on female pepper weevils. This discovery makes it much easier to sex weevils for research purposes, such as determining differences in the chemicals the sexes produce or determining if the sexes respond equally to chemical attractants.
Technical Abstract: The pepper weevil, Anthonomus eugenii Cano (Coleoptera: Curculionidae), is an important pest of peppers (Capsicum spp.) throughout the southern United States, Mexico, and Central America. Recent research on the aggregation pheromone of the pepper weevil, required the ability to sex individuals to identify male-specific chemicals. In addition, weevils captured during field trials of synthetic pheromones were sexed to determine whether the pheromone attracted both sexes. Although pepper weevils can be sexed by examination of their genitalia, often not they are not exposed, especially in weevils captured in pheromone traps. Although secondary sexual dimorphisms have been described for the pepper weevil (e.g., position of antennal insertion and density of punctures on rostrum), these characters are somewhat subjective and are not completely reliable. This study determined that male pepper weevils possess a metatibial mucro which is much larger than that of females. This character is very useful for sex determination of pepper weevils used in laboratory experiments and those captured in field trials of the synthetic pheromone. This method was also less subjective than previously described characters and more reliable. Several other species of Anthonomus were examined to determine if they were dimorphic for this character as well. Of eight species examined, only one was dimorphic for this character.