Submitted to: PLoS One
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/28/2012
Publication Date: 1/16/2013
Citation: Otalora Luna, F., Lapointe, S.L., Dickens, J.C. 2013. Olfactory cues are subordinate to visual stimuli in a neotropical generalist weevil. PLoS One. DOI:10.1371/journal.pone,0053120. Interpretive Summary: Since its introduction in Florida in the 1960s, the tropical root weevil has constrained citrus production there and threatens other citrus growing regions. Although recently discovered attractants for the weevil including a male-produced aggregation pheromone, plant odors and visual signals have potential for survey and management, nothing is known about how these cues interact in the behavior of the weevil. We show that when offered a choice between an attractive visual cue (green light) and odor signal (host plant and male-produced volatiles), the visual cue is preferred. Although the biological significance of the strong preference for the visual cue is unclear, this new knowledge is important to our understanding of the behavior of the tropical root weevil. This research will be used by scientists to further investigate attraction mechanisms used by insects, as well as those developing management strategies for tropical root weevil and other pests.
Technical Abstract: The tropical root weevil Diaprepes abbreviatus is a major pest of multiple crops within its presumed native range in the Caribbean, and has become a serious constraint to citrus production in Florida since its arrival on the mainland United States in the 1960s. Recent work has identified host plant and conspecific volatiles that mediate host- and mate-finding by adult weevils. The responses of male and female D. abbreviatus to narrow bandwidths of visible light emitted by LEDs offered alone and in combination with olfactory stimuli were studied in a specially-designed multiple choice arena combined with a locomotion compensator and recording device. Walking weevils were more attracted to wavelengths close to green and yellow compared with blue or ultraviolet. Adult weevils were also attracted to the odor of its citrus host plant and conspecifics. However, the attractiveness of citrus + conspecific odors decreased abruptly in the presence of a green light revealing a hierarchy between chemical and visual signals. Subordination of olfactory responses by photic stimuli should be considered in the design of strategies aimed at survey or management of Diaprepes weevils and other insects using similar behavioral signal hierarchies.