Vision-Mediated exploitation of a novel host plant by a tephritid fruit fly

Authors: PINERO, JAIME - Lincoln University Of Missouri; Souder, Steven; Vargas, Roger

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2017
Publication Date: 4/5/2017
Citation: Pinero, J.C., Souder, S., Vargas, R.I. 2017. Vision-Mediated exploitation of a novel host plant by a tephritid fruit fly. PLoS One. doi:10.1371/journal.pone.0174636.

Interpretive Summary: Bactrocera cucurbitae(Coquillett)(Diptera:Tephritidae) is an invasive herbivore that is distributed widely in temperate, tropical, and sub-tropical regions of the world. This fly has been documented to rely strongly on vision to locate host fruit. Papaya fruit is visually conspicuous fruit which previously was considered a "occassional' host. We hypothesized that female B.cucurbitae used vision as the main sensory modality to find and exploit the papaya host fruit. This study conducted at Agricultural Research Service (ARS), U.S. Department of Agriculture, Daniel K. Inouye Pacific Basin Agricultural Research Center, Hilo, Hawaii, used a comparative approach that involved a series of behavioral studies under natural and semi-natural conditions. We assessed the ability of female B.cucurbitae to locate and oviposit in papaya fruit using the sensory modalities of olfaction and vision alone and also in combination. The results of these studies demonstrate that, under a variety of conditions, odors emitted by the novel host do not positively stimulate the behavior of the herbivore. Rather, vision seems to be the main mechanism driving the exploitation of the novel host. Volatiles emitted by the novel host papaya fruit did not contribute in any way to the visual response of females. Our findings highlight the remarkable role of vision in the host-location process of B.cucurbitae and provide empirical evidence for this sensory modality as a potential mechanism involved in host range expansion.

Technical Abstract: Shortly after its introduction into the Hawaiian Islands around 1895, the polyphagous, invasive fruit fly Bactrocera cucurbitae (Coquillett)(Diptera:Tephritidae) was provided the opportunity to expand its host range to include a novel host, papaya (Carica papaya). It has been documented that female B.cucurbitae rely strongly on vision to locate host fruit. Given that the papaya fruit is visually conspicuous in the papaya agroecosystem, we hypothesized that female B.cucurbitae used vision as the main sensory modality to find and exploit the novel host fruit. Using a comparative approach that involved a series of studies under natural and semi-natural conditions in Hawaii, we assessed the ability of female B.cucurbitae to locate and oviposit in papaya fruit using the sensory modalities of olfaction and vision alone and also in combination. The results of these studies demonstrate that, under a variety of conditions, volatiles emitted by the novel host do not positively stimulate the behavior of the herbivore. Rather, vision seems to be the main mechanism driving the exploitation of the novel host. Volatiles emitted by the novel host papaya fruit did not contribute in any way to the visual response of females. Our findings highlight the remarkable role of vision in the host-location process of B.cucurbitae and provide empirical evidence for this sensory modality as a potential mechanism involved in host range expansion.