Behavioural response of wheat bulb fly (Delia coarctata, Diptera: Anthomyiidae) larvae to the primary plant metabolite carbon dioxide
2013
Rogers, C.D. | Evans, K.A. | Parker, J. | Pappa, V.A.
Wheat bulb fly (WBF) larvae use chemotaxis to orientate towards host-plant root exudates. This study aimed to investigate the role of the primary plant metabolite carbon dioxide (CO₂) in host-plant location by WBF. Arena based behavioural experiments were used to identify whether CO₂ induced chemotaxis (directional movement in response to a chemical stimulus) or kinesis (non-directional movement in response to a stimulus) from WBF larvae. No chemotactic response was observed when larvae were presented to a point source of CO₂. However, elevated levels of CO₂ induced kinesis, with both track length and tortuosity (number of twists and turns in the movement path) increasing at elevated CO₂ levels of 1000–2000 ppm, demonstrating increased searching behaviour. Soil emission of CO₂ was quantified to compare soil levels with those identified as eliciting behavioural effects on the larvae. Samples removed from soil gave a mean CO₂ concentration of 557 (±46) ppm, which is lower than the lowest concentration of CO₂ found to induce a behavioural response and higher than the lowest CO₂ concentration tested, which was found not to alter behaviour. It is proposed that increased CO₂ concentrations in the soil act as a behavioural trigger, inducing intensive searching of an area by WBF larvae. This increases the likelihood of finding more host-specific identifiers, such as secondary metabolites when near a potential host-plant.
显示更多 [+] 显示较少 [-]