Abstract
There is a significant and growing concern regarding the threat of pest insect species and the risk they pose to global food security and the world-wide economy. Current pest-management practices are dominated by the use of chemical insecticides which can cause significant adverse effects to the health of humans, non-target species and the environment. Therefore, there is a need to develop novel methods of pest control that are less harmful to the health of these systems. Sugar-alcohols are a broad group of low-calorie sugars that have been deemed safe for human consumption and can be found in many sugar-alternative foods and health products. Of these, sorbitol, xylitol and erythritol have been identified as being either appetitive or toxic to certain insect species. Here, the feeding preference and survivorship of these three sugar-alcohols is assessed on two cosmopolitan lepidopteran pests; Helicoverpa armigera (Noctuidae) and Spodoptera litura (Noctuidae) as well as one hemipteran pest; Nezara viridula (Pentatomidae). Feeding preference was assessed with a series of feeding trials whereby insects could choose to feed on a sugar-alcohol, or a control and the volumes of liquid consumed were used to calculate preference indices. Survivorship was assessed using a series of trials whereby insects were able to feed ad libitum on a single treatment and the length of time they remained alive was recorded and from this a series of Kaplan-Meier survivorship curves were calculated. The key results were as follows: (1) H. armigera and S. litura prefer to consume water over sugar-alcohols when given a choice between the two. (2) Sorbitol, xylitol and erythritol had no effect on reducing the survivorship of H. armigera, S. litura and N. viridula. (3) Unexpectedly, sorbitol and xylitol had a significant effect of prolonging the longevity of both H. armigera and S. litura, but this effect was not extended to erythritol. Based on the findings of the presented study, it can be gathered that sorbitol, xylitol and erythritol are unlikely to be useful as toxic or attractive compounds for H. armigera, S. litura and N. viridula. Future research should aim to: (1) Understand the mechanisms behind how sugar-alcohols interact with the biology of these insects. (2) Assess the feeding preference and survivorship of sugar-alcohols on a wider range of pest insect species.