Box plots of biting midge density (number per 100 m²) in study plots receiving different treatments recorded from different time periods.

Box plots of biting midge density (number per 100 m2) in study plots receiving different treatments recorded from different time periods.</p

S1 File -

Biting midge Forcipomyia taiwana is one of the common pests in East Asia. Their nuisance and blood-sucking behavior causes problems not only for human health but also for some industries. This study aims to evaluate the effectiveness of spraying alkaline water on controlling biting midge population and potential side effects of such approach on non-target organisms. Laboratory experiments were conducted to evaluate the effect of alkaline water on oviposition site preference of female biting midges as well as crickets. Effect of alkaline water on distribution pattern of earthworms was also examined. Besides, we also performed field manipulative studies by long term spraying of alkaline water to evaluate the effects on biting midge density, microalgae abundance and ground arthropod communities. The results of laboratory experiments showed that female biting midges laid significantly fewer eggs in surface treated with alkaline water. However, alkaline water treatment did not significantly affect the oviposition site choice of crickets and distribution pattern of earthworms. Result of field manipulations showed that long-term spraying of alkaline water could significantly reduce the abundance of soil microalgae and density of biting midges, but did not affect the diversity of non-target ground arthropods. These results demonstrate that long-term spraying of alkaline water could decrease biting midge density without harming co-existing non-target organisms and therefore is a potentially eco-friendly approach to control such pest.</div

Multidimensional scaling (MDS) plots of ground arthropod diversity in study plots receiving different treatments surveyed before and after field experiments.

Multidimensional scaling (MDS) plots of ground arthropod diversity in study plots receiving different treatments surveyed before and after field experiments.</p

Box plots of number of eggs laid by female <i>F</i>. <i>taiwana</i> on substrates moistened with either regular or alkaline water.

Box plots of number of eggs laid by female F. taiwana on substrates moistened with either regular or alkaline water.</p

Box plots of the abundance of soil microalgae estimated by concentration of chlorophyll a in study plots receiving different treatments.

Box plots of the abundance of soil microalgae estimated by concentration of chlorophyll a in study plots receiving different treatments.</p

Box plots of number of earthworms in tray quadrants moistened with either regular or alkaline water.

Box plots of number of earthworms in tray quadrants moistened with either regular or alkaline water.</p

Results of PERMANOVA test comparing ground arthropod diversity of study plots receiving different water treatments.

Results of PERMANOVA test comparing ground arthropod diversity of study plots receiving different water treatments.</p

Box plots of number of eggs laid by female crickets on soil surfaces moisturized with either regular or alkaline water.

Box plots of number of eggs laid by female crickets on soil surfaces moisturized with either regular or alkaline water.</p

Amino acid (GLU = glutamine, PRO = proline, GLY = glycine, ALA = alanine) compositions in post-treatment MA silks, for <i>Argiope aemula</i> (A) and <i>Cyclosa mulmienensis</i> (B).

<p>* indicates significant differences (<i>P</i><0.05) were detected by a Kruskall-Wallis tests between treatments.</p

Multiple regression models for <i>Argiope aemula</i> between number of radii, mesh size and proline and alanine compositions in post-feeding webs.

<p>Multiple regression models for <i>Argiope aemula</i> between number of radii, mesh size and proline and alanine compositions in post-feeding webs.</p