Quantifying the Abundance and Distribution of Leaf Galls in Male and Female Arroyo Willow

Abstract

The Arroyo Willow (Salix lasiolepis) is a native species found in riparian areas in California, and is a host for numerous insect species. The red galls commonly observed on leaves of the Arroyo Willow are induced by a small wasp known as the Willow Leaf Gall Sawfly, whose larvae grow and feed inside the galls. Previous studies have shown that leaf phenology and leaf chemistry predict the variation in sawfly densities between male and female plants. In this study, we examined the abundance of leaf galls in male and female Arroyo Willow plants and tested if height above the ground explains the abundance of willow leaf galls. We carried out field surveys along a riparian habitat on the CSUCI campus and recorded the abundance of galls at different heights on individual willow trees. We found that the abundance of galls varied among heights, with the highest abundance occurring in the middle parts of the plant. This suggests that the middle parts of the plant may be more vulnerable to insect attack, and that they may provide better conditions for gall formation. Future directions for our study could include the use of willow leaf galls as an indicator of insect diversity and to determine the ecological importance of arroyo willow as a host plant for insect communities.

Details

Session 2

1:30pm – 2:45pm

Del Norte Hall

Room D: 1530

HSI-SMART