PARENT SESSION
Poster Session #29: Animal Population and Community Ecology.
Wednesday, August 8, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
51
The effects of habitat structure on the distribution of the orb-weaving spider Leucauge regnyi in a Puerto Rican rain forest.
Bishop, Leslie1, Gorman, Leah1, Helsel, Julie1, Lees, Britta1, 1
ABSTRACT- In the Luquillo Forest of Puerto Rico, we examined the role of habitat structure, heterogeneity, and plant species associations on the distribution of Leucauge regnyi. To determine vertical distribution, we placed colonization grids at three heights from canopy towers (ground level, 12m, and 22m). L. regnyi colonized the ground level grids significantly more than the other heights; however, other spider species were more abundant on the higher grids. To quantify features of the habitat that are optimal for web site selection, we compared areas with high spider density to low density. In 2m plots, we recorded the total number of webs, heights of each web, number of attachments for each web, and the density and diameter of plant stems. For habitat heterogeneity, we used vertical and horizontal pole touches in order to calculate a heterogeneity index. To quantify plant species associations, in 10m transects we identified each plant species to which a spider web was attached. There is a significant relationship between the presence of webs and habitat heterogeneity. Specific plant species do not seem to be predictors of web sites, but the significant plant feature for silk attachment is woody stem diameter .
KEY WORDS: orb-weaving spiders, habitat structure