The web-spider community of soybean agroecosystems in southwestern Ohio

We documented the web-spider community in a soybean agroecosystem over the entire growing season in 1990 and 1991 and over the period of peak spider abundance in August of 1993. Simultaneously a number of vegetational parameters were quantified in order to determine the extent to which the spider abundance was correlated with characteristics of the plant community. Web-spider abundance was higher in 1991 than in 1990 or 1993 and lower in 1993 than the other two years. The composition of the community in terms of web-types also differed among years with sheet webs (Linyphiidae, Agelenidae) being much more abundant in 1991 and orb webs (Araneidae) more abundant in 1990. In 1991, spider abundance was correlated with specific vegetation characteristics which suggests that the availability of habitat was important to spider colonization and establishment in that year. However, in 1990 spider abundance was not correlated with any of the vegetation characteristics we measured. The late season spider density was positively correlated with weed biomass and the damage inflicted on the soybean leaves by herbivores was negatively correlated with the number of web-spiders across the three years. These data suggest that the web-spider community responds to some aspects of the plant community and that they have the potential to impact plant production by reducing the action of herbivores.