PARENT SESSION
Poster Session #56: Animal Population and Community Ecology II.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Movement patterns of two wolf spider species occurring in an agroecosystem.

Buddle, Christopher^*,1, Rypstra, Ann¹, ¹ Miami University, Oxford, OH

ABSTRACT- Understanding what might cause generalist arthropod predators, such as spiders (Araneae), to move from one area or population to another is especially important in agroecosytems, where spiders prey upon insect pests. We studied whether habitat enhancement and/or the presences of heterospecifics influence the propensity of two wolf spiders (Lycosidae), Hogna helluo (Walckenaer) and Pardosa milvina (Hentz), to emigrate from no-till soybean fields in SW Ohio, USA. These species both naturally occur in soybean fields, although the larger H. helluo seldom attains densities as high as P. milvina. We tracked the movement of marked spiders out of experimental units to which one or both species were added to either natural no-till habitat or enhanced habitat that was created by adding straw mulch to experimental units. Results showed the two species differed in their propensity to emigrate from experimental units: Pardosa milvina was unaffected by any treatment combinations, whereas H. helluo was found to leave experimental areas containing no-till habitat significantly more often than it left regions where the habitat was enhanced. Hogna helluo is therefore less versatile than P. milvina and its populations may be naturally limited in soybean fields because of its inability to find suitable habitat.

KEY WORDS: emigration, habitat quality, Lycosidae, mark-recapture