We tested lethal and sublethal effects of ve commonly applied herbicides on the agrobiont wolf spider Pardosa milvina. Pardosa were collected from two agricultural elds; one kept under continuous crop rotation and sprayed for over twenty years, the other had no pesticide application for the last twelve years. Male and female Pardosa from each site were exposed to one of seven herbicide treatments (atrazine, glyphosate, mesotrione, S-metolachlor, rimsulfuron, a combination of all ve herbicides, or a distilled water control; N = 1201) and maintained for 52 days on the treated soil substrate. We recorded mortality, prey capture behavior, weight change, courtship behavior, and egg sac production across treatments. Mesotrione and the ve-herbicide combination showed signi cantly higher mortality than control substrates while atrazine, glyphosate and S-metolachlor showed signi cantly higher survival than the control. Both male spiders and spiders collected from the conventional eld had reduced survival under some herbicide treatments. Prey capture behavior varied signi cantly by herbicide treatment, sex, and site. We observed signi cant weight change differences in males and differences in egg sac production in females, with, compared to the control, signi cant male weight loss in the rimsulfuron treatment collected from the no herbicide eld, and an increase in egg sac production in atrazine, rimsulfuron, and S-metolachlor among females collected from the no herbicide eld. Our results show some herbicides may have modest but signi cant tness bene ts (atrazine, glyphosate, and S-metolachlor) while others strongly increase the mortality of Pardosa (mesotrione and the combination herbicide treatment).

We tested lethal and sublethal effects of five commonly applied herbicides on the agrobiont wolf spider Pardosa milvina. Pardosa were collected from two agricultural fields; one kept under continuous crop rotation and sprayed for over twenty years, the other had no pesticide application for the last twelve years. Male and female Pardosa from each site were exposed to one of seven herbicide treatments (atrazine, glyphosate, mesotrione, S-metolachlor, rimsulfuron, a combination of all five herbicides, or a distilled water control; N = 1201) and maintained for 52 days on the treated soil substrate. We recorded mortality, prey capture behavior, weight change, courtship behavior, and egg sac production across treatments. Mesotrione and the five-herbicide combination showed significantly higher mortality than control substrates while atrazine, glyphosate and S-metolachlor showed significantly higher survival than the control. Both male spiders and spiders collected from the conventional field had reduced survival under some herbicide treatments. Prey capture behavior varied significantly by herbicide treatment, sex, and site. We observed significant weight change differences in males and differences in egg sac production in females, with, compared to the control, significant male weight loss in the rimsulfuron treatment collected from the no herbicide field, and an increase in egg sac production in atrazine, rimsulfuron, and S-metolachlor among females collected from the no herbicide field. Our results show some herbicides may have modest but significant fitness benefits (atrazine, glyphosate, and S-metolachlor) while others strongly increase the mortality of Pardosa (mesotrione and the combination herbicide treatment).