Lethal and sublethal effects of five common herbicides on the wolf spider, Pardosa milvina (Araneae: Lycosidae)

Abstract

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).

The Herbicide Glyphosate and Its Formulations Impact Animal Behavior across Taxa

“…This may be due to differences between species. While exposure levels from [176] are difficult to compare because of different experimental procedures (5.04 µg/cm 2 at 30.34%), they appear to be comparable among the other three studies (12 g/L [174], 14.4 g/L [152] and 15 mL/L [175]).…”

“…Male agrobiont spiders and beetles exhibit similar courtship behaviors and experience similar success rate and duration of mating regardless of whether the surface they were on contained GBH residues [152]. A similar study on wolf spiders and glyphosate showed no significant effect on courtship or sexual behavior in either sex of the spider [176]. This may be due to differences between species.…”

“…Chronic sublethal exposure to glyphosate and another pesticide, thiacloprid, negatively affected colonies of ants, decreasing the number of eggs and pupae and resulting in smaller colonies [177]. While some studies have found no adverse effects in terms of the impact of GBH on courtship, fertility rates, and maternal behavior [129,152,176,183,185,187], it is important to note that the effects of glyphosate and GBHs on reproductive behavior can vary depending on the species, the level of exposure, and the stage of reproduction. Overall, these studies suggest that exposure to glyphosate can lead to disruptions in maternal behavior, courtship, and fertility which can have negative impacts on the development and survival of offspring.…”

“…Similarly, Gallegos [185] and de Oliveira [183] observed no adverse effects of GBH exposure on maternal behavior, which may be attributed to lower doses and different formulations of GBH than in other similar studies. Griesinger [174] and Ward [176] used different con-centrations and different formulations of GBH, which may be the cause of their conflicting results about courtship behavior. No effect of glyphosate on associative learning was found when a very low dose was administered [190], while other studies used higher concentrations and identified learning deficits [98,104].…”