Title

Developmental effects of glyphosate in a warming world

Lead Author Major

Biological Sciences

Lead Author Status

Junior

Format

Oral Presentation

Faculty Mentor Name

Zachary Stahlschmidt

Faculty Mentor Department

Biology

Abstract/Artist Statement

Glyphosate (GLY) is the most commonly used herbicide in California and has been marketed as non-toxic to animals, but recent work indicates harmful effects of glyphosate-based herbicides (GBHs: GLY in addition to proprietary blends of surfactants that improve the absorption of GLY by plants) in some animals. My study examines the effects of GLY or GBH exposure during development, as well as how GLY/GBH effects are influenced by warming associated with climate change. To determine the effects of GLY/GBH and warming on development, I used the variable field cricket (Gryllus lineaticeps), which is native to California. Freshly hatched crickets were reared at either a 28±10°C daily cycle (control; current field conditions) cycle or a 32±10°C daily cycle (predicted warming conditions). Crickets were provided shelter and unlimited food (dry cat food), and they had access to one of three different water sources—control (tap water), GLY (5 mg of GLY per liter of tap water) or GBH (Roundup® diluted to 5 mg of GLY per liter of tap water). When the crickets molted into adults, I determined developmental success (survival to adulthood), duration of development, body mass, body size (femur length), and bilateral symmetry (similarity between right and left femur lengths), as well as investment into reproduction (ovary mass) and flight musculature. Warming sped up development, but it also reduced adult body mass and size, and investment into reproduction and flight musculature. In contrast, GLY had no significant effects, and GBH only affected development (GBH-exposed crickets reached adulthood faster than other crickets). My study is the first to examine the combined effects of temperature and GLY/GBH in a terrestrial animal, and it suggests that warming may be more important to developing insects than GLY or GBH exposure.

Location

University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211

Start Date

24-4-2021 2:45 PM

End Date

24-4-2021 3:00 PM

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Apr 24th, 2:45 PM Apr 24th, 3:00 PM

Developmental effects of glyphosate in a warming world

University of the Pacific, 3601 Pacific Ave., Stockton, CA 95211

Glyphosate (GLY) is the most commonly used herbicide in California and has been marketed as non-toxic to animals, but recent work indicates harmful effects of glyphosate-based herbicides (GBHs: GLY in addition to proprietary blends of surfactants that improve the absorption of GLY by plants) in some animals. My study examines the effects of GLY or GBH exposure during development, as well as how GLY/GBH effects are influenced by warming associated with climate change. To determine the effects of GLY/GBH and warming on development, I used the variable field cricket (Gryllus lineaticeps), which is native to California. Freshly hatched crickets were reared at either a 28±10°C daily cycle (control; current field conditions) cycle or a 32±10°C daily cycle (predicted warming conditions). Crickets were provided shelter and unlimited food (dry cat food), and they had access to one of three different water sources—control (tap water), GLY (5 mg of GLY per liter of tap water) or GBH (Roundup® diluted to 5 mg of GLY per liter of tap water). When the crickets molted into adults, I determined developmental success (survival to adulthood), duration of development, body mass, body size (femur length), and bilateral symmetry (similarity between right and left femur lengths), as well as investment into reproduction (ovary mass) and flight musculature. Warming sped up development, but it also reduced adult body mass and size, and investment into reproduction and flight musculature. In contrast, GLY had no significant effects, and GBH only affected development (GBH-exposed crickets reached adulthood faster than other crickets). My study is the first to examine the combined effects of temperature and GLY/GBH in a terrestrial animal, and it suggests that warming may be more important to developing insects than GLY or GBH exposure.