Effects of tall fescue cultivars on dung beetle performances

Tall fescue cultivars possess different endophyte strains. Kentucky-31 hosts wild-type strain producing toxic ergot alkaloid, ergovaline. Novel cultivars, BarOptima PLUS E34, Jesup MaxQ, and Texoma MaxQ II, have strains not producing ergovaline but proving protection from insect grazing via other endophytic compounds. We tested: 1) if ergovaline will be detected in cow dung, 2) if dung beetle preferences and performances will differ based on a tall fescue cultivar at a pasture. From Kentucky-31 2017 and 2018 dung samples, ergovaline was detected at 0.04 and 0.27 μg/g, respectively. From 2017 dung collection, Onthophagus taurus larval survival and adult mass was similar across four cultivars, but larval development from Texoma MaxQ II brood-balls was shorter. Oviposition substrate preference, when tested for each cultivar versus dung from uninfected pasture, was positive for Texoma MaxQ and negative or neutral for thee other dung-types. From 2018 dung collection, O. taurus and Digitonthophagus gazella larval survival was reduced on Kentucky-31 than Texoma MaxQ II brood-balls. Oviposition substrate preference between these two dung-types was for Texoma Max Q II in both beetle species. Onthophagus taurus larval development was shorter and adult mass was greater from Texoma Max Q II than Kentucky-31 brood-balls. Thus, dung beetles can differentiate dung from pastures with different tall fescue cultivars. Pastures with novel cultivar, Texoma MaxQ II, may benefit more for dung beetles. Pasture renovations with Texoma MaxQ II may improve pasture ecology by enhancing dung beetle populations.