DOI: 10.5061/dryad.280gb5mzd
title: Behavioral responses to mammalian grazing expose insect herbivores to elevated risk of avian predation

description: Large mammalian herbivores (LMH) are important functional components and
 drivers of biodiversity and ecosystem functioning in grasslands. Yet their
 role in regulating food web dynamics and trophic cascades remains poorly
 understood. In the temperate grasslands of northern China, we explored
 whether and how grazing domestic cattle (Bos taurus) alter the
 predator-prey interactions between a dominant grasshopper (Euchorthippus
 unicolor) and its avian predator the Barn swallow (Hirundo rustica). Using
 two large manipulative field experiments we found that in the presence of
 cattle, grasshoppers increased their jumping frequency threefold, swallows
 increased their foraging visits to these fields six-fold, and grasshopper
 density was reduced by about 50%. By manipulatively controlling the
 grasshopper ability to jump, we showed that jumping enables grasshoppers
 to avoid being incidentally consumed or trampled by cattle. However, it
 increased their consumption rates by swallows 37 folds compared to
 grasshoppers that were unable to jump. Our findings illustrate how LMH can
 indirectly alter predator-prey interactions by affecting behavior of avian
 predators and herbivorous insects. The non-plant mediated effects of LMH
 on plant-dwelling arthropods in grazing ecosystems appears strong and
 common. We highlight that convoluted multispecies interactions may better
 explain how LMH control food-web dynamics in grasslands.
description: # Behavioral responses to mammalian grazing expose insect herbivores to
 elevated risk of avian predation we explored the three trophic
 interactions between cattle (Bos taurus), grasshopper (Euchorthippus
 unicolor) prey, and Barn swallow (Hirundo rustica) predators in a
 temperate grassland in northeast China. We first conducted a grazing
 experiment in the field to test the effects of livestock grazing on the
 jumping behavior and abundance of grasshoppers, and the visiting rate of
 swallows. We then manipulated the grasshopper ability to jump and tested
 whether the change in jumping behavior reduces the grasshopper probability
 to be killed by cattle, and increases their vulnerability to swallow
 predation. ## Description of the Data and file structure (column and
 explanation) Here is a guide to each tab: Tab: grazing_experiment Column
 Explanation Year： Year of data collection in 2021 Block： Experimental
 block within which grazing treatments were embedded Treatment： Grazing
 treatments Ungrazed: cattle excluded Grazed: cattle grazed swallow_visits：
 Number of flying swallow visits in each plot (no./plot)
 jumping_grasshopper： Number of jumping grasshoppers in two permanent
 quadrats in each plot (no./plot) grasshopper_density： Grasshopper density
 (no./m2) walkingsteps_cattle： Walking steps of two cattle in each plot
 (no./plot) LC_cover： Plant cover of L. chinensis grass (%) grass_cover：
 Plant cover of other grasses (%) forb_cover： Plant cover of forbs (%) n/a:
 No data available Tab: behavior_experiment Column Explanation Year： Year
 of data collection in 2022 treatment： Three treatments in the grasshopper
 behavior manipulation experiment Ungrazed: grasshoppers that were able to
 jumped in ungrazed plot Grazed-Jumping: grasshoppers that were able to
 jump in grazed plots Grazed-No Jumping: grasshoppers that were unable to
 jump in grazed plots sample_time： Manipulation experiment was repeated
 three times 1= first time 2=second time 3=third time sex: Gender of
 grasshoppers: male or female Total_No： 50 male and 50 female grasshoppers
 were tethered by monofilament line of different length No_killed_swallow：
 Number of grasshoppers killed by swallow No_killed_cattle： Number of
 grasshoppers killed by cattle Tre_oneway： Combined treatment and
 grasshoppers sex into one column:6 treatments in total. Ungrazed_male
 Grazed-Jumping_male Grazed-No Jumping_male Ungrazed_female
 Grazed-Jumping_female Grazed-No Jumping_female ## Code/Software All data
 were analyzed using the open-source software R version 4.3.0.