Data from: Road salt application increases sodium levels in roadside plants and ants, reshaping tritrophic interactions
Data files
Sep 04, 2026 version files 74.05 KB
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ant_breed.csv
398 B
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antmorph2021.csv
9.17 KB
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antmorph4-6.csv
7.11 KB
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antmorph4-9.csv
7.27 KB
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antmorph6-9.csv
7.24 KB
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antna.csv
4.92 KB
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clover.csv
2.47 KB
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cultivation.csv
4.59 KB
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Fallopia_Na.csv
2.80 KB
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Graph.txt
7.77 KB
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nectar.csv
3.65 KB
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R_statistical_tests.txt
3.65 KB
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README.md
3.61 KB
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Rumex_Na.csv
1.22 KB
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soil_Na.csv
3.71 KB
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stable_isotope.csv
4.47 KB
Abstract
In areas with heavy snowfall and high levels of anthropogenic activity, a large amount of sodium chloride is applied in the winter as an antifreezing agent for the road surface. The effects of road salt application may be widespread among various plants and high-trophic-level organisms. Here, we examined the effects of road salt application on plants and omnivorous ants. Ten study sites were established along national route 7, which is the main road in the northwestern region of Japan. The concentrations of sodium in the soil, leaves of Japanese knotweed and white clover, the extrafloral nectar of Japanese knotweed, and ants increased closer to the national route in spring. Ants acclimated to high-sodium baits gathered at the low-sodium baits, indicating that road salt application changed the food preference of the ants and that the ants increasingly preferred low-sodium foods. The trophic level of ants was lower the closer they were to the national route in spring, suggesting that ants became more herbivorous near the national route, favouring lower-sodium food at lower trophic levels. Our study revealed that road salt application can change insect behaviour through sodium accumulation, leading to changes in biological interactions such as predator–prey relationships.
Dataset DOI: 10.5061/dryad.sn02v6xk5
Statistical analysis
R_statistical_tests.txt: The script for statistical analyses.
The data to detect sodium accumulations in soil, plants, and insects due to road salt application
soil_Na.csv: The data of soil sodium concentration. This data includes the following variables:
- season
- site
- distance(distance from the road; m)
- soil.Na.conc.(Sodium concentration; ng/ul)
Fallopia_Na.csv: The data of the sodium concentration for the leaf of Japanese knotweed. This data includes following variables:
- season
- distance
- site
- Na(Sodium concentration; ng/ul)
clover.csv: The data of the sodium concentration for the leaf of white clover. This data includes the same variables as Fallopia_Na.csv.
Rumex_Na.csv: The data of the sodium concentration for the leaf of bitter dock. This data includes the same variables as Fallopia_Na.csv.
nectar.csv: The data of the sodium concentration for the extrafloral nectar of Japanese knotweed. This data includes the following variables:
- season
- site
- distance
- concentration(Sodium concentration; ng/ul)
antna.csv: The data of the sodium concentration for ants. This data includes the following variables:
- season
- site
- distance
- concentration(Sodium concentration; ng/ul)
The data to test changes in body size of ants due to road salt application
antmorph2021.csv: All data of the thorax length for ants. This data includes following variables:
- place (site)
- season
- distance
- length (body length; mm)
antmorph4-6.csv: The data of the thorax length for ants collected in April and June. This data includes the same variables as antmorph2021.csv.
antmorph4-9.csv: The data of the thorax length for ants collected in April and September. This data includes the same variables as antmorph2021.csv.
antmorph6-9.csv: The data of the thorax length for ants collected in June and September. This data includes the same variables as antmorph2021.csv.
The data to examine the preference of ants for the extrafloral nectar of Japanese knotweed cultivated under different sodium concentrations
cultivation.csv: The data of the sodium concentration for the extrafloral nectar of Japanese knotweed and the number of attracted ants in cultivation experiment. "Nectar" column includes some empty cells, and these data are removed in analysis (See R_statistical_tests.txt). This data includes the following variables:
- term (number of applied days)
- NaCl (amount of applied sodium chloride; g)
- nectar (sodium concentration; ng/ul)
- ant (number of attracted ants)
- nest (ant nest ID)
- planter_group (planter group ID)
The data to examine the preference of ants for water with high sodium concentrations
ant_breed.csv: The data of the preference experiment of ants for water with different sodium concentrations. This data includes the following variables:
- baitNa (sodium concentration of water; %)
- low (the number of ants gathered at low-sodium baits)
- high (the number of ants gathered at high-sodium baits)
The data to detect the effect of road salt application on the trophic level of ants
stable_isotope.csv: Nitrogen stable isotope data of the leaf of Japanese knotweed and ants. This data includes the following variables:
- season
- site
- distance
- true N (delta15N of ant - delta15N of the leaf of Japanese knotweed)
Graphical plotting
Graph.txt: The script for creating each graph.