DOI: 10.5061/dryad.2kt68
title: Data from: How grasshoppers respond to road noise: developmental plasticity and population differentiation in acoustic signalling

description: 1. Increasing levels of anthropogenic noise have the potential to mask
 signals of acoustically communicating species in their natural habitats.
 Animals in noise-polluted habitats typically adjust their signals away
 from high background noise levels to ensure successful signal transmission
 under challenging environmental conditions. Earlier we demonstrated that
 male Chorthippus biguttulus grasshoppers from roadside habitats produce
 courtship signals with elevated frequency components compared to
 conspecifics from non-roadside habitats. 2. Here we use a common garden
 approach to study the mechanisms underlying this response. We transferred
 grasshopper nymphs from seven roadside as well as five non-roadside
 habitats to the laboratory to rear half of them under noisy and the other
 half under quiet conditions in a full factorial two-by-two design.
 Courtship songs of adult males were later recorded under standardized
 quiet conditions. 3. Males exposed to road noise as nymphs produced
 signals with higher frequency components compared to males reared under
 quiet conditions, indicating developmental plasticity as a mechanism
 underlying the signal adjustment to anthropogenic noise in grasshoppers.
 4. In addition, males originating from roadside habitats produced signals
 with higher frequency components and an increased syllable to pause ratio
 - a sexually selected signal trait - compared to males from non-roadside
 habitats. 5. Our results demonstrate for the first time that developmental
 plasticity may play an important role in song trait modifications in
 response to anthropogenic noise. Furthermore they suggest that multiple
 roadside populations may have diverged in parallel, possibly in response
 to selection for minimizing signal masking by road noise.
description: Data_FE-2013-00236-R2These data were collected from Chorthippus biguttulus grasshoppers which were caught from their natural habitats as nymphs (second instar) in North Western Germany in June and July 2012. "Location" describes the broader geographic area (ideally including one roadside habitat and one non-roadside habitat) from which the animals were collected. "Population" is the more specific location (the habitat) where the grasshoppers were caught. "Populations" are either roadside or non-roadside populations from a geographic "Location". "Individuals" are individual male grasshoppers which were mostly recorded more than once. The "Origin" of grasshoppers describes whether they originated from a roadside or a non-roadside population without detailed reference to the geographic locations (as opposed to the "Population" column). Grasshoppers were sorted into two different "Treatments", a noisy and a quiet treatment. In the noisy treatment, grasshoppers were exposed to road noise 24 hours a day, whereas in the quiet treatment, they were kept under normal room noise levels (no sound proof room). Adult males were recorded under constant temperature and under quiet conditions. The respective units for the collected data set are given in the headers, except for syllable to pause ratio of male signals, which is a ratio (length of song syllables in relation to length of the pauses in between).