DOI: 10.5061/dryad.jh9w0vtkb
title: Data from: A potential evolutionary trap for the extended phenotype of a nematomorph parasite

description: Human activities introduce new environmental cues to wild organisms,
 leading to maladaptive behavioural and life-history decisions known as the
 ‘evolutionary trap’. This trap is thought to be a major conservation
 concern for free-living organisms. However, it has never been studied in
 endosymbionts, one of the most successful and diverse life forms on Earth.
 Here, we examine this trap in the extended phenotype of a parasite that
 exploits the visual system of hosts to alter host behaviour for its
 benefit. Arboreal mantids infected by nematomorph parasites are drawn to
 horizontally polarized light, thereby inducing them to enter the water. In
 this study, we found that the degree of linear polarisation (DOP) of
 reflected light served as a reliable environmental cue for identifying
 perennial waters, where nematomorphs can survive in their aquatic life
 stage without drying out. Infected mantids exhibit attraction to
 horizontally polarized light with higher DOP in behavioural assays and
 jump into pools reflecting light with higher DOP in field experiments. The
 asphalt road reflected horizontally polarized light closely resembling the
 polarisation levels observed in perennial waters, likely leading to a
 higher prevalence of mantids on asphalt roads compared to those found in
 natural arboreal habitats. In a field experiment, we observed infected
 mantids walking on asphalt roads more often than on cement roads. These
 findings imply that evolutionary traps can endanger endosymbionts beyond
 their hosts that directly perceive environmental cues.
description: Study animals were collected in nature. Polarized light reflected
 from water bodies and asphalt roads was measured in natural
 environments. Behavioral data were collected in both laboratory and field
 experiments. 
description: # A potential evolutionary trap for the extended phenotype of a
 nematomorph parasite **Description of the data** The dataset consists of
 the data_deposited.xlsx data file, which includes the following sheets.
 #### Data S1: Characteristics of light measured in the study fields no:
 Column number date:  Year/Month/Date time: Time of day type: Habitat type
 type2: perennial or intermittent or asphalt water_die: perennial =
 1,intermittent or asphalt = 0 depth:Water depth (cm); When the measured
 habitat type is asphalt, the column is expressed as 0. degree_mean:Mean
 degree of linear polarization (%) calculated at image sizes of 300x300,
 400x400 and 500x500 pixels. intensity_reflect: Illuminance (lux) of
 reflected light from an object intensity_sky:Illuminance (lux) of direct
 sunlight intensity_relative:Relative intensity of light calculated as
 follows: intensity_reflect/intensity_sky #### Data S2: Two-choice test in
 a laboratory no: Column number date: Year,Month,Date year :Year time: Time
 of day at which the experiment was conducted id: Id of individual inf:
 infected = 1, uninfected = 0 degree: Degree of linear polarization under
 which the experiment was conducted.\ location: Location of a mantis after
 the 10-min experiment; right third of the box = R, left third of the box =
 L and middle third of the box = M location_distance: Distance (cm) of a
 mantis from the left end of the choice box after the 10-min experiment.
 result: Category of the location selected by a mantis after the 10-min
 experiment; hori-pola = horizontally polarized light third, unpola =
 unpolarized light third, M = the mantis did not select either light
 (located at the middle third of the choice box). result_hori: Whether a
 mantis selected the horizontally polarized third (1) or not (0).
 pola_window: Side of the window from which the polarized light was
 illuminate; Right = R, Left = L. light intensity: Intensity of light (lux)
 box: ID of the choice box (A-G). #### Data S3: Prevalence of nematomorph
 infections on the asphalt roads and in the natural habitats date:
 Year/Month/Date host: Mantis species population: Populations surveyed
 place: Location of sampling, asphalt or tree infection: infected = 1,
 uninfected = 0 #### Data S4: Summarized prevalence of nematomorph
 infections on the asphalt roads and in the natural habitats population:
 Populations surveyed host: Species name of mantis place: Location of
 sampling; i.e., asphalt or tree infection: infected or uninfected Count:
 Number of mantids ## Sharing/Access information No other data sharing
 sources are available. Please contact the corresponding author (Takuya
 Sato: [tsato@ecology.kyoto-u.ac.jp](mailto:tsato@ecology.kyoto-u.ac.jp))
 if you are interested in using the data. ## Code/Software No code and
 software are included.