DOI: 10.5061/dryad.vmcvdncxr
title: Data on female oviposition behaviour of the Pararge aegeria butterfly in outdoor cages (2019–2020)

description: We studied oviposition behavior in a butterfly (Pararge aegeria) that used
 to be confined to forest, but recently colonized anthropogenic areas too.
 This provides an ideal study system when trying to understand the
 underlying processes of niche expansion and colonisation success. The
 dataset produced allows us to test to what extent ecotype origin
 (agricultural vs. forest landscape types) and larval developmental
 conditions (open field  vs. canopy-covered forest floors) affect
 multiple features of oviposition behahaviour. We also performed multiple
 behavioural trials per individual and considered changes in oviposition
 site preference within and over trials.  The two provided files
 contain all behavioral or independent variables that were obtained during
 behavioural tracking of the oviposition behaviour of the Speckled Wood
 butterfly (Pararge aegeria) in an outdoor cage in 2019 and 2020. In the
 'femdata' file, each line contains all dependent (e.g.,
 proportion of time spent active) and independent variables (e.g.
 ecotype)  that apply for a single observation trial of 30 minutes
 of a single individual.In total, 211 observation trials were performed, by
 110 different female individuals.  In the 'ovimdata'
 file, each line contains all variables for a single oviposition bout
 (i.e., if a butterfly curls its abdomen on a surface and lays
 eggs).  Examples include number of eggs per bout, the height
 above ground where an egg was laid and temperature at the egg laying site.
 These data were for example used to track changes over consecutive bouts
 within a single trial. In total 275 oviposition bouts were observe, laid
 by 85 different female individuals. Data of the ovimdata file were also
 implemented in the femdata file. For example, in the femdata file
 information can be obtained about the properties of the first oviposition
 bout an individual made during that trial (starting with 'b1').
description: We caught females of either
 forest or agricultural ecotype and allowed their larval offspring to
 experience early-habitat cues in either open field or woodland
 conditions. Two times a week, grass pots were watered and
 checked for pupae. Pupae were collected, placed individually in plastic
 cups, and kept under standardized lab conditions (day/night: 23/16 °C;
 light/dark: 15/9 h) until adult emergence. Two to three days after adult
 emergence, one F1-female and three F1-males were introduced together into
 a small cage (0.3 x 0.3 x 0.3 m) for 24 h to ensure mating. Males and
 females that were allowed to mate came from different broods, but were of
 the same maternal ecotype. After mating, females were kept in the dark at
 lower temperatures (temperature day/night: 16/14 °C) in a Sanyo
 incubator. Adult
 females were tested in large outdoor cages. These cages (12 x
 4.2 x 2.5 m) were located at forest edges, where host grass species of
 <em>P. aegeria</em> naturally occurred. From mid-September to mid-October 2019, and from
 the end of July to mid-September 2020, the behavior of 110 F1-offspring
 females was observed. Each female was individually and gently released
 from a plastic cup that was placed on a small platform in the central part
 of the outdoor cage. Next,
 the female’s behavior was tracked during an observation trial of 30
 minutes. For each female, two observation trials were done, which were
 separated by 1 to 4 hours intervals on days that were suitable for adult
 butterfly activity (i.e., ambient temperature &gt; 15°C and sunny to
 semi-clouded conditions). Before each observation, the following
 environmental variables were recorded: ambient temperature and relative
 humidity (at a central part of the cage, 18 cm above surface in the
 shade), degree of cloudiness (three-level scores: 0: open sky; 1: &lt;
 40% cloud coverage; 2: &gt; 40% cloud coverage), and cage identity.
 Behavioral data (type of behavior, proportion of time spent for each type
 of behavior and proportion of time spent in each segment of the outdoor
 cage) were recorded using the open-source logging software
 BORIS. Types of behavior
 included flying (distinguishing three types: bumping against the cage
 netting, fluttering high or low, and flying in a directional fashion),
 resting, walking, and ovipositing. Once a butterfly took off after an
 oviposition event, a small marking stick was planted and the following
 data were registered after observation: number of eggs, grass species,
 height above ground, air temperature and relative humidity near the egg,
 distance of the oviposition location from woodland edge (0-15 m), presence
 and orientation of nearby vertical structure within a vicinity of 10 cm of
 the egg, and finally, the grade of shade on oviposition substrate within a
 vicinity of 2 cm of the egg (0: fully exposed, 1: more sunlit than shaded,
 2: more shaded than sunlit, 3: fully shaded). After an observation, eggs
 were carefully removed. A single person (S.B.) made all observations from
 inside the cage. After the 30-minute observation trial, the butterfly was
 recaptured by gently placing the cup over the butterfly as soon as it
 stopped flying. Pending their test in the cage and after their
 test, females were kept in a plastic cup in the dark in a cool box. Every
 two consecutive trials were done with a female of the forest and
 agricultural ecotype in random order. Each day, behavioral data were
 collected from 1 to 4 females. Consecutive trials of the same female
 remained in the same cage. Every two days, the observer switched
 cages.