DOI: 10.5061/dryad.mkkwh719d
title: Data from: Dispersal-fecundity trade-offs in wild insect populations

description: Wing reduction is a common feature of upland insect communities. This
 phenomenon is thought to be primarily driven by selection against flight,
 which is typically unfavorable in upland environments due to high winds
 and cold temperatures. In some insect taxa, wing-reduction has been
 directly linked to increased fecundity. However, few studies have directly
 tested for shifts in fecundity linked to flight musculature. Here we test
 for dispersal-fecundity trade-offs in the widespread subalpine stonefly
 Zelandoperla fenestrata. Our analysis of 450 stoneflies across 81
 localities reveals significant dispersal-fecundity tradeoffs.
 Specifically, we identify a positive association between the size of their
 flight muscles and the length of their wings, and a negative association
 between wing length and ovarian mass. Furthermore, we found a significant
 negative relationship between flight musculature and ovary mass. These
 results represent a rare example of a dispersal-fecundity tradeoff in the
 wild, and illustrate that such tradeoffs can potentially involve
 corresponding reductions in both flight musculature and wing development.
 Our findings suggest that widespread taxa subject to variable
 environmental conditions may benefit from flexible allocation of energetic
 resources.
description: We sampled <em>Zelandoperla fenestrata</em> from
 2017-2021. Where possible, sampling was conducted from sites where both
 full-winged and reduced-winged <em>Z. fenestrata</em> ecotypes
 occur in sympatry. Nymphs were collected by hand from underneath stones or
 wood in riffle zones, and raised in the laboratory at 11°C in water from
 their natal stream, until emergence. A total of 450 <em>Z.
 fenestrata</em> specimens collected across 81 localities (223
 females, 227 males) were reared to adulthood in the laboratory, and
 preserved within 24 hours of emergence. The forewing
 and hind tibia lengths of all adult individuals were measured prior to
 dissection, using stereo microscope images calibrated with a micrometer
 scale in ImageJ . We calculated the relative wing length of all
 individuals by dividing wing length by hind tibia length. Meso- and
 meta-thoracic segments (the locations of flight musculature) of both males
 and female stoneflies were detached from legs, wings, and the remainder of
 the body. For the majority of female specimens (<em>n</em> =
 220), individual ovaries (including maturing eggs) were dissected and
 stored separately. All isolated segments were then desiccated by heating,
 and weighed on an analytical balance.
description: # Data from: Dispersal-fecundity trade-offs in wild insect populations
 [https://doi.org/10.5061/dryad.mkkwh719d](https://doi.org/10.5061/dryad.mkkwh719d) ## Description of the data and file structure We sampled *Zelandoperla fenestrata* from 2017-2021. Where possible, sampling was conducted from sites where both full-winged and reduced-winged *Z. fenestrata* ecotypes occur in sympatry. Nymphs were collected by hand from underneath stones or wood in riffle zones, and raised in the laboratory at 11°C in water from their natal stream, until emergence. A total of 450 *Z. fenestrata* specimens collected across 81 localities (223 females, 227 males) were reared to adulthood in the laboratory, and preserved within 24 hours of emergence. The forewing and hind tibia lengths of all adult individuals were measured prior to dissection (**Images-for-repository.zip**), using stereo microscope images calibrated with a micrometer scale in ImageJ (**Stonefly_images_-_key.csv**). We calculated the relative wing length of all individuals by dividing wing length by hind tibia length. Meso- and meta-thoracic segments (the locations of flight musculature) of both males and female stoneflies were detached from legs, wings, and the remainder of the body. For the majority of female specimens (*n* = 220), individual ovaries (including maturing eggs) were dissected and stored separately. All isolated segments were then desiccated by heating, and weighed on an analytical balance (**Raw_data_-_SF_wing_length.csv**). ### Files and variables #### File: Raw\_data\_-\_SF\_wing\_length.csv **Description:** Morphological measurements from 450 adult *Zelandoperla fenestrata* stoneflies ##### Variables: code = internal reference code thorax_mg = mass of thorax body_net_mg = mass of body with thorax removed body_gross_mg = mass of body FMR = flight muscle ratio: thorax_mg/body_gross_mg ovarian_mass_mg = mass of ovaries ovarian_mass_standardised = (mass of ovaries/(body_gross_mg - mass of ovaries))*10 elevation = metres above sea level sex = f (female) or m (male) HTL = hind tibia length WL = wing length WL_HTL_ratio = WL/HTL Blank cells indicate missing data. ## Code/software Microsoft excel can be used to view the data file. #### File: Stonefly\_images\_-\_key.csv **Description:** Key explaining how to extract morphological measurements from stonefly images (images-for-repository.zip) ##### Variables: code = internal reference code Region = New Zealand region where the sample was collected Sex = Sex of the individual (M= male, F= female) WL_scale (pixel/mm): The number of pixels per mm in the image. This information can be used to calculate the wing length (WL) in mm. WL_pixels: The length of the wing in pixels, as measured by imageJ. HTL_scale (pixel/mm): The number of pixels per mm in the image. This information can be used to calculate the hind tibia length (HTL) in mm. HTL_pixels: The length of the hind tibia in pixels, as measured by imageJ. WL(mm): The wing length of the specimen (WL_pixels / WL_scale). HTL (mm) = The wing length of the specimen (HTL_pixels / HTL_scale). WL_HTL_ratio = WL/HTL ## Code/software Microsoft excel can be used to view the data file. #### File: Images-for-repository.zip **Description:** Raw stonefly images used to extract wing length and hind tibia length measurement (using Stonefly_images_-_key.csv) ## Code/software Images can be extracted into a folder with Winzip (or any software used to unzip files). Wing length and hind tibia length (in pixels) can be measured using ImageJ. The actual wing length (in millimeters) can be calculated by dividing the wing length in pixels by the wing length scales (in pixels/mm). The actual hind tibia length can be assessed in a comparable way.