DOI: 10.5061/dryad.31zcrjdx5
title: Plasticine model predation of adult white-lined sphinx moths (Hyles lineata) across time and sites (urban and rural)

description: Human settlements and urbanization are increasing globally with more than
 half of the Earth’s terrestrial surface being impacted by humans. This
 development has resulted in numerous anthropogenic stressors including
 nocturnal sensory pollution (i.e. light pollution), which is a key driver
 of insect declines. Nocturnality is hypothesized to reduce
 predation risk from visually-guided diurnal predators. More than half of
 all insect species, and 80% of Lepidoptera, are estimated to be
 nocturnal. Predation rates on insects are likely a result of
 habitat, time of day, and the local predator composition. We investigated
 how predation rates on plasticine moth replicas differed between urban and
 rural sites, and between night and day. Visually matching
 paper-winged, clay-bodied replicas of the white-lined sphinx moth, Hyles
 lineata, were placed in a natural area within the city of El Paso, Texas,
 and in remote Chihuahuan Desert with minimal human disturbance. These
 replicas were checked during dawn and dusk for three
 days. Predation rates were significantly lower at night than
 during the day regardless of location, and predator composition differed
 between sites. Insectivorous birds were the primary diurnal predators in
 both locations, whereas nocturnal predators were represented primarily by
 insects at the rural site and by mammals at the urban site. These
 findings support the hypothesis that visually-guided predators, such as
 birds, exert higher predation pressures during the day, and supports the
 hypothesis that insect biodiversity, especially of predaceous insects, is
 affected by urbanization.
description: <em>Plasticine
 </em><em>Replicas</em> To quantify
 predation rates and predator composition between time of day and
 urbanization, we developed visually accurate plasticine replicas of adult
 <em>Hyles lineata</em>. Eight <em>H. lineata
 </em>moths in pristine condition were selected from the University
 of Texas at El Paso Biodiversity Collections. Following Troscianko
 & Stevens (2015) and Da Cunha
 <em>et
 al.</em>
 (2024), we quantified wing coloration with a
 UV/VIS Samsung NX1000 camera. We photographed moth specimens both dorsally
 and ventrally with a UV-suitable gray standard (Spectralon; Labsphere; 40%
 reflectance) under clear skies between 13:15 and 14:15 in February and
 March. We then printed moth replica wings on White, Letter Paper (Office
 Depot® Multi-Use Printer & Copy Paper, White, Letter 8.5" x
 11) using a Xerox C310 printer. Photographs of moth specimens and paper
 wings were compared for spectral match. We adjusted the brightness and RGB
 values of the paper wing reflectance using the photo editing software
 General Image Manipulation Program (GIMP) to ensure a close spectral match
 to the moth specimens. This process was repeated until reflectance values
 were similar between moth wings and paper wings, see Figures 1 and 2.
 Paper wings were then cut to the correct shape and size, and inserted into
 4.5 grams of non-toxic brown clay (Brown Craft Smart Oven Baked Polymer)
 molded to the shape of <em>H. lineata</em>’s body. Finally,
 twist ties were used to attach clay replicas to branches.
 <em>Study Sites and </em><em>Replica
 Deployment</em> For moth deployment we selected
 one urban site within El Paso, TX - Knapp Land Nature Preserve (KLNP;
 31.864035, -106.465106) - and one rural site, Indio Mountains Research
 Station (IMRS; 30.776681, -105.016751), which is approximately 180 km from
 El Paso, TX. KLPN is 143 hectares of protected Chihuahuan Desert with high
 human disturbance whereas IMRS consists of 161
 km<sup>2</sup>of undisturbed Chihuahuan Desert.. Additionally,
 KLNP is adjacent to Franklin Mountains State Park, which consists of 9,182
 hectares of preserved Chihuahuan Desert. However, both KLNP and adjoining
 Franklin Mountains State Park are centrally located within El Paso and
 receive high levels of light and noise pollution, as well as other urban
 impacts. During dusk on June 8, 2023, 200 moth replicas
 were placed on native plants at each site, 400 in total, at least 50
 meters apart from other replicas. Replicas were then checked every dawn
 (approx. 04:58-06:00) and dusk (approx. 20:10-21:12) for attack marks for
 72 hours. Attacks recorded at dawn indicated a nocturnal attack and
 attacks at dusk indicated a diurnal attack. All attacked replicas were
 removed from the study and photographed. We categorized attacks as bird,
 mammal, insect, or unknown based on the indentations left on the clay
 replicas (see Low
 <em>et
 al.</em>, 2014
 and  supplementalfigure 1). <em>Statistical
 Analysis</em> Differences in survival
 probabilities after 72 hours between the two sites were tested using
 Kaplan-Meier survival analysis with the log-rank test ‘survival’ package
 in R (Therneau
 & Others, 2015). Missing replicas were incorporated into
 the Kaplan-Meier survival analysis as censored individuals (Seymoure
 <em>et
 al.</em>,
 2024). Chi-square analyses were used for testing differences in
 attack rates between night and day, as well as predator composition. For
 the temporal niche Chi-square analysis, we corrected for a longer daytime
 by multiplying the total number of attacks (140) by the proportion that
 was daytime (15hr/24hr, 0.625) and nighttime (9hr/24hr, 0.375) resulting
 in 87.5 and 52.5 expected attacks for day and night,
 respectively.
description: # Plasticine model predation of adult white-lined sphinx moths (Hyles
 lineata) across time and sites (urban and rural)
 [https://doi.org/10.5061/dryad.31zcrjdx5](https://doi.org/10.5061/dryad.31zcrjdx5) ## Description of the data and file structure Moth predation was assessed across time (day and night) and site (urban and rural) in June of 2023 using plasticine models of adult white-lined sphinx moths (*Hyles lineata*). Moth models were checked for attack marks every twilight for 72 hours.  ### Files and variables #### File: Hyles\_PredationData\_19NOV2024\_Dryad.csv **Description:**  ##### Variables Metadata:  | Moth\_ID is a unique number ranging from 001-400 for the first trial (June 8-June 12) | | :------------------------------------------------------------------------------------ | | Site is either IMRS (rural) or Knapp Land (urban) for trial 1 | | :------------------------------------------------------------ | | Transect is the location within Knapp Land or IMRS. For Knapp Land it would be A (North), B (Central), or C (south). For IMRS it would be either NW, NE, SW, or SE for each of the four directions | | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Set\_Date is the date DDMMMYYYY of when the moth was placed - it should be 08JUN2023 for all moths in the first trial | | :-------------------------------------------------------------------------------------------------------------------- | | Set\_Time is in 24 hr format raning from 00:00 to 23:59 | | :------------------------------------------------------ | | Removal\_Date is the date that the moth was attacked, went missing, or was removed from the study (aka the end of the study) | | :--------------------------------------------------------------------------------------------------------------------------- | | Removal\_Time is the time at which the moth was noticed attacked, missing, or removed | | :------------------------------------------------------------------------------------ | | Hour\_Survived is the number of hours the moth was deployed before being removed/attacked/missing, it should range between 1 and 78 hours | | :---------------------------------------------------------------------------------------------------------------------------------------- | | Day\_Survived is the day number at which the moth was attacked/missing/removed. Should range between 1 and 4. If the moth survives the experiment it will get a 4 | | :---------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Attack is whether the moth was attacked (1) or not attacked (0) | | :-------------------------------------------------------------- | | Day\_Night is whether the attack happened during the day (1) or night (0) or NA if not attacked. | | :----------------------------------------------------------------------------------------------- | | Type\_Attack is whether it was a bird (1), mammal (2), insect (3), other/unidentified (4), and if no attack (NA) | | :--------------------------------------------------------------------------------------------------------------- | | Censored is 0 if the moth went missing or was removed from the study early for any reason other than an attack. A value of 1 was given  if it did not go missing or was removed for reasons related to an attack or the end of the experiment | | :-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Time is if the attack happened during the day or night. If no attack, then NA | | :---------------------------------------------------------------------------- | | Predator is the categorical assignment of predator type for each attack, if no attack then NA | | :-------------------------------------------------------------------------------------------- | | Notes is a section where you can add anything or left blank | | :---------------------------------------------------------- | ## Code/software We analyzed the data using R code, not included. Contact Brett Seymoure if interested in code.