DOI: 10.5061/dryad.rfj6q57n9
title: Augmentative release of two <em>Drosophila</em> parasitoids did not suppress competitor populations in a vineyard

description: In this study, we released two widely used pupal parasitoids, Trichopria
 drosophilae Perkins (Hymenoptera: Diapriidae) and Pachycrepoideus
 vindemiae (Rondani) (Hymenoptera: Pteromalidae), into
 vineyards to test whether augmentative release of T.
 drosophilae or P. vindemiae suppresses the wild
 populations of the other species. We investigated whether the
 augmentative release of two pupal Drosophila parasitoid species
 (Trichopria drosophilae and Pachycrepoideus vindemiae) in the
 vineyard decreases the emergence rate of their competitors. Parasitoid
 emergence rate, parasitism rate, and host mortality were recorded.
description: <strong>The insects</strong> The
 <em>P. vindemiae</em> and <em>T.
 drosophilae</em> populations were collected in a vineyard (36.66°N,
 121.28°E) in Jinan, Shandong Province, China. They are reared in the
 lab by Shandong Academy of Agricultural Sciences using
 <em>Drosophila melanogaster</em> Meigen pupae. All populations
 were maintained in growth chambers at 25±0.5°C, 70%±0.5% relative
 humidity, and a photoperiod of 16:8 hours (Light: Dark).
 <strong>Experimental design</strong>
 Three trials with three different grape cultivars (Ruby Seedless,
 Concord, Kyoho) were conducted in a vineyard in 2022, where pesticide was
 prohibited. Our preliminary investigation before the experiment showed
 that <em>P. vindemiae</em> is the dominant parasitoid with
 over 20 times higher population density than
 <em>T. drosophilae</em> in the studied vineyards. For each
 trial, we established a control plot (without releasing parasitoids)
 plus two treatment plots: one releasing
 <em>T. drosophilae</em> and the other releasing <em>P.
 vindemiae</em>. Experimental plots were spaced 200 to 400 m apart, a
 distance sufficient to prevent cross-plot dispersal as the maximum
 foraging distance of the studied parasitoid species is less than 40 m in
 their life (Hougardy et al., 2022; Stacconi et al., 2018).
 Newly mated female wasps were transferred from the insect rearing
 room into plastic vials (9.5 cm diameter × 10.3 cm height) using an
 aspirator. The lid of each vial was perforated with small holes to ensure
 ventilation. Each vial contained approximately 100 female wasps. A cotton
 ball soaked with a 50% honey solution was placed on top of each vial to
 feed the parasitoids. To sustain an effective population density when the
 host abundance was at its peak, we conducted six separate releases of
 parasitoids. Approximately 1,000 female wasps were released per plot in
 the augmentative release treatment groups on 28 July, 3, 9, 12, 17, and 24
 August. <strong>Pupae collection and
 dissection</strong> Ten grape bunches were
 collected at each plot one week after every parasitoid augmentative
 release. <em>Drosophila</em> pupae on the grapes were
 transferred into plastic boxes that were covered by lids with
 approximately 1-mm-diameter holes for air exchange. A total of 5,467 pupae
 were collected across all plots. The number of emerged
 <em>Drosophila</em> flies and parasitoids from pupae collected
 in each plot was counted. Additionally, 288 live pupae were dissected
 before the emergence of <em>Drosophila</em> flies to assess
 parasitism by the two parasitoid species. At the end of the experiment,
 1,865 dead pupae (from which neither parasitoids nor
 <em>Drosophila</em> flies emerged) were dissected to determine
 if they were parasitized. The emergence rate of parasitoids was quantified
 by the number of adult parasitoids that successfully emerged from
 collected pupae. The parasitism rate of parasitoids was quantified by
 dissecting live host pupae and recording observed stages of parasitoid
 offspring (eggs, larvae, or adults). Total mortality of Drosophila flies
 was determined by adding Parasitoid-emerged pupae (successful parasitism)
 and the dead pupae from which neither flies nor wasps emerged.
 Field experiments inherently face uncontrolled factors such as
 weather variation, microhabitat heterogeneity, and the presence of other
 natural enemies. While we minimized pesticide disturbance and spatial
 interference by plot design, we could not fully account for all
 environmental variables. We do not release any parasitoids in the control
 plots; therefore, the control plots can be used to measure the natural
 parasitoid and host interaction strength.
 <strong>Data analysis</strong> We
 tested whether the emergence and parasitism rate of two parasitoid species
 and the total mortality rate of
 <em>Drosophila</em> flies significantly varied among
 parasitoid releasing treatments using generalized linear mixed-effects
 models (GLMMs with binomial error structure). The investigation time
 nested within the grape variety was included as a random factor. Tukey’s
 HSD tests were conducted whenever a significant difference among
 treatments was detected. All the data analyses were conducted by R ver.
 4.2.3 (R Core Team, 2020).
description: # Augmentative release of two *Drosophila* parasitoids did not suppress
 competitor populations in a vineyard Dataset DOI:
 [10.5061/dryad.rfj6q57n9](10.5061/dryad.rfj6q57n9) ## Description of the
 data and file structure Parasitoid emergence rate, parasitism rate, and
 host mortality were recorded. ### Files and variables #### File:
 Emergence_data.csv **Description:**  ##### Variables * CollectDate: Pupae
 collection time * Plot: 3plots * GrapeString: Two clusters of grapes as a
 unit * Treat: Parasitoids release treatments and control groups, including
 Release *Trichopria drosophilae*, Release *Pachycrepoideus vindemiae,*
 and Control. * Group: 3 different treatments, including a, b, d *
 ReleaseT: Whether to release *Td.*: 1 for yes, 0 for no * ReleaseP:
 Whether to release *Pv.*: 1 for yes, 0 for no * PupaNumber: Number of
 pupae collected * AlonePupaNumber: Selected pupae were individually placed
 in test tubes plugged with cotton, and counts were made after their
 emergence. * AloneTEmergeN: Number of *Td*. emerged in test tubes *
 ATEFemale: Number of female *Td*. emerged in test tubes * ATEMale: Number
 of male *Td*. emerged in test tubes * AlonePEmergeN: Number of *Pv*.
 emerged in test tubes * APEFemale: Number of female *Pv*. emerged in test
 tubes * APEMale: Number of male *Pv*. emerged in test tubes *
 DroEmergeN: Number of *Drosophila* emerged * TEmergeN: Number of *Td*.
 emerged (Excluding the pupae in test tubes and those dissected alive,
 count the number of *Td*. emerged from the remaining pupae) *
 TEmergeFemaleN: Number of female *Td*. emerged (Excluding the pupae in
 test tubes and those dissected alive, count the number of female *Td*.
 emerged from the remaining pupae) * TEmergeMaleN: Number of male *Td*.
 emerged (Excluding the pupae in test tubes and those dissected alive,
 count the number of male *Td*. emerged from the remaining pupae) *
 PEmergeN: Number of *Pv*. emerged (Excluding the pupae in test tubes and
 those dissected alive, count the number of *Pv*. emerged from the
 remaining pupae) * PEmergeFemaleN: Number of female *Pv*. emerged
 (Excluding the pupae in test tubes and those dissected alive, count the
 number of female *Pv*. emerged from the remaining pupae) *
 PEmergeMaleN: Number of male *Pv*. emerged (Excluding the pupae in test
 tubes and those dissected alive, count the number of male *Pv*. emerged
 from the remaining pupae) * FEmergeN: Number of a specific braconid
 species emerged * FEmergeFemaleN: Number of female braconid emerged *
 FEmergeMaleN: Number of male braconid emerged * OtherEmergeN: Number of
 other parasitoids emerged * DeadPupaN: Pupae that neither parasitoids
 nor *Drosophila emerged* * DissectDeadPupaN: Number of dissected pupae
 from which from which neither parasitoids nor Drosophila emerged *
 TNinDP: Number of *Td*. in dead pupae (neither parasitoids nor Drosophila
 emerged) * PNinDP: Number of *Pv*. in dead pupae (neither parasitoids nor
 Drosophila emerged) * FNinDP: Number of braconid in dead pupae (neither
 parasitoids nor Drosophila emerged) * DissectLivePupaN: Number of live
 pupae dissected * PupaNwithT: Number of live pupae dissected with *Td*.
 observed * TNinLP: Total count of *Td*. observed in dissected live pupae *
 PupaNwithP: Number of live pupae dissected with *Pv*. observed *
 PNinLP: Total count of *Pv*. observed in dissected live pupae *
 PEmergeRate: Total emergence rate of *Pv.* * PNumber: Total number of
 *Pv*. emerged * TEmergeRate: Total emergence rate of *Td.* *
 TNumber: Total number of *Td*. emerged * OtherEmergeRate: Emergence rate
 of other parasitoids * TotalEmergeRate: Total emergence rate of two
 parasitoids (*Td*. and *Pv*.) * DroUnknowDeathRate: Unknown reason
 mortality of *Drosophila* (neither parasitoids nor *Drosophila* emerged) *
 DroDeathRate: Total mortality of *Drosophila* * DroDeadPupaNumber: Total
 number of dead pupae  * DroUnknowDeadPupa: Number of unknown reason dead
 pupae (neither parasitoids nor Drosophila emerged) #### File:
 Live_pupae_dissection_data.csv **Description:**  ##### Variables *
 Date: Pupae collection time * Grape: Grape varieties * Treat: Parasitoids
 release treatments and control groups, including Release *Trichopria
 drosophilae* (Td), Release *Pachycrepoideus vindemiae* (Pv), and Control.
 * Group: 3 different treatments, including a, b, d * PupaNumber: Number of
 live pupae dissected * PupaNumberWithT: Number of live pupae dissected
 with *Td*. observed * TPRate: Total parasitism rate of *Td*. * TNumber:
 Total count of *Td*. observed in dissected live pupae  *
 PupaNumberWithP: Number of live pupae dissected with *Pv*. observed *
 PPRate: Total parasitism rate of *Pv*. * PNumber: Total count of *Pv*.
 observed in dissected live pupae * MultiParaPupa: Number
 of multiparasitism Pupae  * MPRate: Multiparasitism rate *
 THyperParaPupa: Number of pupae hyperparasitized by *Td*. * THPRate:
 Hyperparasitism rate of *Td*. * PHyperParaPupa: Number of pupae
 hyperparasitized by *Pv*. * PHPRate: Hyperparasitism rate of *Pv*. *
 TotalPRate: Total parasitism rate of two parasitoids (*Td*. and *Pv*.)
 #### File: Yellow_trap_data.xls **Description:**  ##### Variables *
 Date: Deployment dates of traps * Grape: Grape varieties * Treat: Control
 plots * DroNumber: Number of *Drosophila* * TNumber: Number of *Td*.  on
 traps * TFemale: Number of female *Td*.  on traps * TMale: Number of
 male *Td*.  on traps * PNumber: Number of *Pv*.  on traps *
 PFemale: Number of female *Pv*.  on traps * PMale: Number of male *Pv*. 
 on traps #### File: R_code.txt **Description:**  * This is the code I used
 for data visualization and analysis in R.ver. 4.2.3.  * The following
 packages may be required: “lme4”， “agricolae”， “nlme”，
 “ggplot2”，“multcomp”， “reshape2”， “fitdistrplus”， “lmerTest”， “dplyr”，
 “eoffice”， “tidyr”， “coin”. ## Code/software We tested whether the
 emergence and parasitism rate of two parasitoid species and the total
 mortality rate of *Drosophila* flies significantly varied among parasitoid
 releasing treatments using generalized linear mixed-effects models (GLMMs
 with binomial error structure). The investigation time nested within the
 grape variety was included as a random factor. Tukey’s HSD tests were
 conducted whenever a significant difference among treatments
 was detected. All the data analyses were conducted by R ver. 4.2.3 (R Core
 Team, 2020). ## Access information Other publicly accessible locations of
 the data: * NA Data was derived from the following sources: * NA