Data from: A test of Haldane’s rule in Neodiprion sawflies and implications for the evolution of postzygotic isolation in haplodiploids
Data files
Aug 23, 2024 version files 41.76 KB
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Compiled_hybrid_viability_2022.csv
4.84 KB
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EmbryoViability-2022.csv
3.10 KB
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HR_in_Neodiprion_analyses_20Jan2023.R
12.20 KB
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Male_mating_success.csv
3.18 KB
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Mated_female_fertility.csv
8.10 KB
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README.md
3.80 KB
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SpermMotility.csv
6.53 KB
Abstract
Haldane’s rule—a pattern in which hybrid sterility or inviability is observed in the heterogametic sex of an interspecific cross—is one of the most widely obeyed rules in nature. Because inheritance patterns are similar for sex chromosomes and haplodiploid genomes, Haldane’s rule may apply to haplodiploid taxa, predicting that haploid male hybrids will evolve sterility or inviability before diploid female hybrids. However, there are several genetic and evolutionary mechanisms that may reduce the tendency of haplodiploids to obey Haldane’s rule. Currently, there are insufficient data from haplodiploids to determine how frequently they adhere to Haldane’s rule. To help fill this gap, we crossed a pair of haplodiploid hymenopteran species (Neodiprion lecontei and Neodiprion pinetum) and evaluated the viability and fertility of female and male hybrids. Despite considerable divergence, we found no evidence of reduced fertility in hybrids of either sex, consistent with the hypothesis that hybrid sterility evolves slowly in haplodiploids. For viability, we found a pattern opposite of Haldane’s rule: hybrid females, but not males, had reduced viability. This reduction was most pronounced in one direction of the cross, possibly due to a cytoplasmic-nuclear incompatibility. We also found evidence of extrinsic postzygotic isolation in hybrids of both sexes, raising the possibility that this form or reproductive isolation tends to emerge early in speciation in host-specialized insects. Our work emphasizes the need for more studies on reproductive isolation in haplodiploids, which are abundant in nature, but under-represented in the speciation literature.
README
This Dryad repository contains all data and R commands to evaluate hybrid viability and fertility in Neodiprion sawflies, as described in:
"A test of Haldane’s rule in Neodiprion sawflies and implications for the evolution of postzygotic isolation in haplodiploids."
For questions, contact corresponding author: Catherine Linnen (catherine.linnen@uky.edu)
DATAFILES:
Compiled_hybrid_viability_2022.csv: sex ratio data from 6 different types of families.
Column names are as follows:
"Family": unique identifier for each individual family
"male_emergence": number of adult males
"female_emergence": number of adult females
"cross_type": type of family or cross, as defined by the mother and father
"total": total number of adults emerged
"propFem": proportion of adults that were female
"propMale": proportion of adults that were male
EmbryoViability-2022.csv: Number of eggs that hatched or failed to hatch for families containing pure lecontei, F1 hybrid females, F2 hybrid males, pure pinetum, on white or jack pine.
Column names are as follows:
"Family": Unique family identifier
"Cross_type": type of family or cross, as defined by the mother and father
"Host": host plant chosen by the mother (J = jack pine; W=white pine)
"Eggs": number of eggs laid by the female
"EggsFall": number of eggs that got knocked off during counting
"TotalEggs": total number of eggs after accounting for lost eggs
"EggHatch": number of hatchlings after 48 hrs of hatching
"EggFail": number of eggs that failed to hatch (TotalEggs - EggHatch)
"PropHatch": Proportion of eggs that hatched
"CrossHost": composite variable that combines cross type and host, mostly for plotting.
Mated_female_fertility.csv: whether or not a female laid and number of eggs laid by different types of females (hybrids and pure species)
Column names are as follows:
"Cross": unique identifier for each female
"Oviposited": presence (1) or absence (0) of oviposition
"egg_number": if female laid, number of eggs laid
"Female": type of female (lecontei, pinetum, or reciprocal hybrids)
Male_mating_success.csv: Mating outcomes (yes/no) for lecontei and hybrid males paired with lecontei females.
Column names as follows:
"ID": unique identifier for each attempted cross
"Female": colony ID for each female
"Male": colony ID for each male
"Mated": presence (1) or absence (0) of a mating event in a 2-hr assay
"Type": type of male (hybrid or lecontei male)
SpermMotility.csv: Approximate percentage of sperm bundles that were motile in sperm dissected from testes of different types of males.
Column names as follows:
"Male": unique identifier for each male; some of these correspond to same IDs in male mating success assays
"MaleType": type of male (hybrid, lecontei, or pinetum)
"Family": family/colony ID for each male
"Date dissected":the day the testes dissection took place
"emergence date": the date the male emerged from his cocoon
"time_to_dissection": the number of days between emergence and dissection
"mated": whether (1) or not (0) a male mated with a female prior to dissection
"PercentMotilityTestis1": approximate (to the nearest 5%) percentage of sperm bundles that were moving for testis 1 (whichever testes was visualized first)
"PercentMotilityTestis2": approximate (to the nearest 5%) percentage of sperm bundles that were moving for testis 2 (whichever testes was visualized second)
"AvgMotilityTestes": average between two testes.
R Scripts:
HR_in_Neodiprion_analyses_20Jan2023.R: R code needed to produce all statistical results presented in the paper.
Note all scripts were run using R v 4.2.1 and the following package versions:
- car v3.1-0
emmeans v1.8.0
lmerTest v3.1-3
ggplot2 v3.3.6
dplyr v1.0.9
DescTools v0.99.45
Methods
Adult sex ratio data were collected from laboratory rearing logs from 2013-2017 during times when both species and hybrids were being reared in the lab. Hand-written data were transcribed into an excel file and checked for accuracy before analysis in R.
Embryo viability data were collected from laboratory rearing logs and experimental notebooks for an interspecific cross in which we recorded egg number and counted hatchlings 48 hours after hatching started. Hand-written data were transcribed into an excel file and checked for accuracy before analysis in R.
Female fertility data were collected from laboratory rearing logs and experimental notebooks in which we recorded whether or not eggs were laid and total egg number laid by pure-species and hybrid females. Hand-written data were transcribed into an excel file and checked for accuracy before analysis in R.
Male fertility data were recorded in experimental notebooks as sperm were observed under a microscope. These hand-written data were transcribed into an excel file and checked for accuracy before analysis in R. We also used laboratory rearing notebooks to verify that hybrid males produced viable female offspring.
Male behavioral sterility data were recorded in experimental notebooks during mating assays and then transcribed into an excel file and checked for accuracy before analysis in R.
Usage notes
Missing values are indicated by "NA"