Sexually antagonistic coevolution of the male nuptial gift and female feeding behaviour in decorated crickets

The evolution of nuptial gifts has traditionally been considered a harmonious affair, providing benefits to both mating partners. There is growing evidence, however, that receiving a nuptial gift can be actively detrimental to the female. In decorated crickets (Gryllodes sigillatus), males produce a gelatinous spermatophylax that enhances sperm transfer but provides little nutritional benefit and hinders female post-copulatory mate choice. Here, we examine the sexually antagonistic coevolution of the spermatophylax and the female feeding response to this gift in G. sigillatus maintained in experimental populations with either a male-biased or female-biased adult sex ratio. After 25 generations, males evolving in male-biased populations produced heavier spermatophylaxes with a more manipulative combination of free amino acids than those evolving in female-biased populations. Moreover, when the spermatophylax originated from the same selection regime, females evolving in male-biased populations always had shorter feeding durations than those evolving in female-biased populations indicating the evolution of greater resistance. Across populations, female feeding duration increased with the mass and manipulative combination of free amino acids in the spermatophylax suggesting sexually antagonistic coevolution. Collectively, our work demonstrates a key role for interlocus sexual conflict and sexually antagonistic coevolution in the mating system of G. sigillatus.

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README: Sexually antagonistic coevolution of the male nuptial gift and female feeding behaviour in decorated crickets
We subjected replicated populations of decorated crickets to different regimes of interlocus sexual conflict by altering the adult sex ratio to be male-biased (increased conflict) or female-biased (reduced conflict). After 25 generations of experimental evolution we measured how manipulative the nuptial gifts produced by males (the spermatophylax) were. Manipulativeness of the gift is measured by dry mass (measured using an electronic balance) and amino acid composition (measured by GC-MS). We also measured female resistance in these populations as the time the female spent feeding on this gift (through behavioural observations).

Description of the data and file structure
Microsoft Excel is required to open the data files. We have uploaded 3 files: named "Dryad_Spermatophylax data_raw", "Dryad_Feeding data_raw" and "Dryad_mean spermatophylax and feeding data".

"Dryad_Spermatophylax data_raw" contains all of the raw data on how manipulative the nuptial gift is from the replicate populations. The first column "Selection regime" describes whether the population had a male-biased or female-biased adult sex ratio, the second column "Replicate" describes the replicate population (one to six) and the third column "Male SPHYLAX" is an ID for the male that the spermatophylax was taken from. The next 19 columns is the log10 amount of free amino acids in the spermatophylax. The naming of these columns used the conventional abbreviation for these free amino acids and is provided in the manuscript text. The columns labelled "DF1" and "DF1" are discriminant functions derived from these amino acids to determine how populations with alternate selection regimes have diverged. The column "SPHYLAX dry weight (mg)" provides the dry weight of spermatophylaxes and the column named " Manipulation score" provides the multivariate score of how manipulative the free amino acids is to the female (full details on how this is calculated is provided in the manuscript text).

"Dryad_Feeding data_raw" provides the raw feeding data of females from each population. "Selection regime" and "Replicate" columns are as described for "Dryad_Spermatophylax data_raw". "SPHYLAX origin" describes the population origin of the nuptial gift presented to female - being either from their "own" population or "crossed" from the same replicate population experiencing the opposite selection regime. " ID" provides the unique identity of females and "Feeding duration (secs)" provides the amount of time the female fed on the gift (in seconds).

"Dryad_mean spermatophylax and feeding data" provides the mean data for each of the male manipulation measured and female feeding time taken from the above two data sets. "Selection regime" and "Replicate" are the same as the two above files. "Mean SPHYLAX dry weight" and "Mean manipulation score" are the mean of the data for each replicate population provided in "Dryad_Spermatophylax data_raw". "Mean feeding duration_own population (secs)" and "Mean feeding duration_crossed population (secs)" is the mean feeding time of females when recieving a gift from their own population or crossed from the opposite selection regime, respectively. These mean estimates come from "Dryad_Feeding data_raw".

Sharing/Access information
Links to other publicly accessible locations of the data:
The data contained on Dryad will be also be made publically available via the Research Data Management System at Western Sydney University.

Data was derived from the following sources:
All uploaded data has been collected from experiments conducted by the authors.

Code/Software
No code is provided. All analyses were conducted using IBM SPSS (version 29.0.0.0).

Methods
We manipulated the intensity of interlocus sexual conflict in replicate experimental population by manipulating the adult sex ratio to be either male -biased (increased conflict) or female-biased (reduced conflict). This was done for 25 generations of evolution. We then measured the manipulative properties of the male nuptial gift (the spermatophylax) in these populations (spermatophylax dry mass and amino acid composition), as well as female feeding duration on these gifts (as a measure of resistance to manipulation). We present the raw data and population mean data for these traits. Spermatophylax dry mass was measured using an electronic balance. Spermatophylax amino acid composition was measured using GC-MS. Female feeding behaviour was measured in behavioural assays.

Usage notes
Data is presented in Microsoft Excel.

传统观点认为，婚礼物（nuptial gift）的演化是一种和谐过程，可为交配双方均带来收益。然而，越来越多的研究证据表明，接收婚礼物反而会对雌性个体产生显著的不利影响。在装饰蟋蟀（斑腿双针蟋，Gryllodes sigillatus）中，雄性会分泌一种凝胶状的精护团（spermatophylax），该结构可促进精子传递，但几乎无营养价值，且会阻碍雌性的交配后配偶选择行为。本研究以成年种群性比偏雄或偏雌的实验种群为研究对象，探究斑腿双针蟋的精护团与雌性对该婚礼物的取食响应之间的性拮抗协同演化过程。经过25代演化后，相较于在性比偏雌种群中演化的雄性，在性比偏雄种群中演化的雄性所产生的精护团更重，且其游离氨基酸组合更具操纵性。此外，当精护团来自同一选择处理组时，在性比偏雄种群中演化的雌性的取食时长始终短于在性比偏雌种群中演化的雌性，这表明前者演化出了更强的抗性。在所有种群中，雌性的取食时长随精护团的质量及其游离氨基酸的操纵性组合的增加而延长，这一结果佐证了性拮抗协同演化的存在。综上，本研究揭示了基因座间性冲突与性拮抗协同演化在斑腿双针蟋交配系统中的关键作用。

## README：装饰蟋蟀雄性婚礼物与雌性取食行为的性拮抗协同演化
我们通过调整成年种群性比为偏雄（增强基因座间性冲突强度）或偏雌（减弱基因座间性冲突强度），对装饰蟋蟀的重复实验种群施加了不同强度的基因座间性冲突处理。经过25代实验演化后，我们对雄性产生的婚礼物（精护团）的操纵性进行了测定：该操纵性通过精护团干重（使用电子天平称量）与氨基酸组成（通过气相色谱-质谱联用仪GC-MS测定）两个指标来衡量。同时，我们以雌性在该婚礼物上的取食时长（通过行为观测记录）作为雌性抗性的测定指标。

## 数据与文件结构说明
本数据集需使用Microsoft Excel打开数据文件。本次上传共包含3个数据文件，分别为"Dryad_Spermatophylax data_raw"、"Dryad_Feeding data_raw"以及"Dryad_mean spermatophylax and feeding data"。

"Dryad_Spermatophylax data_raw"包含了所有重复实验种群中婚礼物操纵性的原始数据。其中，第一列"Selection regime（选择处理组）"标注了该种群的成年性比类型（偏雄或偏雌）；第二列"Replicate（重复种群）"标注了重复种群编号（1至6）；第三列"Male SPHYLAX"为精护团供体雄性的唯一标识。后续共19列数据为精护团中游离氨基酸含量的以10为底的对数值，这些列名采用了游离氨基酸的通用缩写，具体说明详见论文正文。列名"DF1"为基于上述氨基酸数据推导得到的判别函数，用于区分不同选择处理组种群的分化差异。"SPHYLAX dry weight (mg)（精护团干重，单位：mg）"列记录了精护团的干重，而"Manipulation score（操纵性得分）"列则记录了反映游离氨基酸对雌性操纵性的多元得分（该指标的详细计算方法参见论文正文）。

"Dryad_Feeding data_raw"包含了各实验种群雌性的取食行为原始数据。其中"Selection regime（选择处理组）"与"Replicate（重复种群）"列的含义与"Dryad_Spermatophylax data_raw"中一致。"SPHYLAX origin（精护团来源）"标注了呈递给雌性的婚礼物的种群来源：既可为该雌性所在的"自身种群"，也可为来自同一重复种群但经历相反选择处理的"杂交种群"。"ID（雌性唯一标识）"列记录了雌性个体的唯一编号，"Feeding duration (secs)（取食时长，单位：秒）"列则记录了雌性在婚礼物上的取食时长。

"Dryad_mean spermatophylax and feeding data"包含了从上述两个原始数据集中提取得到的各重复种群的雄性操纵性指标与雌性取食时长的均值数据。其中"Selection regime（选择处理组）"与"Replicate（重复种群）"列的含义与前述两个文件一致。"Mean SPHYLAX dry weight（平均精护团干重）"与"Mean manipulation score（平均操纵性得分）"列分别为"Dryad_Spermatophylax data_raw"中各重复种群的精护团干重与操纵性得分的平均值。"Mean feeding duration_own population (secs)（自身种群来源取食平均时长，单位：秒）"与"Mean feeding duration_crossed population (secs)（杂交种群来源取食平均时长，单位：秒）"列分别为雌性接受自身种群来源婚礼物与杂交种群来源婚礼物时的取食时长平均值，该数据来源于"Dryad_Feeding data_raw"。

## 数据共享与获取说明
本数据集的公开获取链接：
Dryad平台收录的本数据集同时将通过西悉尼大学研究数据管理系统面向公众开放。

数据来源说明：
本次上传的所有数据均来自本研究团队开展的实验。

## 代码与软件说明
本数据集未附带分析代码，所有统计分析均通过IBM SPSS（版本29.0.0.0）完成。

## 实验方法
我们通过调整实验种群的成年性比为偏雄（增强基因座间性冲突强度）或偏雌（减弱基因座间性冲突强度），对装饰蟋蟀的重复实验种群施加了不同强度的基因座间性冲突处理，并持续开展25代演化。随后，我们对各实验种群中雄性婚礼物（精护团）的操纵特性进行了测定，包括精护团干重与氨基酸组成，并以雌性在该婚礼物上的取食时长作为雌性抗操纵性的衡量指标。本数据集提供了上述性状的原始测量数据与种群均值数据。其中，精护团干重通过电子天平称量获得，精护团氨基酸组成通过气相色谱-质谱联用仪（GC-MS）测定，雌性取食行为则通过行为学实验记录得到。

## 使用说明
本数据集以Microsoft Excel格式存储。