Scaling of ovipositor size in Drosophila suzukii and D. subpulchrella: Altered genital-coupling mechanisms and evolution of allometric slopes

Animal genitalia typically exhibit limited size variation relative to overall body size, a pattern known as negative allometry. The “one-size-fits-all” hypothesis suggests that genital compatibility between sexes constrains the evolution of extreme genital sizes, yet direct evidence remains scarce. Drosophila suzukii presents a unique opportunity to test this hypothesis from the female perspective. This species has evolved an enlarged, sclerotized ovipositor capable of piercing intact fruit skins. However, this innovation necessitated an altered genital coupling mechanism, as the modified ovipositor—also functioning as part of the female genitalia—posed a mechanical obstacle to copulation. In contrast, D. subpulchrella, the closest relative of D. suzukii, retains the ancestral coupling mechanism, which depends on genital size compatibility between sexes. Allometric analyses revealed that D. subpulchrella ovipositors exhibit shallower scaling slopes than other body parts, consistent with..., Sample collection
Two pairs of sympatric populations of D. suzukii and D. subpulchrella, collected in Tokyo and Yamagata, Japan, were used to confirm the consistency across populations of different localities. For the Tokyo populations, the adults that emerged from wild berries (Rubus hirsutus, R. palmatus, R. crataegifolius, R. microphyllus, Cerasus jamasakura, Morus australis) were directly used for morphological measurements. Ripe fruits were collected from a mountainous area in Hachioji, Tokyo, once a week from May to June in 2024. They were individually maintained in glass vials at 20°C in the laboratory until adults emerged. For the Yamagata populations, laboratory-maintained strains were used for the measurements. These strains were originally established from multiple pairs that emerged from Chinese dogwood fruits (Cornus kousa) collected in Minorigaoka, Yamagata, in 2021. They have since been maintained on standard Drosophila medium consisting of cornmeal, glucose, and dry yeas..., # Data from: Scaling of ovipositor size in Drosophila suzukii and D. subpulchrella: Altered genital-coupling mechanisms and evolution of allometric slopes

Dataset DOI: [10.5061/dryad.n5tb2rc78](10.5061/dryad.n5tb2rc78)

## Description of the data and file structure

### Files and variables

#### File: Trait_size.xlsx

**Description:** The values of measured traits and accompanied information for each individual used in the study.

##### Variables

* Sample_ID: a unique number for all individuals used in the analysis.
* Date of collection: the date of the host fruit was collected.
* Date of dissection: the date of sample treatment performed on the emerged adults (dissection, mounting, and image acquisition).
* Host: host name.
* Population: locality of the samples collected. {Tokyo|Yamagata}
* Species: species name of the corresponding individual. {suzukii|subpulchrella}
* head-width: length in μm.
* thorax-length: length in μm.
* ovp1-length: length of a ovipositor in μm.
* ovp1-width:...,

动物生殖器的大小变异通常相较于整体体型受限，这种模式被称为负异速生长（negative allometry）。"one-size-fits-all"（一刀切）假说提出，两性间的生殖器兼容性会限制极端生殖器尺寸的演化，但目前直接相关的证据仍较为匮乏。斑翅果蝇（Drosophila suzukii）为从雌性视角验证该假说提供了独特的研究契机。该物种演化出了膨大且硬化的产卵器（ovipositor），能够刺穿完整的果皮。然而这一演化革新也催生了生殖器交配耦合机制的改变，因为经过改造的产卵器——同时也是雌性生殖器的一部分——会对交配过程造成机械阻碍。与之相对，斑翅果蝇的近缘物种亚美果蝇（Drosophila subpulchrella）则保留了祖先的交配耦合机制，该机制依赖于两性间的生殖器尺寸兼容性。异速生长分析结果显示，亚美果蝇的产卵器缩放斜率相较于其他身体部位更平缓，这与……

### 样本采集
本研究选取了分别采自日本东京和山形县的两对对斑翅果蝇与亚美果蝇的同域种群，以验证不同地理种群间的研究结果一致性。针对东京种群，从野生浆果（腺果悬钩子*Rubus hirsutus*、掌叶悬钩子*R. palmatus*、山楂叶悬钩子*R. crataegifolius*、小叶悬钩子*R. microphyllus*、山樱花*Cerasus jamasakura*、桑树*Morus australis*）中羽化的成虫直接用于形态学测量。2024年5月至6月期间，研究人员每周从东京八王子市的山区采集成熟果实，将其单独置于玻璃管中，在20℃的实验室环境下饲养至成虫羽化。针对山形种群，本研究使用实验室饲养的品系进行测量。这些品系最初于2021年从采自山形县御法ヶ丘（Minorigaoka）的四照花（*Cornus kousa*）果实中羽化的多对成虫建立，此后一直以由玉米粉、葡萄糖和干酵母组成的标准果蝇培养基饲养……

# 数据来源：斑翅果蝇与亚美果蝇产卵器尺寸缩放：交配耦合机制的改变与异速生长斜率的演化

数据集DOI：10.5061/dryad.n5tb2rc78

## 数据与文件结构说明

### 文件与变量

#### 文件：Trait_size.xlsx

**文件说明**：本研究中所有个体的测量性状数值及配套相关信息。

##### 变量
* 样本编号（Sample_ID）：用于区分本次分析中所有个体的唯一编号。
* 宿主果实采集日期：采集宿主果实的日期。
* 解剖日期：对羽化成虫进行样品处理（解剖、封片及图像采集）的日期。
* 宿主：宿主植物名称。
* 种群：样本采集地点，可选值为{东京|山形}。
* 物种：对应个体的物种名称，可选值为{suzukii|subpulchrella}（斑翅果蝇/亚美果蝇）。
* 头宽（head-width）：单位为微米（μm）。
* 胸长（thorax-length）：单位为微米（μm）。
* 产卵器1长度（ovp1-length）：产卵器的长度，单位为微米（μm）。
* 产卵器1宽度（ovp1-width）：……