Divergence in cuticular wax profiles generates partial behavioural isolation between leaf beetle populations with different dispersal traits

Sex pheromones are among the most studied insect mating signals, with their extensive diversity underscoring their crucial role in promoting behavioural isolation during speciation. In Chrysomelidae, cuticular wax (CW), a hydrophobic layer covering the insect cuticle, is a potential barrier that facilitates behavioural isolation. Male leaf beetles use female CW as a mating signal, and their species-specific profiles prevent heterospecific mating between closely related species, implying that divergence in CW profiles promotes reproductive isolation, and, hence, contributes to speciation. However, the role of CW as an isolating barrier remains unclear owing to limited knowledge regarding intraspecific divergence in female CW and its coevolution with male preferences. Through chemical analysis and behavioural experiments, we demonstrated that intraspecific divergence in female CW profiles contributes to partial behavioural isolation between leaf beetle populations with different dispersal..., (a) Insects
The macropterous population originated from Ogata, Akita, Japan (40°0ʹ N, 139°56ʹ E), and the brachypterous population originated from Sendai, Miyagi, Japan (38°16ʹ N, 140°52ʹ E). Each population was reared under the same conditions to avoid the potential effects of extrinsic factors (humidity, temperature, and nutrition) on CW profiles and to investigate genetically based divergence in phenotypes. Both populations were maintained in a climate chamber at 25 ± 1 ℃ and 60% relative humidity under a 16L:8D photoperiod and reared on fresh leaves of Rumex obtusifolius. Newly emerged adults were sexed and kept separately from each other. Unmated adults at 7–8 days post-emergence were used in the experiments.
(b) Hindwing polymorphism
To describe hindwing polymorphism, we examined the development of hindwings in females and males from each macropterous and brachypterous population (n = 25). After the beetles were freeze-killed, their right forewings and hindwings were dissecte..., , # Data from: Divergence in cuticular wax profiles generates partial behavioural isolation between leaf beetle populations with different dispersal traits

Dataset DOI: [10.5061/dryad.kh18932jj](10.5061/dryad.kh18932jj)

## **Description of the data and file structure**

We obtained the data on hindwing polymorphism, chemical composition of cuticular wax, and male mate preferences under two-choice and no-choice situation. The dataset contains 4 folders:

### **Folder: wing_sizes.zip**

#### **Description:** 

This folder contains data on wing sizes to evaluate hindwing polymorphism in *Galerucella grisescens*.

##### **File: wing_sizes_data.csv**

**·** **rep.**: Replicates.

**·** **forewing (mm2):** The sizes of forewings.

**·** **hindwing (mm2):** The sizes of hindwings.

**·** **ratio (h/f):** The ratios of hindwing sizes to forewing sizes. To correct wing size variations caused by body size variations, we used the ratios for evaluating hindwing polymorphism.

### **Folder: gcms.zip...,