Reproductive transitions and sperm utilisation in a facultatively parthenogenetic stick insect

Facultative parthenogenesis enables females to switch from asexual (parthenogenetic) to sexual reproduction after mating, but the process of fertilisation is poorly understood in such animals. In particular, it is not known whether switching reproductive modes requires changes in the eggs themselves, delaying the transition from laying unfertilised to fertilised eggs. Likewise, very little is known about patterns of sperm precedence in facultatively parthenogenetic females that mate with multiple males. In this study, we manipulated reproductive mode in females of the facultatively parthenogenetic stick insect Megacrania batesii. We used offspring sex ratio, fertilisation rate, and paternity analysis to investigate how females descended from distinct natural populations switch between reproductive modes and utilise sperm from different males. In the switch treatment group, females were first allowed to lay unfertilised eggs, and then paired with a male. In the non-switch treatment group..., We used lab-reared females that were collected as eggs from natural Northern genotype mixed-sex (BK, CO, MB, MK) and Southern genotype all-female (B1, CB, TB) populations (Fig. 1) of M. batesii in far-north Queensland, Australia (population codes correspond to Wilner et al., 2025a). Adult females were divided into two treatment groups: “switch” (N = 17) and “non-switch” (N = 18). In the switch group, females were first housed alone and, after the onset of oviposition, allowed to lay unfertilised eggs for 20 days. In the non-switch group, females were paired with a male (first male) soon after their adult moult (mean = 1.78 ± 1.06 days) and, after the onset of oviposition, allowed to mate and lay eggs for 20 days. The eggs laid over the first 20 days were then removed. The number of eggs laid during this 20-day period did not differ between unpaired (switch treatment) females and male-paired (non-switch treatment) females (see Fig. 4A in Wilner et al., 2025a). Switch treatment femal..., # Data from: Reproductive transitions and sperm utilisation in a facultatively parthenogenetic stick insect

Dataset DOI: [10.5061/dryad.5hqbzkhhd](10.5061/dryad.5hqbzkhhd)

## Description of the data and file structure:

There are five main csv files (listed below).

### Files and variables

#### File: all_seq_daughters.csv

**Description:** Sequenced daughters 

##### Variables: 9

* origin_mom_type: Whether the population is Mixed-sex (reported as NMS) or All-female (reported as SAF).
* dna_extracted_date: DNA extracted date
* treat_id: Treatment group ID
* treat_grp: Treatment group names: the reproductive switch mode, represented as switch for those females paired with males throughout the experiment while non-switch for those females' initial reproductive mode was asexual.
* timing_of_eggs: E1 represents first 10-day period while E2 represents second 10-day period egg collections
* hatched_date: Hatched date for each hatchling
* sex_offspring: The sex of the hatchling, represente...,