Data for: Juvenile leg autotomy predicts adult male morph in a New Zealand harvestman with weapon polymorphism

Intraspecific weapon polymorphisms that arise via conditional thresholds may be affected by juvenile experiences such as predator encounters, yet this idea has rarely been tested. The New Zealand harvestman Forsteropsalis pureora has three male morphs: majors (alphas and betas) are large-bodied with large chelicerae used in male-male contests, while minors (gammas) are small-bodied with small chelicerae and scramble to find mates. Individuals use leg autotomy to escape predators and there is no regeneration of the missing leg. Here, we tested whether juvenile experience affects adult morph using leg autotomy scars as a proxy of predator encounters. Juvenile males that lost at least one leg (with either locomotory or sensory function) had a 45 times higher probability of becoming a minor morph at adulthood than intact juvenile males. Leg loss during development may affect foraging, locomotion, and/or physiology, potentially linking a juvenile’s predator encounters to their final adult mo..., Adult males (N = 86) of F. pureora were collected between Waitomo and Te Anga, New Zealand, across four sites: Ruakuri Bushwalk, Waitomo (38°15'53.7\"S 175°04'46.4\"E); private land, Te Anga (38°15'41.4\"S 175°00'53.6\"E); Tawarau Forest, Te Anga (38°17'24.8\"S 174°56'50.2\"E); and Marokopa Falls Track, Te Anga (38°15'33.6\"S 174°50'54.6\"E). Individuals were hand collected between 21:00 and 02:00 hours in January and February 2018. 
Sexual maturity was confirmed by the presence of a functional genital operculum, which is fused during the juvenile stage but can be opened upon the adult moult (Gnaspini 2007). Following Powell et al. (2020), we assigned each male to either major morph (alphas and betas, N = 63) or minor morph (gamma, N = 23). Morph frequency in our sample, with about 75% of majors and 25% of minors, closely followed that of the larger sample in Powell et al. (2020). Males were randomly collected, but it is possible that fewer minors were located because they were moving cryptical..., The .csv file can be opened with Microsoft Excel, Notepad, OpenOffice Calc, among other programs.Â