Data from: It’s lonely at the front: contrasting evolutionary trajectories in male and female invaders

Invasive species often exhibit rapid evolutionary changes, and provide powerful insights into the selective forces shaping phenotypic traits. Invasions may impose strong pressures on sexual dimorphism in morphological traits that influence performance in dispersal and/or sexual interactions. We measured relative lengths of forelimbs and hindlimbs of >3000 field-caught adult cane toads (Rhinella marina) from 67 sites in Hawai’i and Australia (1 to 80 years post-colonisation), along with 489 captive-bred individuals from multiple Australian sites raised in a “common garden” (to examine heritability of morphology). As cane toads spread from east to west across Australia, the ancestral condition (long limbs, especially in males) was modified. Limb length relative to body size was first reduced (lower in intermediate-aged populations than range-core), but then increased again (perhaps due to spatial sorting rather than natural selection) in the invasion vanguard. In contrast, the sex divergence in relative limb length has progressively decreased during the toads’ Australian invasion. Our common garden experiment revealed significant heritability (12–27%) of limb dimensions, suggesting that the observed morphological shifts are due in part to evolutionary change. Cane toads thus have evolved a significant shift in sexual dimorphism in relative limb lengths during their brief (81-year) spread through tropical Australia.