Females with masculine neck marks are passed over as mates
Male eastern fence lizards like ladies that look like ladies.
The males of the species, Sceloporus undulatus, have bright blue patches outlined in black along their throats and abdomens. About three-fourths of females have smaller, less-vibrant blue patches, giving them the name “bearded ladies.”
When given a choice of two females in a lab experiment, males preferred to mate with those with fewer or no blue scales, a new study finds. Males did mate with bearded ladies, but the resulting egg clutches weighed less than those of the more feminine lizards. The masculine females also laid eggs 13 days later than “beardless” lizards, researchers from Pennsylvania State University report November 5 in Biology Letters. The findings suggest that beardless females may reproduce better, making them more attractive to males.
The researchers speculate that bearded females might persist because they are more aggressive in fending off female competitors and predators.
L. Swierk and T. Langkilde. Bearded ladies: females suffer fitness consequences when bearing male traits. Biology Letters. Published online November 5, 2013. doi: 10.1098/rsbl.2013.0644.
M. Rosen. Legless geckos slither using skin ridges. Science News. Vol. 184, November 2, 2013, p. 8.