Data from: Male-mimicking females increase male-male interactions, and decrease male survival and condition in a female-polymorphic damselfly

Biologists are still discovering diverse and powerful ways sexual
conflicts shape biodiversity. The present study examines how the
proportion of females in a population that exhibit male mimicry, a mating
resistance trait, influences conspecific males’ behavior, condition and
survival. Like most female-polymorphic damselflies, Ischnura ramburii
harbors both “andromorph” females, which closely resemble males, and
sexually dimorphic “gynomorph” counterparts. There is evidence that male
mimicry helps andromorphs evade detection and harassment, but males can
also learn to target locally prevalent morph(s) via prior mate encounters.
I hypothesized that the presence of male mimics could therefore predispose
males to mate recognition errors, and thereby increase rates of costly
male-male interactions. Consistent with this hypothesis, male-male
interaction rates were highest in mesocosms containing more andromorph
(vs. gynomorph) females. Males in andromorph-biased mesocosms also had
lower final body mass and higher mortality than males assigned to
gynomorph-majority treatments. Male survival and body mass were each
negatively affect by mesocosm density, and mortality data revealed a
marginally significant interaction between andromorph frequency and
population density. These findings suggest that, under sufficiently
crowded conditions, female mating resistance traits such as male mimicry
could have pronounced indirect effects on male behavior, condition, and
survival.

Survival_and_mass_dataData on male survival and body mass from mesocosm experimentsBehavioral_ObservationsData from behavioral observations of focal males