10.5061/DRYAD.41NS1RN9N
Hook, Kristin
0000-0001-5864-0316
University of Maryland, Baltimore
Fisher, Heidi
University of Maryland, Baltimore
Weber, W. David
University of Maryland, Baltimore
Hoekstra, Hopi
Harvard University
Data from: Sibling rivalry: males with more brothers develop larger testes
Dryad
dataset
2019
offspring sex ratio
Eunice Kennedy Shriver National Institute of Child Health and Human Development
https://ror.org/04byxyr05
R00HD071972
National Science Foundation
https://ror.org/021nxhr62
1711817
2019-12-06T00:00:00Z
2019-12-06T00:00:00Z
en
https://doi.org/10.1002/ece3.4337
36849 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
When females mate with multiple partners in a reproductive cycle, the
relative number of competing sperm from rival males is often the most
critical factor in determining paternity. Gamete production is directly
related to testis size in most species, and is associated with both mating
behavior and perceived risk of competition. Deer mice, Peromyscus
maniculatus, are naturally promiscuous and males invest significantly more
in sperm production than males of P. polionotus, their monogamous
sister‐species. Here, we show that the larger testes in P. maniculatus are
retained after decades of enforced monogamy in captivity. While these
results suggest that differences in sperm production between species with
divergent evolutionary histories can be maintained in captivity, we also
show that the early rearing environment of males can strongly influence
their testis size as adults. Using a second‐generation hybrid population
to increase variation within the population, we show that males reared in
litters with more brothers develop larger testes as adults. Importantly,
this difference in testis size is also associated with increased
fertility. Together, our findings suggest that sperm production may be
both broadly shaped by natural selection over evolutionary timescales and
also finely tuned during early development.
See methods within the manuscript