Data from: Maternal investment increases with altitude in a frog on the Tibetan plateau

Reproducing females can allocate energy between the production of eggs of
different size or number, both of which can strongly influence fitness.
Environmental conditions often drive these reproductive tradeoffs, because
of direct influences on offspring survival. Many vertebrates show positive
relationships between female body size and altitude, resulting in the
production of larger clutches at higher altitudes. We report a different
tradeoff in the high-altitude endemic frog Rana kukunoris (n=11
populations, 2000-3500 m): females living at higher altitudes produce
heavier clutches of larger eggs without a concomitant increase in female
body size or clutch size. Reproduction at high altitudes thus favours
current reproduction at a cost to short-term maintenance and growth. The
harsh environmental conditions at high altitudes can impose strong and
opposing selection pressure on egg and adult life history stages.