The ability of wood frog eggs to withstand prolonged terrestrial stranding: an empirical study

Abstract

In Maryland, the wood frog, Rana sylvatica, oviposits in ephemeral ponds and pools during early spring. Seasonal precipitation is often unpredictable and egg masses may become exposed as ponds recede. The ability of wood frog eggs to withstand prolonged terrestrial exposure was tested in the laboratory. Egg mortality rate was exponential. Compared with a submerged control, 49% of the eggs died within 2 days, but 11% of the eggs were alive after 10 days and a few survived as long as 14 days. Wood frogs are thought to have evolved communal egg laying as a mechanism to minimize thermal stress during development. We suggest that this behavior also enabled egg masses to withstand terrestrial stranding. Today, advantages accrued through reduced thermal exposure and resistance to desiccation likely act in concert to stabilize communal egg-laying behavior.