Abandoned frog eggs can hatch early

Embryos react to dereliction of parental care

STANDARDS OF CARE  A clutch of Fleischmann’s glass frog eggs, nicely plumped up with water, depends entirely on dad (shown) to avoid drying out — and will react if he quits on the eggs.

Courtesy of J. Delia

If deadbeat dads among frogs shirk their parental duties, neglected egg clutches can respond by hatching early.

Eggs laid on the undersides of leaves by the glass frogs Hyalinobatrachium fleischmanni depend entirely on fathers for care. And, says Jesse Delia of Boston University, “some are just bad dads.”

Males keep the eggs hydrated by gradually absorbing water from a wet spot and then releasing it over the course of about 40 minutes to an egg clutch. A diligent dad may make five or six water trips a night. But he also has to fight off rival males encroaching on his territory and court the mothers of his next egg batches.

Embryos neglected in his crowded schedule can eventually hatch early if they’ve had at least three days of care, Delia and his colleagues report April 30 in the Proceedings of the Royal Society B. (Clutches hatched successfully as early as 12 days after being laid. Well-tended clutches take up to 27 days.) The link between abandonment and early hatching shows up in the frogs’ natural behavior in southern Mexico and in experiments in which researchers removed dads. Hatching early saves the embryos from drying out in their eggs but may not give them the best start to life outside the egg.

The study is the first to document embryos escaping from bad parenting, Delia says. 

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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