Reproductive Isolation

REPRODUCTIVE ISOLATION OF DIVERGENT POPULATIONS

Geographically and genetically isolated populations of the Red-eyed Treefrog (Agalychnis callidryas) in Costa Rica differ in coloration and size. The extent of among-population divergence is unusually high for treefrogs, especially at this small geographic scale (50 – 150 KM). These populations are ideal for examining the mechanisms that underlie population differentiation and lineage diversification. We are testing the extent of both prezygotic and postzygotic reproductive isolation among differentiated populations through captive breeding experiments.

Our purpose is two-fold: (1) to examine the extent of postzygotic reproductive isolation of divergent populations by determining whether offspring from outcrossed populations show reduced survival rate and/or rate of growth (fitness) than purebred offspring; and (2) to understand the heritability of color pattern in this species. Our lab collaborates with Kristine Kaiser (CSUN) and Andres Vega (AMBICOR, Costa Rica).

Pavones (southwestern Costa Rica)

Pavones (southwestern Costa Rica)

Gandoca (Southeastern Costa Rica).

Gandoca (Southeastern Costa Rica).

La Selva Biological Research Station (Northeastern, Costa Rica)

La Selva Biological Research Station (Northeastern, Costa Rica)

Cabo Blanco (Northpacific, Costa Rica)

Cabo Blanco (Northpacific, Costa Rica)

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Tadpole of red-eyed treefrog

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Recent metamorph, Red-eyed treefrog

Breeder Frogs

An outcrossed pairing of Red-eyed treefrogs. Larger female (on bottom) of blue morph with smaller male of brown morph engage in amplexus in captive breeding chamber.

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Undergraduate student Nicole Looper weighs a Red-eyed treefrog tadpole.

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A metamorphic individual from an outcrossed pairing of two populations of Red-eyed treefrog.