Leptodactylus insularum is a tropical frog occuring in Colombia, Costa Rica, Panama, Trinidad and Tobago, Venezuela. In this video, a female Leptodactylus insularum pumps her abdomen in the water, and tries to lead the school towards a different area in the swamp. Females attend schools for varying amounts of time, and this is a fairly young school, which may explain why they are slow to follow her. Or perhaps they’re feeding on a great patch and don’t want to leave!
Why some parents invest more or less to their offspring? How do parents fine-tune their investment based on environmental conditions? Does the offspring change their behavior based on resource availability? How does the conflict between parent and offspring resolve especially in bad years when resources are limited? Evolutionary biologists try to find answers to these kinds of questions under a hypothetical framework called “parent-offspring conflict”.
Only about half of the Leptodactylus insularum mothers provide care for their tadpoles, but Kristiina found that the only tadpole schools to survive had maternal care. So why don’t all females protect their young? Females can help tadpoles avoid desiccation by digging channels to connect puddles, and they even defend the tadpoles against predators (seen here attacking her hand as she attempted to put flagging tape near a nest:
If resources are scarce a demanding offspring (like the begging dislays nestling chicks do) can stress their parents and can lead to reproductive failure. One study on captive canaries has shown that chicks adjust their begging display based on conditions before their birth. This suggests that there may be some “epigenetic” signals putting a gag on excessively demanding chicks.
Parent-offspring conflict resolution is a hot topic among behavioral evolutionary biologists. These videos were recorded by Kristiina Hurme in Gamboa, Panama in 2006 during her dissertation research on maternal care in the frog Leptodactylus insularum. You can learn more about the natural history of this frog in her webpage.
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