Little Brother for Breakfast

science

Aaaand, we’re back! This time around I was able to play around with manipulating physical (size) and genetic (relatedness) variables between aggressive cannibal tadpoles (the infamous Dendrobates tinctorius) in collaboration with Lutz Fromhage, Janne Valkonen, and Bibiana Rojas.

The D R A M A is for real. . . it turns out that both size and relatedness play a role in driving aggression between tadpoles, where individuals are more aggressive towards a counterpart with increased size asymmetries and decreased genetic relatedness. In other words, large non-siblings are significantly more aggressive than large siblings (exhibiting almost twice the amount of aggressive behaviors).

But it doesn’t stop there.

The most fascinating thing (IMO) is the shift in latency to aggression depending on relatedness. We find that there is inversion in biting behavior as size differences increases, where sibling pairs with large size differences attack significantly faster than non-siblings. Thus, although large siblings were less aggressive overall, they had a shorter latency to aggression in dyads with large size differences.

Is that not simply fascinating? Why are siblings who are quite disproportionate in size demonstrating aggressive behavior so quickly? Perhaps that biting is not simply an aggressive behavior, but a means for identification and the assessment of relatedness? Or perhaps it is a behavioral response to establish dominance within a pair?

No matter how you slice it, there is something going on in their little tadpole brains where individual behavior is different when faced with non-related or related individuals. From this clear kin discrimination and really cool cognition work headed by Fischer (2020), we believe that there is kin recognition in Dendrobates tinctorius. To read more about the details of our study and learn about aggression in cannibals, check out our pre-print!

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