Meeting Abstract
Although aggressive phenotypes can have important implications on individual fitness, they also have the potential for generating trade-offs. Understanding their costs and their proximal causes will help us to better understand the evolutionary processes shaping aggression. Oxidative stress (OS) is a physiological imbalance between oxidant and antioxidant molecules in favor of the former, which can generate damage to proteins, lipids and DNA. Here we present the results from experiments of simulated territorial intrusion (STI) in the rufous hornero (Furnarius rufus) that were designed to test whether aggressive behavior can induce OS. We performed the STIs during the fertile period of the females using a dummy and intra-specific playbacks. Treated birds (18 males and 9 females) were exposed to the intrusion for 20 minutes, whereas control birds (24 males and 7 females) were captured immediately after playback started. We then collected a blood sample to measure three commonly used oxidative stress markers: one marker of oxidative damage (dROMs) and two markers of antioxidant capacity (OXY and GPX). Compared to control birds, males and females decreased their OXY capacity after the STI with females showing a more accentuated decrease. Furthermore, in females, aggressiveness parameters explained the OXY levels during the STIs. In males and females ROMs and GPX did not change after the intrusion. These results show that in the rufous hornero an aggressive interaction of 20 minutes is enough to elicit a change in the oxidative status, and that females are more sensitive than males. Overall, we discover for the first time that aggression can induce OS and provide novel insights about a sex-specific mechanism that could potentially explain differences in aggressive behaviour.
