scholarly journals Not one hormone or another: Aggression differentially affects progesterone and testosterone in a South American ovenbird

2018 ◽  
Author(s):  
Nicolas M. Adreani ◽  
Wolfgang Goymann ◽  
Lucia Mentesana
Keyword(s):  
Parental Care ◽  
Social Interactions ◽  
Breeding Cycle ◽  
South American ◽  
Male Behavior ◽  
Free Living ◽  
Mating Period ◽  
Territorial Aggression ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

AbstractBehaviors such as territorial interactions among individuals can modulate vertebrate physiology and vice versa. Testosterone has been pointed out as a key hormone that can be rapidly affected by aggressive interactions. However, experimental evidence for such a link is mixed. In addition, behaviors can elicit changes in multiple hormones, which in turn have the potential to synergistically feedback to behavior. For example testosterone and progesterone can act interdependently in modulating male behavior. However, if aggression can affect progesterone levels in males remain unknown and – to the best of our knowledge – no one has yet tackled if and how aggressive behavior simultaneously affects testosterone and progesterone in free-living animals. We addressed these questions by performing simulated territorial intrusion experiments measuring both hormones and their ratio in male rufous horneros (Aves, Furnarius rufus) during the mating and parental care periods. Aggression affected testosterone and progesterone differentially depending on the period of testing: challenged birds had higher levels of progesterone during the mating period and lower levels of testosterone during parental care compared to controls. Challenged individuals had similar progesterone to testosterone ratios during both periods and these ratios were higher than those of control birds. In summary, territorial aggression triggered hormonal pathways differentially depending on the stage of the breeding cycle, but equally altered their ratio independent of it. Our results indicate that multiple related hormones could be playing a role rather than each hormone alone in response to social interactions.

Opposite Changes in Plasma Testosterone and Corticosterone Levels Following a Simulated Territorial Challenge in Male Great Tits

Behaviour ◽  
2004 ◽  
Vol 141 (4) ◽  
pp. 451-467 ◽  
Author(s):  
Rianne Pinxten ◽  
Lutgarde Arckens ◽  
Els van Duyse ◽  
Marcel Eens ◽  
Veerle Darras
Keyword(s):  
Parus Major ◽  
Time Of Day ◽  
Behavioural Response ◽  
Egg Laying ◽  
Plasma Testosterone ◽  
Breeding Cycle ◽  
Territorial Defence ◽  
Breeding Stage ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

AbstractThe apparent ability of plasma testosterone (T) and corticosterone (B) levels to fluctuate rapidly in response to agonistic interactions, suggests that these hormones may play an important role in an animal's acute behavioural response during such interactions. In the present study, free-living male great tits, Parus major, were subjected to a simulated territorial intrusion (STI) during the egg laying, incubation and nestling stage of first broods. Plasma T and B levels of challenged males were compared to those of control males matched for breeding stage, day in breeding stage, and time of day. Plasma B levels were significantly higher in challenged males compared to control males during the egg laying and incubation stage but not during the nestling stage. On the other hand, challenged males had significantly lower plasma T levels than control males throughout the breeding cycle. While having low plasma T and elevated plasma B levels, challenged males showed a vigorous and unrelenting territorial response to the STI. Plasma T and B levels of challenged males did not correlate with the intensity of the behavioural response to the STI. These findings do not agree with the predictions of the 'challenge hypothesis' that males exposed to a territorial challenge while having breeding baseline T levels will respond with an increase in T or that T correlates with the intensity of aggression during a challenge. Together, our findings suggest a role for B rather than T in the regulation of territorial defence in male great tits.

scholarly journals Free-Living Male Mountain White-Crowned Sparrows Exhibit Territorial Aggression Without Modulating Total or Free Plasma Testosterone

The Condor ◽  
2007 ◽  
Vol 109 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Sharon E. Lynn ◽  
Thomas P. Hahn ◽  
Creagh W. Breuner
Keyword(s):  
Aggressive Behavior ◽  
Free Testosterone ◽  
Plasma Testosterone ◽  
Zonotrichia Leucophrys ◽  
Territorial Aggression ◽  
Testosterone Secretion ◽  
Corticosteroid Binding Globulin ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion ◽  
Free Plasma

Abstract Abstract In some species, expression of territorial aggression is accompanied by a rise in testosterone secretion, but in others aggressive behavior is expressed while testosterone levels remain unchanged. Corticosteroid binding globulin (CBG) binds both corticosterone and testosterone in avian plasma. Thus, increasing corticosterone may result in fluctuations in unbound (“free”) testosterone; this could result in greater biological activity of testosterone without an increase in testosterone secretion. We investigated whether such plasma interactions of testosterone, corticosterone, and CBG might result in alterations of free testosterone in male Mountain White-crowned Sparrows (Zonotrichia leucophrys oriantha). We conducted simulated territorial intrusions during incubation and compared total and free testosterone of males captured immediately following a simulated territorial intrusion with that of males captured passively. All experimental males showed aggressive behavior, but apparently did not modulate total or free testosterone relative to controls.

Fine structure of the free-living parakeet pineal in relation to the breeding cycle

1993 ◽  
Vol 15 (3) ◽  
pp. 122-131 ◽  
Author(s):  
T.N. Krishna Prasadan ◽  
Vibhakar C. Kotak
Keyword(s):  
Fine Structure ◽  
Breeding Cycle ◽  
Free Living

Use of Stereo Duet Playback to Investigate Traditional Duet Playback Methods and Mechanisms of Cooperative Territorial Defence in Magpie-Larks

Behaviour ◽  
2004 ◽  
Vol 141 (6) ◽  
pp. 741-753 ◽  
Author(s):  
Helèna Harrington ◽  
Audrey Miller ◽  
Sarah Mcdowell ◽  
Amy Rogers ◽  
Joanne Panagos ◽  
...  
Keyword(s):  
Intraspecific Aggression ◽  
Same Sex ◽  
Territorial Defence ◽  
Male And Female ◽  
Single Speaker ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion ◽  
Australian Magpie ◽  
Response Variables

AbstractDuets are precisely coordinated acoustic displays, usually involving members of a mated pair. Studies investigating avian duet function often employ a single speaker playback system to compare response of focal pairs to simulated territorial intrusion by duetting and solo birds. It has recently been suggested that a 'stereo duet playback', in which male and female duet components are separated and broadcast through two different speakers, would provide a more realistic duet stimulus. We conduct the first comparison of a traditional single speaker versus a new stereo duet playback design and provide evidence that Australian magpie-larks, Grallina cyanoleuca, make significantly more flights towards duet playback presented in a more realistic stereo context. Male and female magpie-lark pairs did not split up and attack one 'intruder' each when presented with a stereo duet playback. Instead they moved towards the same speaker together as a united pair, showing a tendency to approach the speaker initiating the duet intrusion. Distance between the two speakers in a stereo duet design did not have a significant effect on the response variables measured. We conclude that magpie-larks can distinguish between use of a single speaker or stereo duet playback to broadcast a duet and suggest that cooperative defence against duetting intruders in magpie-larks is a result of joint territorial defence rather than intraspecific aggression against same-sex intruders.

scholarly journals Progesterone modulates aggression in sex-role reversed female African black coucals

2008 ◽  
Vol 275 (1638) ◽  
pp. 1053-1060 ◽  
Author(s):  
Wolfgang Goymann ◽  
Andrea Wittenzellner ◽  
Ingrid Schwabl ◽  
Musa Makomba
Keyword(s):  
Aggressive Behaviour ◽  
Sex Role ◽  
Bird Species ◽  
General Mechanism ◽  
Hormonal Changes ◽  
Free Living ◽  
Experimental Conditions ◽  
Resource Defence ◽  
Territorial Aggression ◽  
African Black

Testosterone is assumed to be the key hormone related to resource-defence aggression. While this role has been confirmed mostly in the context of reproduction in male vertebrates, the effect of testosterone on the expression of resource-defence aggression in female vertebrates is not so well established. Furthermore, laboratory work suggests that progesterone inhibits aggressive behaviour in females. In this study, we investigated the hormonal changes underlying territorial aggression in free-living female African black coucals, Centropus grillii (Aves; Cuculidae). Females of this sex-role reversed polyandrous bird species should be particularly prone to be affected by testosterone because they aggressively defend territories similar to males of other species. We show, however, that territorial aggression in female black coucals is modulated by progesterone. After aggressive territorial challenges female black coucals expressed lower levels of progesterone than unchallenged territorial females and females without territories, suggesting that progesterone may suppress territorial aggression and is downregulated during aggressive encounters. Indeed, females treated with physiological concentrations of progesterone were less aggressive than females with placebo implants. This is one of the first demonstrations of a corresponding hormone–behaviour interaction under challenged and experimental conditions in free-living females. We anticipate that our observation in a sex-role reversed species may provide a more general mechanism, by which progesterone—in interaction with testosterone—may regulate resource-defence aggression in female vertebrates.

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