Enemies are not always dear: male song sparrows adjust dear enemy effect expression in response to female fertility

AbstractIn many species, the ability to defend a territory is essential for a male to obtain any reproductive success at all, and even among territorial individuals, variation in the strength of territory defense could have a significant impact on how much reproductive success is obtained. Previous studies have documented consistent individual differences in the vigor with which male song sparrows (Melospiza melodia) defend their territories, as measured by the strength of their reactions to territorial intrusions simulated through song playback. Variation in the strength of defense could reflect intrinsic differences among individuals in their resource holding potential (RHP), or variation in extrinsic factors. In this study, we examined whether variation in the strength of territory defense corresponds to differences in intrinsic factors such as the age or experience of the territory owner, the extrinsic factor of the level of aggression shown by neighbours, or both. Results indicate that males that previously held territories on the study site, regardless of whether they were holding the same territory as the previous year, show higher levels of territory defense than males that are new to the study site, and, assuming that returning males are older males, suggest that age is more important than experience on a specific territory in determining strength of territory defense. In addition, we found evidence that males with high levels of territorial aggression tend to be spatially clustered. The pattern observed suggests that a combination of intrinsic and extrinsic factors contribute to the expression of individual differences in territorial aggression.

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Response to multiple song types in male song sparrows and field sparrows

Animal Behaviour ◽

10.1016/s0003-3472(83)80251-6 ◽

1983 ◽

Vol 31 (3) ◽

pp. 948-949 ◽

Cited By ~ 14

Author(s):

William A. Searcy

Keyword(s):

Male Song ◽

Song Sparrows ◽

Song Types

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Effects of Acute Treatment with 8-OH-DPAT and Fluoxetine on Aggressive Behaviour in Male Song Sparrows (Melospiza melodia morphna)

Journal of Neuroendocrinology ◽

10.1046/j.1365-2826.2003.00968.x ◽

2003 ◽

Vol 15 (2) ◽

pp. 150-160 ◽

Cited By ~ 44

Author(s):

T. S. Sperry ◽

C. K. Thompson ◽

J. C. Wingfield

Keyword(s):

Aggressive Behaviour ◽

Acute Treatment ◽

Melospiza Melodia ◽

Male Song ◽

Song Sparrows

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Aggression towards unfamiliar intruders by male lizards Eurolophosaurus nanuzae depends on contestant’s body traits: a test of the dear enemy effect

Behaviour ◽

10.1163/1568539x-00003438 ◽

2017 ◽

Vol 154 (6) ◽

pp. 693-708 ◽

Cited By ~ 1

Author(s):

Eduardo C. Quintana ◽

Conrado A.B. Galdino

Keyword(s):

Saving Energy ◽

Potential Threat ◽

Dear Enemy ◽

Holding Power ◽

Resource Holding Power ◽

Dear Enemy Phenomenon ◽

Dear Enemy Effect ◽

Tail Condition

A reduction of territory owners’ aggression towards their neighbours in relation to the intrusion of strangers characterises the dear enemy phenomenon. Supposedly, the disparity in aggression levels of territory owners is due to a higher threat imposed by strangers compared to the threat imposed by neighbours. To evaluate the occurrence of the phenomenon in males of the small-sized lizard Eurolophosaurus nanuzae we performed a field manipulative study. We considered three models to run intrusions in males’ territories: neighbour, tailed stranger (unfamiliar) and tailless stranger intruders. Our results lend support to the presence of dear enemy for this species as residents acted more aggressively towards strangers than to neighbours. In addition, the information we provide supports the relative threat hypothesis as territory owners were more aggressive towards tailed stranger intruders than to tailless stranger intruders. In this sense, tail condition can represent a trait that signals the ‘resource holding power’ (RHP) of a lizard. Therefore, we show that beyond neighbourhood recognition, residents are able to evaluate the potential threat of stranger intruders in general, thereby extending the evolutionary gains of the dear enemy by saving energy even in the context they are expected to acts with higher costs.

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Dear enemy effect in the Mexican volcano mouse Neotomodon alstoni: Implications of sex in the agonistic behaviour among neighbours

Behavioural Processes ◽

10.1016/j.beproc.2020.104251 ◽

2020 ◽

Vol 181 ◽

pp. 104251

Author(s):

Jorge Vázquez ◽

Juan A. Fargallo ◽

Nallely Jiménez ◽

Fernando Aguilar-Montiel ◽

Luisa Rodríguez-Martínez

Keyword(s):

Agonistic Behaviour ◽

Dear Enemy ◽

Dear Enemy Effect

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Songs of song sparrows (Melospiza melodia): individual variation and dialects

Canadian Journal of Zoology ◽

10.1139/z72-041 ◽

1972 ◽

Vol 50 (3) ◽

pp. 301-309 ◽

Cited By ~ 75

Author(s):

Margaret A. Harris ◽

Robert E. Lemon

Keyword(s):

Individual Variation ◽

Melospiza Melodia ◽

Populated Area ◽

Male Song ◽

Relative Occurrence ◽

Song Sparrows

Male song sparrows from two areas in Quebec had repertoires of several song patterns, each one of which was generally made up of two repeated units, or syllables, plus unrepeated note complexes. Variability between individuals was large, but there was also some similarity: while most syllable types were sung by one individual only, some were shared with others in the population. The relative occurrence of the different syllable types was similar in two sites at Pare Cote Ste. Catherine but between Pare Cote Ste. Catherine and Mont St. Hilaire (separated by 23 mi) there was almost complete lack of similarity, which was taken as evidence that dialects existed. Birds from the less densely populated area at Mont St. Hilaire had slightly smaller repertoires of syllables and song patterns.

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Differential attack by a cichlid fish on resident and non-resident fish of another cichlid species

Behaviour ◽

10.1163/156853912x629139 ◽

2012 ◽

Vol 149 (1) ◽

pp. 99-109 ◽

Cited By ~ 5

Author(s):

Satoshi Awata ◽

Masanori Kohda ◽

Haruki Ochi

Keyword(s):

Field Experiment ◽

Lake Tanganyika ◽

Cichlid Fish ◽

Previous Experience ◽

Alternative Mechanism ◽

Differential Attack ◽

Dear Enemy ◽

Resident Fish ◽

Cichlid Species ◽

Dear Enemy Effect

AbstractAn algivorous cichlid, Variabilichromis moorii( Vm), defends permanent territories in Lake Tanganyika, Africa. A zoobenthivorous cichlid, Neolamprologus mustax( Nm), spends 60% of daylight hours foraging in Vmterritories, from which other zoobenthivorous fishes are chased out and consequently which are much richer in prey animals than areas outside of Vmterritories. We conducted a field experiment to examine whether Nmresidents and non-residents received different degrees of attacks from Vm. Nmfish were caught in their territories, released at a point distant from these territories, and followed to observe interactions with Vmfish. The frequency of attacks received by the displaced Nmfish was greater than attacks received by Nmresidents, indicating that Nmresidents had easier access to Vmterritories than non-residents did. A possible mechanism for this is reduced aggression of Vmtowards Nmresidents, as a result of the ‘dear enemy’ effect that has been reported in territorial contests between rivals. An alternative mechanism is that tolerance towards Nmdiffers among Vmfish and Nmresidents selectively visit more tolerant Vmfish due to previous experience while non-residents randomly approach both tolerant and hostile Vmfish. The ability of Vmto discriminate between Nmresidents and non-residents is essential to the former mechanism but not to the latter. To more specifically examine which mechanism works in the Vm– Nmcommensal system, we will need to follow individually identified Vmfish interacting with Nmresidents and non-residents.

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