Determinants of territory size of the dusky gregory

Jan, R.-Q.; Ho, Cheng-Tze; Shiah, Fuh Kwo

doi:10.1111/j.1095-8649.2003.00270.x

Cited by 15 publications

(22 citation statements)

References 19 publications

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“…baseline) and during sTI. Baseline territorial interactions involve quick aggressive chases that keep most intruders at bay (Jan et al, 2003). Moreover, many such intra-specific interactions in our observations were with neighboring individuals.…”

Section: Research Articlementioning

confidence: 79%

“…Temeles, 1994). In the dusky gregory, however, neighbors provoke more aggression than stranger conspecifics when presented in a territorial intrusion test (Jan et al, 2003). Nevertheless, such different challenges (neighbor versus stranger) might constitute different threat levels and thereby affect hormonal systems in different ways.…”

Section: Research Articlementioning

confidence: 99%

“…Each individual passing that area was considered in interaction with the nest-holder. The 2 m diameter was chosen because S. nigricans are known to attack intruders at a distance around the center of the territory of 0.6 to 2.8 m (Jan et al, 2003), and this area generally did not overlap with territories of other individuals. …”

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confidence: 99%

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Intra- and interspecific challenges modulate cortisol but not androgen levels in a year-round territorial damselfish

Ros

Vullioud

Bruintjes

et al. 2014

Journal of Experimental Biology

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Interactions between individuals of different species are commonplace in animal communities. Some behaviors displayed during these interspecific social interactions may be very similar to those displayed during intraspecific social interactions. However, whether functional analogies between intra-and interspecific behaviors translate at the proximate level into an overlap in their underlying endocrine mechanisms remains largely unknown. Because steroids both mediate social behaviors and respond to them, we approached this question by comparing the behavioral and steroid response of free-living dusky gregories (Stegastes nigricans) to standardized territorial intrusions (sTI) of either conspecific or heterospecific food competitors. Stegastes nigricans is a year-round territorial fish that 'cultivates' the algae on which it feeds and is highly aggressive to both intra-and interspecific intruders. Behavioral differences between intra-and interspecific aggressive responses to sTI were marginal, and sTI tests caused an increase in cortisol levels that was positively related with the levels of aggression. In contrast, androgen levels did not increase in response to sTI, yet they showed a positive relationship with agonistic behavior. These results parallel a pattern that was first described for year-round territorial bird species. Furthermore, they suggest that changes in endocrinehormone levels during territoriality might be independent of the species that induces the territorial response. KEY WORDS: Teleost, Testosterone, 11-ketotestosterone, Cortisol, Territorial aggression, Interspecific behavior INTRODUCTIONAnimals live in competitive social environments in which each behavioral response may have important fitness costs or benefits. To manipulate their social environment, individuals frequently use competitive agonistic behaviors including overt aggression (Wingfield et al., 2006;Székely et al., 2010). These aggressive behaviors can be classified based on the type of tactic the individual is using (e.g. reactive versus proactive situations) and on the context (e.g. spatial, sexual, parental, antipredator) in which they are expressed (Koolhaas et al., 1999;Wingfield et al., 2006). The context of aggression has been postulated to have important influences on the evolution of the underlying hormone-behavior relationships as in the commonly found associations between gonadal hormones such as testosterone and estradiol and aggressive behaviors during sexual competition, and between stress hormones such as cortisol and defensive aggression in response to threats (Wingfield et al., 2006). These relationships can act both ways in that social challenges modulate the release of sex or stress steroid hormones, while the release of these hormones in turn facilitates different behavioral responses [i.e. the reciprocal model or challenge hypothesis (see Wingfield et al., 1990;Hirschenhauser and Oliveira, 2006;Oliveira and Gonçalves, 2008)]. Although these relationships may be species-specific and dependent on age and...

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Section: Research Articlementioning

confidence: 79%

Section: Research Articlementioning

confidence: 99%

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Intra- and interspecific challenges modulate cortisol but not androgen levels in a year-round territorial damselfish

Ros

Vullioud

Bruintjes

et al. 2014

Journal of Experimental Biology

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“…Its territory has multiple purposes as it supplies algae to feed on, shelter between the coral, and substrate for breeding. During the reproductive period, which is restricted to summer months (see Galzin, 1987;Jan et al, 2003;Karino and Nakazono, 1993), females temporarily leave their territory to spawn in the territories of males (Karino, 1999;Karino and Nakazono, 1993). Gonads are regressed in non-reproductively active S. nigricans (Karino, 1999), and seasonal variation in gonad size has been described at low to intermediate levels in the winter period (Galzin, 1987 In both experiments individuals were collected (at 2-10 m depth) by spraying a small amount of clove oil (20% clove oil diluted in 80% ethanol) in the territories, and capturing the slightly sedated individuals using a hand net.…”

Section: Methodsmentioning

confidence: 99%

“…Individual recognition and past experience are mechanisms which have been acknowledged to mediate aggression (Oliveira, 2004) and might thus account for the differential expression of territorial aggression as a function of intruder's identity. Such factors have indeed been put forward to explain the variation of intraspecific aggression in S. nigricans (Jan et al, 2003) as well as differences between intra-and interspecific aggression in related species (Di Paola et al, 2012;Myrberg and Thresher, 1974). Further detailed observations and experiments on S. nigricans, especially on free-living individuals, are however required to clarify the similarities between intra-and interspecific territorial aggression towards P. lacrymatus as well as other intruding species.…”

Section: Causation Of Interspecific Social Behaviormentioning

confidence: 99%

Intra- and interspecific aggression do not modulate androgen levels in dusky gregories, yet male aggression is reduced by an androgen blocker

Vullioud

Bshary

Ros

2013

Hormones and Behavior

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Discussions about social behavior are generally limited to fitness effects of interactions occurring between conspecifics. However, many fitness relevant interactions take place between individuals belonging to different species. Our detailed knowledge about the role of hormones in intraspecific interactions provides a starting point to investigate how far interspecific interactions are governed by the same physiological mechanisms. Here, we carried out standardized resident-intruder (sRI) tests in the laboratory to investigate the relationship between androgens and both intra-and interspecific aggression in a year-round territorial coral reef fish, the dusky gregory, Stegastes nigricans. This damselfish species fiercely defend cultivated algal crops, used as a food source, against a broad array of species, mainly food competitors, and thus represent an ideal model system for comparisons of intra-and interspecific territorial aggression. In a first experiment, resident S. nigricans showed elevated territorial aggression against intra-and interspecific intruders, yet neither elicited a significant increase in androgen levels. However, in a second experiment where we treated residents with flutamide, an androgen receptor blocker, males but not females showed decreased aggression, both towards intra-and interspecific intruders. Thus androgens appear to affect aggression in a broader territorial context where species identity of the intruder appears to play no role. This supports the idea that the same hormonal mechanism may be relevant in intra-and interspecific interactions. We further propose that in such a case, where physiological mechanisms of behavioral responses are found to be context dependent, interspecific territorial aggression should be considered a social behavior.

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Dietary separation between two blennies and the Pacific gregory in northern Taiwan: evidence from stomach content and stable isotope analyses

Kao

Dai

et al. 2006

Mar Biol

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Two blennies, Ecsenius lineatus Klausewitz and Ecsenius namiyei (Jordan and Evermann), and a cohabiting territorial damselfish, the Pacific gregory, Stegastes fasciolatus (Ogilby), were collected from shallow reefs in northern Taiwan between September and November 2004, and in October 2005 for stomach content and d 13 C and d 15 N analyses in an effort to study how extensively their food sources overlapped and to delineate the pattern of cohabiting interactions. These analyses showed differences in food use between the Ecsenius blennies and S. fasciolatus. However, there were inconsistencies. Epiphytic algae were their major food items of E. namiyei and E. lineatus. Macroalgae were rarely taken. Nevertheless, d 13 C and d 15 N signatures suggested that E. namiyei and E. lineatus might have assimilated mainly macroalgae-derived detritus instead of epiphytic algae. In contrast, macroalgae were the major food items of S. fasciolatus, followed by epiphytic algae. Differences in both d 13 C and 15 N values indicated that for S. fasciolatus, algae (both macroalgae and epiphytic algae) might not be as important as the stomach contents showed. Instead, polychaetes were possibly its major food source. Differences between stomach contents and evidence from the separation of stable isotope signatures between blennies and the Pacific gregory indicate that some of the interspecific interactions derived from exploitative competition may have been alleviated. Moreover, their widespread territory overlap is possibly a sign of mutualism: S. fasciolatus allows territory sharing, while Ecsenius blennies, in return, clean up the algal mat by removing sand and detritus.

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Determinants of territory size of the dusky gregory

Cited by 15 publications

References 19 publications

Intra- and interspecific challenges modulate cortisol but not androgen levels in a year-round territorial damselfish

Intra- and interspecific challenges modulate cortisol but not androgen levels in a year-round territorial damselfish

Intra- and interspecific aggression do not modulate androgen levels in dusky gregories, yet male aggression is reduced by an androgen blocker

Dietary separation between two blennies and the Pacific gregory in northern Taiwan: evidence from stomach content and stable isotope analyses

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