Hormonal influences on natal dispersal in free-living Belding's ground squirrels (Spermophilus beldingi)

Holekamp, Kay E.; Smale, Laura; Simpson, H. Blair; Holekamp, N A

doi:10.1016/0018-506x(84)90031-x

Cited by 54 publications

(13 citation statements)

References 36 publications

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“…Maternal testosterone level is known to influence offspring behavioural traits like aggressiveness or risktaking behaviour (Groothuis & Carere 2005) as well as dispersal propensity (Dufty & Belthoff 2001). For example, perinatal exposure to testosterone subsequently results in dispersal of treated individuals in Belding's ground squirrels (Holekamp et al 1984;Nunes et al 1998). These results support the organizational hypothesis in which gonadal steroids act during foetal or neonatal life on neural tissues destined to mediate behaviours.…”

Section: Proximate Factors Associated With Personality-dependent Dispsupporting

confidence: 75%

“…These results support the organizational hypothesis in which gonadal steroids act during foetal or neonatal life on neural tissues destined to mediate behaviours. Holekamp et al (1984) further suggested that testosterone may promote dispersal behaviour through its mediating effects on juveniles' exploratory and social behaviours, and on their responsiveness to frightening stimuli.…”

Section: Proximate Factors Associated With Personality-dependent Dispmentioning

confidence: 99%

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Personality-dependent dispersal: characterization, ontogeny and consequences for spatially structured populations

Côté

Clobert

Brodin

et al. 2010

Phil. Trans. R. Soc. B

582

547

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Dispersal is one of the most fundamental components of ecology, and affects processes as diverse as population growth, metapopulation dynamics, gene flow and adaptation. Although the act of moving from one habitat to another entails major costs to the disperser, empirical and theoretical studies suggest that these costs can be reduced by having morphological, physiological or behavioural specializations for dispersal. A few recent studies on different systems showed that individuals exhibit personality-dependent dispersal, meaning that dispersal tendency is associated with boldness, sociability or aggressiveness. Indeed, in several species, dispersers not only develop behavioural differences at the onset of dispersal, but display these behavioural characteristics through their life cycle. While personality-dependent dispersal has been demonstrated in only a few species, we believe that it is a widespread phenomenon with important ecological consequences. Here, we review the evidence for behavioural differences between dispersers and residents, to what extent they constitute personalities. We also examine how a link between personality traits and dispersal behaviours can be produced and how personality-dependent dispersal affects the dynamics of metapopulations and biological invasions. Finally, we suggest future research directions for population biologists, behavioural ecologists and conservation biologists such as how the direction and the strength of the relationship between personality traits and dispersal vary with ecological contexts.

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Section: Proximate Factors Associated With Personality-dependent Dispsupporting

confidence: 75%

Section: Proximate Factors Associated With Personality-dependent Dispmentioning

confidence: 99%

Personality-dependent dispersal: characterization, ontogeny and consequences for spatially structured populations

Côté

Clobert

Brodin

et al. 2010

Phil. Trans. R. Soc. B

582

547

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“…On 273 D1, D9, and D14, test males showed significantly higher testosterone levels than control 274 males (D1: 47.08 ± 3.97ng/ml vs. 1.88 ± 0.60 ng/ml; N = 9, V = 45, p = 0.004; D9: 20.32 275 ± 3.45 ng/ml vs. 1.82 ± 0.59 ng/ml; N = 9, V = 45, p = 0.004; D14: 18.64 ± 5.13 ng/ml vs. we demonstrated that an experimental increase of testosterone levels in philopatric group-356 living males increase activity, boldness and decrease anxiety, i.e. traits that may facilitate 357 dispersal (Holekamp et al 1984). However, we found no evidence that increased 358 testosterone levels enhance aggressive behavior nor decrease the expression of 359 alloparental care.…”

Section: Serum Hormone Levels 271mentioning

confidence: 88%

Experimental increase of testosterone increases boldness and decreases anxiety in male African striped mouse helpers

Raynaud¹,

Schradin²

2014

Physiology & Behavior

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Males of many species can adjust their behaviors to environmental conditions by changing reproductive tactics. Testosterone surges in adult breeding males typically inhibit the expression of paternal care while facilitating the expression of aggression during environmental changes. Similarly, in non-breeding philopatric males of cooperatively breeding species, up-regulation of testosterone may inhibit alloparental care while facilitating dispersal, i.e. males might become bolder and more explorative. We tested this hypothesis in philopatric male African striped mice, Rhabdomys pumilio. Striped mouse males can either remain in their natal group providing alloparental care or they can disperse seeking mating opportunities. Compared to philopatric males, dispersed males typically show higher testosterone levels and lower corticosterone levels, and more aggression towards pups and same sex conspecifics. We experimentally increased the testosterone levels of philopatric males kept in their family group when pups were present. Testosterone-treated males did not differ significantly from control males in alloparental care and in aggression toward same-sex conspecifics. Compared to control males, testosterone treated males were bolder, more active, less anxious; they also showed lower corticosterone levels. Philopatric males were sensitive to our testosterone treatment for dispersal-and anxiety-like behavior but insensitive for social behaviors. Our results suggest a role of testosterone in dispersal. We tested this hypothesis in philopatric male African striped mice, Rhabdomys pumilio. 28Striped mouse males can either remain in their natal group providing alloparental care or 29 they can disperse seeking mating opportunities. Compared to philopatric males, dispersed 30 males typically show higher testosterone levels and lower corticosterone levels, and more 31 aggression towards pups and same sex conspecifics. We experimentally increased the 32 testosterone levels of philopatric males kept in their family group when pups were present. 33Testosterone-treated males did not differ significantly from control males in alloparental 34 care and in aggression toward same-sex conspecifics. Compared to control males, 35 testosterone treated males were bolder, more active, less anxious; they also showed lower 36 corticosterone levels. Philopatric males were sensitive to our testosterone treatment for 37 dispersal-and anxiety-like behavior but insensitive for social behaviors. Our results 38 suggest a role of testosterone in dispersal. 39

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“…Although corticosterone has been shown to rise during the dispersal phase of the life cycle in some organisms (Holekamp et al 1984, Silverin 1997, Belthoff and Dufty 1998 and thus may cause movement, these cases all involve young animals dispersing for the first time.…”

Section: Corticosterone and Colony Choicementioning

confidence: 99%

“…We sampled birds for hormones and monitored where they settled in later years, allowing the estimation of formal transition probabilities between colonies for birds with different hormone levels. Although seasonal fluctuations in testosterone and corticosterone are thought to correlate with dispersal behavior in some animals (Holekamp et al 1984, Silverin 1997, Belthoff and Dufty 1998, no previous study has looked at how annual choice of a colony size is related to hormonal profiles of individuals. We examine how choice of both a colony site and a colony size is potentially influenced by corticosterone and testosterone, and we do this by estimating multistate transition probabilities for individuals moving both between sites in space and between groups of different sizes relative to their previous colony size.…”

Section: Introductionmentioning

confidence: 99%

Steroid Hormone Levels Are Related to Choice of Colony Size in Cliff Swallows

Brown

Raouf

et al. 2005

Ecology

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Abstract. One hypothesis to explain the extensive variation in colony size seen in most taxa is that individuals sort themselves among groups based on phenotypic characteristics that correlate with their performance in groups of different sizes. We investigated how baseline levels of the steroid hormones, corticosterone and testosterone, were associated with choice of colony size and the likelihood of moving to a different site in later years in colonially nesting Cliff Swallows (Petrochelidon pyrrhonota) in southwestern Nebraska, USA, in 2000-2004. We sampled hormone levels of birds caught at colonies and, using mark-recapture, monitored their movement and choice of colony size through subsequent years in the study area. Maximum likelihood estimation and multistate model fitting (with program MARK) revealed that birds with baseline corticosterone levels above the average for the colony and time of sampling were less likely to choose a colony of the same size or larger in a later year than were birds with corticosterone levels below the average. This result held for Cliff Swallows in both fumigated (parasite-free) sites and colonies naturally infested with ectoparasites. Relative baseline corticosterone level was unrelated to the likelihood of movement between different colony sites, and corticosterone level measured after birds were held for 60 minutes was unrelated to either colony-size choice or the probability of movement. Males whose testosterone levels were above the average for the colony and time of sampling were more likely to choose a colony of the same size or larger in a later year than were ones whose testosterone levels were below the average, but the opposite pattern was found for females. The results indicate that steroid hormone level is a predictor of whether a Cliff Swallow will settle in a relatively small or large colony, and support the hypothesis that variation in colony size reflects, in part, a distribution of birds with inherently different neuroendocrinological characteristics.

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Hormonal influences on natal dispersal in free-living Belding's ground squirrels (Spermophilus beldingi)

Cited by 54 publications

References 36 publications

Personality-dependent dispersal: characterization, ontogeny and consequences for spatially structured populations

Personality-dependent dispersal: characterization, ontogeny and consequences for spatially structured populations

Experimental increase of testosterone increases boldness and decreases anxiety in male African striped mouse helpers

Steroid Hormone Levels Are Related to Choice of Colony Size in Cliff Swallows

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