Isolation rearing does not constrain social plasticity in a family-living lizard

Riley, Julia; Guidou, Côme; Fryns, Caroline; Mourier, Johann; Leu, Stephan T.; Noble, Daniel W. A.; Byrne, Richard W.; Whiting, Martin J.

doi:10.1093/beheco/ary007

Cited by 13 publications

(7 citation statements)

References 66 publications

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“…In general, skinks have been found to be socially competent and adaptable to novel social environments (Riley et al 2018). At Ōrokonui, the overall stability observed within the Otago skink population is biologically representative of particular pairs of individuals having sustained relationships that last beyond the mating period, as well as pairs of individuals that never interacted with each other, despite their close spatial proximity.…”

Section: Discussionmentioning

confidence: 99%

Social networks and social stability in a translocated population of Otago skinks (Oligosoma otagense)

Elangovan¹,

Bovill²,

Cree³

et al. 2021

NZJE

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The social behaviour of New Zealand's native lizards is poorly understood. We explored the social behaviour of the Otago skink (Oligosoma otagense), one of New Zealand's largest and rarest species of lizards. The Otago skink has previously been observed in the wild in pairs and groups, but little else is known about its social behaviour. We studied the social behaviour of a translocated population of 32 skinks in an outdoor enclosure at Ōrokonui Ecosanctuary. Regular photo surveys were conducted from November 2017 to October 2018 to identify skinks and the social interactions among them. Skinks were observed to be either solitary or interacting in groups consisting of two to eight individuals. Social network analysis was used to determine the strength of the interactions between adult males, adult females, subadults and juveniles. We assessed the stability of social interactions in the population over time by comparing the persistence of social interactions between seasons (summer, autumn/winter and winter/spring) while taking into account the size and composition of a social group. Interactions between adults and subadults were stable across autumn/winter and winter/spring whereas juveniles showed no stability in their interaction patterns during this time. During the course of the study, there was an overall stability in the social networks, indicating that the stability of social interactions present in the translocated population is largely driven by the adults and subadults in the enclosure. Our work suggests that incorporating an understanding of sociality into capture procedures may minimise disruption to social structures and ultimately improve outcomes of translocation.

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Section: Discussionmentioning

confidence: 99%

Social networks and social stability in a translocated population of Otago skinks (Oligosoma otagense)

Elangovan¹,

Bovill²,

Cree³

et al. 2021

NZJE

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“…In December 2013, we collected 27 gravid, female E. striolata by hand, lasso, or Elliot trap near Albury, NSW, Australia (35.98"S, 146.97"E) for a series of experimental studies investigating the effect of social environment on behavioral development (Riley et al, 2016;Riley et al, 2017, Riley et al, 2018a, Riley et al, 2018b. After capture, we uniquely marked each individual with a Passive Integrated Transponder (PIT) tag and took a tissue sample (removing less than 0.5 cm of the tip of the tail with scissors).…”

Section: Lizard Collection Housing and Monitoringmentioning

confidence: 99%

Sperm Storage in a Family-Living Lizard, the Tree Skink (Egernia striolata)

Riley

Stow

Bolton

et al. 2021

Journal of Heredity

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The ability to produce viable offspring without recently mating, either through sperm storage or parthenogenesis, can provide fitness advantages under a suite of challenging ecological scenarios. Using genetic analysis, we demonstrate that three wild-caught female Tree Skinks (Egernia striolata) reproduced in captivity with no access to males for over a year, and that this is best explained by sperm storage. To the best of our knowledge, this is the first time female sperm storage has been documented in any monogamous family-living reptile, including social Australian egerniine skinks (from the subfamily Egerniinae). Furthermore, by using paternal reconstruction of genotypes we show that captive-born offspring produced by the same females in the preceding year, presumably without sperm storage, were sired by different males. We qualitatively compared aspects of these females’ mates and offspring between years. The parents of each litter were unrelated, but paternal and offspring genotypes from litters resulting from stored sperm were more heterozygous than those inferred to be from recent matings. Family-living egerniine skinks generally have low rates of multiple paternity, yet our study suggests that female sperm storage, potentially from outside social partners, offers the real possibility of benefits. Possible benefits include increasing genetic compatibility of mates and avoiding inbreeding depression via cryptic female choice. Sperm storage in Tree Skinks, a family-living lizard with a monogamous mating system, suggests that females may bet-hedge through extra-pair copulation with more heterozygous males, reinforcing the idea that females could have more control on reproductive outcomes than previously thought.

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“…The CV of edge weights (similar to "social differentiation" or "clustering coefficient"; Whitehead, 2008) of a focal skink quantifies variability of an individual's associations. High CV values suggests that the focal skink's associations are variable; in contrast, low CV values means that focal skink's associations with conspecifics are relatively homogeneous (Riley et al, 2018b). We used three separate linear models to test if these network metrics differed between adult female, adult male, and juvenile skinks (details in Supplementary Materials).…”

Section: Social Network Analysismentioning

confidence: 99%

“…First, how does variation in individual social behavior link to fitness? Previous work has shown, within an experimental context, that Tree Skinks can be plastic in their social associations, potentially maximizing individual benefits within a dynamically changing environment (Riley et al, 2018b). In the field, Bonnett (1999) found that individual vigilance rates (head movements per minute) were lower for grouped sub-adults than lone sub-adults, but this trend was not observed in adults.…”

Section: Variation In Social Behavior At the Individual And Population Levelmentioning

confidence: 99%

Socioecology of the Australian Tree Skink (Egernia striolata)

et al. 2021

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There is great diversity in social behavior across the animal kingdom. Understanding the factors responsible for this diversity can help inform theory about how sociality evolves and is maintained. The Australian Tree Skink (Egernia striolata) exhibits inter- and intra-population variability in sociality and is therefore a good system for informing models of social evolution. Here, we conducted a multi-year study of a Tree Skink population to describe intra-population variation in the social organization and mating system of this species. Skinks aggregated in small groups of 2–5 individuals, and these aggregations were typically associated with shared shelter sites (crevices and hollows within rocks and trees). Aggregations were typically made up of one or more adult females and, often, one male and/or juvenile(s). Social network and spatial overlap analyses showed that social associations were strongly biased toward kin. Tree skinks also exhibited high site fidelity regardless of age or sex. There were high levels of genetic monogamy observed with most females (87%) and males (68%) only breeding with a single partner. Our results indicate that Tree Skinks reside in small family groups and are monogamous, which corresponds with existing research across populations. Similar to previous work, our study area consisted of discrete habitat patches (i.e., rock outcrops, trees, or both), which likely limits offspring dispersal and promotes social tolerance between parents and their offspring. Our study clearly demonstrates that there is intra-population variability in Tree Skink social behavior, but it also provides evidence that there is a high degree of inter-population consistency in sociality across their geographic range. We also highlight promising possible avenues for future research, specifically discussing the importance of studying the nature and extent of Tree Skink parental care and quantifying the fitness outcomes of kin-based sociality in this species, which are topics that will further our understanding of the mechanisms underlying variation in vertebrate social behavior.

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Isolation rearing does not constrain social plasticity in a family-living lizard

Cited by 13 publications

References 66 publications

Social networks and social stability in a translocated population of Otago skinks (Oligosoma otagense)

Social networks and social stability in a translocated population of Otago skinks (Oligosoma otagense)

Sperm Storage in a Family-Living Lizard, the Tree Skink (Egernia striolata)

Socioecology of the Australian Tree Skink (Egernia striolata)

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