| 1. |
- Cunningham, G. D., et al.
(author)
-
Degrees of change: between and within population variation in thermal reaction norms of phenology in a viviparous lizard
- 2020
-
In: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 101:10
-
Journal article (peer-reviewed)abstract
- As the earth warms, populations will be faced with novel environments to which they may not be adapted. In the short term, populations can be buffered against the negative effects, or maximize the beneficial effects, of such environmental change via phenotypic plasticity and, in the longer term, via adaptive evolution. However, the extent and direction of these population-level responses will be dependent on the degree to which responses vary among the individuals within them (i.e., within population variation in plasticity), which is, itself, likely to vary among populations. Despite this, we have estimates of among-individual variation in plastic responses across multiple populations for only a few systems. This lack of data limits our ability to predict the consequences of environmental change for population and species persistence accurately. Here, we utilized a 16-yr data set from climatically distinct populations of the viviparous skinkNiveoscincus ocellatustracking over 1,200 litters from more than 600 females from each population to examine inter- and intrapopulation variability in the response of parturition date to environmental temperature. We found that these populations share a common population-mean reaction norm but differ in the degree to which reaction norms vary among individuals. These results suggest that even where populations share a common mean-level response, we cannot assume that they will be affected similarly by altered environmental conditions. If we are to assess how changing climates will impact species and populations accurately, we require estimates of how plastic responses vary both among and within populations.
|
|
| 2. |
|
|
| 3. |
- Botterill-James, Thomas, et al.
(author)
-
Experimental manipulation suggests effect of polyandry but not mate familiarity on within-pair aggression in the social skink, Liopholis whitii
- 2017
-
In: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 71:4
-
Journal article (peer-reviewed)abstract
- Abstract: Long-term monogamy is a key characteristic of family living across animals. The evolutionary maintenance of long-term monogamy has been suggested to be facilitated by increased reproductive coordination as a result of mate familiarity, leading to increased reproductive success. However, such effects can be compromised if females mate outside the pair bond (e.g. female polyandry), introducing conflicts of interest between the male and female. Here, we experimentally test the effects of both mate familiarity and female polyandry on agonistic behaviour and reproduction in a family living lizard, Liopholis whitii. We found that mate familiarity did not decrease the level of aggression between pairs whereas reducing female polyandry did. However, we did not find an effect of either mate familiarity or female polyandry on female reproductive output. These results suggest that male behavioural responses to female polyandry may influence pair stability in Liopholis whitii, providing support for the growing appreciation of the multiple ways in which female polyandry can influence the stability of family living. Significance statement: Family living is underpinned by social pair bonds between adults (i.e. stable social monogamy). Therefore, key to understanding the emergence and maintenance of family living is identifying factors influencing pair bonds. We manipulated both female polyandry and mate familiarly in replicated enclosure experiment using social lizards to test their role in mediating within-pair aggression and ultimately the coordination of reproductive behaviour and hence reproductive output. We found that polyandry but not mate familiarity influenced levels of aggression between pairs but this did not transmit into concomitant effects on reproductive output.
|
|
| 4. |
- Fitzpatrick, L. J., et al.
(author)
-
Tail loss and telomeres: consequences of large-scale tissue regeneration in a terrestrial ectotherm
- 2019
-
In: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 15:7
-
Journal article (peer-reviewed)abstract
- Large-scale tissue regeneration has potential consequences for telomere length through increases in cell division and changes in metabolism which increase the potential for oxidative stress damage to telomeres. The effects of regeneration on telomere dynamics have been studied in fish and marine invertebrates, but the literature is scarce for terrestrial species. We experimentally induced tail autotomy in a lizard (Niveoscincus ocellatus) and assessed relative telomere length (RTL) in blood samples before and after partial tail regeneration while concurrently measuring reactive oxygen species (ROS) levels. The change in ROS levels was a significant explanatory variable for the change in RTL over the 60-day experiment. At the average value of ROS change, the mean RTL increased significantly in the control group (intact tails), but there was no such evidence in the regenerating group. By contrast, ROS levels decreased significantly in the regenerating group, but there was no such evidence in the control group. Combined, these results suggest that tail regeneration following autotomy involves a response to oxidative stress and this potentially comes at a cost to telomere repair. This change in telomere maintenance demonstrates a potential long-term cost of tail regeneration beyond the regrowth of tissue itself.
|
|
| 5. |
- Fitzpatrick, L. J., et al.
(author)
-
Temperature and telomeres: thermal treatment influences telomere dynamics through a complex interplay of cellular processes in a cold-climate skink
- 2019
-
In: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 191:4, s. 767-776
-
Journal article (peer-reviewed)abstract
- Telomere dynamics vary fundamentally between endothermic populations and species as a result of differences in life history, yet we know little about these patterns in ectotherms. In ectotherms, the relationships between climate, metabolism and life history suggest that telomere attrition should be higher at relatively high environmental temperatures compared to relatively low environmental temperatures, but these effects may vary between populations due to local adaptation. To address this hypothesis, we sampled reactive oxygen species (ROS) and telomere length of lizards from warm lowland and cool highland populations of a climatically widespread lizard species that we exposed to hot or cold basking treatments. The hot treatment increased relative telomere length compared to the cold treatment independent of climatic origin or ROS levels. Lizards from the cool highland region had lower ROS levels than those from the warm lowland region. Within the highland lizards, ROS increased more in the cold basking treatment than the hot basking treatment. These results are in the opposite direction to those predicted, suggesting that the relationships between temperature, metabolism, ROS and telomere dynamics are not straightforward. Future work incorporating detailed understanding of the thermal reaction norms of these and other linked traits is needed to fully understand these processes. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
|
|
| 6. |
- Halliwell, Ben, et al.
(author)
-
Habitat saturation promotes delayed dispersal in a social reptile
- 2017
-
In: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 28:2, s. 515-522
-
Journal article (peer-reviewed)abstract
- When and where offspring disperse has important implications for the evolutionary emergence and maintenance of group living. In noncooperative breeders, direct benefits of delayed dispersal are relatively limited, suggesting that decisions regarding whether or not to remain in the parental territory are largely driven by the availability of suitable habitat in which to settle. Although there is ample evidence of correlations between habitat saturation and delayed dispersal, experimental tests are rare, particularly for species with facultative group formation. We manipulated the density of conspecifics in enclosed populations of a family living reptile to experimentally evaluate the influence of habitat saturation on the tendency to delay dispersal. Habitat saturation did not influence whether or not offspring explored their surroundings. However, when conspecific density was high, more offspring delayed dispersal and those that did settle in high-density enclosures had reduced survival. These patterns appear to be due to increased dispersal costs imposed by conspecific aggression; offspring that explored high-density enclosures had reduced body condition and a greater risk of mortality. We discuss these results in the context of the evolutionary origins of family living.
|
|
| 7. |
- Pettersen, A. K., et al.
(author)
-
Population divergence in maternal investment and embryo energy use and allocation suggests adaptive responses to cool climates
- 2023
-
In: Journal of Animal Ecology. - 0021-8790. ; 92:9, s. 1771-1785
-
Journal article (peer-reviewed)abstract
- The thermal sensitivity of early life stages can play a fundamental role in constraining species distributions. For egg-laying ectotherms, cool temperatures often extend development time and exacerbate developmental energy cost. Despite these costs, egg laying is still observed at high latitudes and altitudes. How embryos overcome the developmental constraints posed by cool climates is crucial knowledge for explaining the persistence of oviparous species in such environments and for understanding thermal adaptation more broadly. Here, we studied maternal investment and embryo energy use and allocation in wall lizards spanning altitudinal regions, as potential mechanisms that enable successful development to hatching in cool climates. Specifically, we compared population-level differences in (1) investment from mothers (egg mass, embryo retention and thyroid yolk hormone concentration), (2) embryo energy expenditure during development, and (3) embryo energy allocation from yolk towards tissue. We found evidence that energy expenditure was greater under cool compared with warm incubation temperatures. Females from relatively cool regions did not compensate for this energetic cost of development by producing larger eggs or increasing thyroid hormone concentration in yolk. Instead, embryos from the high-altitude region used less energy to complete development, that is, they developed faster without a concomitant increase in metabolic rate, compared with those from the low-altitude region. Embryos from high altitudes also allocated relatively more energy towards tissue production, hatching with lower residual yolk: tissue ratios than low-altitude region embryos. These results are consistent with local adaptation to cool climate and suggest that this is underpinned by mechanisms that regulate embryonic utilisation of yolk reserves and its allocation towards tissue, rather than shifts in maternal investment of yolk content or composition.
|
|
| 8. |
- While, Geoffrey M., et al.
(author)
-
Egernia lizards
- 2015
-
In: Current Biology. - : Elsevier BV. - 1879-0445 .- 0960-9822. ; 25:14, s. 593-595
-
Journal article (other academic/artistic)
|
|
| 9. |
- Bouffet-Halle, Alix, et al.
(author)
-
Characterisation and cross-amplification of sex-specific genetic markers in Australasian Egerniinae lizards and their implications for understanding the evolution of sex determination and social complexity
- 2022
-
In: Australian Journal of Zoology. - 0004-959X. ; 69:2, s. 33-40
-
Journal article (peer-reviewed)abstract
- Sex is a pervasive factor that underpins functional phenotypic variation across a range of traits. Although sex can usually be distinguished morphologically, in some species this is not possible. The development of genetic markers for sex identification is, thus, key if we are to incorporate sex into an understanding of ecological or evolutionary process. Here we develop genetic markers for the identification of sex within an iconic Australian lizard group, the Egernia group, which is notable for its complex social behaviour. We used restriction-site associated DNA sequencing to characterise sex-specific genetic sequences for a key member of the group, Liopholis whitii, and designed primers for four of these putative sex-specific sequences. These primers amplified across some, but not all, species of the group. Our results provided several important insights. They suggest conservatism of a XX/XY sex determination system within the group as well as sex-specific genomic regions that appear independent of the conserved genomic regions identified in other skink species. More broadly, the development of sex markers for the Egernia group opens up a range of potential research questions related to the role that sex plays in the mediation of social behaviour and, through this, the emergence and stability of social life.
|
|
| 10. |
- Fitzpatrick, L. J., et al.
(author)
-
Individual telomere dynamics and their links to life history in a viviparous lizard
- 2021
-
In: Proceedings of the Royal Society B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 288:1951
-
Journal article (peer-reviewed)abstract
- Emerging patterns suggest telomere dynamics and life history are fundamentally linked in endotherms through life-history traits that mediate the processes underlying telomere attrition. Unlike endotherms, ectotherms maintain the ability to lengthen somatic telomeres throughout life and the link between life-history strategies and ectotherm telomere dynamics is unknown. In a well-characterized model system (Niveoscincus ocellatus), we used long-term longitudinal data to study telomere dynamics across climatically divergent populations. We found longer telomeres in individuals from the cool highlands than those from the warm lowlands at birth and as adults. The key determinant of adult telomere length across populations was telomere length at birth, with population-specific effects of age and growth on adult telomere length. The reproductive effort had no proximate effect on telomere length in either population. Maternal factors influenced telomere length at birth in the warm lowlands but not the cool highlands. Our results demonstrate that life-history traits can have pervasive and context-dependent effects on telomere dynamics in ectotherms both within and between populations. We argue that these telomere dynamics may reflect the populations' different life histories, with the slow-growing cool highland population investing more into telomere lengthening compared to the earlier-maturing warm lowland population.
|
|
