Demography can favour female-advantageous alleles

When female fecundity is relatively independent of male abundance, while male reproduction is proportional to female abundance, females have a larger effect on population dynamics than males (i.e. female demographic dominance). This population dynamic phenomenon might not appear to influence evolution, because male and female genomes still contribute equally much to the next generation. However, here we examine two evolutionary scenarios to provide a proof of principle that spatial structure can make female demographic dominance matter. Our two simulation models combine dispersal evolution with local adaptation subjected to intralocus sexual conflict and environmentally driven sex ratio biases, respectively. Both models have equilibria where one environment (without being intrinsically poorer) has so few reproductive females that trait evolution becomes disproportionately determined by those environments where females survive better (intralocus sexual conflict model), or where daughters are overproduced (environmental sex determination model). Surprisingly, however, the two facts that selection favours alleles that benefit females, and population growth is improved when female fitness is high, together do not imply that all measures of population performance are improved. The sex-specificity of the source-sink dynamics predicts that populations can evolve to fail to persist in habitats where alleles do poorly when expressed in females

Genetic and environmental drivers of colour and pattern in the Australian jacky dragon (Amphibolurus muricatus)

The underlying drivers of variation in the colouration (colour and pattern) of animals can be genetic, non-genetic, or more likely, a combination of both. Understanding the role of heritable genetic elements, as well as non-genetic factors such as age, habitat or temperature, in shaping colouration can provide insight into the evolution and function of these traits, as well as the speed of response to changing environments. This project examined the genetic and non-genetic drivers of continuous variation in colouration in a lizard, the jacky dragon (Amphibolurus muricatus). We leveraged a large captive experiment that manipulated parental and offspring thermal environment to simultaneously estimate the genetic and non-genetic drivers of variation in colouration. We found that the overall brightness, the elongation of the longitudinal stripes on the dorsum and the contrast between light and dark patches of the pattern were all heritable. Colouration varied according to the age of the hatchling; however, the thermal environment of neither the parents nor offspring contributed significantly to colouration. It appears that developmental plasticity and maternal effects associated with temperature are not important drivers of variation in our measures of colouration

Climate and predation dominate juvenile and adult recruitment in a turtle with temperature-dependent sex determination

Conditions experienced early in life can influence phenotypes in ecologically important ways, as exemplified by organisms with environmental sex determination. For organisms with temperature-dependent sex determination (TSD), variation in nest temperatures induces phenotypic variation that could impact population growth rates. In environments that vary over space and time, how does this variation influence key demographic parameters (cohort sex ratio and hatchling recruitment) in early life stages of populations exhibiting TSD? We leverage a 17-year data set on a population of painted turtles, Chrysemys picta, to investigate how spatial variation in nest vegetation cover and temporal variation in climate influence early life-history demography. We found that spatial variation in nest cover strongly influenced nest temperature and sex ratio, but was not correlated with clutch size, nest predation, total nest failure, or hatching success. Temporal variation in climate influenced percentage of total nest failure and cohort sex ratio, but not depredation rate, mean clutch size, or mean hatching success. Total hatchling recruitment in a year was influenced primarily by temporal variation in climate-independent factors, number of nests constructed, and depredation rate. Recruitment of female hatchlings was determined by stochastic variation in nest depredation and annual climate and also by the total nest production. Overall population demography depends more strongly on annual variation in climate and predation than it does on the intricacies of nest-specific biology. Finally, we demonstrate that recruitment of female hatchlings translates into recruitment of breeding females into the population, thus linking climate (and other) effects on early life stages to adult demographics

HatchlingData

Hatchling phenotypic data presented according to parental basking treatmen

Data from: Parental thermal environment alters offspring sex ratio and fitness in an oviparous lizard

The environment experienced by parents can impact the phenotype of their offspring (parental effects), a critical component of organismal ecology and evolution in variable or changing environments. Although temperature is a central feature of the environment for ectotherms, its role in parental effects has been little explored until recently. Here, parental basking opportunity was manipulated in an oviparous lizard with temperature-dependent sex determination, the jacky dragon (Amphibolurus muricatus). Eggs were incubated at a temperature that typically produces a 50:50 sex ratio, and hatchlings were reared in a standard thermal environment. Offspring of parents in short bask conditions appeared to have better fitness outcomes in captive conditions than those of parents in long bask conditions – they had greater growth and survival as a function of their mass. In addition, the sex of offspring (male or female) depended on the interaction between parental treatment and egg mass, and treatment impacted whether sons or daughters grew larger in their first season. The interactive effects of treatment on offspring sex and growth are consistent with adaptive explanations for the existence of temperature-dependent sex determination in this species. Moreover, the greater performance recorded in short bask offspring may represent an anticipatory parental effect to aid offspring in predicted conditions of restricted thermal opportunity. Together, these responses constitute a crucial component of the population response to spatial or temporal variation in temperature

FemaleData

Reproductive success of females according to basking treatmen

ClutchData

Clutch data according to basking treatmen

Monitoring the health status of free-ranging tammar wallabies using hematology, serum biochemistry, and parasite loads

Population differences in body condition, parasitic burden, hematology, and serum biochemistry of free-living tammar wallabies (Macropus eugenii) are presented and compared to studies reporting values in captive tammar wallabies. The nutritional distinction in the composition and quality of the available vegetation on Garden Island produces 3 sub-populations that differ in their human disturbance, body condition, rates of reproduction, and survival, providing unique opportunities to examine condition-related health parameters in free-living wallabies. Our results show several hematology analytes (in particular, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration), all the measured serum biochemistry analytes (urea, creatinine, triglycerides, and albumin), and total gastrointestinal parasite burden are significantly associated with body condition (body mass index), providing reliable indices of wallaby condition and habitat quality. The means and standard errors for hematology analytes (in particular, hemoglobin, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration) and all serum biochemistry values for free-ranging wallabies lie below and outside of reference ranges for captive wallabies, despite the naval base sub-population benefiting from human modified habitats with a consistent availability of food. This indicates that free-ranging tammar wallabies may be suffering from some challenges that captive wallabies do not face. The hematology and serum biochemistry values coupled with body condition indices suggest wallabies in the south bush sub-population are under greater nutritional stress and suffering from prolonged malnutrition. Examining all parameters in a single year and across years would be beneficial to further investigate habitat differences driving this change to help distinguish if vegetative structure and associated nutritional deficiencies and/or disease are limiting this population. Health monitoring is an integral part of the management of both captive and free-living populations and the data presented here will serve as an effective management tool in assessing the health status of free-living tammar wallabies