Acceleration data reveal the energy management strategy of a marine ectotherm during reproduction

1. Maintaining a high and stable body temperature is often critical for female ectotherms during reproduction. Yet this strategy may be energetically costly, and therefore challenging, during this period of already high-energy demand. 2. Here, the 6-week deployment of tri-axial accelerometers (n = 6) on a marine ectotherm, the loggerhead turtle (Caretta caretta), reproducing at the northern limit of the species’ breeding range (i.e. in a thermally dynamic environment) revealed the behavioural mechanisms underlying its energy management strategy during the breeding season. 3. The estimated activity levels of female loggerheads using overall dynamic body acceleration (ODBA) were high during the breeding season, suggesting that marine turtles may not be able to remain inactive for long periods in the same manner as terrestrial ectotherms, because of the thermally dynamic nature of their environment. 4. However, activity levels were not constant throughout the season, being impacted by both ambient water temperature and female reproductive status. In cold water at the beginning of the nesting season, high levels of activity suggested that females behaviourally thermoregulated by seeking out warm water patches along the shoreline. Interactions with male turtles (courtship and/or avoidance) may also explain this high level of activity. As sea temperatures warmed up and the amount of energy devoted to reproduction probably increased, the turtles spent more time resting during long sequential flat-bottomed dives, and reduced any unnecessary locomotory activity. 5. Turtles may therefore adjust their activity patterns in response to seasonal variations in abiotic (i.e. ambient temperature) and biotic (i.e. reproductive status) factors. This may help minimize activity-linked metabolic rate and maximize reproductive output over a season while breeding in thermally dynamic environments. 6. A mechanistic model gave support to these empirical results. The model revealed that actively maintaining high and stable body temperature is of clear benefit to female turtles at temperate breeding sites. While energetically costly, such active thermoregulatory behaviour may speed up egg maturation, allowing turtles to initiate nesting earlier in the season, and hence maximize reproductive output.

The everyday image: reproduction and participation

An exhibition of five small paintings and seven lithographs that explore images of images of the everyday, the gaze and voyeurism. Chicago Art Department, Pilsen, Chicago.

Short- and long-term consequences of early developmental conditions : a case study on wild and domesticated zebra finches

Divergent selection pressures among populations can result not only in significant differentiation in morphology, physiology and behaviour, but also in how these traits are related to each other, thereby driving the processes of local adaptation and speciation. In the Australian zebra finch, we investigated whether domesticated stock, bred in captivity over tens of generations, differ in their response to a life-history manipulation, compared to birds taken directly from the wild. In a ‘common aviary’ experiment, we thereto experimentally manipulated the environmental conditions experienced by nestlings early in life by means of a brood size manipulation, and subsequently assessed its short- and long-term consequences on growth, ornamentation, immune function and reproduction. As expected, we found that early environmental conditions had a marked effect on both short- and long-term morphological and life-history traits in all birds. However, although there were pronounced differences between wild and domesticated birds with respect to the absolute expression of many of these traits, which are indicative of the different selection pressures wild and domesticated birds were exposed to in the recent past, manipulated rearing conditions affected morphology and ornamentation of wild and domesticated finches in a very similar way. This suggests that despite significant differentiation between wild and domesticated birds, selection has not altered the relationships among traits. Thus, life-history strategies and investment trade-offs may be relatively stable and not easily altered by selection. This is a reassuring finding in the light of the widespread use of domesticated birds in studies of life-history evolution and sexual selection, and suggests that adaptive explanations may be legitimate when referring to captive bird studies.

Cost of reproduction in the Queensland fruit fly: Y-model versus lethal protein hypothesis

The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan–reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal protein hypothesis), we measured lifespan and egg production in Queensland fruit flies varying in reproductive status (mated, virgin and sterilized females, virgin males) that were fed one of 18 diets varying in protein and carbohydrate amounts. The Y-model predicts that for sterilized females and for males, which require little protein for reproduction, there will be no effect of P : C ratio on lifespan; the lethal protein hypothesis predicts that the effect of P : C ratio should be similar in all groups. In support of the lethal protein hypothesis, and counter to the Y-model, the P : C ratio of the ingested diets had similar effects for all groups. We conclude that the trade-off between lifespan and reproduction is mediated by the detrimental side-effects of protein ingestion on lifespan.

Reproduction in five sympatric batoid species (family urolophidae) from south-eastern Australia

This PhD determines the reproductive biology of five stingaree species caught as bycatch from south-eastern Australian commercial fisheries for fisheries stock assessments, ecological risk assessments, and species extinction risk evaluations.

O where are you going? O do you imagine? Reproduction and response : a reflexive sociology of scholarship of teaching and learning in practical legal training

My doctoral research studies Australian PLT practitioners’ engagement with scholarship of teaching and learning. I argue that many PLT practitioners are motivated to engage with scholarship of teaching and learning in their work. There are, however, individual and extra-individual impediments.
PLT practitioners are lawyers that teach in institutional practical legal training (“PLT”). Satisfactory completion of mandatory PLT is an eligibility requirement for admission to the Australian legal profession. The PLT requirement is additional to academic legal qualifications. PLT is undertaken at a post-graduate level with, or after, the academic law degree.
My study investigates PLT practitioners’ motivations and capabilities to engage with scholarship of teaching and learning (“SoTL”). I study organisational symbolic support for SoTL in PLT, and organisational allocation of resources to SoTL in PLT.
The study involves individual and extra-individual domains of PLT practitioners’ work. It considers how social structures (e.g. “the juridical”) are inscribed into individuals’ practices (“teaching”) and, conversely, whether practices influence social structures.
My research adopts qualitative methodologies. These involve inter-disciplinary exchanges between law, legal education, practice research, sociology of law, cultural theory, and theory and practice of teaching and learning. My theoretical framework draws on Pierre Bourdieu’s “reflexive sociology”, and Michel de Certeau’s “heterological science”.
I sourced data from documents, and semi-structured interviews with 36 Australian PLT practitioners. Documentary sources include statutory instruments, speeches, reports, practice directions, histories, and scholarly publications.
To analyse the data I adopted Kelle’s characterisation of “theoretical sensitivity”, drawing on “explicit” and “emergent” analysis strategies derived from “grounded theory”. The explicit strategies were based on my theoretical framework. The emergent strategy involved sensitivity to non-explicit concepts and theories that emerged from the data. Computer-aided qualitative data analysis software expedited these methods.
My findings to date question dominant legal structures’ readiness for change, the implications of this for teaching and learning in PLT, and in particular for PLT practitioners’ engagement with SoTL in PLT.
The espoused rationale for mandatory PLT (in statutes) is improvement for the protection of clients, the administration of justice, and to assure quality legal services. The tacit rationale is improved quality of legal education, and experiences, for lawyers-to-be. My thesis argues dominant structures in legal education impede the espoused and tacit objectives, and impede PLT practitioners’ engagement with scholarship of teaching and learning.

Climate-induced reaction norms for life-history traits in pythons

Climate change modelers predict increasingly frequent “extreme events,” so it is critical to quantify whether organismal responses (such as reproductive output) measured over the range of usual climatic conditions can predict responses under more extreme conditions. In a 20-year field study on water pythons (Liasis fuscus), we quantified the effects of climatically driven annual variation in food supply on demographic traits of female pythons (feeding rate, body size, body mass, and reproductive output). Reaction norms linking food supply to feeding rates and residual body mass were broadly linear, whereas norms linking food supply to female body size became curvilinear when a dramatic (flooding-induced) famine reduced the mean body size at sexual maturity. Thus, the reaction norms recorded over 16 years of “normal” (albeit highly variable) climatic conditions gave little insight into the population's response to a more extreme nutritional crisis.