Biology subjects

Langrock, R.

Publications and source records attributed to Langrock, R..

3 recordsLinked to original sources

bioRxiv2025

Hsp90 buffers behavioral plasticity by regulating Pdf transcription in clock neurons of Drosophila melanogaster

Circadian rhythms are prevalent on Earth and temporally organize behaviour and physiology of organisms to occur in species-specific temporal niches. However, species differ in how strictly individuals are controlled by their circadian clock, suggesting that it may offer a selective advantage for an individual to extend its temporal niche under certain circumstances, for example during stressful environmental conditions. A potential mechanism controlling temporal niche adherence involves the evolutionary capacitor and chaperon protein HSP90, known to assist the proper folding of important signalling molecules. If HSP90 becomes rate limiting (e.g., under environmental stress) hidden genetic variation will be expressed, producing novel and potentially beneficial phenotypes for the individual. While this role of HSP90 is well established for morphological traits, we show here that it extends to regulation of temporal behavioural patterns. We show that within a small subset of clock neurons in the fly brain, HSP83, the fly homologue of HSP90, mitigates inter-individual behavioural plasticity. We provide evidence for the requirement of HSP83 for efficient transcription of the gene encoding the circadian neuropeptide Pigment Dispersing Factor (PDF), and for correct PDF accumulation in central clock neurons. Strikingly, Hsp83 mutants affect synchronized oscillations of the clock protein PERIOD (PER) in subsets of circadian clock neurons in the same way as flies without PDF, further supporting a role of Hsp83 in regulating Pdf. Our findings therefore provide a mechanistic explanation for HSP83 function in regulation of behavioural plasticity, and offer an explanation for how to restrict temporal niche extension to stressful environmental conditions.

neuroscience↗

bioRxiv2023

Daily time constraints limit behavioural capacity to cope with thermally increased metabolic demands

Increased environmental temperatures result in greater energy demands for ectotherms, however, it is currently not clear if these energy demands can effectively be met by increased foraging effort. Here, we tested the temperature dependence of foraging effort and metabolic rate in an aquatic ectotherm across its entire natural thermal range. We developed a novel hidden Markov model to detect behavioural states in long-term body acceleration data collected from free-ranging bull sharks between 19 and 33 {degrees}C, and found that increasing temperature altered both the timing and extent of foraging effort. Our data revealed asymmetrical increases of metabolic demands and foraging effort; standard metabolic rates increased exponentially with temperature, but foraging effort increased logarithmically. The observed decoupling of foraging effort and energy demand suggests individuals face increased energy deficits at higher temperatures, confirmed by concomitant reductions in body condition measured in this population with increasing temperatures. We suggest that alterations in the well-established trade-offs between foraging and predation risk coupled with time constraints imposed by high temperatures limit the capacity of animals to cope with environmental temperatures well below critical temperatures.

ecology↗

bioRxiv2021

Movement patterns and activity levels are shaped by the neonatal environment in Antarctic fur seal pups

Tracking studies of juveniles are rare compared to those of adults, and consequently little is known about the influence of intrinsic and extrinsic factors on activity during this critical life stage. We used hourly GPS data, collected from 66 Antarctic fur seal pups from birth until moulting, to investigate the explanatory power of multiple individual-based and environmental variables on activity levels. Pups were sampled from two nearby breeding colonies of contrasting density during two subsequent years, and a two-state hidden Markov model was used to identify modalities in their movement behaviour, specifically active and inactive states. We found that movement was typified by central place exploration, with active movement away from and subsequent return to a location of inactivity. The probability of such directed exploration was unaffected by several factors known to influence marine mammal movement including sex, body condition, and temperature. Compared to pups born at the high-density colony, pups at low-density were more active, increased their activity with age, and transitioned earlier into the tussock grass, which offers protection from predators and extreme weather. Our study illustrates the importance of extrinsic factors, such as colony of birth, to early-life activity patterns and highlights the adaptive potential of movement.

animal behavior and cognition↗