First description of migratory behavior of humpback whales from an Antarctic feeding ground to a tropical calving ground

Background Despite exhibiting one of the longest migrations in the world, half of the humpback whale migratory cycle has remained unexamined. Until now, no study has provided a continuous description of humpback whale migratory behavior from a feeding ground to a calving ground. We present new information on satellite-derived offshore migratory movements of 16 Breeding Stock G humpback whales from Antarctic feeding grounds to South American calving grounds. Satellite locations were used to demonstrate migratory corridors, while the impact of departure date on migration speed was assessed using a linear regression. A Bayesian hierarchical state–space animal movement model (HSSM) was utilized to investigate the presence of Area Restricted Search (ARS) en route. Results 35,642 Argos locations from 16 tagged whales from 2012 to 2017 were collected. The 16 whales were tracked for a mean of 38.5 days of migration (range 10–151 days). The length of individually derived tracks ranged from 645 to 6381 km. Humpbacks were widely dispersed geographically during the initial and middle stages of their migration, but convened in two convergence regions near the southernmost point of Chile as well as Peru’s Illescas Peninsula. The state–space model showed almost no instances of ARS along the migratory route. The linear regression assessing whether departure date affected migration speed showed suggestive but inconclusive support for a positive trend between the two variables. Results suggestive of stratification by sex and reproductive status were found for departure date and route choice. Conclusions This multi-year study sets a baseline against which the effects of climate change on humpback whales can be studied across years and conditions and provides an excellent starting point for the investigation into humpback whale migration.

Memories of Migrations Past: Sociality and Cognition in Dynamic, Seasonal Environments

Seasonal migrations are a widespread and broadly successful strategy for animals to exploit periodic and localized resources over large spatial scales. It remains an open and largely case-specific question whether long-distance migrations are resilient to environmental disruptions. High levels of mobility suggest an ability to shift ranges that can confer resilience. On the other hand, a conservative, hard-wired commitment to a risky behavior can be costly if conditions change. Mechanisms that contribute to migration include identification and responsiveness to resources, sociality, and cognitive processes such as spatial memory and learning. Our goal was to explore the extent to which these factors interact not only to maintain a migratory behavior but also to provide resilience against environmental changes. We develop a diffusion-advection model of animal movement in which an endogenous migratory behavior is modified by recent experiences via a memory process, and animals have a social swarming-like behavior over a range of spatial scales. We found that this relatively simple framework was able to adapt to a stable, seasonal resource dynamic under a broad range of parameter values. Furthermore, the model was able to acquire an adaptive migration behavior with time. However, the resilience of the process depended on all the parameters under consideration, with many complex trade-offs. For example, the spatial scale of sociality needed to be large enough to capture changes in the resource, but not so large that the acquired collective information was overly diluted. A long-term reference memory was important for hedging against a highly stochastic process, but a higher weighting of more recent memory was needed for adapting to directional changes in resource phenology. Our model provides a general and versatile framework for exploring the interaction of memory, movement, social and resource dynamics, even as environmental conditions globally are undergoing rapid change.

Variation in movement patterns of mule deer: have we oversimplified migration?

Background Conservation and management of migratory animals has gained attention in recent years, but the majority of research has focused on stereotypical ‘migrant’ and ‘resident’ behaviors, often failing to incorporate any atypical behaviors or characterize migratory behaviors beyond distance and timing of the migration. With migration threatened by anthropogenic development and climate change, it is crucial that we understand the full range of migratory behaviors. Our objective was to demonstrate and characterize the variation in migration strategies, including typical and atypical migratory behaviors for mule deer (Odocoileus hemionus) in Utah, USA. Methods Because calculation of common metrics such as distance, timing, and use of stopovers during migration did not adequately describe the variation we observed in migratory behavior for this species—particularly when animals visited multiple (> 3) ranges for extended lengths of time—we developed additional methods and categories to describe observed variation in migratory behavior. We first categorized trajectories based on the number of discrete, separate ranges and range shifts between them. Then, we further characterized the variation in migration strategies by examining the timing, duration, and distance traveled within each of the categories. We also examined if and how frequently individual deer switched among categories from year to year. Results We classified 1218 movement trajectories from 722 adult female mule deer, and found that 54.4% were dual-range migrants, who made one round-trip to one distinct range. Multi-range migrants (23.6%) made one round-trip during which they stayed at multiple discrete ranges. Commuters (1.0%) traveled to the same range multiple times, and poly migrants (1.5%) made multiple round-trips to different ranges. Gradual movers (2.5%) did not show a discrete range shift but moved gradually between ranges, whereas residents (12.6%) never left their home ranges, and dispersers (4.4%) left but never returned. Of the deer that we monitored for multiple years, 51.2% switched among categories. Conclusion We conclude that the substantial number of atypical migratory strategies, as well as the number of deer that switched categories, underlines the importance of studying these less-stereotyped behaviors that may be exhibited by large proportions of populations. Acknowledging and investigating the full complexity and diversity in migratory strategies might uncover unknowns with respect to underlying factors and drivers of migration, and can help shape effective conservation strategies.

St18 specifies globus pallidus projection neuron identity in MGE lineage

The medial ganglionic eminence (MGE) is a progenitor domain in the subpallium that produces both locally-projecting interneurons which undergo tangential migration in structures such as the cortex as well as long-range projection neurons that occupy subcortical nuclei. Very little is known about the transcriptional mechanisms specifying the migratory behavior and axonal projection patterns of these two broad classes of MGE-derived neurons. In this study, we identify St18 as a novel transcriptional determinant specifying projection neuron fate in the MGE lineage. St18 is transiently expressed in the MGE subventricular zone (SVZ) and mantle, and we assessed its function using an ES cell-based model of MGE development. Induction of St18 is sufficient to direct ES-derived MGE neurons to adopt a projection neuron-like identity as defined by migration and morphology. Using genetic loss-of-function in mice, we find that St18 is required for the production of globus pallidus pars externa (GPe) prototypic projection neurons. Single cell RNA sequencing revealed that St18 regulates MGE output of specific neuronal populations: in the absence of St18, we observe a large expansion of cortical interneurons at the expense of putative GPe neurons. Through gene expression analysis we identified a downstream effector of St18, Cbx7, which is a component of Polycomb repressor complex 1. We find that Cbx7 is essential for projection neuron-like migration and is not involved in St18-mediated projection neuron-like morphology. Our results characterize a novel transcriptional determinant that directs GPe prototypic projection neuron identity. Further, we identified a downstream target of St18, Cbx7, which regulates only the migratory behavior of long-range projection neurons, suggesting that specific features of MGE projection neuron identity may be governed in a compartmentalized fashion by distinct transcriptional modules downstream of St18.

Ethanol pre-exposure enhances alcohol-seeking behavior at cellular level by chemoattraction and exhibits bleb-driven cellular stress response in uniform ethanol concentration

This study investigates the effect of ethanol and its pre-exposure on cell migration. Here, fibroblast cells were first pre-treated with ethanol, and their migratory behavior was tested in both chemotaxis and chemokinesis setup. 1% ethanol was taken as a potential chemotactic agent. The study reveals that in presence of ethanol gradient cells display migration towards ethanol, and pre-exposure further augments this migratory behavior by altering their chemotactic responsiveness. In uniform ethanol concentration, cells first undergo three staged adaptations to the new environment: shrinking, blebbing, and recovery, where cells use bleb-driven cell protection machinery to adapt. Thus, migration is initially stalled. But once the cells resume locomotion, no significant difference in migratory parameters is observed. Overall, this study establishes ethanol as a chemoattractant for fibroblasts, with cells showing enhanced alcohol-seeking behavior upon pre-exposure. Such behavior is reminiscent of seeking and tolerance exhibited by alcohol-dependent addictive behavior in higher organisms including humans.

OPTC-2. Identification of enriched genes and pathways associated to hypoxia induced migration in patient-derived glioma stem cell lines by RNAseq

Glioblastomas (GBM), the most prevalent and lethal primary brain tumors, are characterized by high intertumoral heterogeneity, diffuse infiltration, and resistance to conventional therapies. Notably, the ability of tumor cells to invade surrounding tissues is one of their most damaging characteristics, it not only causes resistance to therapies such as surgery and radiotherapy but is ultimately the primary cause of death. Therapies that cause hypoxia (e.g. anti-angiogenic therapies) have been shown to increase invasiveness, leading to resistance to the therapy itself and further complications for the patients. Using patient-derived glioma stem cell lines (GSCL) we have discovered cell lines that display heterogeneous migratory behavior in response to hypoxia. As expected we observed that four GSCLs studied had increased migration in hypoxia. Strikingly, two other cell lines studied showed decreased migration in hypoxia. This unforeseen result reflects the heterogeneous nature of GBM and the difference between these GSCLs could be key to understanding this variable. To delve into the molecular context that could explain these differences we performed an exploratory RNAseq analysis on four of the GSCLs, two that showed hypoxia-induced migration and two with decreased migration in hypoxia, and evaluated genes differentially expressed in hypoxia versus normoxia. We also carried out gene ontology and pathway enrichment analysis to discover molecular and pathway patterns consistent with the migratory behaviors observed in each group of GSCLs. The results show how that a similar migratory response to hypoxia coincides with particular sets of enriched genes and pathways. Specifically, we found NOTCH and WNT signaling pathways upregulated in GSCLs which showed increased migration in hypoxia while the IFN-gamma pathway upregulated in GSCLs with decreased migration in hypoxia. Knowing the individual molecular mechanisms responsible for the migratory behavior could allow for tailor-made therapies that reduce the dissemination of these tumors.

REPRODUCTIVE AND MIGRATION ATTITUDES OF CONTEMPORARY YOUTH OF THE EAEU STATES (RUSSIA, KAZAKHSTAN, KYRGYZSTAN: A CASE STUDY)

The article is devoted to the current aspects of demographic development in the EAEU member states in the context of studying the specifics of the reproductive and migratory behavior of young people in Russia, Kazakhstan and Kyrgyzstan. The modern generation of young people in post-Soviet countries over the past three decades has been influenced by various factors that have radically transformed their views on family, childbirth and migration. Their attitudes towards reproductive and migratory behavior will dominate the future demographic trends not only in each of the studied countries, but also in the Eurasian space as a whole. Therefore, a detailed study of the attitudes of the young and educated generation is the most important task of demographic and sociological sciences. Based on the results of a sociological survey conducted using a unified methodology, the article examines the features of reproductive and migratory behavior in countries at different stages of the “demographic transition.” It reveals the peculiarities of the respondents’ attitude from the three states to official marriage, age preferences for starting a family and giving birth to their first child. Reproductive judgments regarding anticipated and ideal number of children are identified. The use of the ranking method allowed to detect ​​the normative childbearing models in the three countries and the differences between them. The conclusion states that in all the states in question, the prevailing socio-economic conditions are an obstacle to the implementation of the existing ideal reproductive attitudes. The gender peculiarities of the views of young people in the three countries on extramarital unions, reproductive patterns and “planned childlessness” were noted. The article demonstrates that, with regard to the results of the study, in the next 25 to 30 years families in Russia will likely have a small number of children, in Kazakhstan—an average number, and reproductive behavior in Kyrgyzstan will likely retain its tendency towards having many children. The article also contains conclusions about specific migration attitudes based on the replies to questions about the preferred place to apply professional skills, create a family and have children. The dependence of migration attitudes on gender and country of residence has been revealed. Based on empirical data, the groups of respondents characterized by pragmatic, patriotic and antipatriotic migratory behavior have been identified. It was determined that young people who live in Kyrgyzstan are more focused on moving to a new place of residence, while all respondents are quite cosmopolitan in regard to the place of application of their professional skills, and students are most patriotic about the place to start a family.