16 strange new parasitoid wasp species discovered in Vietnam

A field survey in Vietnam searching for Loboscelidia, a rare group of parasitoid wasps, has increased the total known number of species worldwide by 30% and uncovered their unique egg-burying behavior

Peer-Reviewed Publication

KYUSHU UNIVERSITY

 

IMAGE: 16 NEW SPECIES HAVE BEEN ADDED TO THE GROUP, LOBOSCELIDIA, BASED ON THEIR UNIQUE PHYSICAL CHARACTERISTICS. SCALE BAR = 0.5 MM view more 

CREDIT: YU HISASUE ET AL. (2023) EUROPEAN JOURNAL OF TAXONOMY, KYUSHU UNIVERSITY

Fukuoka, Japan— Researchers at Kyushu University and Vietnam’s National Museum of Nature have discovered 16 new species of Loboscelidia, a strange-looking and elusive group of parasitoid wasps. The scientists also reported for the first time the unique parasitic behavior of a captive female of one species, Loboscelidia squamosa, who was observed digging a hole in the soil to hide her host’s egg.

The findings were published in the European Journal of Taxonomy.

While we are more familiar with hunting wasps like yellowjackets, with their dramatic black and yellow stripes and painful stings, parasitoid wasps make up the vast majority of wasp species. They are often tiny (Loboscelidia wasps are between 2-5 mm in body length, smaller than a pencil-top eraser) and while unnoticed by humans, they play a crucial role in regulating the ecosystem.

“Parasitoid wasps act as a parasite of other insects. They lay their eggs in or on the bodies or eggs of their host, ultimately killing them,” says Assistant Professor Toshiharu Mita of Kyushu University’s Faculty of Agriculture, who led the research.

Despite their ecological importance, very little is known about many groups of parasitoid wasps, including Loboscelidia. Prior research into the group has suggested that they parasitize the eggs of stick insects, also known as walking sticks.

“Loboscelidia was first discovered around 150 years ago, but we still lack important knowledge about their biology. This study was the first time we were able to observe their parasitic behavior,” says first author, Dr. Yu Hisasue, formerly a PhD student supervised by Mita.

Mita and Hisasue, along with their colleague, Dr. Thai-Hong Pham of the National Museum of Nature, Vietnam, conducted field surveys at six sites across Vietnam, setting traps and using nets to capture the tiny parasitoid wasps.

On one occasion, they trapped a living female from one of the newly described species, Loboscelidia squamosa. They released her into a plastic container containing soil and placed a stick insect egg inside. The female wasp punctured the egg, laid her own egg inside and then searched for a location to bury the parasitized egg. She used her head to dig a hole, placed the host egg inside and plugged the entrance with soil.

This parasitic behavior is very developed, and similar to the nest building behavior seen in solitary hunting wasps. The researchers therefore believe that further research could help shed light on how these behaviors evolved in other wasps. It could also help explain the unique specialized head structure of Loboscelidia wasps, which could be useful for digging holes in the soil.

By the end of the field survey, the scientists had collected 70 individuals from the Loboscelidia group, taking high-resolution close-up photos of each wasp. One unusual feature of the wasps was the presence of hairs at the back of their head and on their body, with the arrangement and density of body hairs differing between each species.

In total, the scientists identified 16 new species, bringing the known number of species worldwide up to 67.

“The Loboscelidia wasps were thought to be rare group with a small number of species, but with one stroke, we have increased the number of species by 30%,” says Mita.

Importantly, each species was typically found in a very limited area, usually only at one collection site. This makes it likely that the group has many more species that still could be discovered with further field surveys. However, it also highlights the vulnerability of each species.

“As each species is only found in a small area, any disruption to their habitat could result in the loss of that species forever,” concludes Hisasue.

A series of photos captures the moment a captive female wasp from the species Loboscelidia squamosa lays her egg inside a stick insect egg before carrying and burying it in the soil. This marks the first time that this parasitic behavior has been observed.

CREDIT

Yu Hisasue, Kyushu University

For more information about this research, see "Taxonomic revision of the genus Loboscelidia Westwood, 1874 (Hymenoptera: Chrysididae: Loboscelidiinae) from Vietnam" Yu HISASUE, Thai-Hong PHAM, Toshiharu MITA in European Journal of Taxonomy, https://doi.org/10.5852/ejt.2023.877.2203

About Kyushu University 
Kyushu University is one of Japan's leading research-oriented institutes of higher education since its founding in 1911. Home to around 19,000 students and 8,000 faculty and staff, Kyushu U's world-class research centers cover a wide range of study areas and research fields, from the humanities and arts to engineering and medical sciences. Its multiple campuses—including one of the largest in Japan—are located around Fukuoka City, a coastal metropolis on the southwestern Japanese island of Kyushu that is frequently ranked among the world's most livable cities and historically known as Japan's gateway to Asia. Through its Vision 2030, Kyushu U will 'Drive Social Change with Integrative Knowledge.' Its synergistic application of knowledge will encompass all of academia and solve issues in society while innovating new systems for a better future.

First author, Yu Hisasue, looks in the leaf litter for tiny Loboscelidia wasps.

CREDIT

Toshiharu Mita, Kyushu University

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JOURNAL

European Journal of Taxonomy

DOI

10.5852/ejt.2023.877.2203 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Taxonomic revision of the genus Loboscelidia Westwood, 1874 (Hymenoptera: Chrysididae: Loboscelidiinae) from Vietnam

 

Insights into the biodiversity of annelids in the world’s largest deep-sea mineral exploration region

Peer-Reviewed Publication

PENSOFT PUBLISHERS

 

IMAGE: ANNELID SAMPLES FOUND IN THE CLARION-CLIPPERTON ZONE. view more 

CREDIT: WIKLUND ET AL.

The demand for rare raw materials, such as cobalt, is fuelling the exploration of the deep-sea floor for mining. Commercial deep-sea mining is currently prohibited in areas beyond national jurisdiction, but companies are permitted exploratory operations in certain areas to assess their mineral wealth and measure environmental baselines. The Clarion-Clipperton Zone (CCZ) is an area of the Pacific deep-sea floor spanning up to 6 million km2, found roughly between Hawaii and Mexico. Currently, it has 17 contracts for mineral exploration covering 1.2 million km2. However, despite relatively extensive mineral exploration beginning in the 1960’s, baseline biodiversity knowledge of the region is still severely lacking. Even the most basic scientific question: “What lives there?” has not been fully answered yet.

In a new paper researchers report on the marine life of the CCZ, focusing on annelid worms. Annelids represent one of the largest group of macroinvertebrates living within the mud covering the sea floor of CCZ, both in terms of number of individuals and the number of species. Data from recent oceanographic cruises enabled researchers from the University of Gothenburg, Sweden and the Natural History Museum London to discover more than 300 species of annelids from around 5000 records. The annelid species, many considered to be new to science, were discovered through employment of traditional morphological approaches and modern molecular techniques. The current study focuses on 129 such species across 22 annelid families. Previously, the authors of this study formalized 18 new species, while altogether reporting on 60 CCZ species, including most recently 6 species in family Lumbrineridae. The lead author Helena Wiklund from University of Gothenburg comments: ‘Taxonomy is the most important knowledge gap we have when studying these unique habitats and the potential impact of mining operations. We need to know what lives there to inform the protection of these ecosystems.”

To further understand the CCZ, scientists sail the Pacific Ocean on research expeditions that employ sampling techniques ranging from the technical, like remote-controlled vehicles that traverse the ocean floor, to the simple, like a sturdy box corer collecting sediment at the bottom.

“Sadly, the soft-bodied annelids are often damaged during the collection and sediment sieving onboard” says annelid taxonomist Lenka Neal from the Natural History Museum London. As a result, the traditional morphological approach is often of limited use when working with the deep-sea specimens, with taxonomists increasingly employing DNA techniques as well.

Over the last decade, scientists have generated a large amount of annelid data. Such data are only of use when made available through publication to the wider scientific community and other stakeholders. “A priority is to make the data are FAIR, or Findable, Accessible, Interoperable and Reusable so it can be redeployed easily, if you’ll excuse the pun, for future analysis” says co-author Muriel Rabone. “The same applies to samples, where accessibility of the specimen vouchers and molecular samples allows for reproducibility and continuation of the work. This is one step of the process. And ultimately, having more robust knowledge can lead to more robust evidence-based environmental policy”.

“More often than not, ecological papers describing biodiversity do not include a list of all the species and specimens used to make the broader ecological inferences, and even more rarely make the specimens and all associated metadata available in a FAIR way. In this study, we have made a significant and time-consuming attempt to do this, in a region of the global oceans where critical policy decisions are being made that could impact the way humanity obtains its resources and manages its environment in a sustainable way,” the researchers write in their paper, which was published in the open-access Biodiversity Data Journal.

The team behind the research hope that this still partial checklist of CCZ annelids, many in too poor state of preservation to be immediately described, is a key step forward towards creating future field guides for the area’s wildlife. Given that mining operations in the area could be imminent with the International Seabed Authority considering applications this year, the use of biological data for environmental management has become more important than ever.

This research was supported by funding from UK Seabed Resources Ltd.

Further enquiries: University of Gothenburg Press contact: susanne.liljenstrom@marine.gu.se

Original source:

Wiklund H, Rabone M, Glover AG, Bribiesca-Contreras G, Drennan R, Stewart ECD, Boolukos CM, King LD, Sherlock E, Smith CR, Dahlgren TG, Neal L (2023) Checklist of newly-vouchered annelid taxa from the Clarion-Clipperton Zone, central Pacific Ocean, based on morphology and genetic delimitation. Biodiversity Data Journal 11: e86921. https://doi.org/10.3897/BDJ.11.e86921

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JOURNAL

Biodiversity Data Journal

DOI

10.3897/BDJ.11.e86921 

ARTICLE PUBLICATION DATE

15-Sep-2023

 

China global Merged Surface Temperature dataset (CMST) reveals 2023 on Track to Be Hottest Year Ever

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: OBSERVATORY WITH MACAO METEOROLOGICAL AND GEOPHYSICS BUREAU view more 

CREDIT: QINGXIANG LI

The climate crisis is reaching unprecedented levels of urgency as global temperatures soar to record-breaking heights, with July 2023 marking another alarming milestone. United Nations Secretary-General  António Guterres  declared it a "disaster for the whole planet," emphasizing that the era of "global warming" has given way to an era of "global boiling." This alarming assessment is supported by recent findings from Professor Qingxiang Li 's team at the School of Atmospheric Sciences, Sun Yat-sen University, based on the China global Merged Surface Temperature dataset 2.0 (CMST 2.0). Prof. Li is also a distinguished research fellow at the Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences.

Unprecedented Monthly Highs since May

Professor Qingxiang Li 's team analyzed the CMST 2.0 dataset and discovered that 2023 has already experienced the third hottest first half-year since records began, narrowly trailing behind the warmest year in 2016 and the second warmest in 2020. The global mean sea surface temperatures (SSTs) surged to an all-time high in April, while global mean land surface air temperatures followed suit by reaching their second-highest monthly level in June. This combination resulted in May being crowned the hottest month ever recorded for global mean surface temperatures.

The research further reveals that global surface temperatures continue to rise into the second half of 2023, driven by factors including El Niño and widespread wildfires. Both global mean SSTs and global mean land surface air temperatures reached unprecedented highs for July, shattering previous records. Given the current trajectory and short-term forecast results of El Niño, along with the extremely positive phase of the Atlantic Multidecadal Oscillation (AMO), which strongly influences global surface temperatures, 2023 is on track to become the hottest year on record. Moreover, 2024 may witness even higher global surface temperatures.

The research is published as a News&Views article on September 19 in Advances in Atmospheric Sciences.

The CMST 2.0 Dataset - A Global Benchmark

The CMST 2.0 dataset, developed by Professor Li Qingxiang's team, stands as the most comprehensive global surface temperature benchmark dataset to date. It incorporates data from China, filling a critical gap in global temperature monitoring. The dataset integrates over a century's worth of global land surface air temperature data and incorporates state-of-the-art research from across the globe, resulting in an invaluable resource for climate scientists and policymakers. In 2022, the dataset was expanded to include Arctic surface temperature data, enhancing its global coverage.

Accessible to both the scientific community and the general public, the CMST 2.0 dataset is freely available on the Global Climate Change Observation and Modeling Data Platform at http://www.gwpu.net/en/.

Understanding the Complex Factors behind Global Warming

While human activities, including greenhouse gas emissions, are the primary drivers of long-term global warming, short-term variations are influenced by internal climate system changes such as El Niño and the Pacific Decadal Oscillation (PDO). As global warming accelerates, the likelihood of extreme weather events and disasters increases, necessitating urgent action.

Global warming also has profound regional impacts, manifesting in extreme temperature fluctuations. For instance, in East Asia, circulation anomalies like the North Atlantic Oscillation (NAO) have led to frequent extreme cold events in winter, offsetting the overall rise in average temperatures. However, the rise in summer maximum temperatures and the decline in winter minimum temperatures result in larger fluctuations in extreme temperatures.

Furthermore, the pace of human discomfort due to rapid temperature increases, particularly in low-latitude regions, is a growing concern that demands our attention. The CMST 2.0 dataset and Professor Qingxiang Li's team's research underscore the urgency of addressing the climate crisis. 

Global mean surface temperature anomalies for the whole year/first half of the year based on the CMST 2.0 (The blue line represents the GMST in the first half of the year, the gray bar represents the annual GMST (the dark gray column refers to the average predicted temperature in 2023 in the past 5 years), the black line represents the GMST, and the red line represents the regional mean ST in China)

CREDIT

Qingxiang Li

JOURNAL

Advances in Atmospheric Sciences

DOI

10.1007/s00376-023-3200-9 

ARTICLE TITLE

Record-breaking High-temperature Outlook for 2023: An Assessment Based on the China Global Merged Temperature (CMST) Dataset

ARTICLE PUBLICATION DATE

19-Sep-2023

Turning the tide: Ghana's innovative approach to tackle marine plastic pollution with citizen science

Peer-Reviewed Publication

INTERNATIONAL INSTITUTE FOR APPLIED SYSTEMS ANALYSIS

Working with IIASA researchers, Ghana has adopted a citizen science approach to addressing the problem of plastic pollution in marine environments, becoming the first country to integrate this type of data on marine plastic litter into its official monitoring and reporting processes. A new study presents this innovative approach on Ghana’s citizen science journey and offers a pathway that can potentially be adopted in other countries.

Marine plastic litter poses a significant threat to marine ecosystems, wildlife, human health, and economies dependent on industries like tourism and fishing. Recognizing the urgency of the issue, the United Nations Environment Assembly adopted a resolution to combat plastic pollution in 2022. This issue is also recognized in the framework of the UN Sustainable Development Goals (SDGs). Understanding the full extent of the marine plastics problem, however, remains challenging due to the vastness of the Earth’s oceans and the complex circulation of plastic litter. Traditional monitoring methods are costly and often outdated, leaving significant data gaps.

The study, which has been published in Sustainability Science, demonstrates how existing citizen science data and networks can be leveraged to address the data gap on marine litter at national level and feed into global SDG monitoring and reporting processes, showing how Ghana has become a success story. The authors also highlight how these data and networks can help to inform relevant policies and action at a national level with global impact.

"Citizen science is more than just plugging data gaps; it is a powerful bridge between the public, the world of science, and policy. It not only raises awareness and inspires action to tackle challenges, but also fosters a democratic approach to policymaking, where the voice of the people becomes integral to shaping our collective future," explains Dilek Fraisl, lead author and a researcher in the Novel Data Ecosystems for Sustainability Research Group of the IIASA Advancing Systems Analysis Program

Ghana generates approximately 1.1 million tons of plastic waste annually, with only 5% being collected and recycled. To address this, the Ghanaian government has committed to sustainable plastic waste management and became the first country to join the Global Plastic Action Partnership in 2019. In addition, a growing citizen science community in Ghana provided an opportunity for citizen science to go beyond being a valuable data source on marine litter, to include the removal of litter from the environment and engaging with volunteers to promote education and raise awareness on the issue.

Through its International Coastal Cleanup initiative, the Ocean Conservancy (OC) has established a standardized approach to gather and categorize plastic pollution and marine litter data during cleanup campaigns. Various community groups and organizations in Ghana, including local civil society organizations, have adopted this methodology for their own cleanup campaigns. Data from these exercises are ultimately consolidated into the OC’s Trash Information Data for Education and Solutions (TIDES) database, which is publicly accessible and houses the world's largest collection of ocean trash data. Users can examine this data at both global and local levels, down to specific beach locations. As the International Coastal Cleanup platform operates in 155 countries worldwide, there is significant potential to employ this data for global-level monitoring, specifically for achieving SDG14 related to life below water. The Earth Challenge Marine Litter Data Integration Platform, an interoperable plastic pollution dataset, integrates data from various citizen science projects including the OC’s TIDES, offering potential for monitoring plastic pollution globally.

The case study has had a significant impact on addressing marine litter issues in Ghana and beyond. Specifically, it will contribute to the development of the country's Integrated Coastal and Marine Management Policy. Government partners involved in the study, Ghana Statistical Service, and the Environmental Protection Agency Ghana, as the country leads of the project, have become more familiar with citizen science methodologies and data, and gained a better understanding of citizen science activities related to marine litter in the country. Civil society organizations engaged in beach cleanups and data collection have also realized the potential and impact of their data for official statistics and policymaking. As a result, the country has become the first to officially report on plastic debris density under SDG 14.1.1b, using citizen science data.

“Ghana's citizen science experience has provided valuable insights into how data generated by citizen scientists can inform policies at the national level while contributing to global progress on the SDGs. It also offers a replicable pathway for other countries interested in incorporating citizen science data into their SDG monitoring efforts, not only for marine plastic litter but potentially for other indicators as well,” notes coauthor Linda See, who is associated with the same research program at IIASA.

“With less than seven years remaining to achieve the SDGs, we have to acknowledge the valuable opportunities presented by citizen science initiatives. They play a pivotal role in addressing data deficiencies and contribute to bolstering inclusive data ecosystems, informed decision making, and concerted action. We need to foster awareness and comprehension of citizen science data and methodologies to nurture the growth of more reliable partnerships around citizen science data and achieve evidence-based, all-encompassing policies and collaborative efforts on a global scale for the SDGs and sustainable development more broadly,” Fraisl concludes.

Reference
Fraisl, D., See, L., Bowers, R., Seidu, O., Boakye Fredua, K., Bowser, A., Meloche, M., Weller, S., Amaglo-Kobla, T., Ghafari, D., Laso Bayas, J.C., Campbell, J., Cameron, G., Fritz, S., McCallum, I. (2023). The contributions of citizen science to SDG monitoring and reporting on marine plastics. Sustainability Science. DOI: 10.1007/s11625-023-01402-4

 

About IIASA:
The International Institute for Applied Systems Analysis (IIASA) is an international scientific institute that conducts research into the critical issues of global environmental, economic, technological, and social change that we face in the twenty-first century. Our findings provide valuable options to policymakers to shape the future of our changing world. IIASA is independent and funded by prestigious research funding agencies in Africa, the Americas, Asia, and Europe. www.iiasa.ac.at

 

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JOURNAL

Sustainability Science

DOI

10.1007/s11625-023-01402-4 

ARTICLE TITLE

The contributions of citizen science to SDG monitoring and reporting on marine plastics

ARTICLE PUBLICATION DATE

19-Sep-2023

 

IPK’s PhenoSphere brings functional plant science much closer to real field environments

Peer-Reviewed Publication

LEIBNIZ INSTITUTE OF PLANT GENETICS AND CROP PLANT RESEARCH

 

IMAGE: FIELD-LIKE ENVIRONMENTAL CONDITIONS CAN BE SIMULATED REPRODUCIBLY IN THE IPK PHENOSPHERE view more 

CREDIT: IPK LEIBNIZ INSTITUTE/ J. BERGSTEIN

For fundamental and for application-oriented research there is a need to expose crop plants to relevant field-like conditions in a reproducible manner. “We present IPK’s PhenoSphere to the plant science community as a novel tool to study the plant’s response to variation in weather variables and other environmental conditions”, says Prof. Dr. Thomas Altmann, head of IPK’s department “Molecular Genetics”. The PhenoSphere enables detailed analyses of performance-related trait expression and causal biological mechanisms in plant populations exposed to weather conditions of current and anticipated future climate scenarios - such as greater drought, higher temperatures and increased CO2 concentration.

Its technical capabilities overcome several limitations of typical growth chambers and glasshouses. Here, deliberate temperature profiles can be realized with an hourly resolution, light quality and quantity can be manipulated on a minute resolution scale. Clouds can also be simulated via the sophisticated lighting system as well as wind speed and direction can be changed on the sub-hour scale, atmospheric CO2 levels can be increased. Water and fertilization can be automatically applied daily, and the large-volume containers allow the use of different soil types and compositions and the modulation of the soil temperature. “This will support systems biology analyzes carried out to elucidate molecular mechanisms underlying the expression of agronomically relevant traits. It furthermore enables testing hypotheses derived from different approaches such as network analysis and modelling”, says Prof. Dr. Thomas Altmann.

The first results are very promising. Simulating a single maize growing season within the PhenoSphere and using large-volume soil containers resulted in plant growth and development progression that matched the rates that the same population exhibited upon cultivation in the corresponding field season. “Field grown plants and plants inside the experiment required the same amount of time to reach peak growth speed, maturity of leaves, and tasselling” says Dr. Marc Heuermann, first author of the study. “The correlation between the weather simulation and the outdoor environment concerning temperature, thermal time, and VPD profiles over the cultivation periods was highest when using real days as templates in the single season simulation“, explains Dr. Marc Heuermann. And in any case the single season simulation proved superior to the glasshouse and the averaged season in the PhenoSphere.

The PhenoSphere thus fills the gap between hitherto established controlled-environment phenotyping systems and field phenotyping trials. “The ability of eliciting field-like growth and development in the dynamic but controlled environment of the PhenoSphere is a very substantial and important advance and goes far beyond previous improvements in standard climatized glasshouses cultivation procedures”, says Prof. Dr. Thomas Altmann.

The optimized and validated field-like environment simulation programs can now be used to perform also (seed) yield trials, which require a specific experimental setup and designs fundamentally different from the benchmarking experiments of this study.

 

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JOURNAL

Nature Communications

DOI

10.1038/s41467-023-41332-4 

ARTICLE TITLE

Natural plant growth and development achieved in the IPK PhenoSphere by dynamic environment simulation

ARTICLE PUBLICATION DATE

18-Sep-2023

 

At which age we are at our happiest

Psychology

Peer-Reviewed Publication

RUHR-UNIVERSITY BOCHUM

More than 460,000 participants

In their study, the researchers examined trends in subjective well-being over the lifespan based on 443 samples from longitudinal studies with a total of 460,902 participants. “We focused on changes in three central components of subjective well-being,” explains Professor Susanne Bücker, who initially worked on the study in Bochum and has since moved to Cologne: “Life satisfaction, positive emotional states and negative emotional states.”

The findings show that the life satisfaction decreased between the ages of 9 and 16, then increased slightly until the age of 70, and then decreased once again until the age of 96. Positive emotional states showed a general decline from age 9 to age 94, while negative emotional states fluctuated slightly between ages 9 and 22, then declined until age 60 and then increased once again. The authors identified greater median changes in positive and negative emotional states than in life satisfaction.

Positive trend over a wide period of life

“Overall, the study indicated a positive trend over a wide period of life, if we look at life satisfaction and negative emotional states,” as Susanne Bücker sums up the results. The researchers attribute the slight decline in life satisfaction between the ages of 9 and 16 to, for example, changes to the body and to the social life that take place during puberty. Satisfaction rises again from young adulthood onwards. Positive feelings tend to decrease from childhood to late adulthood. In very late adulthood, all components of subjective well-being tended to worsen rather than improve. “This could be related to the fact that in very old people, physical performance decreases, health often deteriorates, and social contacts diminish; not least because their peers pass away,” speculates the researcher.

The study highlights the need to consider and promote subjective well-being with its various components across the lifespan, as the authors of the study conclude. Their findings could provide significant guidance for the development of intervention programmes, especially those aimed at maintaining or improving subjective well-being late in life.

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JOURNAL

Psychological Bulletin

DOI

10.1037/bul0000401 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

The development of subjective well-being across the lifespan: A meta-analytic review of longitudinal studies

ARTICLE PUBLICATION DATE

18-Sep-2023

 

The “Choreography” between hormones and the brain key to understanding how women adapt to motherhood

Peer-Reviewed Publication

UNIVERSITAT AUTONOMA DE BARCELONA

 

IMAGE: EXPERTS TEAM OF THE COGNITIVE NEUROSCIENCE RESEARCH UNIT (URCN) OF THE UAB'S DEPARTMENT OF PSYCHIATRY AND LEGAL MEDICINE. view more 

CREDIT: UNIVERSITAT AUTÒNOMA DE BARCELONA (UAB)

Researchers from the Universitat Autònoma de Barcelona (UAB), the Gregorio Marañón Health Research Institute and the Hospital del Mar Research Institute have published the first paper that reviews the scientific literature existing until now on the neurobiological adaptation occurring during pregnancy and postpartum in humans and other animals.

The article, with Camila Servin-Barthet and Magdalena Martínez as first authors and Òscar Vilarroya and Susana Carmona as senior authors, was published in Nature Reviews Neuroscience and will be featured on the cover of the October issue of the journal.

The researchers reviewed a total of 174 articles, in which they analysed the connections among three fundamental areas: changes in brain structure, hormonal evolution, and maternal behaviour, to open new lines of research and advance in women-oriented research.

According to the scientists, all information points to the fluctuation of hormones, mainly related to estrogens, as being what triggers plasticity processes in the brain during a human pregnancy and postpartum period. However, more research is needed to explain what types of plasticity processes (which imply changes in brain cell function, structure, and connectivity) are involved in the transition to motherhood in humans, and how they affect maternal behaviour.Motherhood and morphological changes

Motherhood is a physiologically and psychologically life-changing event, which includes a series of adaptations in how the mother behaves, aimed at ensuring the well-being of her offspring.

Researchers from the UAB and the Hospital del Mar Research Institute were the first to demonstrate in 2017 that a pregnancy implied changes in the brain morphology of first-time mothers, reducing the volume of grey matter in regions involved in social relation, and that these changes were maintained for at least two years after giving birth. Since then, researchers have observed that the brain’s grey matter changes in volume in the different stages of maternity and postpartum and that it is always accompanied by extreme hormone fluctuations.

In the article, researchers describe for the first time three fundamental factors in understanding the adaptation to motherhood in humans. First are estrogens (oestradiol), as the main hormone candidates in inducing changes in the brain. Second is the brain circuit related to social cognition (involving the medial frontal cortex and precuneus, as well as other areas), as the specific region in which these changes take place. And third, there are the psychological changes, i.e., the cognitive and emotional processes necessary to develop a mother-child relationship that adapts to the different phases of pregnancy and postpartum. This third factor is what most differentiates humans from other animals and little is known about it.

Roadmap for future research

Based on the evidence published, the researchers point out which neuroplasticity processes most likely contribute to the changes identified, and how these can be related to pregnancy and maternal behaviour hormones. They also prepared a roadmap with different lines of research to advance the study of human adaptation to motherhood.

One first line of research should focus on identifying brain cell substrates. According to the experts, it is improbable that the large-scale dynamics of changes in grey matter at morphological and molecular levels be produced exclusively by plasticity. In rats, researchers observed that hormonal fluctuation, particularly at the end of the pregnancy, affects the plasticity of neurons and microglia, with a greater proliferation of this latter cell type.

A second line should work towards describing the mechanisms by which sexual hormones, especially estrogens, bring on the changes detected in structural and behavioural reorganisation. Given the hormonal environment existing during the pregnancy and postpartum period and the interactive nature of these molecules, it is most likely that these changes are the result of a complex exchange of steriods and hormonal peptides. To understand this role better, research must be conducted on a greater number of hormones and metabolites, with special attention put on oxytocin and prolactin.

The third challenge focuses on identifying the psychological evolution occurring during pregnancy and postpartum and characterising the functional changes in the brain responsible for the development of human conduct. In studies with rats, molecular and morphological changes were observed accompanied by the emergence of maternal behaviour, but not so in humans. Not only that, but the association between neuroanatomic changes and different aspects of maternal behaviour in humans are few and difficult to replicate. Improving the methodology in MRI studies in humans and questionnaires will allow us better to infer the link between the brain changes observed and the different components of maternal behaviour. All this while bearing in mind extrinsic postpartum factors, which could induce changes in the circuits related to maternal care.

A scarce number of studies conducted on women

Most studies conducted up to date have used rats. That is why the researchers put emphasis on the importance of developing research studies on women. “There are coincidences between humans and other animals, but there are many cerebral differences, particularly on the cerebral cortex, the most evolved part of the brain, and hormonal differences, given that the "choreography" between sexual hormones is different in each species”, explains Camila Servin, researcher from the UAB Department of Psychiatry and Legal Medicine and at the Hospital del Mar Reseach Institute.

“Until 2017 we had not begun to study changes in the brain occuring during pregnancy, and until now very little has been studied on the role of hormones and the psychological environment”, explains Òscar Vilarroya, researcher from the UAB Department of Psychiatry and Legal Medicine and at the Hospital del Mar Reseach Institute. “Surprisingly,the study of what is one of the most generalised and important human experiences has never taken central stage”, the neuroscientist concludes.

Also participating in the paper were researchers from the Biomedical Research Networking Centre in Mental Health (CIBERSAM) and from Ohio State University.

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JOURNAL

Nature Reviews Neuroscience

DOI

10.1038/s41583-023-00733-6 

METHOD OF RESEARCH

Literature review

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The transition to motherhood: linking hormones, brain and behaviour

ARTICLE PUBLICATION DATE

18-Sep-2023