What will it take to save the regent honeyeater from extinction?

Peer-Reviewed Publication

AUSTRALIAN NATIONAL UNIVERSITY

 

IMAGE: NESTING REGENT HONEYEATER. IMAGE: NATHAN SHERWOOD. view more 

CREDIT: NATHAN SHERWOOD

New research from The Australian National University (ANU) shows unless conservation actions are urgently stepped up, one of our most beautiful songbirds, the regent honeyeater, will be extinct within 20 years.  

The new study reveals current, already intensive, conservation efforts are not sufficient, and a huge redoubling of effort is needed if we are to save these birds from extinction.  
 
“The regent honeyeater population has been decimated by the loss of over 90 per cent of their preferred woodland habitats,” lead author Professor Rob Heinsohn from ANU said. 

"Less than 80 years ago, it was one of the most commonly encountered species, ranging from Adelaide to Rockhampton. Now it is on track to follow the dodo into extinction.” 

Today there are fewer than 300 regent honeyeaters left, making it one of our rarest bird species. Habitat loss has forced them to compete with larger species for remaining habitat. 

The ANU team commenced a large-scale project in 2015 to better understand the regent honeyeater population decline, but found they are an exceptionally difficult bird to study in the wild. As nomads, they wander long distances in search of nectar. After 6 years of intensive fieldwork, the team discovered that the birds’ breeding success has declined due to predation at the nest by species such as pied currawongs, noisy miners and possums. 

In their new publication the team built population models utilising all available knowledge to predict what will happen to the wild population. 

“Our models show that current conservation efforts have provided essential life support for the regent honeyeaters, but do not go far enough," co-author Dr Ross Crates said. 

“We were able to isolate the three key conservation priorities necessary to secure the birds’ future."  

First, the models show nest success rates of both wild and released zoo-bred birds must nearly double. This requires protecting nests from predation.  

​Second, the number of zoo-bred birds released into the Blue Mountains must increase and be sustained for at least 20 years alongside nest protection. Taronga Conservation Society have been breeding the birds in captivity and are working hard to increase the numbers for release into the wild. 

Third, the models stress that the regent honeyeater population can only be secured into the future if more habitat can be protected and restored. 

“Without more habitat, reintroductions and nest protection efforts will be futile, because the flock sizes will never reach the critical mass needed for the birds to breed safely without our protection," Professor Heinsohn said.  

"Our study provides both hope and a dire warning – we can save these birds, but it will take a lot of effort and resources over a long time to pull it off.” 

The research is published in Biological Conservation. It was co-authored by members of the Regent Honeyeater Recovery team including Birdlife Australia and Taronga Conservation Society. 

CAPTION

Regent honeyeater. Image: Murray Chambers

CREDIT

Murray Chambers

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JOURNAL

Biological Conservation

DOI

10.1016/j.biocon.2021.109430 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Population viability in data deficient nomadic species: What it will take to save regent honeyeaters from extinction

ARTICLE PUBLICATION DATE

5-Jan-2022

COI STATEMENT

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Emotionally manipulative political ads fail at swaying new voters, but excel at ensuring party loyalty

Results of study that examined 2018 US midterm election video ads suggests that even inspirational messages are unlikely to sway voters from the other side

Peer-Reviewed Publication

FRONTIERS

Both Democrats and Republicans in US elections are more likely to be emotionally moved or angered by political advertising produced by the party to which they identify. This suggests that most ads today do little to sway the other side, but rather help motivate a party’s faithful to support a candidate through actions such as making a campaign donation or showing up at the ballot box.

While it may seem that the two major political parties in the United States don’t have much in common, the ways both types of voters respond emotionally to political advertising is very much influenced by their party affiliation. A first-of-its-kind study, published in Frontiers in Psychology, investigated this behavior based on short political video ads intended to either emotionally move or anger voters, with implications for how parties communicate their messages and spend their ad dollars.

The comparative study involved 146 participants who viewed eight videos from the 2018 midterm US elections – four each from Democratic and Republican candidates – with content explicitly designed to evoke either anger or kama muta. The latter is a specific positive emotion related to social relationships. It is similar to the concept of ‘being moved’ but in the context of intensifying or building unity within a particular community.

Are political ads effective?

Not surprisingly, the researchers found people get moved and angered by political ads, which motivates them to support their side, but only by the ads that fit their prior political preference. In other words, the ads did not manage to arouse much emotion in people who favored the opposing party, and what feelings were aroused didn’t have much of an effect.

“At a very general level, it may be surprising to some people that political ads are not all attack ads,” said lead author David Grüning, a research scientist at Heidelberg University in Germany. “Even in today’s polarized political climate, many ads attempt to inspire and move their target audience.”

However, while previous research implied that political appeals to kama muta could help cross party lines, the new paper finds scant evidence for that.

“Feeling moved by an ad from the party you prefer to begin with has a stronger effect than if the other party moved you,” Grüning noted.

Grüning said it is unclear why there is a discrepancy to past findings. He suggested that perhaps the ads from the 2016 US elections, which included the presidential race between Hillary Clinton and Donald Trump, featured stronger messages.

“We now see that this is possible and need to test this better in future work,” he said, “but, yes, it’s clear now that sometimes, kama muta can be discounted and disregarded.”

Effects of political advertising

The study has several implications based on the findings. For instance, party affiliation in the videos used by the study was not explicit, so participants were left to guess an ad’s affiliation –  sometimes incorrectly. In those cases, the video still had more emotional influence on viewers if they believed it was created by their political party of choice, even if the opposite was true.

That suggests campaign ads would do well to “unambiguously communicate their political affiliation to prevent unwillingly feeding the support of political competitors,” according to Grüning and co-author Thomas W Schubert at the University of Oslo. Unless, of course, candidates want to distance themselves from their own party, they added.

The results of the study would also imply that political ads in modern politics have little effect in actually winning over voters from the other side. Rather, they may influence party faithful to give donations or turn out on election day.

“So far, we have only looked at motivation and intention to support, which is much easier to measure,” Grüning said. “An essential next step would be to examine supportive behavior as an outcome of being moved or angered by political ads.”

Perhaps, most importantly, the research demonstrates that voters on both sides of the issues are emotional human beings, which is sometimes lost in today’s acrimonious atmosphere.

“So there is a perhaps unexpected bipartisan unity in what divides the parties,” Grüning said.

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JOURNAL

Frontiers in Psychology

DOI

10.3389/fpsyg.2021.781851 

Researchers discover earliest ant mimics in mid-Cretaceous Kachin amber

Peer-Reviewed Publication

CHINESE ACADEMY OF SCIENCES HEADQUARTERS

 

IMAGE: REPRESENTATIVE TAXA OF ALIENOPTERIDAE AND UMENOCOLEIDAE view more 

CREDIT: NIGPAS

Myrmecomorphy is a phenomenon in which some animals mimic ants morphologically and behaviorally. It is an example of the broader biological phenomenon of mimicry, which is widely distributed in nature.

LUO Cihang, a graduate student supervised by Prof. WANG Bo, and his colleagues from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) have discovered a new type of alienopterid nymph from mid-Cretaceous Kachin amber of Myanmar. The discovery shows that ant mimicry already existed in the mid-Cretaceous, thereby extending its geological range by approximately 50 million years.

This study was published in Earth-Science Reviews on Dec. 30.

Myrmecomorphy has evolved in more than 2,000 living species of 11 different arthropod orders. However, the fossil record of myrmecomorphy is extremely sparse and researchers know little about its origin and evolution. 

By using quantitative geometric morphometric analysis, the researchers discovered that the body shape of these alienopterid nymphs is very close to that of sphecomyrmine ants (a kind of extinct ant). Moreover, the antennae shape and legs of these alienopterid nymphs are close to that of ants, and the ratios of the antennae and legs to body length are approximately the same as in some sphecomyrmine ants.

CAPTION

Reconstruction drawings of Alienopteridae

CREDIT

LI Jiahao

The researchers confirmed that thoraco-abdominal waist-like constrictions of some of the alienopterid adults (adults of those ant mimics) resemble Hymenoptera. The strongly shortened forewings of some alienopterid adults closely resemble the tegulae of Hymenoptera and the hind wing is structurally similar to hymenopteran wings. But the body shape and size of some of these alienopterid adults are similar to some large aculeate Hymenoptera from the same deposit, especially ampulicid wasps.

CAPTION

Alienopterid nymphs and ants; ants are marked with “M”

CREDIT

NIGPAS

CAPTION

Ecological reconstruction of Alienopteridae. A: Ecological reconstruction of alienopterid nymphs; the brown insects with two cerci are alienopterid nymphs, and the other brown insects are ants. B: Ecological reconstruction of alienopterid adults.

CREDIT

YANG Dinghua

These results thus suggest that the nymphs and adults of this mid-Cretaceous alienopterid imitate entirely different hymenopteran models. Therefore, according to Prof. WANG, this research probably provides the first fossil record of transformational mimicry, i.e., mimicking different organisms during different stages of development. 

This research was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology of China and the National Natural Science Foundation of China.

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JOURNAL

Earth-Science Reviews

DOI

10.1016/j.earscirev.2021.103914 

Green-Med Diet Seems to Slow Age-Related Neurodegeneration

Data based on 18 month Ben-Gurion University-led DIRECT PLUS brain MRI trial

Peer-Reviewed Publication

BEN-GURION UNIVERSITY OF THE NEGEV

BEER-SHEVA, Israel, January 13, 2022 – A green Mediterranean diet, high in polyphenols and low in red and processed meat, seems to slow age-related brain atrophy, according to a new Ben-Gurion University of the Negev-led international study. The DIRECT PLUS 18-month long randomized control trial among ~300 participants is one of the longest and largest brain MRI trials in the world.

Their findings were published Tuesday in The American Journal of Clinical Nutrition.

The effect of diet on age-related brain atrophy is largely unproven. Participants were divided into three groups according to diet, and whole brain MRI measurements were taken before, and after the trial. Hippocampal-occupancy (HOC) and lateral-ventricle-volume (LVV) were measured as indicators of brain atrophy and predictors of future dementia. Brain MRI-derived data were quantified and segmented using NeuroQuant, an FDA (Food and Drug Administration) authorized fully automated tool.

Two hundred eighty-four men and women (88% men) aged 31-82 were randomly divided into three groups: A healthy dietary guidelines group, a Mediterranean diet group and a green Mediterranean diet. In the Mediterranean diet group, the participants were further provided walnuts rich in polyphenols. In the green- Mediterranean group the participants were further provided high polyphenol green components: 3-4 daily cups of green tea and a daily green shake of Mankai duckweed, as a substitute for dinner, with minimal consumption of red and processed meat. In addition, all three groups participated in physical activity programs based on aerobic exercise, including free gym memberships.

The trial was performed by Dr. Alon Kaplan and Prof. Iris Shai, professor at Ben-Gurion University, Israel, and adjunct professor at Harvard University, together with several international teams of brain experts. The researchers were surprised to identify dramatic changes in MRI-related brain atrophy within 18-24 months, whereas the rate of brain atrophy markers (i.e., hippocampal occupancy decline and lateral ventricle volume expansion) were significantly accelerated from the age of 50 years and up.

The researchers discovered a significant attenuation in brain atrophy over the 18 months in those who adhered to both Mediterranean diets; with greater magnitude in the green-MED group, specifically among participants over age 50. In addition, the researchers noticed that an improvement in insulin sensitivity was independently associated with attenuated brain atrophy.    

Greater Mankai, green tea, and walnuts consumption and less red and processed meat consumption were significantly associated with lower hippocampal occupancy decline.

Participants were initially chosen based on abdominal girth size or dyslipidemia. They were all employees at a remote workplace in Israel (Nuclear Research Center in Dimona) where they did not leave the premises during the workday, and the lunch provided was monitored.

"The beneficial association between the green Mediterranean diet and age-related neurodegeneration might be partially explained by the abundance of polyphenols in plant-based food sources which have antioxidant and anti-inflammatory metabolites. Polyphenols can cross the blood-brain barrier (BBB), reduce neuroinflammation, and induce cell proliferation and adult-onset neurogenesis in the hippocampus," writes Prof. Shai, the lead author.

 “Our findings might suggest a simple, safe, and promising avenue to slow age-related neurodegeneration by adhering to a green-Mediterranean diet,” adds Dr. Alon Kaplan.

This study was funded by grants from the German Research Foundation (DFG), (project number 209933838 - SFB 1052; B11), Israel Ministry of Health grant 87472511; Israel Ministry of Science and Technology grant 3-13604; and the California Walnuts Commission.

None of the funding providers were involved in any stage of the design, conduct, or analysis of the study, and they had no access to the study results before publication.

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JOURNAL

American Journal of Clinical Nutrition

DOI

10.1093/ajcn/nqac001 

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

The effect of a high-polyphenol Mediterranean diet (GREEN-MED) combined with physical activity on age-related brain atrophy: the DIRECT PLUS randomized controlled trial

ARTICLE PUBLICATION DATE

11-Jan-2022

Touch induces rapid floral closure in gentians

Peer-Reviewed Publication

SCIENCE CHINA PRESS

 

VIDEO: MECHANICAL STIMULATION APPLIED TO A FLOWER OF GENTIANA PSEUDOAQUATICA (BLUE MORPH) AND THE PROCESS OF INDUCED FLORAL CLOSURE. HTTPS://DOI.ORG/10.6084/M9.FIGSHARE.14822652 view more 

CREDIT: ©SCIENCE CHINA PRESS

This study is led by Dr. Can Dai (Hubei University), Dr. Yanbing Gong (Wuhan University), and Dr. Qingfeng Wang (Wuhan Botanical Garden, the Chinese Academy of Sciences). During the second Tibetan plateau scientific expedition in 2020, the research team accidentally found that the corollas of Gentiana clarkei and G. pseudoaquatica (white morph) (Gentianaceae) closed within seconds after they touched the flowers at Xiongmuco, Nagqu. “It was startling to witness with naked eyes. The flowers disappeared momentarily in front of you,” Dai says. After visiting more than twenty sites, they found four species of Gentiana that responded to mechanical stimulation with rapid corolla contraction and full closure (see the video below). It only took 7–210 s for flowers of G. pseudoaquatica (both blue and white morphs), G. prostrata var. karelinii, G. clarkei, and an unidentified gentian species to exhibit such movements.

What selective pressures might have given rise to the evolution of rapid thigmonastic petal movements in gentians? The researchers firstly looked into abiotic factors, since rain (hail) or wind is very common at plateaus and can interact with flowers in the form of mechanical perturbation. In the field observation, however, the flowers of Gentiana were typically well closed before a thunderstorm, rain, or hail could physically hit the corolla. Previous studies have shown that environmental cues, particularly temperature, are the key factors controlling flower opening and closure in gentians. It is evident that when the sunlight disappears and precipitation approaches plateaus, the temperature drops dramatically. Thus, it seems that flowers are well protected by temperature induced closure other than mechano-sensitivity. As to the possibility of wind, although the researchers have not caught any evidence of induced floral closure by wind in nature, they conducted experiments using artificial wind and found that only very strong wind (24-27 m/s) could elicit responsive petal behaviors in gentians. However, wind of such power is devastating and very unlikely to take place during summer (anthesis) in Tibet.

A type of large floral visitors, bumblebees, perhaps lies in the kernel of floral thigmonasty in gentians. The researchers noticed that three species of bumblebees visited flowers of G. clarkei and made slits in floral tubes in order to obtain nectar illegitimately. Due to bumblebees’ large body sizes and vigorous manipulations, 98.8 % of the flowers they visited displayed induced floral closure (see the video below). The injuries caused by nectar robbing were substantial. Nearly 80% of flowers experienced exterior damage, of which 6% showed injuries in ovary. Hence, the touch-response machinery in gentian flowers might be useful in escaping from further visits when a robber still hovered nearby. The relatively low incidence of ovary damages likely implied effective protection against lethal injuries caused by repeated floral larceny.

To add another level of complexity, some bumblebees also displayed regular legitimate visiting behavior to flowers of G. clarkei, resulting in rapid floral closure as well. If the bumblebees can transfer pollen among flowers, it is then reasonable to extrapolate that induced floral closure may also play roles in promoting pollen deposition, stimulating pollen germination, or encouraging outcrossing. “Undoubtedly, further examinations on fecundity consequences are needed,” Wang says, “without which, we won't be able to disentangle the adaptive significance of thigmonastic corolla behaviors.” An induced defense? A pollination stimulator? Both explanations sound very exciting and call for in-depth studies.

See the article:

Touch induces rapid floral closure in gentians

https://doi.org/10.1016/j.scib.2021.12.026

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JOURNAL

Science Bulletin

DOI

10.1016/j.scib.2021.12.026 

Citizen science data from Berlin show that urban areas can be a refuge for bats, if certain conditions are met

Peer-Reviewed Publication

LEIBNIZ INSTITUTE FOR ZOO AND WILDLIFE RESEARCH (IZW)

 

IMAGE: CITIZEN SCIENTIST WITH A BAT DETECTOR IN BERLIN view more 

CREDIT: CHRISTOF HÄBERLE / LEIBNIZ-IZW

Urbanisation is a notable threat to bat populations all over the world, especially through artificial light and the reduction of habitat and food supply. If certain conditions are met, some spaces within metropolitan areas can be suitable for bats, so managing these spaces appropriately could contribute to bat conservation. With the help of more than 200 citizen scientists in Berlin, a team of scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) examined these conditions and investigated how they affect the abundance and distribution of bat species. They conclude that maintaining a low level of artificial light at night is important for all bats in cities. In addition, access to vegetation and water bodies is essential for many of them. The results and conclusions are published in the scientific journal “Environmental Pollution”.

Biodiversity loss jeopardises important ecosystem functions and hence human health and well-being at magnitudes comparable to other processes of global change such as climate change. Major drivers of biodiversity loss are habitat loss and degradation through agriculture and logging, but also through urbanisation, which causes a dramatic transformation from natural to extremely anthropogenic landscapes. These processes continue to have severe detrimental effects on many of the more than 1400 species of bats, a substantial proportion of the entire mammalian diversity. “Increasing our knowledge about the conditions under which bats suffer or thrive in these different ecosystems – including cities – is crucial for bat conservation”, says Dr Daniel Lewanzik from the Leibniz-IZW Department of Evolutionary Ecology. Lewanzik and his colleagues teamed up with more than 200 citizen scientists to record ultrasonic vocalisations of five bat species up to six times at 600 sampling sites in Berlin over the course of two years. “This large dataset allowed us to investigate how features of the urban landscape influenced the presence of bats. This helped us to identify those environmental variables which are favourable for bat populations”, explains PD Dr Christian Voigt, head of the Leibniz-IZW Department of Evolutionary Ecology and senior author of the paper.

The results underpin the suspicion that artificial light at night negatively affects all bat species, even decreasing the occurrence of species previously considered “light tolerant”. Soprano pipistrelles were particularly light sensitive: Already at medium light levels they were rarely detected in urban areas and they disappeared completely at higher levels of illumination. Additionally, soprano pipistrelles were almost four times more likely to occur in areas with white light than with orange light, whereas Nathusius’ pipistrelles and mouse-eared bats did not show a preference for any light colour. In addition, the response of mouse-eared bats to increasing light levels was subject to seasonal influences: While their activity decreased with increasing light levels in summer, this was not the case in autumn.

Canopy cover, open water and the level of impervious surfaces such as streets and buildings also had a significant effect on some species which was modulated by their foraging habits. Species that forage along vegetation edges (such as pipistrelles) require trees for commuting and foraging, those that hunt directly above water surfaces (e.g. Daubenton’s bat) depend on the presence of open water. Most investigated species, particularly open-space foraging species, avoided high levels of impervious surfaces, for example streets framed by building blocks.

“Our findings highlight the importance of an extensive reduction of artificial light at night to the absolute minimum needed for human activities and of using dimming protocols, for example triggered by motion sensors wherever and whenever applicable”, Lewanzik and Voigt summarise. They further recommend maintaining existing and creating new vegetation patches where possible. It is essential to connect these fragments with each other and with water bodies via uninterrupted vegetation and dark corridors (e.g. residential gardens and tree lines). The investigation shows that even cities can provide suitable habitat for protected and threatened species when these recommendations are followed.

Collecting data together with citizen scientists had different positive effects, the authors say. “Collaborating with more than 200 highly motivated helpers made it possible to collect data simultaneously over the entire urban area of Berlin”, says Dr Miriam Brandt, head of the Leibniz-IZW unit Science Management unit and leader of the project “WTimpact”. WTimpact, in the frame of which the research on bats in Berlin was conducted, is a collaborative project funded by the German Federal Ministry of Education and Research from 2017 to 2021. “At the same time, we were able to introduce interested citizens to a part of urban nature that usually remains unnoticed - many participants were surprised to find bats in urban environments where they would not have expected them.”

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JOURNAL

Environmental Pollution

DOI

j.envpol.2021.118785 

Tiger shark migrations altered by climate change, new study finds

New migration patterns leave sharks more vulnerable to fishing

Peer-Reviewed Publication

UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE & ATMOSPHERIC SCIENCE

 

VIDEO: IN A NEW STUDY, NEIL HAMMERSCHLAG, PH.D., AND COLLEAGUES USED MULTIPLE APPROACHES TO EVALUATE THE EFFECTS OF OCEAN WARMING ON TIGER SHARK MOVEMENTS IN THE WESTERN NORTH ATLANTIC. OVER THE PAST ~40 YEARS, SHARK DISTRIBUTIONS HAVE EXPANDED POLEWARD, PARALLELING RISING TEMPERATURES. MOREOVER, SATELLITE TRACKING OF SHARKS OVER THE PAST DECADE HAS REVEALED THEIR ANNUAL MIGRATIONS HAVE EXTENDED FARTHER POLEWARD AND ARRIVAL TIMES TO NORTHERN AREAS HAVE ALSO OCCURRED EARLIER IN THE YEAR DURING EXTREMELY WARM PERIODS, WHICH HAS SUBSEQUENTLY DECREASED THEIR PROTECTIONS FROM FISHING. POTENTIAL CONSEQUENCES OF THESE CLIMATE-DRIVEN ALTERATIONS INCLUDE INCREASING SHARK VULNERABILITY TO FISHING, DISRUPTION OF PREDATOR-PREY INTERACTIONS AND CHANGES IN ENCOUNTER RATES WITH HUMANS. HAMMERSCHLAG, N., MCDONNELL, L. H., RIDER, M. J., STREET, G. M., HAZEN, E. L., NATANSON, L. J., MCCANDLESS, C. T., BOUDREAU, M. R., GALLAGHER, A. J., PINSKY, M. L., & KIRTMAN, B. (2022). OCEAN WARMING ALTERS THE DISTRIBUTIONAL RANGE, MIGRATORY TIMING, AND SPATIAL PROTECTIONS OF AN APEX PREDATOR, THE TIGER SHARK (GALEOCERDO CUVIER). GLOBAL CHANGE BIOLOGY, 00, 1–16. view more 

CREDIT: UNIVERSITY OF MIAMI ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE

A new study led by scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science revealed that the locations and timing of tiger shark movement in the western North Atlantic Ocean have changed from rising ocean temperatures. These climate-driven changes have subsequently shifted tiger shark movements outside of protected areas, leaving the sharks more vulnerable to commercial fishing.

The movements of tiger sharks, (Galeocerdo cuvier) the largest cold-blooded apex predator in tropical and warm-temperate seas, are constrained by the need to stay in warm waters. While waters off the U.S. northeast coastline have historically been too cold for tiger sharks, temperatures have warmed significantly in recent years making them suitable for the tiger shark.

“Tiger shark annual migrations have expanded poleward, paralleling rising water temperatures,” said Neil Hammerschlag, director of the UM Shark Research and Conservation Program and lead author of the study. “These results have consequences for tiger shark conservation, since shifts in their movements outside of marine protected areas may leave them more vulnerable to commercial fishing.”

Hammerschlag and the research team discovered these climate-driven changes by analyzing nine years of tracking data from satellite tagged tiger sharks, combined with nearly forty years of conventional tag and recapture information supplied by the National Oceanic and Atmospheric Administration (NOAA) Cooperative Shark Tagging Program and satellite derived sea-surface temperature data.

The study found that during the last decade, when ocean temperatures were the warmest on record, for every one-degree Celsius increase in water temperatures above average, tiger shark migrations extended farther poleward by roughly 250 miles (over 400 kilometers) and sharks also migrated about 14 days earlier to waters off the U.S. northeastern coast.

The results may have greater ecosystem implications. “Given their role as apex predators, these changes to tiger shark movements may alter predator-prey interactions, leading to ecological imbalances, and more frequent encounters with humans.” said Hammerschlag.

The study, titled “Ocean warming alters the distributional range, migratory timing, and spatial protections of an apex predator, the tiger shark (Galeocerdo cuvier)” was published January 13, 2022 in the journal Global Change Biology.

The study’s authors include: Neil Hammerschlag, Laura McDonnell, Mitchell Rider, Ben Kirtman from the UM Rosenstiel School; Garrett Street and Melanie Boudreau from Mississippi State University; Elliott Hazen, Lisa Natanson, Camilla McCandless from NOAA Fisheries; Austin J. Gallagher from Beneath the Waves; and Malin Pinsky from Rutgers University.

The Batchelor Foundation, Disney Conservation Fund, Wells Fargo, Guy Harvey Ocean Foundation, the Herbert W. Hoover Foundation, the International Seakeepers Society, Oceana, Hoff Productions for National Geographic, and the West Coast Inland Navigation District provided support for the study.

Link to video: https://youtu.be/vyLbf7KSXAk

About the University of Miami

The University of Miami is a private research university and academic health system with a distinct geographic capacity to connect institutions, individuals, and ideas across the hemisphere and around the world. The University’s vibrant and diverse academic community comprises 12 schools and colleges serving more than 17,000 undergraduate and graduate students in more than 180 majors and programs. Located within one of the most dynamic and multicultural cities in the world, the University is building new bridges across geographic, cultural, and intellectual borders, bringing a passion for scholarly excellence, a spirit of innovation, a respect for including and elevating diverse voices, and a commitment to tackling the challenges facing our world. Founded in the 1940’s, the Rosenstiel School of Marine and Atmospheric Science has grown into one of the world’s premier marine and atmospheric research institutions. Offering dynamic interdisciplinary academics, the Rosenstiel School is dedicated to helping communities to better understand the planet, participating in the establishment of environmental policies, and aiding in the improvement of society and quality of life. www.rsmas.miami.edu.

  

CAPTION

In a new study, Neil Hammerschlag, Ph.D., and colleagues used multiple approaches to evaluate the effects of ocean warming on tiger shark movements in the Western North Atlantic. Over the past ~40 years, shark distributions have expanded poleward, paralleling rising temperatures. Moreover, satellite tracking of sharks over the past decade has revealed their annual migrations have extended farther poleward and arrival times to northern areas have also occurred earlier in the year during extremely warm periods, which has subsequently decreased their protections from fishing. Potential consequences of these climate-driven alterations include increasing shark vulnerability to fishing, disruption of predator-prey interactions and changes in encounter rates with humans. Hammerschlag, N., McDonnell, L. H., Rider, M. J., Street, G. M., Hazen, E. L., Natanson, L. J., McCandless, C. T., Boudreau, M. R., Gallagher, A. J., Pinsky, M. L., & Kirtman, B. (2022). Ocean warming alters the distributional range, migratory timing, and spatial protections of an apex predator, the tiger shark (Galeocerdo cuvier). Global Change Biology, 00, 1–16.

CREDIT

Bianca Rangel

 

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JOURNAL

Global Change Biology

DOI

10.1111/gcb.16045 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Ocean warming alters the distributional range, migratory timing, and spatial protections of an apex predator, the tiger shark (Galeocerdo cuvier).

ARTICLE PUBLICATION DATE

13-Jan-2022

COI STATEMENT

none

The “gold” of the Midas cichlids

Peer-Reviewed Publication

UNIVERSITY OF KONSTANZ

All he touched turned to gold – says the legend of King Midas from Greek mythology. All Midas cichlids from Central America start out life as black-and-white striped fish and then, almost magically, some of these fishes gradually lose their black colouration and turn bright golden. Behind the "golden touch", which most probably plays a role here, is not the Greek god Dionysus, but a heretoforth unknown gene of the fishes. A team of scientists led by Konstanz biologist Professor Axel Meyer has now published the discovery and characterization of the gene along with a description of different variants that might be the reason for the colour polymorphism in these fishes in the journal Nature Communications.

One species, different versions
Sometimes individuals of the same species differ greatly in their shape or colouration. Scientifically, this phenomenon is referred to as "polymorphism". The 13 fish species that belong to the Central American Midas cichlids (Amphilophus cf. citrinellus) and live in crater lakes in Nicaragua are a vivid example of this: While these fishes always have a dark colouration at first, the "genetically golden" ones turn orange – usually when they become sexually mature – so that there are two colour variants among the adults.

The colour change from dark to "golden", which occurs in about ten percent of the animals, is strictly speaking a decolourization: Over the course of a few weeks, more and more cells containing the dark pigment melanin in the skin of the fishes die and thus cause the bright orange/yellow colour of the adult "golden" animals. This pigment is the same that determines the colour of hair and eyes in humans. So it is the loss of dark, melanin-containing cells that brings out the vibrant colours of the fishes.

In search of the genetic cause
As the colouration of the Midas cichlids has fascinated scientists since its discovery over 100 years ago, it has already been known that the gold colouration is passed on from one generation to the next. The inheritance of the trait follows classical Mendelian rules and the gold colouration is the dominant trait. "Similar to us humans, the chromosome set of the fishes is present in duplicate in every cell. Since the golden colouration is dominant over the dark colour type, a single genetic copy of the 'gold variant' per cell is sufficient for the fishes to develop the golden colouration in the course of their lives," explains Axel Meyer, professor at the Department of Biology at the University of Konstanz.

In past studies, the Meyer-lab was able to narrow down the location of the genetic cause for the colour polymorphism of the Midas cichlids to chromosome 11. However, the genetic mechanism itself responsible for the colour-change of the fishes had remained unknown until now. To get to the bottom of the mystery, the researchers analyzed genetic material from dark and golden Midas cichlids from different crater lakes using "association mapping". The observable trait of colouration is mapped onto a genetic map of the fishes’ genome through genetic crossing over generations, whereby the variation between cohorts of siblings and their grandparents allows to localize the genetic cause of the trait on the genetic map. "The first thing we noticed in this analysis were inconsistencies in the results. Something did not quite fit, literally a piece of the puzzle was missing", says Axel Meyer.

The "goldentouch" gene
The Konstanz scientists suspected that the already existing reference genome of the Midas cichlid used for the analysis might be incomplete in the sense that it does not contain the gene responsible for the colouration at all. Consequently, they decided to produce an improved reference genome using the new "long-read" sequencing method. This part of the study was mainly carried out by Dr Frederico Henning, now professor at the Federal University of Rio de Janeiro (Brazil), and Dr Claudius Kratochwil, now working as a group leader at the University of Helsinki (Finland). Both are former postdocs of Axel Meyer's research group. To do this, the complete genome of a lab-raised Midas cichlid that was heterozygous for colouration was sequenced. Heterozygous means that the individual fish has the genetic information for the golden colouration on one copy of its chromosome 11, and that for the dark colour variant on its other chromosome 11. Then the researchers repeated their original analysis.

"We first discovered a previously undescribed gene on chromosome 11 in our new reference genome, which was present in two different variants in our fish: Variant d for 'dark' and variant G for 'golden'," Axel Meyer reports. Repeating the mapping studies then revealed that this gene is very likely to be associated with the colouration of the Midas cichlids: Fishes with a double copy of the d variant showed a dark colouration in adulthood, whereas those with one or two copies of the dominant G variant showed an orange/yellow colouration. In reference to the legend of King Midas, the researchers named the newly discovered gene "goldentouch".

Further investigations
The results thus provided the first strong indication that the goldentouch gene is likely to play a significant role in the development of different colour variants in Midas cichlids. To learn more about the newly described gene, the researchers continued with a series of molecular follow-up experiments. Initially, they found that the gold variant of the gene is significantly longer than the dark variant. The reason for this is a piece of selfish DNA that has migrated into the gene – a "jumping gene" or "transposon". This extra piece of genetic code causes the gold variant of the gene to fold differently at the molecular level than the dark variant. This in turn has consequences for the gene expression – the synthesis of proteins as the end product of the information contained in the gene.

The researchers also found that in all colour variants of the Midas cichlid, the gene is switched on mainly in the scales, but almost not at all in other locations, such as the internal organs. This underpins a specific function of the gene products in the outer skin layers of the fishes. "We also found that the goldentouch gene is expressed to a lesser extent in the scales of the golden Midas cichlids than in the dark ones. So there are differences in the number of gene products between the colour variants, which might explain the different colour types," Axel Meyer explains.

Thus, even if the final proof that the variants of the goldentouch gene described in the current study are the direct cause for the development of the colour variants in the Midas cichlid is still pending, there are already several indications that this is the case. "With our study, we have come a big step closer to deciphering the mystery of the Midas cichlids. In future studies, we will have to confirm the causal link to the goldentouch gene and figure out how the gene controls the colour change of the fishes at the molecular level in detail", Axel Meyer adds.
 

Key facts: Original publication: Claudius F. Kratochwil, Andreas F. Kautt, Alexander Nater, Andreas Härer, Yipeng Liang, Frederico Henning, Axel Meyer (2022): An intronic transposon insertion associates with a trans-species color polymorphism in Midas cichlid fishes. Nature Communications; DOI: https://doi.org/10.1038/s41467-021-27685-8 Biologists from Konstanz describe a new gene in the Central American Midas cichlid fish and name it "goldentouch" referring to the legend of King Midas. The researchers identify a newly discovered variant of the gene that presumably causes the golden colouration found in about ten percent of the otherwise dark-coloured adult animals. The gold variant was caused by the insertion of a "jumping gene" (transposon). The consequence of this transposon insertion is that the gene folds differently at the molecular level (structural variant), which in turn has an impact on the synthesis of proteins in the scales of the fishes. Scientific contact for interviews: Professor Axel Meyer, University of Konstanz; phone: + 49 7531 88-4163, -88-3069; email: axel.meyer@uni-konstanz.de Funding sources: European Research Council (ERC), German Research Foundation (DFG), European Molecular Biology Organization (EMBO), Swiss National Science Foundation, Instituto Serrapilheira, CAPES, Baden-Württemberg foundation (BWS) as well as start-up funding from the University of Helsinki

Note to editors:
You can download a photo here:
https://cms.uni-konstanz.de/fileadmin/pi/fileserver/2022/das_gold.jpg
Caption: A pair of Midas cichlids (here: Amphilophus xiloaensis) from the Nicaraguan crater lake Xiloá, protecting their offspring.
Copyright: Ad Konings, Cichlid Press

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JOURNAL

Nature Communications

DOI

10.1038/s41467-021-27685-8