【offer information, OKAYAMA University】Keeping Toxic Cadmium Out of Rice, The Genetic Way

September 06, 2022

 

Release Subtitle:

Researchers discover that the duplication of a transporter gene lowers toxic cadmium accumulation in rice without affecting quality and yield

Release Summary Text:

The consumption of rice accounts for nearly half the total intake of cadmium, a toxic heavy metal, among humans. Now, scientists have found that the duplication of a cadmium transporter gene in the Pokkali rice cultivar reduces cadmium accumulation in the shoots and grain. They introduced this trait into a different rice cultivar and saw reduced cadmium accumulation with no effect on grain yield and quality, providing a useful target to breed low-cadmium-accumulating rice cultivars.

Full text of release:

Rice is a staple food for nearly half the world’s population. However, it accumulates more cadmium from the soil than other cereals like barley and wheat. Reports estimate that 40–65% of our total intake of cadmium, a toxic heavy metal, is from rice. Eating cadmium-contaminated rice poses a serious health risk to humans, with conditions like Itai-itai disease being associated with high cadmium intake.

Efforts have been previously made to reduce the quantity of cadmium in rice through methods like importing clean soil, water management, and mixing contaminated soil with biochar and lime. However, these methods are time-consuming and expensive. To remedy this, scientists have turned to cross-breeding to cultivate rice that accumulate less cadmium.

“We have been working on the mechanisms of cadmium accumulation in rice and barley for a long time and have identified several key genes involved in its accumulation,” says Prof. Jian Feng Ma, who is affiliated to the Institute of Plant Sciences and Resources at Okayama University, Japan. Recently, Prof Ma published a paper in the journal Nature Food detailing the genetic mechanisms that play a role in this process. The paper was published online on 18 August 2022 (19 August 2022 Japan time).

After examining 132 accessions of rice, Prof Ma and the members of his research group found that the gene, OsNramp5, when duplicated in tandem, reduced the accumulation of cadmium in Pokkali, a variety of rice that has been cultivated for 3000 years in Kerala, India. According to previous reports, OsNramp5 encodes a cadmium and manganese transporter protein in rice. The same gene, when duplicated in tandem, turns to increase the uptake of both the minerals into the root cells. Consequently, manganese competes with cadmium in the cells for translocation to the shoots, which in turn reduces the accumulation of cadmium in these parts.

The scientists found that out of the 132 accessions of rice, the tandem duplication of OsNramp5 was naturally found only in Pokkali, which can grow in salt-laden coastal soil.

The researchers also noted that the spatial expression level of OsNramp5 was always around two-fold higher in the roots of Pokkali than that in the roots of Koshihikari.

As Pokkali stores extremely low cadmium in its shoots, the scientists introgressed (a term for the transfer of genetic information across species) the duplicated OsNramp5 gene in Koshihikari, a variety of rice that is very popular in Japan but accumulates relatively high levels of cadmium. Explaining how targeted breeding can help humans, Prof. Ma says, “We identified a gene responsible for differential accumulation of cadmium in rice grain based on natural variations in cadmium accumulation. Then, we applied this gene to successfully breed rice cultivars with low cadmium accumulation in the grain.”

The team found that the Koshihikari cultivar with the duplicated gene accumulated significantly lower amounts of cadmium without comprising on the grain quality or yield.

Recounting the benefits of a low cadmium-accumulating rice variety, Prof. Ma explains, “Cadmium is a toxic heavy metal and threatens our health through the food chain. Our study provided a useful material for breeding varieties of rice with low cadmium accumulation, which contributes to produce safe and healthy food. We hope that this gene will be widely used in breeding different rice cultivars with low cadmium accumulation. This will protect us from cadmium poisoning.”

Release URL:
https://www.eurekalert.org/news-releases/963250

Reference:

Duplication of a manganese/cadmium transporter gene reduces cadmium accumulation in rice grain

Journal: Nature Food
DOI:10.1038/s43016-022-00569-w


Contact Person:Jian Feng Ma

Dr. Jian Feng Ma is a Professor affiliated to the Institute of Plant Sciences and Resources at Okayama University, Japan. His area of expertise is plant nutrition. He has been awarded the Japan Prize of Agricultural Science and Yomiuri Prize of Agricultural Science in 2019 and the Japanese Society of Plant Physiologists Award in 2022 for outstanding achievements in plant science research. He has published over 300 papers in his particular field and was selected as the Most Cited Researcher for seven years since 2015. In addition, based on multiple evaluation criteria, he was ranked No. 1 in Plant Biology and Botany field in Japan and No. 3 in a single year (2020) in the world.

In Pokkali, due to duplicated OsNramp5, the roots take up more Mn and Cd into the root cells compared with other rice varieties (for example, Koshihikari). Most Cd taken up through OsNramp5 is sequestered into vacuoles by OsHMA3, while most Mn is translocated to the shoots through OsMTP9. Higher Mn concentration in the root cells competes with Cd for an unidentified efflux transporter, resulting in decreased loading of Cd to the xylem and subsequently to the shoots and grains. The dotted arrow shows decreased Cd loading by high Mn. The cyan and purple colours indicate Mn and Cd, respectively.

 

 https://www.okayama-u.ac.jp/eng/research_highlights/index_id167.html

【offer information, OKAYAMA University】Elucidating the Molecular Targets of “Eicosapentaenoic Acid”: A Natural Remedy for Chronic Pain

August 09, 2022

 

Release Subtitle:

Study finds that eicosapentaenoic acid, an omega-3 fatty acid, inhibits an important signaling molecule, thereby reducing chronic pain

Release Summary Text:

Eicosapentaenoic acid (EPA)—an omega-3 fatty acid—is known to reduce both neuropathic and inflammatory pain, but the underlying molecular targets for EPA remain unknown. Researchers from Okayama University have now identified ‘vesicular nucleotide transporter’ as a novel molecular target of EPA, and elucidated mechanisms underlying the analgesic effect of EPA. Their findings suggest that nutrient-based EPA may serve as an effective pain-relief alternative with minimal side-effects compared to opioids.

Full text of release:

Eicosapentaenoic acid (EPA) is an essential nutrient belonging to the omega-3 group of polyunsaturated fatty acids (PUFAs). As the human body cannot synthesize PUFAs, dietary supplements containing EPA are required for normal physiological functions. Found abundantly in natural sources like fish, hemp oil, and linseed oil, EPA is known to exhibit anti-inflammatory, neuroprotective, and cardiovascular protective activities. Additionally, recent studies have demonstrated its therapeutic effects in reducing mortality risk after myocardial infarction, improving insulin resistance, reducing blood lipid levels, and inhibiting platelet aggregation. Omega-3 PUFAs have also been shown to decrease inflammatory responses following COVID-19 infection. Despite the wide spectrum of its therapeutic effects, the molecular target(s) and the underlying mechanism of EPA’s action remain elusive.

Research Professor Takaaki Miyaji from Okayama University, Japan, and his team of researchers have now uncovered a novel molecular target of EPA in their recent work published in the journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) on July 18, 2022. Explaining the rationale behind their study, Research Professor Miyaji, the corresponding author of this paper, says, “Conventional molecular targets such as COX-2 inhibitors can explain the anti-inflammatory and analgesic effects for inflammatory pain, but not neuropathic pain, of EPA. However, since EPA significantly attenuates both inflammatory and neuropathic pain, there is a strong possibility that there exists another important molecular target of EPA related to neuropathy.” Diving deeper, the team, thus, sought to understand the mechanism of action of EPA in alleviating both inflammatory and neuropathic pain.

During neurological, metabolic, and immunological disruptions, “purinergic” chemical transmission (a form of extracellular signaling mediated by purine derivatives), leads to the binding of energy carriers like adenosine triphosphate (ATP) to “purinoreceptors,” which induces and exacerbates neuropathic and inflammatory pain perception. This binding is mediated by a vesicular nucleotide transporter (VNUT), which thus becomes the key molecule in the initiation of purinergic signaling. The researchers hypothesized that EPA targets VNUT, thereby blocking purinergic chemical transmission and reducing pain perception.

Research Professor Miyaji and his team tested this hypothesis both in-vitro, using human derived VNUT, and in-vivo, using a VNUT-deficient mouse model.

They found that EPA competes with chlorine ions that normally activate VNUT and inhibits VNUT-mediated release of ATP. Moreover, they observed this effect with EPA and its metabolites only, and not with docosahexaenoic acid, another omega-3 fatty acid, thus, suggesting that the structure of omega-3 fatty acids with side chains is necessary for VNUT inhibition.

Further, they induced neuropathic pain in wild-type and VNUT-deficient mice using chemotherapeutic agents that are used in cancer treatment. Notably, EPA accentuated pain in wild-type animals, but not in VNUT-deficient mice, thus corroborating their earlier finding on the inhibitory effect of EPA on VNUT. Similarly, insulin resistance induced by neuropathic pain has been shown to be reduced by EPA treatment in wild-type, but not in VNUT-deficient mice.

“We found that low concentrations of EPA completely and reversibly inhibited the release of ATP from neurons, without inhibiting the release of other neurotransmitters. Compared with other drugs, EPA demonstrated a higher analgesic effect and fewer side effects,” explains Research Professor Miyaji.

Besides, neuropathic pain and associated insulin resistance, the analgesic effects of EPA can be further extended to chronic pain associated with several other conditions like chemotherapy, diabetes, rheumatism, gout, sciatic nerve ligation, and inflammation. Additionally, purinergic chemical transmission is also associated with a variety of conditions including Alzheimer’s disease and depression, for which EPA can be explored as a therapeutic strategy.

Moreover, opioids and other pain-relief medications can have long-term side effects and result in addictions. In the absence of optimal drug treatments with fewer side effects, chronic pain leads to a decreased quality of life, besides increasing the economic burden of treatment. With this discovery, ‘nutrient-based EPA’ and its metabolites can be indicated in the management of chronic pain, while also keeping potential side effects at bay.

Elaborating the long-term implications of their research, Research Professor Miyaji adds, “Our results can help develop novel nutrient-based treatment and prevention strategies by targeting purinergic chemical transmission for inflammatory, neurological, and metabolic diseases, without the adverse side-effects of conventional pain-relieving medications.”

Who wouldn’t be excited at the prospect of having safer and natural pain relief strategies? We certainly are!

Release URL:
https://www.eurekalert.org/news-releases/961154

Reference:

Vesicular nucleotide transporter is a molecular target of eicosapentaenoic acid for neuropathic and inflammatory pain treatment

Journal: Proceedings of the National Academy of Sciences of the United States of America

DOI:10.1073/pnas.2122158119


Contact Person:Takaaki Miyaji

Takaaki Miyaji is a research professor affiliated with the Advanced Science Research Center at the Okayama University, Japan. He completed his doctoral studies from Okayama University in 2009 before embarking on his professional journey. His research spans across life sciences, such as pharmaceuticals, nutrition, health sciences, and pharmacology. Research Professor Miyaji along with his peers, was the first in the world to identify a Vitamin C transporter in plants. He is also the recipient of the 2018 Young Scientists’ Prize of Commendation for Science and Technology. He wishes to contribute to the domain of life sciences with his research expertise.

New study identifies vesicular nucleotide transporter as a novel target of eicosapentaenoic acid (EPA) and highlights the mechanism underlying the analgesic effect of EPA. EPA potently attenuates neuropathic and inflammatory pain and insulin resistance, with fewer side effects

 

 https://www.okayama-u.ac.jp/eng/research_highlights/index_id166.html

【offer information, OKAYAMA University】To Cell Surface and Beyond: Tracing Subcellular Glycoprotein Transport Using Modified Cholera Toxin

July 26, 2022

 

Release Subtitle:

Researchers design and trace a modified cholera toxin to cell organelles for insights on glycoprotein trafficking inside compartments of cells

Release Summary Text:

How are sugar moieties added to proteins inside cells? Although extensively studied, details of the mechanism involved in protein glycosylation at the level of organelles—subcellular compartments—remain fuzzy, owing to difficulties in visualizing the transport of glycoproteins inside these organelles. To unravel the mystery, researchers from Japan have now designed and synthesized an artificial protein derived from the cholera toxin that can be monitored inside the cell as it travels to cell organelles.

Full text of release:

Proteins usually undergo modifications during or after their synthesis in the endoplasmic reticulum (ER) and Golgi apparatus network inside eukaryotic cells. One such modification is glycosylation, whereby sugars, such as glycans, are added to newly synthesized proteins. Glycans allow proteins to fold properly, in turn making them stable and biologically active for various cell processes. However, the exact mechanism of glycosylation in the ER and Golgi are still not known. One way to study the process of glycosylation during protein synthesis is to deliver synthetic proteins to specific cell organelles and observe their subcellular dynamics. But this is often hindered by the lack of specific delivery methods to organelles like the ER and Golgi.

To this end, Dr. Ayano Satoh from Okayama University and Dr. Yuta Maki, Kazuki Kawata, Dr. Yanbo Liu, Kang-Ying Goo, Dr. Ryo Okamoto, and Prof. Dr. Yasuhiro Kajihara from Osaka University, Japan investigated the feasibility of modifying cholera toxin (CT) for targeted delivery to the ER and Golgi. CT is a protein produced by the bacterium Vibrio cholerae and is responsible for the hallmark symptoms of diarrhea—repeated loose, watery stools. The toxin is made up of two subunits: CTA, which causes diarrhea, and CTB, which helps the toxin enter cells. CT enters the cell through the membrane into small cellular vehicles called endosomes that deliver it to the Golgi bodies. From there, an ER-specific amino acid sequence of CTA takes CT into the ER, where the toxin springs into action to cause diarrhea. “CT is a protein that naturally gets delivered specifically to the Golgi and ER. This made it an attractive candidate for our investigation,” says Dr. Satoh, explaining the reason behind selecting this protein for their study, which was first published on May 23, 2022, in Chemistry – A European Journal.

The team synthesized an artificial, glycosylated form of the non-toxic CTB and tracked its intracellular journey using the HiBiT bioluminescence system engineered from the luciferase enzyme. In the system that the team used, the larger fragment of luciferase was added to particular receptors on the ER and Golgi. CTB was tagged with the smaller fragment of luciferase. The system works by emitting light when the two fragments bind to each other. Thus, the team tracked the artificial CTB’s movement through the organelles in real time by checking for the emittance of light. Talking about the highlights of their study, Dr. Satoh says, “We designed and chemically synthesized the glycosyl-CTB and demonstrated its trafficking into the ER and Golgi of living cells. We also established a method to quantitatively monitor the trafficking of CTB to these organelles.”

The successful monitoring and delivery of the artificial CTB may pave the way for a new phase of research in understanding protein modification in compartments of living cells. The team emphasizes that their method of preparing CTB allows for developing various mutant forms of the protein as well as CTB bearing different glycans on its surface to help investigate the functions of N-glycan in cells.

Not only the study of glycans but CTB-mediated delivery can also be a promising tool for target-specific drug delivery in cells and organelles. Dr. Satoh observes, “Our system for targeting specific organelles may help treat diseases caused by the absence of enzymes localized in specific organelles.”

What is her vision for the future? “Current drug delivery techniques are limited because they only target the cell surface. Our system may extend the limits of current technology and enable the delivery of drug wherever it is needed,” says a hopeful Dr. Satoh.

We have our fingers crossed for her vision to come true and revolutionize the field of medicine!

Release URL:
https://www.eurekalert.org/news-releases/959718

Reference:

Design and Synthesis of Glycosylated Cholera Toxin B Subunit as a Tracer of Glycoprotein Trafficking in Organelles of Living Cells

Journal: Chemistry – A European Journal
DOI:10.1002/chem.202201253


Contact Person:Ayano Satoh

Dr. Ayano Satoh is an Associate Professor of the Graduate School of Interdisciplinary Science and Engineering in Health Systems and the Faculty of Engineering at the Okayama University, Okayama, Japan. She obtained her Bachelor’s and Master’s degrees in Chemistry from Ochanomizu University, Tokyo, Japan. She then received her PhD at the Graduate School of Humanities and Sciences, Ochanomizu University, where she worked on affinity interactions among lipids, glycans, and proteins with Dr. Isamu Matsumoto. Before joining Okayama University, she worked with Dr. Graham Warren at Yale University, first as a Postdoctoral Researcher, and then as a Research Scientist. At Yale University, she worked on transport within the Golgi apparatus.

Drug “B” binds to the surface of the cell and is transported to the Golgi apparatus. The drug contains an endoplasmic reticulum (ER)-specific sequence to further guide its transport to the ER. Transport to the ER is stopped if the drug bears N-glycosylation “Y.”

 

 https://www.okayama-u.ac.jp/eng/research_highlights/index_id165.html

【offer information, OKAYAMA University】New AI Model for the Accurate Diagnosis of Neoplasia Associated with Inflammatory Bowel Disease

July 14, 2022

 

Release Subtitle:

Researchers have developed a new AI model which diagnoses and classifies neoplastic lesions in patients with IBD with high accuracy

Release Summary Text:

The treatment of inflammatory bowel disease (IBD)-associated dysplasia is often challenging due to diagnostic techniques that are unable to accurately differentiate and classify the severity of neoplastic lesions. Now, researchers from Okayama University in Japan have developed an AI-system based on a conventional neural network, by training it with endoscopic images of neoplastic lesions. This system displayed a higher diagnostic ability in the classification of the lesions, as compared to that of endoscopists.

Full text of release:

The incidence of inflammatory bowel disease (IBD)—an intractable disease characterized by chronic inflammation of the gastrointestinal (GI) tract—has increased significantly in Japan. Chronic inflammation associated with IBD often leads to the development of cancer in the colorectal region.

For patients who have visible or low-grade dysplasia (abnormal cell growth which may not be malignant), endoscopic resection, a technique used to remove cancerous lesions, and colonoscopy are usually employed. However, for patients with a high rate of neoplasia (severe cell growth which is malignant), a total proctocolectomy, i.e., complete removal of the colon and rectum is the standard treatment, which is highly detrimental to their quality of lives.

Hence, identifying the severity and grade of the neoplasia during diagnosis is essential before proceeding with treatment. Unfortunately, the presence of inflammation in the colorectal region makes it difficult for endoscopists to classify the type of IBD neoplasia (IBDN). This leaves biopsy as the only viable option, which is associated with high risks and often leads to inaccurate diagnoses, highlighting the need for a simpler diagnostic technique with high accuracy.

To this end, a team of researchers from Okayama University Graduate School of Medicine, including Assistant Professor Hideaki Kinugasa, Doctor Shumpei Yamamoto, Professor Sakiko Hiraoka, and Professor Yoshiro Kawahara conducted a pilot study to develop an artificial intelligence (AI) system that classifies IBDN lesions accurately. In addition, as part of this study, which was published in Gastroenterology and Hepatology first on May 29, 2022, they compared the diagnostic ability of endoscopists with that of the new AI system.

First, the team used a conventional neural network (CNN)—a type of neural network used for the analysis of visual imagery—known as Efficient-Net-B3, to develop the AI-system’s prototype. They trained this system using 862 endoscopic images of 99 IBDN lesions from patients with IBD derived from two hospitals between 2003 and 2021, and validated it using a deep-learning framework. Next, they asked endoscopists with over 8 years of experience in gastrointestinal endoscopy to analyse the images and classify the lesions into two types based on the need for proctocolectomy, and compared their classification to that of the AI-system.

As a result of data-augmentation, the AI-system generated approximately six million images from the original data set, which were then used to analyse clinicopathological characteristics of patients and the lesions.

Based on these analyses, the team found that most patients had ulcerative colitis—a type of IBD, with more than 95% of them presenting pancolitis and left-sided colitis. Moreover, the AI-system displayed an image-based diagnostic ability with 64.5% sensitivity, 89.5% specificity, and 80.6% accuracy, and a lesion-based diagnostic ability with 74.4% sensitivity, 85% specificity, and 80.8% accuracy. What’s interesting is that the correct diagnosis rate of the AI system was 79.0, while that of endoscopists was 77.8.

What do these findings imply? “Our AI-system prototype proved successful in determining the degree of malignancy of IBD-tumors and is valuable enough to contribute to clinical practice in the coming years”, said Assistant Prof. Kinugasa in response.

The team also highlighted that combining this AI-based automatic diagnosis of neoplastic lesions with existing endoscopic diagnostic techniques might provide superior diagnostic results in real-time.

While discussing the system’s additional advantages and real-life applications, Assistant Prof. Kinugasa added, “Using this AI-system can ensure that endoscopists do not misdiagnose IBD neoplastic lesions, patients receive prompt treatment, and more appropriate treatment strategies are developed and applied for early as well as advanced stages of IBD”.

Here’s hoping that this AI-system revolutionizes the diagnosis of IBD-associated neoplasia and improves the lives of patients with IBD in Japan and the rest of the world!

Release URL:
https://www.eurekalert.org/news-releases/958630

Reference:

The diagnostic ability to classify neoplasias occurring in inflammatory bowel disease by artificial intelligence and endoscopists: A pilot study

Journal: Journal of Gastroenterology and Hepatology
DOI:10.1111/jgh.15904

Contact Person:Hideaki Kinugasa

Dr. Hideki Kinugasa is an Assistant Professor at the Department of Gastroenterology and Hepatology at Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama, Japan. His research is primarily focused on colorectal cancer, gastrointestinal cancer, circulating tumor DNA, liquid biopsy, fusobacterium, pancreatic neoplasms, and endoscopic diagnosis and treatment. Within the last year, he has already contributed to the publication of 49 research papers and his work has been cited by various researchers.

Image of adenocarcinoma observed using a deep-learning tool (Grad-CAM) which was correctly diagnosed by AI, and incorrectly diagnosed by certain endoscopists.

 

 https://www.okayama-u.ac.jp/eng/research_highlights/index_id164.html

【offer information, OKAYAMA University】Observing Different Mating Tactics in the Japanese Scorpionfly

June 29, 2022

 

Release Subtitle:

Researchers find that scorpionflies from different locations use varying mating and courtship tactics

Release Summary Text:

Alternative mating strategies of the Japanese scorpionfly have been studied sparingly over the years, primarily focusing on individual populations. Now, two scientists from Okayama University compare the mating habits of male Japanese scorpionflies from two locations—Aichi and Okayama—and reveal that the weaker males of these regional populations adopt distinctly different mating tactics to attract female scorpionflies after losing to the stronger males, possibly indicating a genetic influence in their mating behavior.

Full text of release:

Owing to the high competition and the prevalence of natural selection, many male insects must develop alternative tactics to mate with a female. Weaker males who lose in a competition (or loser males) may resort to hovering or sneaking around in order to find a mate. Recent studies have also shown that alternative mating behavior is influenced by environmental factors such as food availability, predation, and population density. For example, scorpionflies—which are often used to study the mating behavior of insects—use three alternative mating tactics—gifting nutritious saliva, gifting food, and forced mating—to obtain a mate. Male Japanese scorpionflies also employ feeding mating (i.e., mating while females feed without gifting them anything or releasing pheromones).

Previous studies looking at alternative mating tactics in scorpionflies have shown that the weaker males of closely-related species employ varying methods to procreate, however no research has been done to find the alternative mating tactics of males within the same species from different geographical locations. To this end, Dr. Ryo Ishihara (who is affiliated to the School of Agriculture and a recipient of the Special Educational and Research Fellowship) and Professor Takahisa Miyatake (from the Faculty of Environmental and Life Science) of Okayama University, Japan, published a study in the Journal of Ethology on 15 June 2022. This study details the differences in alternative mating tactics of Japanese scorpionflies hailing from two different places—Aichi and Okayama prefectures in Japan.

“A recent study among scorpionflies from Okayama reported their mating behavior and I noticed the results were very different from those reported in previous studies among scorpionflies from Aichi. This piqued my curiosity, and I wanted to verify whether behavioral differences were really occurring between the two regions,” said Dr. Ishihara, who takes an avid interest in entomology.

The researchers observed mating behaviors in a total of 25 males in Aichi, and 30 males almost 300 km away in Okayama, over a period of six hours in designated feeding areas. They noticed that one of the first behaviors in both the populations of loser males was waiting.

The loser males of Okayama resorted to ‘sneaking’ back into the feeding area, where they positioned themselves near the food offered by the winner male as a nuptial gift and waited till another female arrived. They would then present the food as a nuptial gift and attempt to mate with this female. Of the 28 loser males who employing this tactic, 24 successfully mated. On the other hand, 17 males among the scorpionflies in Aichi ran away, seven were found ‘sneaking’ (though even these scorpionflies left after one or two failed attempts at mating), and one attempted to forcefully mate with visiting females.

A significant number of defeated male scorpionflies from the Aichi population, the researchers concluded, chose to leave the feeding area while a majority of Okayama males preferred ‘sneaking’ and trying to mate again. It was also noticed that the defeated males from Okayama waited longer than the ones from Aichi.

Why was this so?

“Well, there are certain factors that are thought to influence alternative mating in Japanese scorpionflies. One of these is the frequency and number of females visiting the feeding areas,” Dr. Ishihara explains. Females in Okayama appeared more frequently and in greater numbers in feeding areas. As a result, defeated males waited longer and used ‘sneaking’ tactics for successful mating with visiting females. The females in Aichi visited the feeding areas less frequently, leading to defeated males who looked for other feeding areas, or resorted to attempts at forceful mating.

The findings in the wild were corroborated with laboratory experiments. From these results, the researchers inferred that there is also a genetic component that influences alternative mating and courtship habits.

Dr Ishihara emphasized the importance of the study and said, “This is the first example of two regionally different populations of the same species of scorpionfly showing variations in alternative mating tactics. Our research may be used to understand the long-term environmental indicators of habitat, predict the strength and direction of sexual selection, and identify early factors in the evolution of mating tactics.”

Release URL:
https://www.eurekalert.org/news-releases/957073

Reference:

Differences in mating tactics performed by males of two local populations of the Japanese scorpionfly Panorpa japonica

Journal: Journal of Ethology
DOI:10.1007/s10164-022-00753-2

Contact Person:Ryo Ishihara

Dr. Ryo Ishihara is a Fellow of the Special Educational and Research Fellowship and is affiliated to the School of Agriculture at the Okayama University in Japan. He has a total of eight publications to his name with his primary focus being ethology and animal behavior. His most recent works include mating tactics of scorpionfly, death feigning in beetles, and swarming behavior of mayfly.

When two male Japanese scorpionflies fight, the loser males among scorpionflies must employ alternate tactics in order to mate with a female. Researchers from Okayama University, Japan, report the variations in alternate mating tactics employed by males in two regionally different populations of the same species of scorpionfly.

 

https://www.okayama-u.ac.jp/eng/research_highlights/index_id163.html