It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, July 05, 2024
Abolition of French Tonnage Tax Could Lead to Reflagging
The potential abolition of the French tonnage tax regime, a favorable tax framework for shipping companies, is causing significant concern within the industry as early legislative elections reignited a debate started with the Finance Bill for 2024. The French tonnage tax regime also supports thousands of jobs and encourages shipowners to register under the French flag, bolstering national maritime influence and economic activity.
The French Court of Auditors estimates a potential 9.4 billion euro loss in tax revenues for 2022-2023 due to the tonnage tax regime, sparking debate on whether abolishing it would indeed boost public revenues.
Many believe that eliminating the tonnage tax could drive shipowners to relocate to other European jurisdictions with similar tax benefits, potentially reducing France's competitive edge in the global shipping industry.
It is reasonable to believe that shipowners currently under French tonnage tax regime would consider changing flag to another European flag, avoiding French corporate taxation whilst still retaining the benefit of their French tax leases. Other jurisdictions, sometimes referred to as ‘flags of convenience’, have even lower to non-existent taxation of earnings.
While the tax advantages of abolishing the French tonnage tax may seem attractive, the economic implications are far-reaching, and the strategic disadvantages of abolishing the tonnage tax call for restraint. The regime not only supports the maritime industry, it also aligns with France’s strategic interests as a leading maritime nation.
Romain Farnoux is a lawyer in Reed Smith’s Transportation Industry Group.
The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.
Carbon Capture is No Silver Bullet, But Holds Opportunities for Shipping
Can onboard carbon capture and storage (CCS) technology be a viable tool in shipping’s decarbonization journey? Answering this question requires a holistic perspective, accounting for the entire carbon value chain. In short, the technical ability to capture and store CO2 is only part of the equation – what happens to the captured carbon is equally important.
Recent studies have revealed promising results on the technical feasibility of capturing CO2 on board ships, showing achievable capture rates between 82% and 90%. For example, a joint research project by Bureau Veritas and Wah Kwong has confirmed the technical viability of integrating a carbon capture, liquefaction and storage system on two in-service bulk carriers.
Bureau Veritas’ latest technology report examines the available evidence on the technical viability of current carbon capture and storage technology for the maritime market. It concludes that while CCS can be a promising option to reduce shipping’s greenhouse gas emissions, it is no silver bullet and must be used in conjunction with other decarbonization strategies to achieve the maritime industry’s goals.
Furthermore, the report points out that for onboard carbon capture to make sense, it needs to be assessed in the context of the overall value chain. In practice, we need to consider the handling and disposal of the captured CO2, the infrastructure needed to handle and process it in ports, the availability and location of storage sites, and potential markets for carbon.
The potential of CCS for shipping
While alternative fuels will be instrumental in bringing shipping to net-zero, there are still questions surrounding their availability in time to meet the first IMO checkpoint of reducing the total annual GHG emissions from international shipping by at least 20%, striving for 30%, by 2030.
Shipping needs new solutions, in addition to energy-saving devices and voyage optimization, in order to achieve its decarbonization targets, particularly in the short to medium term. Therefore, the role of carbon capture technology in reducing CO2 emissions from existing engines cannot be overlooked.
The experience gained in the use of carbon capture technologies in onshore installations can be leveraged for their commercialization and application to maritime transport. However, the cost and applicability of carbon capture on board vessels will vary greatly depending on the type of technology used, but also on the ship’s type, size and the fuel used.
Regulatory, technical and operational challenges
Carbon capture is not without its challenges. One of the most significant uncertainties is how CCS technologies will be addressed by the IMO and other regional regulatory frameworks. From an operational perspective, concerns have been raised regarding potential corrosion, the safe handling of CO2, as well as the available space to accommodate the equipment and storage tanks onboard.
Furthermore, carbon capture is an energy-intensive process, requiring a significant amount of heat to regenerate the solvent (in other words, reverse the CO2 absorption reaction). This, among other factors, can lead to a considerable increase in fuel consumption related to system operation, depending on the desired capture rate.
A 2022 study by the Maersk Mc-Kinney Moller Center for Zero Carbon Shipping illustrates this challenge. While the maximum achievable capture rate was considered to be 82%, the study pointed out that actual CO2 savings were lower when considering the rise in fuel consumption – up to 45% – caused by the CO2 system itself.
Another study by Stena Bulk and the Oil & Gas Climate Initiative on a Suezmax tanker running on heavy fuel oil achieved 90% capture rates. However, the vessel’s fuel consumption was increased by 53% when operating at that rate. In comparison, fuel consumption only increased by 22% with a CO2 capture rate of 50%, and no additional fuel was consumed with a CO2 capture rate of 8%.
A supply chain perspective
When assessing the feasibility of carbon capture technology onboard vessels, it is vital to do so within the context of the entire CCUS value chain, taking into account the potential challenges and opportunities related to the management of the captured CO2.
BV’s recent CCS report also highlights the significant role that shipping can play in facilitating the development of a global carbon capture, utilization, and storage (CCUS) value chain as a major mode of CO2 transportation, particularly given the growing interest in offshore storage sites.
Globally, some 230 million metric tons of CO2 are already used in industrial applications every year. This includes the production of fertilizers, steel, and food and beverages. Moreover, captured CO2 can be used to produce molecules for synthetic fuels such as e-methane and e-methanol, which provide a low-carbon alternative to fossil fuels, including for the shipping industry.
Shipping’s role in CCUS value chains
Shipping already plays an important role in the CCUS value chain as one of the main modes of transport for CO2. Liquid CO2 carriers are used to transport relatively small quantities of food-grade liquid CO2 for the food and beverage industry, with capacities ranging from 1,200 m3 to 1,800 m3 at maximum working pressures of 18 bar gauge and a maximum service temperature of -40°C.
Whereas pipeline systems are used to transport large quantities of CO2 over relatively short distances, they are generally associated with a high initial investment cost and lack of flexibility. On the other hand, shipping transportation offers flexibility in terms of CO2 sources, routes, and shorter set-up times. They, therefore, appear to be an alternative solution to pipelines in the case of scattered emitters over long distances and for relatively smaller transport quantities.
Finally, it is also worth noting that several countries and regions are promoting the development of carbon capture, utilization and storage (CCUS) by introducing financial support and regulatory frameworks to back CCUS R&D and project development. With the right regulations and infrastructure in place, shipping could benefit from the development of a truly circular CO2 economy, whilst contributing to the industry’s own ambitious decarbonization targets.
Marcos Salido, Environmental Project Manager (Strategy & Advanced Services) at Bureau Veritas Marine & Offshore, is the lead author of the report “Onboard Carbon Capture: An Overview of Technologies to Capture CO2 Onboard Ships."
The opinions expressed herein are the author's and not necessarily those of The Maritime Executive.
WAR IS ECOCIDE
Report: Abandoned Tanker Sinks Off Yemen
Lavant settles low in the water, June 22 (Sovcomflot)
The aging tanker Lavant, which sustained uncontrollable flooding off the southeastern coast of Yemen in June, appears to have disappeared and has likely sunk, multiple intelligence sources have confirmed to Reuters. The 30-year-old ship's loss is considered a conventional marine casualty, not one of the many attacks perpetrated by Yemen's Houthi rebel movement.
UKMTO, which first reported the flooding incident aboard Lavant, has not confirmed the vessel's sinking. The organization's last security update for the region was released Sunday.
On the morning of June 22, the Lavant reported uncontrollable flooding at a position about 100 nm southeast of Nishtun, Yemen. The master ordered the crew to abandon ship, and they were rescued by a Gabon-flagged vessel, the ex-Sovcomflot crude oil tanker NS Africa.
Lavant was abandoned and left adrift at 14 31 N 053 08 E, about 130 nautical miles due south of the Yemeni-Omani border. It may have sunk by the end of June, according to previous press reports.
Lavant was a 30-year-old product tanker with an uncertain record. The vessel had no known flag state after January 2023, no known call sign, and no port state inspections after 2017. Its last listed class renewal survey occurred nine years ago, and its last two known flags were the Paris MoU black list registries of Comoros and Tanzania. It was operated by a single-vessel shipmanagement entity with a P.O. box address in Dubai.
According to Russian media reports, Lavant was under way to Somalia when the crew made their distress call.
NS Africa is operated by Dubai firm Stream Ship Management, an entity identified by Ukrainian researchers as a compliance vehicle for semi-sanctioned Russian state shipping firm Sovcomflot. Though Sovcomflot is no longer legally linked to NS Africa after a series of ownership and management transfers, it claimed responsibility for NS Africa's SARresponse.
IMO Asks for ROV to Support Cleanup Off Yemen After Rubymar Sank
Oil slick forming while the Rubymar was drifting in the Red Sea (CENTCOM)
The International Maritime Organization has gone public with an appeal to the world community inviting in-kind contributions of spill response equipment to support the Republic of Yemen. The organization published an appeal released last week that seeks the donation of a remotely operated underwater vehicle (ROUV or ROV) along with a list of equipment to be used in cleanup efforts.
The call for contributions of oil pollution response equipment the IMO says is to support operations related to the sinking of Rubymar (32,200 dwt) off the coast of Yemen in March 2024. The Belize-flagged vessel was attacked by the Houthis on February 18 and abandoned in the Red Sea. It is believed the Houthis later boarded the disabled vessel to hasten its demise.
During the time the vessel was drifting and slowly taking on water, the U.S. Central Command and others highlighted the growing environmental disaster. The IMO is highlighting that there were 200 tonnes of heavy fuel oil and 80 tonnes of marine diesel on board. In the days following the attack, an oil slick grew behind the vessel reported to reach 18 miles from the wreck.
Another major concern is that the Rubymar was transporting over 41,000 tons of ammonium phosphate-sulfate fertilizer when it was attacked. Environmentalists have emphasized the dangers if it leaks into the Red Sea. The ship went down in about 328 feet (100 meters) of water.
“The ship is currently partially submerged at the location of its sinking, with the remaining bunker fuel and fertilizer cargo onboard representing a significant environmental threat to the Republic of Yemen, in particular to the nearby Hanish Islands, a biologically rich area,” writes the IMO.
Recognizing the lack of specialized oil spill response equipment within the country to respond to a possible leak or other environmental issues, the IMO is inviting in-kind contributions of spill response equipment in support of the Republic of Yemen. In addition to the ROV, they are calling for equipment including a shovelhead skimmer, nozzles used in cleaning efforts, towing brindles, anchoring equipment, and a broad range of personal protective equipment.
The Rubymar was the first vessel confirmed to have sunk due to the Houthi attacks. A second vessel, the Tutor, was also sunk by the Houthi while the vessel was drifting in the Red Sea after an attack. At least two other vessels were badly damaged by fires due to the attacks but are believed to be afloat with reports of salvage efforts. A third vessel, a small tanker, is also being reported as having sank in the Gulf of Aden but this is not being linked to the Houthi but instead, it was an older vessel that reported mechanical problems. A Sovcomflot tanker rescued the crew when they abandoned ship and Reuters is now citing local officials who are saying the ship has disappeared from radar.
The IMO had previously wanted about the severe environmental dangers in the region during the efforts to salvage the FSO Safer. The effort led by the UN successfully moved the oil to another storage tanker but was stopped due to the current conflict before the safer was removed and recycled.
Russian Attack Damages Port Infrastructure in Odesa
Ukraine is working to expand shipping activity from its Black Sea ports (file photo pre-war)
Russian forces launched a ballistic missile attack on the Odea port region on Thursday evening, July 4, causing damage and starting at least one fire. The attacks came as Ukraine works to continue to rebuild shipping volumes and after reports of a drone-boat attack on the Russian port of Novorossiysk in the Eastern Black Sea region.
Ukrainian forces reported that one person was killed and seven were injured in the attack on the Odesa port complex. The Ukrainian Air Force said that the attack was directed toward Chornomorsk, one of the key port regions for the country. Port facilities and administrative buildings were damaged as well as reports of damage to housing. There were unconfirmed reports of explosions in the city of Odesa.
Odesa and the port region have come under frequent attacks in the past although there had not been recent reports of damage. On May 1, Russian forces attacked the port region in Odesa and according to Ukrainian media damaged a private postal facility and $76,000 in shipments.
In addition to the attack on the Odesa region, there were widespread reports of Russian drones targeting multiple sites in Ukraine. The Ukrainian Air Force said a total of 22 drones were identified while it claimed to have downed 21 of the attacks.
Yesterday’s attack followed Russian reports that its forces prevented a drone attack on Novorossiysk from causing significant damage. The last round of drone attacks to reach Novorossiysk was on May 17.
Ukraine has been working to expand its shipping operations from the Black Sea ports. The head of the parliamentary finance committee, Danylo Hetmantsev posted data on social media highlighting the growth in activity in the first six months of 2024. He noted that a year ago Ukraine had been hampered by the UN-led initiative which required inspections and permits for ships to enter the region.
Hetmantsev said without the restraints of the UN program and using the corridor established by the Ukrainian military they were able to grow shipments by 68 percent in the first half of 2024 versus 2023. While two-thirds continue to be agricultural products, they were also able to add metal and mining products contributing to the growth and providing critical export income for the country.
The report said a total of six seaports are now active in Ukraine. This spring major carriers MSC Mediterranean Shipping Company, Maersk, and Hapag-Lloyd each restored the container services from the Black Sea ports. Recently, it was reported that Ukrainian ferry service on the Black Sea would also be restored starting this month.
Ukraine Launches Drone-Boat Attack on Novorossiysk
Ukraine launched a drone attack on the port of Novorossiysk on Wednesday morning, the Russian Ministry of Defense has confirmed.
Novorossiysk is a large commercial seaport in the northeastern corner of the Black Sea, about 350 nautical miles away from Ukrainian-controlled coastlines. Over the past year, it has become a safe haven for the Russian Navy's Black Sea Fleet, which has been repeatedly attacked by Ukraine's drone-boat and missile forces. Ukrainian units have destroyed or damaged an estimated 15 Russian ships since the beginning of the invasion in 2022, and the surviving vessels of the Black Sea Fleet have abandoned their home base in Crimea in favor of the relative security of Novorossiysk.
The port is heavily defended with floating barriers, diver-detection units (dolphin pens), helicopter gunships and shore batteries. Despite these defenses, Ukraine continues to attack it with its long-range unmanned drone boats - the same devices it has used with success against Russian warships in the past.
In a statement, the Russian Ministry of Defense said that its forces spotted and destroyed two Ukrainian drone boats as they approached Novorossiysk in the early hours of Wednesday morning. The reported damage was limited to light impacts to two buildings, according to local mayor Andrei Kravchenko.
As a precaution, Kravchenko shut down access to a waterfront embankment and issued an air-raid warning. Authorities advised local residents to take shelter in a room facing away from the sea, and to stay away from windows.
Ukraine has not claimed responsibility for the attack, nor reported any damage inflicted on Russian assets.
The last round of drone attacks to reach Novorossiysk was on May 17, part of a massive wave of an estimated 100 aerial and surface drones launched at Russian targets across the front.
Shipping Industry Needs to Improve to Prevent Injury and Suicide Says Gard
More could be done to prevent a worringly high number of suicides and an increase in the frequency of injury claims says Gard (IMO)
A new report examining key trends within crew-related insurance claims identifies concerns with an increase in injuries as well as a “worryingly high number” of the percentage of deaths caused by suicide among seafarers. While there is a positive trend in illness-related claims (excluding COVID) the report warns that the industry must do better on issues such as mental health and addressing concerns such as isolation and working conditions.
Norwegian insurer Gard analyzed claims over the past five years reporting that personal claims made up nearly half of all the cases reported to the marine insurer. They reviewed 20,000 personal claims reporting most involved crew, although some incidents involved stevedores or passengers, concluding that there is a concern that crew claim frequency has been trending up since 2021.
“As an industry, we are unfortunately far from where we would like to be when it comes to crew fatalities and injuries. Respecting human rights at sea also relates to making sure seafarers’ place of work, on keel, is safe, healthy, and attractive,” said Lene-Camilla Nordlie, Vice President and Head of People Claims at Gard.
Seeking to identify the most frequent issues of injuries, illness, and other risks that seafarers can face, Gard says that more than 40 percent of the P&I claim amounts paid relate to claims from people. The company reports it believes that more can be done to prevent some of these accidents. They write that most cases of crew deaths are preventable.
Over 400 crew fatalities have been recorded by Gard over the past five years. While most deaths among seafarers (74 percent) are from illness, they highlight that 15 percent were due to injuries. More concerning to the insurer is that 11 percent of the crew fatalities are due to suicide.
“This is a worryingly high number and we believe that the actual number could in fact be much higher due to underreporting,” writes Gard. Among medical issues, they cite mental health among the top 10 saying that annually since 2020 they receive reports of 47 cases, 18 cases of suicides, and 16 cases of missing persons. Mental health cases they report grew significantly during the pandemic likely as a consequence of strain and isolation.
The frequency of injury claims was up 44 percent between 2020 and 2023 with Gard registering close to 1,000 injury claims in 2023. They are most often caused by slips, trips, and falls. The second most common cause is being hit by an object or a line, mostly during mooring operations. They report a high number of crush injury claims, such as fingers caught in hatch covers, as well as burns, falls, and injuries from heavy lifting.
“The health, safety, and wellbeing of seafarers is the single most important factor for safe operations on board ships,” writes Gard. By publishing the report, they hope to increase the focus on the issues to encourage preventative measures by shipowners, managers, and seafarers.
Development of a wearable patch for accurate and continuous measurement of trace perspiration amounts
Tsukuba, Japan—Maintaining bodily water balance is essential for survival. Although sweat serves as a key indicator of physical and mental health, existing wearable technologies can only monitor substantial sweat volumes.
To overcome this limitation, the researchers have developed a lightweight (1 g), thin (1-mm thick) wearable patch attachable to the skin. This patch is capable of accurately measuring trace amounts of insensible perspiration, which refers to the water vapor that evaporates from the body surface even during rest. The patch's channels, comprising sponges made from a superhydrophilic polymer, emulate the water absorption mechanisms observed in plants. This design facilitates the rapid and reliable monitoring of trace sweat amounts. Additionally, the sweat entering the channels is colored using a food dye to visually confirm the volume and rate of perspiration, thus indicating the state of dehydration. The patch also incorporates a sensor that continuously monitors the concentration of hydrogen ions (pH) and chemical components such as sodium, potassium, and glucose ions, enabling the real-time detection of variations in such concentrations.
Experiments involving the application of this patch to various body parts during daily activities confirmed its effectiveness and measurement reliability. This novel wearable patch holds significant promise for applications in dehydration management, stress and tension monitoring, disease detection, sports performance optimization, and others. As the patch is individually worn and utilized, it is poised to make substantial contributions to the advancement of personalized medication.
### This work was supported by the Pioneering Research Initiated by the Next Generation (JST SPRIN), under Grant Number JPMJSP2124.
Original Paper
Title of original paper: Nature-Inspired Superhydrophilic Biosponge as Structural Beneficial Platform for Sweating Analysis Patch
Nature-Inspired Superhydrophilic Biosponge as Structural Beneficial Platform for Sweating Analysis Patch
Isolation and characterization of amylase enzyme produced by indigenous bacteria from sugar factory waste
This article by Dr. Eli Hendrik Sanjaya and colleagues is published in the journal, The Open Biotechnology Journal
BENTHAM SCIENCE PUBLISHERS
Amylases are important enzymes that break down complex carbohydrates to simple sugar molecules. They are important for digesting food and allowing the body mobilize carbohydrates for metabolism. Amylases are also commonly used commonly used as biocatalysts in many industries including food processing, detergents and pharmaceutical preparations. Indonesia is a net importer of amylases which has implications for the cost of relevant industrial processes and new product development. To reduce production costs, it is important to produce amylase locally using native microorganisms.
That is exactly what a team of chemists and biotechnologists at Universitas Negeri Malang, led by Eli Hendrik Sanjaya set out to do. An expert in wastewater processing and treatment, Dr. Sanjaya’s group attempted to isolate amylase-producing bacteria from the liquid waste of sugar local factories and optimize the production of the amylase enzyme.
The research team achieved this through seven stages: preparing samples, isolating amylase-producing bacteria, producing crude amylase extract, testing amylase activity, optimizing amylase production, determining the specific activity, and identifying the bacteria through genotyping.
The researchers successfully identified three bacterial isolates (G-7, G-8, and G-12) that produce amylase enzymes from sugar factory waste. They noted that the optimal conditions for amylase production were 37°C, at pH 7.0, during the exponential growth phase. Isolate G-8 produced the enzyme most efficiently at 24 hours with a specific activity of 0.198 U/mg. Isolates G-7 and G-12 reached their peak production at 48 hours, with specific activities of 0.108 U/mg and 0.208 U/mg, respectively.
16S rRNA gene analysis identified the three local strains as Bacillus infantis, Bacillus flexus, and Pseudomonas nitroreducens, respectively.
“All three species have shown great potential for amylase enzymes production,” notes Dr. Sanjaya. This is the impetus the local industry might need to drive industrial processes towards sustainability. “We can hopefully reduce amylase imports in Indonesia. To meet industrial demand, amylase enzyme activity can be increased by purifying the enzyme amylase from crude extract.”
Isolation and Characterization of Amylase Enzyme Produced by Indigenous Bacteria from Sugar Factory Waste
New method cracked for high-capacity, secure quantum communication
LIGHT PUBLISHING CENTER, CHANGCHUN INSTITUTE OF OPTICS, FINE MECHANICS AND PHYSICS, CAS
IMAGE:
THE SIGNAL PHOTON, MANIPULATED BY THE INTEGRATED PHOTONIC CIRCUIT, CREATES A 4D QUDIT REPRESENTED BY THE SET OF ORANGE SPHERES. MEANWHILE, THE IDLER PHOTON, REPRESENTED BY THE BLUE SPHERE, ACTS AS A REMOTE CONTROL FOR THE SIGNAL PHOTON.
CREDIT: BY HAOQI ZHAO, YICHI ZHANG, ZIHE GAO, JIEUN YIM, SHUANG WU, NATALIA M. LITCHINITSER, LI GE, AND LIANG FENG
Scientists have made a significant breakthrough in creating a new method for transmitting quantum information using particles of light called qudits. These qudits promise a future quantum internet that is both secure and powerful.
Traditionally, quantum information is encoded on qubits, which can exist in a state of 0, 1, or both at the same time (superposition). This quality makes them ideal for complex calculations but limits the amount of data they can carry in communication. Conversely, qudits can encode information in higher dimensions, transmitting more data in a single go.
The new technique harnesses two properties of light – spatial mode and polarization – to create four-dimensional qudits. These qudits are built on a special chip that allows for precise manipulation. This manipulation translates to faster data transfer rates and increased resistance to errors compared to conventional methods.
One of the key advantages of this approach is the qudits' ability to maintain their quantum properties over long distances. This makes them perfect for applications like satellite-based quantum communication, where data needs to travel vast distances without losing its integrity.
The process starts with generating a special entangled state using two photons. Entanglement is a phenomenon where two particles become linked, sharing the same fate regardless of physical separation. In this case, one photon (the signal photon) is manipulated on the chip to create a 4D qudit using its spatial mode and polarization. The other photon (idler photon) remains unchanged and acts as a remote control for the signal photon (Fig. 1). By manipulating the idler photon, scientists can control the state of the signal photon and encode information onto it (Fig. 2).
This new method has the potential to revolutionize the field of quantum communication. It paves the way for a high-speed quantum internet that can transmit massive amounts of data securely over long distances. Additionally, it can lead to the development of unbreakable encryption protocols and contribute to the creation of powerful quantum computers capable of tackling problems beyond the reach of classical computers.
The researchers are currently focusing on improving the accuracy of the qudits and scaling up the technology to handle even higher dimensions. They believe this approach has the potential to revolutionize quantum communication.
Fig. 2. State manipulation and information encoding of the signal photon.
(a) The experimentally retrieved (upper row) and theoretically predicted (lower row) density matrices of two selected quantum states. (b) Theoretically (left panel) and experimentally retrieved (right panel) probability-of-detection matrix.
CREDIT
by Haoqi Zhao, Yichi Zhang, Zihe Gao, Jieun Yim, Shuang Wu, Natalia M. Litchinitser, Li Ge, and Liang Feng
SCIENTISTS FROM THE NATIONAL UNIVERSITY OF SINGAPORE CONDUCTED SMELL TESTS WITH THE CATERPILLARS OF THE SQUINTING BUSH BROWN BUTTERFLY, BICYCLUS ANYNANA, AND FOUND THAT CATERPILLARS’ FOOD PREFERENCES ARE DETERMINED BY FACTORS, OR SUBSTANCES, PRESENT IN THEIR BLOOD AND THESE PREFERENCES COULD BE PASSED ON TO OFFSPRING THROUGH THE BLOODSTREAM.
CREDIT: ASSOCIATE PROFESSOR WILLIAM PIEL, YALE-NUS COLLEGE
Many caterpillars are known for their specific food preferences, which they bring with them when they morph into butterflies. For instance, the monarch butterfly only feeds on milkweed plants, while the Lime butterfly feeds on lime leaves. Despite deriving from a common ancestral species, these unique diet preferences are a point of interest for researchers at the National University of Singapore (NUS).
In an earlier study by researchers at the Department of Biological Sciences under the NUS Faculty of Science, they demonstrated that when caterpillars fed on leaves outside of their usual diet, they would prefer the smell of that type of plant after a few days. Remarkably, these caterpillars also passed on the acquired smell preference to their offspring.
Such a phenomenon is also seen in nature when caterpillars find themselves on a new food plant when the female butterfly lays eggs on the wrong plant by mistake. The new plant is edible but has a new smell, the caterpillars will learn to prefer this new smell and pass this preference on to their offspring. This type of inheritance may facilitate host switching and ultimately the formation of new species, each with their own food preferences.
“Since new food preferences develop in the brain of caterpillars, it was unclear how such preferences were inherited by their offspring,” explained Professor Antónia Monteiro, who led the research team.
Dr. V. Gowri, the PhD graduate who is first author of the study said, “Offspring develop from the fusion of two cells (an egg and a sperm) produced in the gonads of each parent, which are located far from the brain. It was unclear how a smell preference was communicated to these cells.”
To discover the factors that influence this adaptive behaviour, the research team conducted experiments and showed that the blood of the caterpillar, called haemolymph, which bathes both the brain and the reproductive organs, contains factors that promote the inheritance of the new smell preference.
The NUS team published their findings in the scientific journalBiology Letters on 15 May 2024.
The catepillar’s smell test
A caterpillar’s blood can mediate the transport of factors from the brain to the gonads, impacting smell preferences in the next generation. Alternatively, it could transport these factors from the food to the brain of the embryo in the next generation, if included in the sperm or egg cells that create that embryo.
To test if the blood of caterpillars contained such factors, the newly hatched caterpillars were fed either the plants containing the new smell or a control plant. Some catepillar’s blood was then collected from their body once they matured. The collected blood was injected into catepillars that did not consume either type of food.
From this experiment, the researchers observed that the catepillars that received the blood from the control-fed catepillars stuck to their usual menu. By contrast, those that received blood from catepillars fed with food containing the new smell started to lean towards this change in diet. Most interestingly, so did their offspring, born many days later.
“This was very surprising to us, as this experiment shows that learning a preference towards a smell can occur without the need for the smell to enter the caterpillar’s body via the antennae, as suggested in textbooks”, said Prof Monteiro.
These experiments suggest a possible mechanism that could help caterpillars switch their food preferences over the course of evolution. The researchers hope to further explore the mechanism of smell preference inheritance and isolate the specific factors being inherited from one generation to the next.
