(Press-News.org) A survey on larvae of Japanese wasps revealed that not only is their diet more diverse than previously thought, it also showed that wild colonies prey on more species of vertebrates than had been reported in the past. The Kobe University study highlights the potential for management practices that are sustainable both ecologically and culturally.
The wasp species Vespula shidai has long been reared for its edible larvae, a delicacy in central Japan. The rural woodlands of Japan which these wasps inhabit are areas of high biodiversity. Though this practice of rearing and consuming V. shidai larvae, known locally as hachinoko, has existed for decades, there is little knowledge on the difference in feeding habits between those that have been reared by humans and those that have been harvested in the wild, with only fragmentary updates since the mid-1950s. Now, advancements in genetic techniques have provided a clearer picture of the wasp’s dietary habits.
Kobe University entomologist SAGA Tatsuya and his team performed a study on the gut contents of larvae found in both wild and reared nests using DNA metabarcoding, a technique that can identify multiple species from a single sample. Saga says, “The research idea was inspired by my firsthand experience of eating the larvae of the giant hornet without removing the intestines and seeing that the intestines are filled with various creatures. As the beetle fragments jiggled in the mouth, I thought that examining the intestines will reveal what the wasps are eating.”
The results of this study, published in the Journal of Insects as Food and Feed, found that the wasps preyed on 324 different, including insects, arachnids, birds, mammals, reptiles, amphibians and fish. Although most nests from both subsets were shown to feed on mostly birds and mammals, the results showed significant differences in prey composition between wild and reared nests. In particular, a far greater variety of vertebrate species were captured in wild nests, suggesting that nutrient-rich vertebrate carcasses are vital to the wasps’ development. That said, both wild and reared nests showed similarly high levels of captured insect species, implying that wasps may retain their potential role in insect population control even under rearing conditions. What this also indicates is that reared wasps seem to be less reliant on wild carrion, which has the potential to alter carrion dynamics and alter the local scavenging ecosystem.
While DNA metabarcoding was necessary to identify specific species contained within the gut of the larvae, the difference in prey composition between the wild and reared subsets was so pronounced that those with extensive rearing experience could even taste it. As part of this study, a questionnaire survey was given to consumers of hachinoko, in which 58% of respondents with rearing experience answered that not only could they taste the difference, they often preferred wild hachinoko to their reared counterparts based on flavor and aroma. However, further studies are required to clarify the effects of rearing experience on taste perception.
On the significance of this research, lead researcher Saga says, “In recent years, food products based on indicators such as low environmental impact and high production efficiency have been the focus of attention, but I was made keenly aware once again of the value of a culture in which humans have lived in and interacted with nature and fed on its creatures.” This study, which integrates scientific insights and cultural traditions, is vital to ensuring both the ecological mindfulness and viability of wasp rearing, while also highlighting the potential for management practices that are both culturally informed and promote ecological sustainability. As this study was conducted exclusively in the autumn and with relatively few nests in a limited area, future studies should expand to different regions and seasons while further investigating social and cultural factors affecting feed choice to guide sustainable management of this unique delicacy.
This research was conducted in collaboration with researchers from Okayama University.
Kobe University is a national university with roots dating back to the Kobe Higher Commercial School founded in 1902. It is now one of Japan’s leading comprehensive research universities with nearly 16,000 students and nearly 1,700 faculty in 11 faculties and schools and 15 graduate schools. Combining the social and natural sciences to cultivate leaders with an interdisciplinary perspective, Kobe University creates knowledge and fosters innovation to address society’s challenges.
END
Hey vespids, what's for dinner? DNA analysis of wasp larvae’s diverse diet
2025-05-23
ELSE PRESS RELEASES FROM THIS DATE:
Street smarts: how a hawk learned to use traffic signals to hunt more successfully
2025-05-23
Many years ago, I got to spend some time in Ngorongoro Crater, a unique place in Africa where immense herds of animals are being watched by equally immense crowds of 4x4-riding tourists, and traffic jams of all kinds are frequent. On my last evening there, a local guide told me at a campfire that some buffalo in the crater had figured out the meaning of car turn signals and used that understanding to get out of the way of turning Jeeps and Land Rovers.
I never had a chance to return to the crater and still don’t know if that story was true, but it got me interested in animals’ perception of – and interactions with – human-made vehicles. Of course, the most ...
Muscle quality may hold clues to early cognitive decline
2025-05-23
Over the past decade, much research has focused on the connection between skeletal muscle health and cognitive disorders. Scientists have found that sarcopenia, a geriatric syndrome characterized by progressive loss of skeletal muscle mass and function, appears to be strongly associated with an elevated risk of dementia. The complex relationship between our muscles and brain health represents a promising frontier in preventive medicine, particularly as global populations continue to age.
However, to date, most studies on the link between muscle health and dementia have predominantly targeted elderly populations or individuals already diagnosed with cognitive impairment. ...
Autophagy and lysosomal pathways orchestrate unconventional secretion of Parkinson’s disease protein
2025-05-23
Intracellular protein trafficking and secretion of proteins into the extracellular environment are sequential and tightly regulated processes in eukaryotic cells. Conventionally, proteins that are bound for secretion harbor an N-terminal signal peptide that guides their movement from the endoplasmic reticulum (ER) and Golgi apparatus to the exterior of the cell. However, some proteins can bypass this system using unconventional mechanisms, including direct translocation across the plasma membrane, transporter-mediated ...
Mystery of “very odd” elasmosaur finally solved: one of North America’s most famous fossils identified as new species
2025-05-23
A group of fossils of elasmosaurs – some of the most famous in North America – have just been formally identified as belonging to a “very odd” new genus of the sea monster, unlike any previously known.
Long-necked and measuring in at 12 metres, Traskasaura sandrae – as it is officially named today in this new study – possessed heavy, sharp, robust teeth, ideal for crushing.
Findings, published in the peer-reviewed Journal of Systematic Palaeontology, highlight Traskasaura as having a strange mix of primitive and derived traits unlike any other elasmosaur.
Its unique suite ...
Half the remaining habitat of Australia's most at-risk species is unprotected
2025-05-23
Australia needs to urgently prioritise state and national conservation policies according to a new study, with the findings warning more than 220 critically endangered species are at risk of being lost due to their small distributions coupled with uneven protections.
In the first known study of its kind, the team led by Griffith University, assessed how much of each species’ habitat in Australia was outside protected areas and considered to have agricultural capability, potentially elevating risk of conversion.
They ...
Study reveals influence behind illegal bear bile consumption in Việt Nam
2025-05-23
SAN DIEGO (May 22, 2025) – A new scientific study led by San Diego Zoo Wildlife Alliance researchers sheds light on the social dynamics that drive the continued consumption of bear bile in Việt Nam, revealing that gift-giving among close social networks plays a crucial role in sustaining demand. The findings suggest that conservation efforts could be more effective if they focus on shifting behaviors within influential social groups rather than broad public awareness campaigns.
Bear bile, extracted from the gallbladders of Asiatic black bears and sun ...
Satellites offer new view of Chesapeake Bay’s marine heat waves
2025-05-23
Heat waves destroy crops, drive wildfires, and kill humans and wildlife, but these extreme weather events aren’t just limited to land. Large bodies of water can also be hit by heat waves that linger for weeks, months and sometimes years—much like “The Blob,” a sprawling hot spot off the U.S. West Coast that wreaked havoc on Pacific Ocean ecosystems from 2013 to 2016.
New University of Maryland-led research reveals that the Chesapeake Bay has seen “significant increases” in annual marine heat waves, defined in the study as “prolonged periods of anomalously warm water.” Published in the journal Estuaries and Coasts, the study leveraged ...
Experimental drug may benefit some patients with rare form of ALS
2025-05-22
NEW YORK, NY (May 22, 2025)--When Columbia neurologist and scientist Neil Shneider speaks to his ALS patients who volunteer for experimental therapies, he’s unwaveringly honest. “Patients always ask me, “What can I hope to get out of this?” Shneider says. “And I always say, in most clinical trials, our hope is that we can slow the disease or maybe even halt progression.”
So it was a big surprise when some of the patients treated with an experimental drug—a therapy that emerged from Shneider’s research efforts—showed improvements.
“When testing new drugs for ALS, we do not expect to ...
Early testing could make risky falls a thing of the past for elderly people
2025-05-22
As we get older, our bodies stop performing as they once did. We aren’t as strong as we once were, we don’t see as well as we used to and we start becoming less mobile. These changes inevitably lead to almost a third of people over the age 65 falling each year, resulting in injuries and occasionally death. In the United States alone, it costs the healthcare system billions of dollars annually. However, while aging is a certainty, falling may be preventable. ‘One big challenge is that small balance impairments can go unnoticed until someone actually falls. So, we wanted to ask: Can we detect these impairments before someone gets hurt?’ explains Jiaen ...
A rule-breaking, colorful silicone that could conduct electricity
2025-05-22
Images
A newly discovered silicone variant is a semiconductor, University of Michigan researchers have discovered—upending assumptions that the material class is exclusively insulating.
"The material opens up the opportunity for new types of flat panel displays, flexible photovoltaics, wearable sensors or even clothing that can display different patterns or images," said Richard Laine, U-M professor of materials science and engineering and macromolecular science and engineering and corresponding author ...