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Wildlife & Nature

Scientists Fight Tree-Killing Beetle with Beetle-Killing Wasps

The emerald ash borer is responsible for the destruction of tens of millions of ash trees in 30 states. (istock)
The emerald ash borer is responsible for the destruction of tens of millions of ash trees in 30 states. (istock)

By ecoRI News staff

When the invasive emerald ash borer, a beetle native to Asia, was found in Rhode Island in 2018, it was a sign that most of the state’s mature ash trees were likely to die soon. Now a team of entomologists from the University of Rhode Island is fighting the invader with predatory wasps from its native land in hopes that the region’s next generation of ash trees will survive.

Lisa Tewksbury, director of the URI Biocontrol Laboratory, and her students have been on the lookout for the emerald ash borer for more than a decade, soon after it was first discovered in the United States in Michigan. Now that they know it’s here, they are deploying three species of parasitic wasp from Asia that lay their eggs in the beetle’s eggs or larvae. When the wasp eggs hatch, the wasp larvae consume the beetle eggs and larvae from the inside.

“The beetle doesn’t have any natural enemies in the U.S., so we’re reuniting it with its natural enemies from back where it came from,” Tewksbury said. “We’re using one organism to control another.”

The parasitic wasps — they don’t have common names, but their Latin names are Oobius agrili, Tetrastichus planipennisi, and Spathius galinae — have been extensively tested to ensure that they will only prey upon emerald ash borers. They are being raised at a federal laboratory in Michigan and shipped to Rhode Island as pupae that are about to become adult wasps inside blocks of ash wood, which the URI team delivers to areas where the beetle has previously been found. Once there, the wasps will emerge and lay eggs in beetle larvae in the ash trees nearby.

Tewksbury has a permit from the U.S. Department of Agriculture to release the wasps in targeted locations.

Ash trees make up just 2 percent of forests in Rhode Island, but they are found extensively in parks and along streets throughout the state.

“The emerald ash borer isn’t a huge concern for our forests,” Tewksbury said. “But it will be a concern to people who have ash trees in their yards and on their streets. There are a lot of them in Newport and Providence.”

Last year, Tewksbury released the three parasitic wasps in Hopkinton, near where the beetles were first discovered, and this year they are being released in five additional locations in Burrillville and Cumberland. The last round of releases for this year are taking place this month, and ongoing statewide surveillance for the beetle will indicate where additional wasp releases may take place next year.

Next year will also be the beginning of an effort to determine if the wasps have become established and are doing their job. Tewksbury will peel back the bark of dead and dying ash trees to see if she can find evidence of dead beetle larvae.

“We are resigned to the fact that we’re going to lose most of our larger ash trees, but by doing this biological control effort we’re hoping the wasps can protect the smaller trees so we’ll have some ash left in the future,” Tewksbury said.

Targeted biocontrol efforts such as this are often the most cost-effective and least damaging way of fighting invasive insects, according to Tewksbury. Her lab is involved in testing another predatory wasp for possible future deployment against what she expects will be the state’s next harmful pest, the spotted lanternfly, another tree-killing invasive species from Asia that is expected to arrive in Rhode Island in two or three years.

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Sterile fruit flies contribute to reduction in Queensland fruit fly population

Releases of sterile fruit flies at two Australian locations have significantly reduced Queensland fruit fly numbers.

The pilot, which ran from September 2019 to mid-April 2020 in Hillston, NSW and Cobram, VIC involved releasing sterile fruit flies each week from a plane and is part of the Hort Innovation research project – Post Factory Pilot of SITPlus Fly production.*

Cobram agronomist Russell Fox said, “The sterile fruit fly releases have worked well so far and are widely supported by local growers and community. The program is a very useful complement to the regional fruit fly management strategy.”

Goulburn Murray Valley Regional Fruit Fly Coordinator Ross Abberfield said, “The timing of the SITPlus project has been ideal to fit in with our area wide management activity.

“In Cobram, the sterile fruit fly releases contributed to an 83% reduction in Queensland fruit fly activity.”

Plant and Food Research New Zealand Plant and Food Scientist, Lloyd Stringer said, “The rate of capture of wild male Queensland fruit fly in traps is on average 10 times higher in Mooroopna than in Cobram where sterile flies are being used.”

In Hillston, initial analysis indicates wild Queensland fruit fly were detected in very low numbers in town and almost undetected on nearby farms. Residents claimed they were able to eat their backyard fruit for the first time in years.

The project is a pilot that enables grower groups to confidently consider the Sterile Insect Technique, or SIT, for management of Queensland fruit fly. The project is testing efficacy of Queensland fruit fly SIT in the field and rearing sterile flies in localised centres. It’s also testing the development of quality control procedures in the dedicated rearing out centres. The project also underpins economic modelling for future operational Queensland fruit fly SIT use.

Hort Innovation SITPlus Program Director Dan Ryan said, “A well-established method of pest insect control, the sterile insect technique is based on the mass rearing, sterilisation, and release of targeted pest insects. Once released in the environment, the sterile insects’ mate with their wild counterparts which disrupts reproduction and suppresses pest population numbers.”

Ross Abberfield said, “In the Goulburn-Murray Valley, an area-wide management program coordinated through Moira Shire Council has been in place since June 2017. This activity has included the removal of feral fruit trees, abandoned orchards, and neglected urban trees on both public and private land. This non-SIT area-wide management program activity has shown that Queensland fruit fly activity has reduced by 57%.”

Dan Ryan said, “The area-wide program has been an important contribution to achieving Cobram’s outstanding success.”

Season two of the SITPlus Pilot begins in mid-September and will continue through to April 2021.

Publication date: Tue 8 Sep 2020

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ARS News ServiceSpotted lanternfly adult and nymphs on a tree branchSpotted lanternfly winged adult and nymphs.ARS Scientists Seek Answers from Spotted Lanternfly DispersalFor media inquiries contact: Autumn Canaday, (202) 669-5480
September 11, 2020The black spots and beautiful colors can be deceiving.At first glance, the Spotted Lanternfly (Lycorma delicatula) is a beautiful insect whose colors mimic the beloved ladybug with its polka-dotted outer wings and red hind wing. But this is not the family-friendly insect that people love to see crawling on their wrist or captured in a framed print in a powder room.The Spotted Lanternfly is an invasive species that destroy fruit crops, trees and plants by hopping from plant to plant, crop to crop, and tree to tree. Although native to regions in China, India, and Vietnam, it was first detected in Berks County, Pennsylvania in 2014. Since then, Pennsylvania vineyards have seen considerable damage in high infestation areas and the Mid-Atlantic states of Delaware, Maryland, New Jersey, Virginia and West Virginia have also suffered from its presence. Insecticides are effective at killing the insect on grapevines, but they are expensive and of limited use because of constant re-infestation from the Spotted Lanternfly dispersing from wild hosts to surrounding vineyards.The good thing is that the Spotted Lanternfly isn’t known to bite or sting—but they are known to ruin an agricultural harvest. So, U.S. Department of Agriculture Scientists Dr. Tracy Leskey and Dr. Laura Nixon of the Appalachian Fruit Research Station in Kearneysville, West Virginia, initiated research on the invasive pest to see if they could develop sustainable pest management strategies and use the insect’s dispersal patterns for other prolific specialty crop pests.Leskey and Nixon collected Spotted Lanternfly nymphs and adults from host plants in sites within a quarantine zone in Virginia. They then measured the pest’s vertical climbing and horizontal jumping capacity and evaluated the effect of fluorescent marking powders on the nymph and adult’s mobility and ability to survive. Each color of powder (green, blue, orange, and pink) was tested at least twice per host plant. When the presence of fluorescent powder wasn’t visible, a UV flashlight was shone onto a nymph to confirm fluorescence. To establish baseline vertical walking and horizontal jumping dispersal capacity, Leskey and Nixon also evaluated all mobile life stages using bioassays conducted under field conditions in the quarantine zone.The findings were surprising. Spotted Lanternfly nymphs climbed significantly longer vertical distances compared with adults, while early adults (pre-oviposition period) jumped longer horizontal distances compared with nymphs or late adults (oviposition period) based on single jump measurements. The research also showed that marking nymphs and adults with fluorescent powder has no significant effect on vertical or horizontal movement and did not affect their mortality. Rather, research showed that the pest can be marked with fluorescent powders and retrieved from potted host plants within 24 hours. This means that marking the Spotted Lanternfly with fluorescent powder can serve as an appropriate method for measuring their dispersal in the environment. This can ultimately help researchers understand the Spotted Lanternfly’s migration pattern and find a way to prevent future movement and destruction.Dr. Leskey and Dr. Nixon are currently working to continue their research of Spotted Lanternfly dispersal behavior so they can continue to deliver scientific solutions to national and global agricultural challenges.The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.Interested in reading more about ARS research? Visit our news archiveU.S. DEPARTMENT OF AGRICULTURE
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Aphelenchoides besseyi

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EPPO Datasheet: Aphelenchoides besseyi

Last updated: 2020-07-24

IDENTITY

Preferred name:Aphelenchoides besseyi
Authority: Christie
Taxonomic position: Animalia: Nematoda: Chromadorea: Rhabditida: Aphelenchoididae
Other scientific names: Aphelenchoides oryzae Yokoo, Asteroaphelenchoides besseyi (Christie) Drozdovski
Common names in English: rice leaf nematode, rice white-tip nematode, strawberry crimp disease nematode, white-tip nematode
view more common names online…
Notes on taxonomy and nomenclature

The taxonomy used in this datasheet reflects developments suggested by several recent publications, summarised in Decraemer & Hunt (2013), which place Aphelenchoides in the Order Rhabditida, Suborder Tylenchina. This contrasts with the taxonomy nomenclature occasionally used by some authors (such as the CABI Invasive Species Compendium CABI, 2019; Wheeler & Crow, 2020), which place Aphelenchoides in the Order Aphelenchida, Suborder Aphelenchina (Hunt, 1993). Whilst this makes no difference to classification from the level of Superfamily (Aphelenchoidea) to species level (Aphelenchoides besseyi), those studying the species might need to be aware of differences in the literature.EPPO Categorization: A2 list
EU Categorization: RNQP (Annex IV)
view more categorizations online…
EPPO Code: APLOBE HOSTS 2020-07-24 GEOGRAPHICAL DISTRIBUTION 2020-07-24 BIOLOGY 2020-07-24 DETECTION AND IDENTIFICATION 2020-07-24 PATHWAYS FOR MOVEMENT 2020-07-24 PEST SIGNIFICANCE 2020-07-24 PHYTOSANITARY MEASURES 2020-07-24 REFERENCES 2020-07-24 ACKNOWLEDGEMENTS 2020-07-24 How to cite this datasheet? Datasheet history 2020-07-24

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Matt Hayes:

‘Researchers help inform cassava breeding worldwide’

“Scientists in Cornell’s NextGen Cassava project have uncovered new details regarding cassava’s genetic architecture that may help breeders more easily pinpoint traits for one of Africa’s most vital crops.

Their findings are reported in a study published July 31 in Plant Molecular Biology.

The scientists analyzed large breeding populations measured extensively over successive years and stages of selection in multi-environment field trials in Nigeria. The genome-wide association analysis explored genomic regions most responsible for desirable traits in cassava, a food crop that provides the main source of calories for 500 million people across the globe.

The scientists found more than 40 quantitative trait loci associated with a total of 14 traits, responsible for characteristics such as disease responses, nutritional quality and yield. The traits were classified broadly into four categories – biotic stress, quality, plant agronomy and agro-morphology.

“Our findings provide critical new entries into the catalogue of major loci available to cassava breeders,” said Ismail Rabbi, a molecular geneticist and plant breeder at the International Institute of Tropical Agriculture (IITA) and a member of the NextGen project. “These markers should greatly improve cassava research and provide another powerful tool for the breeders’ toolbox.”

“Cassava is an incredibly useful food and industrial crop today and will be more so in the future as climate change reshapes agriculture everywhere, but first we must better understand its complex genome,” said Chiedozie Egesi, NextGen program director and co-author on the study.

Based in the Department of Global Development, the NextGen Cassava Breeding project supports scientists from many disciplines with advanced technologies and methods. The project works to empower smallholder cassava farmers in sub-Saharan Africa by developing, releasing and distributing improved cassava varieties.

Plant diseases and pests like cassava mosaic disease (CMD) and cassava green mite are major constraints to cassava production in Africa, India and across Asia, including Vietnam and Thailand. Infections of CMD can lead to yield losses of 82%, or more than 30 million tons each year.

“A complete understanding of cassava’s genetic architecture is the critical step needed to accelerating genetic improvement and bring lasting benefits to farmers and consumers who depend on this crop for food and income throughout the world,” said Egesi, who’s also a visiting scientist in the Department of Global Development and an adjunct professor of plant breeding and genetics in the School of Integrative Plant Science, in the College of Agriculture and Life Sciences.

While the findings revealed novel genomic regions, it also revealed additional markers associated with previously measured traits.

Data from the study was made freely available through several commercial genotyping service vendors. The scientists plan further studies using germplasm from other regions, including East Africa and Latin America, which they say should bolster the catalogue of major effect loci available for molecular breeding.

Study co-authors include Cornell adjunct professor Jean-Luc Jannink and researchers from IITA and the National Root Crops Research Institute in Nigeria. Researchers from the Boyce Thompson Institute and the U.S. Department of Agriculture-Agriculture Research Service also contributed.

NextGen Cassava is funded by the Bill & Melinda Gates Foundation and by UK Aid, a British government initiative.

Matt Hayes is associate director for communications for Global Development in the College of Agriculture and Life Sciences.”

By Matt Hayes for Cornell University

Publication date: Thu 27 Aug 2020

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Dear friends and colleagues,

I want to share with you an open-access book that I co-edited for the Earthscan Food and Agricultural series of the publisher Taylor and Francis/Routledge.

The book is entitled “Transforming Agriculture in Southern Africa”. It contains 34 short chapters written by experts and covers a wide range of topics across scientific fields dealing with agriculture of the smallholder farmer.

The book targets Southern Africa but the chapters are designed to be of importance where ever smallholder farmers are fighting for food security and survival.

The book can be downloaded as a pdf file or read online in order to save space on the computer.

The Link:       https://urldefense.proofpoint.com/v2/url?u=https-3A__www.taylorfrancis.com_books_e_9780429401701&d=DwID-g&c=Cu5g146wZdoqVuKpTNsYHeFX_rg6kWhlkLF8Eft-wwo&r=20cHrmWg3G9lvuF1XJ0DAVTU8QbZGlMPZmMplM_ZfXU&m=2nE3aWaVBmOKJun642gNsk6je4V0RG1jcd6z56IyIDE&s=XApFy5Tvt8DCmUqsZKLsFDAGckvFsFJQDoPn0fjzcXU&e=

Please send this link to your colleagues and if you have access to Newsletters of organizations working in international development in agriculture please forward it to them too.

I hope you can use the book in your work and maybe even in classes for students.

Best regards

Richard Sikora

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Presented by Michigan State University

The COVID-19 Pandemic has greatly impacted agricultural research systems worldwide. In numerous countries,
the research programs have been disrupted. The research institutions around world have taken positive steps to
continue their research programs while safeguarding the health of research personnel. A distinguished global
panel from USA, Asia, Africa, Middle-East, Europe and Latin America will share their experiences and innovations
in managing research programs amid COVID-19 Pandemic.
The webinar will discuss and share experiences on the following broad areas:
• Impacts of COVID-19 Pandemic on disruptions of agricultural research systems worldwide.
• How research programs in different countries have addressed and continued research activities during
COVID-19 Pandemic.
• What innovative approaches and guidelines have been developed and implemented by various
research institutions worldwide.
• Challenges faced, Lessons Learned and ideas for improvements for the future.
SPEAKER PANEL
ORGANIZED BY MICHIGAN STATE UNIVERSITY COLLEGE OF AGRICULTURE AND NATURAL RESOURCES AND MSU AGBIORESEARCH
Panel Lead/Moderator:
Dr. Douglas Buhler, Director, AgBioResearch, Assistant Vice President of Research and Innovation, Michigan State
University, East Lansing, USA
Panel Members:
• Dr. George Smith, Associate Director, AgBioResearch, Michigan State University, East Lansing, USA.
• Dr. Ben Durham, Chief Director, Bio-Innovation, Department of Science and Technology, Pretoria, South Africa.
• Dr. Ashok Kumar Singh, Director, Indian Agriculture Research Institute (IARI), New Delhi, India.
• Dr. Shireen Assem, Vice President, Agriculture Research Center (ARC), Giza, Cairo, Egypt.
• Professor Bob Doherty, N8 AgriFood Chair, University of York, United Kingdom (UK).
• Dr. Dilson Antônio Bisognin, Professor, Universidade Federal de Santa Maria, Camobi, Santa Maria, Brazil.
• Dr. Andi Trisyano, Professor, Faculty of Agriculture, University of Gadjah Mada, Yogyakarta, Indonesia.
REGISTER TO ATTEND
https://msu.zoom.us/webinar/register/WN_gFQhrcuHT9uOaD7bMF3VCA

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Phys.Org

AUGUST 13, 2020

Insect diversity boosted by combination of crop diversity and semi-natural habitats

by British Ecological Society

crop
Credit: CC0 Public Domain

To enhance the number of beneficial insect species in agricultural land, preserving semi-natural habitats and promoting crop diversity are both needed, according to new research published in the British Ecological Society’s Journal of Applied of Ecology.

The study, by researchers in Sweden, the UK, Italy, Germany, Spain and France, found that increasing the diversity of crops in agricultural landscapes increased the diversity of beneficial insects such as pollinators. However, this benefit was only seen in landscapes with high proportions of semi-natural habitats such as forests and grassland.

In landscapes with both high crop diversity and semi-natural habitat cover, the researchers observed an increased diversity of ground beetle species as well as pollinators like bees and hoverflies. These insects have the potential to benefit crops through predating pests or pollinating flowering crop plants, both important for crop yields.

The same effects were not found for spiders, which surprised the researchers. “We expected pollinators to benefit because they are a highly mobile species, but the difference between ground beetles and spiders is harder to explain since both share similar adaptations to inhabit local crops.” said Guillermo Aguilera of the Swedish University of Agricultural Sciences and lead author of the study.

Many beneficial insects and invertebrates are in decline, partly due to intensive crop management practices and a loss of semi-natural habitats from agriculture land, meaning the results have important implications. Guillermo Aguilera said: “We show that increasing local insect communities is possible in landscapes with semi-natural habitats by increasing crop diversity. Therefore, reducing the arable land and increasing semi-natural habitats is not always the only way for obtaining benefits from insects.”

Insects and other invertebrates provide important ecosystem services. “Ground beetles and spiders are predators of species that can become pests. Wild pollinators have one of the most important roles in flowering crops. Both services, pest control and pollination, are important for the final crop yield.” explains Guillermo Aguilera.

A greater diversity of crops may benefit pollinators through giving them a more varied and continuous food source. Oilseed rape, the most abundant flowering crop in the study area, provides massive resources for pollinators. However, its flowers are only open for a short period of time. Growing other crops that flower throughout the year could help support pollinators.

Semi-natural habitats provide nesting sites and additional food for both pollinators and predators. They’re likely to be particularly beneficial to mobile species of ground beetles which often colonise crop fields from these habitats.

The researchers compiled data from seven previous studies that looked at invertebrate abundances in crop fields. The data spanned 154 crop fields in southern Sweden, an area consisting of arable land and semi-natural habitats, like grassland and woodland, between 2007 and 2017.

“The ultimate goal was to investigate the effect of crop diversity in the landscape with local communities of invertebrates” said Guillermo Aguilera. “After obtaining the invertebrate information and the coordinates of the fields where they were collected, we analysed the diversity of crops present in the landscape at the time of the sampling as well as the amount of semi-natural habitats such as grasslands.”

The research focussed on southern Sweden, the most agriculturally important region in the country in terms of crop production. While this gave the researchers a large study area, they acknowledge that it’s hard to generalise the results to a more global landscape.

Guillermo Aguilera said “It would be interesting to see what happens in other landscapes with a higher crop diversity by default than Sweden. It would also be interesting to look at how invertebrate communities respond to other forms of diversification in agriculture landscapes. For instance, the management of certain crops is something that can vary a lot between countries or regions.”


Explore furtherSmaller farm fields can reduce biodiversity loss and increase wild plants, birds, beetles, and bats


More information: Guillermo Aguilera et al, Crop diversity benefits carabid and pollinator communities in landscapes with semi‐natural habitats, Journal of Applied Ecology (2020). DOI: 10.1111/1365-2664.13712Journal information:Journal of Applied EcologyProvided by British Ecological Society4 shares

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Science News

NEWSARCHAEOLOGY

The oldest known grass beds from 200,000 years ago included insect repellents

The ancient bed remnants include fossilized grass, bug-repelling ash and aromatic leaves

South Africa’s Border Cave
South Africa’s Border Cave, shown here at its entrance, contains bits and pieces of the oldest known grass bedding, dating to around 200,000 years ago, researchers say.A. KRUGER

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By Bruce Bower

AUGUST 13, 2020 AT 2:00 PM

People living in southern Africa around 200,000 years ago not only slept on grass bedding but occasionally burned it, apparently to keep from going buggy.

Remnants of the oldest known grass bedding, discovered in South Africa’s Border Cave, lay on the ashes of previously burned bedding, say archaeologist Lyn Wadley of the University of the Witwatersrand in Johannesburg and her colleagues. Ash spread beneath bound bunches of grass may have been used to repel crawling, biting insects, which cannot easily move through fine powder, the researchers report in the Aug. 14 Science. Wadley’s team also found bits of burned wood in the bedding containing fragments of camphor leaves, an aromatic plant that can be used as a bug repellent.

Prior to this new find, the oldest plant bedding — mainly consisting of sedge leaves, ash and aromatic plants likely used to keep insects away — dated to around 77,000 years ago at South Africa’s Sibudu rock-shelter.

At Border Cave, chemical and microscopic analyses of excavated sediment showed that a series of beds had been assembled from grasses, such as Guinea grass and red grass. Guinea grass currently grows at Border Cave’s entrance. Bedding past its prime was likely burned in small fire pits, the researchers suspect. Remains of fire pits were found not far from Border Cave’s former grass beds.

Grass fragments uncovered in South African cave
Preserved grass fragments uncovered in a South African cave, left, are by far the oldest known examples of grass bedding, researchers say. Close-up images of those fragments taken by a scanning electron microscope, such as the one shown at right, helped to narrow down what type of grasses were used for bedding.L. WADLEY

Humans in southern Africa intentionally lit fires by around 1 million years ago (SN: 4/2/12). But Border Cave provides the first evidence that ancient grass bedding was burned on purpose.

Small, sharpened stones were also found among grass and ash remains, suggesting that people occasionally sat on cave bedding while making stone tools.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

L. Wadley et al. Fire and grass-bedding construction 200 thousand years ago at Border Cave, South Africa. Science. Vol. 369, August 14, 2020, p. 863. doi: 10.1126/science.abc7239.

Bruce Bower

About Bruce Bower

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeolo

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Science News

Water beetles can live on after being eaten and excreted by a frog

One insect crawled through the amphibian’s insides in just six minutes

Pond frog
This pond frog (Pelophylax nigromaculatus) makes easy prey of water beetles. But one beetle species (Regimbartia attenuate) can escape predation by traversing the amphibian’s digestive tract and emerge, still kicking, out the other end.SHENJI SUGIURA

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By Jonathan Lambert

AUGUST 3, 2020 AT 11:00 AM

For most insects, the sticky, slingshot ride straight into a frog’s mouth spells the end. But not for one stubborn water beetle.

Instead of succumbing to the frog’s digestive juices, an eaten Regimbartia attenuata traverses the amphibian’s throat, swims through the stomach, slides along the intestines and climbs out the frog’s butt, alive and well.

“This is legitimately the first article in a while that made me say, ‘Huh! How weird!’” says Crystal Maier, an entomologist at Harvard University’s Museum of Comparative Zoology. “There are still a lot of truly bizarre habits of insects that still wait to be discovered,” she says.

Surviving digestion-by-predator is rare, but not unheard of in the animal kingdom. Some snails survive the trip through fish and birds by sealing their shells and waiting it out. But research published August 3 in Current Biology is the first to document prey actively escaping through the backside of a predator.

Feeding beetles to predators to see what happens is a regular activity for Shinji Sugiura, an ecologist at Kobe University in Japan. In 2018, he discovered that bombardier beetles can force toads to vomit the insects back up by releasing a mix of hot, noxious chemicals from their rear ends (SN: 2/6/18). 

On a hunch that R. attenuata might have evolved its own interesting evasive behaviors, Sugiura paired a beetle with a frog that the insect often encounters while swimming through Japanese rice paddies. In his laboratory, he watched.

The frog made easy prey of the unsuspecting beetle. While the amphibians lack teeth that could kill prey with a crunch, a trip through the acidic, oxygen-poor digestive system should be sufficient to neutralize the insect. But as Sugiura monitored the frog, he saw the shiny black beetle slip out from the frog’s behind and scurry away, seemingly unharmed.https://www.youtube.com/embed/_W0UJD_i3Mo?feature=oembed&enablejsapi=1&origin=https:%2F%2Fwww.sciencenews.orgAbout two hours before this video begins, this pond frog (Pelophylax nigromaculatus) ate a water beetle (Regimbartia attenuata). After traversing the digestive tract, the beetle emerges from the back end of the amphibian, alive. It’s the first documented example of prey actively escaping a predator through the digestive system.

“I was very surprised,” he says. “I was expecting that the frogs might just spit out the beetles or something.”

After more than 30 additional beetle-frog pairings, Sugiura found that over 90 percent of beetles survived being eaten, greatly outshining other animals known to survive digestion-by-predator. Those creatures typically survive less than 20 percent of the time. On average, it took six hours for the beetles to escape, though one intrepid individual completed the journey in just six minutes. 

Sugiura confirmed that the beetles were actively escaping from the frog’s digestive tract by using sticky wax to fix some beetles’ legs together. None of these immobilized beetles survived, and their carcasses took a day or longer to pass through the frogs.

R. attenuata’s aquatic lifestyle likely prepared the beetle to survive digestion, Sugiura says. Its streamlined, but sturdy, exoskeleton may shield the insect from digestive juices. And its ability to breath underwater via air pockets tucked under its hardened wings likely prevents suffocation.

Sugiura plans to test the limits of R. attenuata’s abilities by pairing the insect with larger frogs, toads and even fish. “I’m looking forward to finding unimaginable types of antipredator defense,” he says.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

S. Sugiura. Active escape of prey from predator vent via the digestive tractCurrent Biology. Published online August 3, 2020. doi: 10.1016/j. cub.2020.06.026.

S. Wada, K. Kawakami and S. Chiba. Snails can survive passage through a bird’s digestive systemJournal of Biogeography. Vol. 39, January 2012, p. 69. doi: 10.1111/j.1365-2699.2011.02559.x.

R.J. Brown. Freshwater mollusks survive fish gut passageArctic. Vol. 60, June 2007, p.  124. http://www.jstor.org/stable/40513128.

About Jonathan Lambert

Jonathan Lambert is the staff writer for biological sciences, covering everything from the origin of species to microbial ecology. He has a master’s degree in evolutionary biology from Cornell University.

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