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Cousin of crop-killing bacteria mutating rapidly

Citrus-destroying bacterial relative may also be infectious

AUTHOR:JULES BERNSTEIN

August 12, 2022

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A bacterial species closely related to deadly citrus greening disease is rapidly evolving its ability to infect insect hosts, and possibly plants as well.

Asian citrus psyllid
Asian citrus psyllids, which transmit Liberibacter bacteria to citrus trees. The new Liberibacter species was found in a related type of psyllid. (California Department of Food and Agriculture)

The newly identified species belongs to Liberibacter, a family of bacteria known to infect several economically important crops. There are nine known Liberibacter species, including one that infects potatoes and three that are associated with citrus greening. 

Citrus greening, also known as Huanglongbing, is the number one killer of citrus trees worldwide. Though many are working on solutions, there is presently no effective prevention or treatment option on the market. 

Given its relatives’ destructive qualities, UC Riverside scientists set out to understand the ways the new species, L. capsica, genetically resembles other types of Liberibacter. 

“As with new strains of COVID-19, bacteria become variants of concern if their mutations can impact pathogenic or transmissible properties,” said Allison Hansen, UCR entomologist and study lead. 

peppers
Peppers like the ones in Brazil on which a pair of psyllids were found harboring L. capsica.
​(PierreSelim)

Many Liberibacters share genes that enable their ability to live inside a host. 

“These bacteria acquire DNA from their hosts, so without a host, they’re gone, they will die,” Hansen said. 

For this study, the research team identified 21 genes in L. capsica that are rapidly evolving amino acid mutations associated with infectious qualities. This evolution is documented in a new Microbiology Spectrum journal paper

One subset of mutations the team found repeatedly are on genes affecting pilus, tiny bacterial “hairs” that allow the bacteria to move into host insects and uptake DNA. Insects then transmit the bacteria to plants.

L. capsica was found by chance in a pair of flying insects on a pepper plant in Brazil. These insects, psyllids, are known pepper pests. However, it’s not yet known whether L. capsica infect peppers or other crops.

Gathering direct evidence about whether the bacteria infect pepper tissues may prove difficult, as Hansen’s team only had a single sample, and L. capsica cannot be grown in a laboratory.

The psyllids were collected in Brazil by Diana Percy, an entomologist at the University of British Columbia and Hansen’s frequent collaborator. Percy travels the world searching for psyllids but did not know these would harbor novel bacteria. That discovery was made in Hansen’s laboratory after Percy shared the psyllids she obtained abroad.

potato psyllid
The potato psyllid infects a potato plant with L. solanacearum, the bacteria causing zebra chip disease. (Whitney Cranshaw/Colorado State University)

“We’re informing scientists in Brazil and other places to screen plants for it,” Hansen said. “It should be on everyone’s radar for outbreak potential given the propensity of Liberibacter for being serious plant pathogens on domesticated crops.”

Integral to this study was the work of Ariana Sanchez, a UCR undergraduate microbiology major interested in bacterial pathogens transmitted by insects. Sanchez is the entomology department’s first Inclusivity Scholar. 

The department created the Advancing Inclusivity in Entomology scholarship in response to the Black Lives Matter movement and death of George Floyd in 2020. Faculty recognized the need to support students from marginalized groups who have a passion for studying insects but face systemic barriers excluding them from research opportunities. 

By helping identify the ways in which L. capsica is evolving, Sanchez has made an important contribution to Liberibacter knowledge. 

“Being able to understand pathogens like these, and how they interact with the insects that carry them, is so critical for the security of our food supply,” Hansen said. 

Cover image: Fruit infected with citrus greening. (emarys/iStock/Getty)

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Parasitic behavior of the root-knot nematode is negatively regulated by root-derived volatiles of C. metuliferus

by Nanjing Agricultural University The Academy of Science

<img src="https://scx1.b-cdn.net/csz/news/800a/2022/parasitic-behavior-of.jpg&quot; alt="Parasitic behavior of the root-knot nematode is negatively regulated by root-derived volatiles of the cucumber wild relative Cuc" title="Behavioral response of J2 nematodes to XTMC and CM3 root tips. a Schematic representation of XTMC and CM3 root tips for in vitro chemotaxis assays. b Comparison of the number J2s per root tip of XTMC and CM3 at 6 hours post-inoculation. Data are presented as means ± standard deviation (n = 33). **P 
Behavioral response of J2 nematodes to XTMC and CM3 root tips. a Schematic representation of XTMC and CM3 root tips for in vitro chemotaxis assays. b Comparison of the number J2s per root tip of XTMC and CM3 at 6 hours post-inoculation. Data are presented as means ± standard deviation (n = 33). **P < .01 (Wilcoxon signed rank test). c J2s around root tips of XTMC and CM3 at 6 hours post-inoculation. Credit: Nanjing Agricultural University

Recently, scientists from the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Science provided new insights into the correlation between cucurbit root volatiles and root-knot nematode parasitism, paving the way for development of more sustainable cucumber production.

The researchers used the resistant C. metuliferus line CM3 and the susceptible cucumber line Xintaimici (XTMC) as study materials. CM3 roots repelled second-stage (J2) larvae of Meloidogyne incognita, whereas the roots of XTMC plants attracted the larvae. CM3 and XTMC were found to contain similar amounts of root volatiles, but many specific volatiles, including nine hydrocarbons, three alcohols, two aldehydes, two ketones, one ester, and one phenol, were detected only in CM3 roots.

One of these specific volatiles, (methoxymethyl)-benzene, repelled M. incognita, whereas creosol and (Z)-2-penten-1-ol attracted it. Interestingly, creosol and (Z)-2-penten-1-ol effectively killed M. incognita at high concentrations. The researchers also found that a mixture of CM3 root volatiles increased cucumber resistance to M. incognita.

“This is the first study on volatile compounds in the roots of cucurbitaceous crops. The results provide insights into the interaction between the host and plant-parasitic nematodes in the soil, studying why C. metuliferus repels nematodes and whether there are any substances that can help cucumber avoid nematode infection or kill nematodes around roots is of great significance to cucumber production, which can be used to manage nematodes,” said the authors.

The study was published in Horticulture Research.


Explore further

Tomato plants are more resistant against nematodes when colonized by a fungus


More information: Xiaoxiao Xie et al, Negative regulation of root-knot nematode parasitic behavior by root-derived volatiles of wild relatives of Cucumis metuliferus CM3, Horticulture Research (2022). DOI: 10.1093/hr/uhac051

Using a natural enemy to kill brown marmorated stink bug eggs

by CABI

 Cultivating Anastatus japonicus Ashmead to fight the brown marmorated stink bug
Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae) attacking factitious host eggs. Credit: Jin-Ping Zhang

A study involving scientists from the Chinese Ministry of Agriculture and Rural Affairs (MARA)-CABI Joint Laboratory (Joint Lab) has highlighted the mass rearing capabilities of a natural enemy to fight the brown marmorated stink bug pest.

Dr. Feng Zhang, CABI’s Regional Director, East & South-East Asia, led research which shows how the solitary egg endoparasitoid Anastatus japonicus Ashmead (Hymenoptera: Eupelmidae) can be produced efficiently to tackle the brown marmorated stink bug Halyomorpha halys Stål (Hemiptera: Pentatomidae) in China.

He, and colleagues from the Joint Lab as well as from the University of California,the Guangdong Academy of Agricultural Sciences, the Sun Yat-Sen University, and the Hexi University, believe that mass rearing of the wasp could achieve long-term sustainable management of the brown marmorated stink bug on important economic crops such as kiwifruit.

The brown marmorated stink bug, is a polyphagous pest native to East Asia and invasive in the United States, Canada, Europe, and Chile. It can cause significant damage to many important crops in both its native and invaded ranges.

Occasional outbreaks have been reported in kiwifruit orchards in China. Losses of approximately 30% in kiwifruit production, for example, have been reported in some orchards in Italy. In 2016, the brown marmorated stink bug caused US $60m worth of damage to Georgia’s hazelnut crop and in 2010, US $37m worth of apples were destroyed in parts of the U.S..

Chemical control with broad-spectrum insecticides have been broadly used to control the brown marmorated stink bug in conventional farming systems. This is despite harm to human health and the environment.

The study, published in the journal Pest Management Science, states that biological control programs with indigenous or introduced parasitoids have been initiated to explore more environmentally friendly, sustainable methods for brown marmorated stink bug control.

Dr. Zhang said, “Our present study is the first important step towards the successful use of A. japonicus. We assessed the reproductive attributes of A. japonicus reared on the factitious host Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Anthelidae)—particularly adult longevity and both age specific and lifetime fecundity.

“We also evaluated the age-specific functional response of individual A. japonicus females to varying densities of A. pernyi, as well as their response to conspecific females (i.e., mutual interference) in terms of progeny production and progeny sex ratio.

“We found that higher lifetime fecundity, longer oviposition period and female-biased progeny production in the beginning of production not only make the rearing system of A. pernyi–A. japonicus more cost effective but also make it feasible to use A. japonicus for inundative biological control against the brown marmorated stink bug.”

In conclusion, the scientists suggest that large-scale and cost-effective A. pernyi-based mass rearing and field release testing are needed to evaluate field efficacy and non-target effects before recommending the use of mass releases of A. japonicus for control of the brown marmorated stink bug to growers.


Explore further

First discovery of adventive populations of Trissolcus japonicus


More information: Qian‐Qian Mi et al, Reproductive attributes and functional response of Anastatus japonicus on eggs of Antheraea pernyi, a factitious host, Pest Management Science (2022). DOI: 10.1002/ps.7088

Journal information: Pest Management Science 

Provided by CABI

Continuous long tracking of migrating insects

By flying with hawkmoths during migration, scientists reveal that insects employ sophisticated flight strategies similar to vertebrates

Date:August 11, 2022Source:Max-Planck-GesellschaftSummary:By flying with hawkmoths during migration, scientists reveal the insects employ sophisticated flight strategies similar to vertebratesShare:

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Insects are the world’s smallest flying migrants, but they can maintain perfectly straight flight paths even in unfavorable wind conditions, according to a new study from the Max Planck Institute of Animal Behavior (MPI-AB) and the University of Konstanz. Researchers radio tracked migrating hawkmoths for up to 80 kilometers—the longest distance that any insect has been continuously monitored in the wild. By closely following individuals during migration, the world-first study unlocks a century-old mystery of what insects do over their long-range journeys. The study, published in Science, confirms that hawkmoths can accurately maintain straight trajectories over long distances, employing sophisticated strategies to counter and correct for unfavorable wind conditions. The findings reveal that insects are capable of accurate navigation, confirming that an internal compass guides them on their long journeys.

With trillions of individuals migrating every year, insects are some of the most common migrating animals on Earth. They include species of renown, such as the monarch butterfly, as well as species of enormous societal and environmental importance, such as locusts, mosquitos, and bees. But even though insect migrants far outnumber better-known migrants, such as birds or mammals, their migration is the least understood form of long-range animal movement.

The problem, for the most part, has been methodological. “Studying insects on the move is a formidable challenge,” says first author Myles Menz, who conducted the research at MPI-AB and is now a lecturer at James Cook University in Australia. “They’re usually too numerous to mark and find again, and too small to carry tracking devices.”

Much of what we know about insect migration has come from studies that sample insects at a single moment in time, such as through radar or direct observation, which has left vast blank spots in our knowledge. “Understanding what insects do during migration, and how they respond to weather, is a last frontier in migration science,” says Menz.

The current study, which followed radio-tagged individuals in a light aircraft, is the first to continuously study nocturnal migrating insects in the wild and represents the longest distance over which any insect has been continuously tracked in the field. The team, which includes researchers from the MPI-AB and University of Konstanz in Germany and the University of Exeter in the UK, focused on the death’s-head hawkmoth—a large, nocturnal migrant that travels up to 4000 kilometers between Europe and Africa every year. Like many insects, the species is a multi-generational migrant, which means that no individual knows the entire route.

At the MPI-AB in Konstanz, Germany, the team reared caterpillars until adulthood in the laboratory to ensure that individuals were naïve. When moths emerged as adults, they were fixed with radio tags weighing 0.2 grams—less than 15% of adults’ body weight. “The moths would probably eat more weight than that in a night, so these tags are extremely light for the insects,” says Menz.

The researchers released the tagged moths and waited for flight to begin, after which they chose a single individual to follow at a time. The team followed 14 moths each for up to 80 kilometers or 4 hours—a stretch long enough to be considered migratory flight—using antennas mounted on a Cessna airplane to detect precise locations every five to 15 minutes. Insects were followed in the south-south-west direction from Konstanz into the Alps, which follows the route taken by hawkmoths towards the Mediterranean and Northwest Africa.

Due to practical constraints of flying in an aircraft, the scientists tracked moths continuously until the insects stopped on route. “When you’re in an airplane, it becomes extremely difficult to wait for the insects to begin migrating again because you would have to be in the air when this happens, which could be anytime in the night,” says senior author Martin Wikelski, a movement ecologist from the MPI-AB and University of Konstanz, who piloted the plane during the study.

The results show that moths maintained perfectly straight trajectories for long distances during flight. This was not because they waited for favorable tailwinds. Rather, they employed a range of flight strategies to buffer against prevailing winds, allowing them to hold their course throughout the night. When winds were favorable, they flew high and slow, allowing the air to carry them. But during harsh headwinds or cross winds, they flew low to the ground and increased speed to keep control of their path.

Says Menz: “For years it was assumed that insect migration was mostly about getting blown around. But we show that insects are capable of being great navigators, on par with birds, and are far less vulnerable to wind conditions than we thought.”

“By showing that it is technically possible to continuously monitor individual insects over migration, and to observe their flight behavior in detail, we hope to inspire more studies to answer many more big questions in this area.”

For the study authors, the next step is to answer the question of how moths are able to maintain such straight lines. “Based on past lab work, it’s possible that the insects are using internal compasses, both visual and magnetic, to chart their way around the world,” says Menz.


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Materials provided by Max-Planck-GesellschaftNote: Content may be edited for style and length.


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Journal Reference:

  1. Myles H. M. Menz, Martina Scacco, Hans-Martin Bürki-Spycher, Hannah J. Williams, Don R. Reynolds, Jason W. Chapman, Martin Wikelski. Individual tracking reveals long-distance flight-path control in a nocturnally migrating mothScience, 2022; 377 (6607): 764 DOI: 10.1126/science.abn1663

Cite This Page:

Max-Planck-Gesellschaft. “Continuous long tracking of migrating insects: By flying with hawkmoths during migration, scientists reveal that insects employ sophisticated flight strategies similar to vertebrates.” ScienceDaily. ScienceDaily, 11 August 2022. <www.sciencedaily.com/releases/2022/08/220811143026.htm>.

TEST CONFIRMS PALM ‘BUTT ROT’ BEFORE IT’S TOO LATE

AUGUST 10TH, 2022POSTED BY LOURDES MEDEROS-U. FLORIDA

“The conk (above) is the only distinguishing symptom of the disease and indicates a palm tree is not recoverable,” says Braham Dhillon. (Credit: Lourdes Mederos/U. Florida)

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A DNA-based diagnostic method confirms a wood-decaying fungus in palms months before the symptoms of Ganoderma butt rot appear.

More than 65 species of palm trees in the United States are vulnerable to a wood-decaying fungus that can damage or destroy palms.

A fungus, Ganoderma zonatum, causes the lethal disease known as Ganoderma butt rot of palms. Its mysterious nature has stunted research for decades, making early detection of the silent killer impossible until now.

As reported in the journal Plant Disease, previously compiled sequence data from genetically validated North American Ganoderma species were used to develop the tool. The result is a diagnostic protocol that can detect the genetic make-up of the lethal Ganoderma zonatum pathogen.

“We were able to find the unique genetic markers exclusive to Ganoderma zonatum,” says Braham Dhillon, a molecular plant pathologist at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Fort Lauderdale Research and Education Center.

“This has great implications for developing management methods for the disease from this point forward. It saves time and money and opens the doors for additional research on understanding how this pathogen survives and spreads in the landscape.”

A tree specialist can collect samples as wood shavings from the trunk and submit them to a lab for diagnosis with the new procedure. Results are available in a week.

The detection method can be readily adopted into protocols of plant diagnostic facilities since the technology and equipment are routinely available without the need for additional instrumentation or chemicals.

“Early detection of the fungus, or any disease, is a crucial step towards building and implementing better disease management strategies and mitigating potential risks from palm deaths and destruction of property due to palm tree decay,” says Dhillon.

Palm trees of all varieties grace the lands of homeowners, public parks, business complexes, and roadways. The fungus, common in homeowner and public spaces, is a slow-growing pathogen, occupies the trunk, and degrades the vascular water-conducting tissue. This produces initial symptoms of wilting and dying palm fronds in the lower part of the canopy. These symptoms are also associated with other diseases like Fusarium wilt and lethal bronzing, which makes it difficult to properly diagnose.

In the later stages of the disease, a fruiting body called a conk, or basiodiomata, appears at the lower surface of the trunk and confirms the presence of Ganoderma butt rot.

“The conk is the only distinguishing symptom of the disease and indicates a palm tree is not recoverable,” says Dhillon. “The conk produces millions of spores that can travel by wind contributing to disease spread.”

As the fungus moves up the trunk, it compromises the structural integrity of the palm, says Dhillon. “In later stages of the disease, the decayed palm trunk is susceptible to breaking and becomes a hazard to properties, pedestrians, and vehicular traffic. Depending on the girth of the trunk, the decay process can take up several months to a year.”

Until now, the appearance of the conk, or an invasive dissection of the infected trunk and culturing of the fungus, are the only ways to confirm the diagnosis of the lethal disease, explains Dhillon.

For the study, scientists sequenced a variety of samples, including 24 cultures from 15 Ganoderma species collected from a previous study and archived at the Center for Forest Mycology Research Culture Collection and Herbarium, US Department of Agriculture Forest Service.

They also collected healthy and naturally infected sawdust palm samples from eight palm species. Infected palms in the study were categorized for one of two symptoms: wilted palm fronds or presence of a conk. Other samples included conks, infected tissues, soil, and DNA from palm-infected lethal yellowing and lethal bronzing specimens. Researchers validated the method on DNA isolated from 60 samples.

Source: University of Florida

Original Study DOI: 10.1094/PDIS-12-21-2837-RE

Breeder develops disease-resistant snack cucumbers varieties

“Developing varieties with resistances takes time but it’s an important role we play as plant breeders”

Rijk Zwaan is taking innovation to new heights in snack cucumbers by focusing on high wire varieties with the combination of Powdery Mildew (PM) and Cucumber Green Mottled Mosaic Virus (CGMMV) resistance. This is the latest development in the company’s ever-growing range of flavorsome snack cucumbers in various sizes and colors, all with the best possible resistances to help growers harvest a healthy crop.

Snack varieties with resistances to CGMMV and Powdery Mildew (PM)
Since introducing Quarto RZ – one of the first varieties of snack cucumber – in 2005, Rijk Zwaan has worked with growers and listened to consumers to breed new varieties that are not only agronomically sound and productive, but also delicious and visually appealing. “Developing varieties with resistances takes time but it’s an important role we play as plant breeders,” says Marcel van Koppen, a Dutch-based crop specialist at Rijk Zwaan. “Growers face pressure from a number of diseases such as mildew as well as viruses that can have serious consequences for crop viability. In 2019, we enhanced the snack cucumber range with the introduction of Quayal RZ as a PM-resistant version of Qwerty RZ. We’ve now taken our range to the next level once again by asking our breeders to develop snack cucumber varieties with a combination of PM and CGMMV resistances. This will be a significant improvement for growers and other value chain partners.”

Innovating the snack cucumber category for consumers
It is important to keep the segment fresh and exciting, since more than 35% of consumers in some markets eat snack cucumbers. One of Rijk Zwaan’s new varieties is Quirk RZ, a unique bi-coloured ‘baby apple’ snack cucumber with a sweet taste and good shelf life. Additionally the company has made further improvements in the smaller cucumber segment, resulting in the development of one-bites as well as a white-skinned variety which looks very striking in snack cucumber medleys. 

The future is sky
Rijk Zwaan continuously conducts research into new cucumber varieties, important resistances and technical characteristics. From generation to generation, the company maintains an ongoing dialogue with growers to anticipate new challenges in changing cultivation conditions, such as high wire. That’s why most of the company’s current varieties are suitable for both umbrella and high wire systems. “The future is the sky,” they say.

For more information:
Rijk Zwaan
info@rijkzwaan.com
www.rijkzwaan.com      

Publication date: Wed 10 Aug 2022

Banana freckle disease spreads to 12 new locations across Northern Territory

The Northern Territory government has confirmed multiple outbreaks of the fungal disease known as banana freckle. After initially being found on a single property near Rum Jungle in May, the government today identified 12 new sites of infection at Fly Creek, Batchelor, Marrakai and the Tiwi Islands.

The disease was detected last month on the government’s own Coastal Plains Research Farm and has also been confirmed on one commercial farm. The total number of infected properties has grown to 29.

NT chief plant health officer Anne Walters said government and industry were ready to announce an eradication plan for the disease, but that had now been put on hold following widespread detections.

“I don’t think anything has gone wrong … it is obviously widespread but what seems to be the case is that it’s still quite localised in those areas we’ve found it,” she said. “The pattern is not clear on how this disease is spreading, so obviously tracing will be a critical component in the next stage of the program.”

Source: abc.net.au

Publication date: Tue 9 Aug 2022

Weevils in caves, fish, and an ant that ‘babysits’ caterpillars among 139 new species classified by CSIRO

ABC Science

 / 

By environment reporter Nick Kilvert

Posted Mon 8 Aug 2022 at 3:00pmMonday 8 Aug 2022 at 3:00pm, updated Mon 8 Aug 2022 at 4:34pmMonday 8 Aug 2022 at 4:34pm

A strange pink organism on a leaf.
A gall caused by a newly classified species of gall wasp called Antron lovellae.(Supplied: CSIRO/Ron Russo)

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The CSIRO has released details of more than 136 new species of animals and three plants identified in the past year.

The new species include four fish, 117 insects, 11 jumping spiders, three plants, a frog, a millipede, an earthworm, and a marine trematode — a parasitic flatworm. 

The trematode was found inside a fish.

Close up of sucker mouth.
The oral sucker of Enenterum petrae under microscope. Baby Petra doesn’t know how lucky she is.(Supplied: Daniel Huston/Zootaxa)

Now called Enenterum petrae, it was named after the baby daughter of its identifier, Petra.

David Yeates, director of the CSIRO’s Australian National Insect Collection, said choosing a favourite out of the newly identified species was a bit like being asked to “choose a favourite child”.

However, he said one of the most interesting is a species of ant — now known as Anonychomyrma inclinata — which “babysits” the caterpillars from one of Australia’s  rarest butterflies, the bulloak jewel butterfly.

An ant.
The newly named ant Anonychomyrma inclinata is the ‘obligate attendant’ for the rare and beautiful bulloak jewel butterfly Hypochrysops piceatus.(Supplied: CSIRO/Jon Lewis)

“The ants carry the little caterpillars out from under the bark of the bulloak tree to feed on the soft tips of the leaves or needles at night; they carry them out and then back,” Dr Yeates said.

It’s a symbiotic relationship, where the ants protect the caterpillars from other ants, and get something in return, he said.

The butterfly, the ant and the mistletoe

To save one of Australia’s rarest butterflies we also need to save an unnamed ant species, an endangered woodland and a parasitic plant.

An illustration of trees with birds, ants, butterflies and raindrops, and a hand holding a chainsaw in the foreground.

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“The ants feed on a sugary substance that the caterpillars produce from glands. The ants get this nice sugary secretion and the butterflies get protection.”

As well as it being a fascinating strategy, that knowledge helps to direct efforts to conserve the bulloak jewel butterfly.

“When we’re trying to manage that rare and beautiful butterfly, we know it only occurs where that ant occurs in that particular [species of] tree.”

A colourful butterfly.
The bulloak jewel butterfly has a symbiotic relationship with an ant that looks after its young.(Supplied: CSIRO/Michael Braby)

With only an estimated 25 per cent of Australian species having been formally identified, this work highlights the important role that the CSIRO’s National Research Collections perform, according to Dr Yeates.

Australian fauna — especially insects — is still poorly researched compared with fauna  in most other developed countries.

“That’s an important point for Australians to understand. Australia is still the land of discovery.

“We have a first world economy, good infrastructure, but we drive past new species all the time.

“For a biologist to come here from Europe or China for example, they think it’s the land of milk and honey, because there are so many new species for them to work on.”

A pink and yellow fish.
The purple-tip anthias is found in around 110 metres of water.(Supplied: CSIRO/Queensland Museum)

Other species in today’s haul include the purple-tip anthias, which has been found in waters between about 110 and 119 metres deep, off southeast Queensland.

Of the newly named fish species, three were types of anthias, and the fourth was a silverspot weedfish.

A mottled red fish.
The silverspot weedfish is found off southwest Western Australia in 55-100m depth.(Supplied: CSIRO)

Most new fish species that are being classified are small, non-commercially viable species that tend to live in deep water where they are rarely encountered.

While that appears to be the trend, Dr Yeates said a few years ago a large, deepwater cod species was discovered at a fish market.

A lineup of beetles.
Specimens of Undarobius howarthi and U. irvini, the two new species of weevils in the new genus Undarobius found in lava caves at Undara Volcanic National Park in north-eastern Queensland.(Supplied: CSIRO)

Of the newly discovered insects,  34 were beetles, including two new weevils found in the lava tubes at Undara Volcanic national park in Far North Queensland.

A weevil close up.
A new species of weevil discovered in the Undara lava tubes in Far North Queensland.(Supplied: CSIRO)

The two weevil species are the first cave-dwelling weevils to be described in Australia, according to the CSIRO.

The weevils have long, arachnid-like legs, are blind, and appear to have adapted to life in the darkness.

It’s possible that the two species, called Undarobius howarthi and U. irvini are relics from a period when the region was covered in rainforest.

A person stands in a cave with a torch.
Entomologists visiting the Bayliss Cave, a lava cave in Undara Volcanic National Park, to search for beetles.  (Supplied: CSIRO)

Not all the insects identified by CSIRO and their partners were from Australia; 39 were species of gall wasps from the Americas.

Gall wasps typically cause grotesque growths to form on plants, and can create problems if they become invasive pests, such as the native citrus gall wasp, which has spread across Australia.

How do scientists know if it is a new species?

One of the many challenges in identifying new species, is working out whether you in fact have a new animal, or just a funny looking, but known one.

Animals and plants can develop different physical properties, known as phenotypic expression, depending on pressures in their particular environment.

The Tasmanian blue gum for example, can reach 100 metres in height in Tasmania’s forests, but stunted versions of the same species just a few metres tall are found on the coast.

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Eucalypt bushland

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Other species may change markedly depending on gender, and what stage of life they are at.

Which is why it’s important to have large collections such as the Australian National Research Collection.

Having lots of species in one place allows scientists to compare features to properly distinguish between their characteristics.

Even then, very specific expertise is required to work out where the animal or plants sits in its phylogenetic tree.

“What happens is that specimens that belong to new species accumulate in collections, and it’s a fair bit of effort to figure out if they’re new or not,” Dr Yeates said.

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“It can take quite a bit of time and effort, including looking at their genes and genomes to determine if they really are different.”

It’s likely that many species will become extinct in Australia, or have already become extinct, before we’ve had a chance to identify them.

Figuring out what’s what, means we can better understand where conservation efforts need to be targeted, according to Dr Yeates.

“We can start to get information on how to manage it, whether it’s declining, and what factors might impact its survival.”

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Eye Doctor’s Tool Offers New Look at Marvel of Moth Eyes

ENTOMOLOGY TODAY  2 COMMENTS

A tool commonly used in ophthalmology finds a new use in entomology: Observing how a moth’s eye adjusts to see in both light and dark environments. Moths such as the winter cutworm (Noctua pronuba, also known as the large yellow underwing), use a light-absorbing pigment that moves position to limit the light within the eye. The process takes approximately 30 minutes and only occurs in live specimens, making it difficult to observe. A new technique using optical coherence tomography, however, opens new doors for studying this process. (Image by Sam R via iNaturalistCC BY-NC 4.0)

By Ed Ricciuti

If you are into puns, you might call it an eye-opening innovation.

An optometrist in the United Kingdom has adapted technology for diagnosing human eye disease to instead scan how the eye of a living nocturnal moth regulates light input. To date, this light-regulation process has been visualized only in still images from dead specimens, but the new technique records in real time the moth eye adapting to changing light as it unfolds, dynamically.

An article by optometrist Simon Berry, MCOptom, published in June in the journal Environmental Entomology, describes the first use of optical coherence tomography (OCT) to view anatomical detail in the compound eye, common to insects, crustaceans, and other arthropods. Like medical ultrasound, OCT technology images biological tissue but does so by using light instead of sound. It is widely used in ophthalmology to obtain cross-sectional information about structures within the eye, making it an important diagnostic tool in the evaluation of human eye diseases. You may have peered into one if you have been examined for macular disease or if you are elderly; it is used routinely in many patients over 70.

Adapting to seeing in the dark is one of the evolutionary problems that nocturnal animals have had to overcome. Conversely, they can be challenged by the bright light of day. “During the night the light levels are low, so their eyes need to be very sensitive; but, they also need a way of adapting to environmental light conditions, and protecting those sensitive organs, if a bright light is encountered,” says Berry. “Human eyes have a pupil that changes size to regulate light input to the eye. Moths use a light-absorbing pigment that moves position to limit the light within the eye.”

In the moth’s eye, photopigment granules are stored between crystalline cone-shaped structures, or Semper cells, beneath the cornea. Behind that layer, the compound eye of nocturnal insects—defined as a “superposition” eye—has a transparent region called the clear zone. To decrease the brightness of light, the dark pigment is extruded from the cones into the clear zone. Like clouds blocking the sun, the pigment restricts the amount of light reaching the rhabdoms, photoreceptive structures in a layer at the back of the eye. In darkness, the pigment migrates away from the zone back into the cone layer. In effect, the concentration of pigment granules lessens to permit more light and increases to reduce it. (Image by Juliet Percival, originally published in Berry 2022, Environmental Entomology)

In the moth’s eye, photopigment granules are stored between crystalline cone-shaped structures, or Semper cells, beneath the cornea. Behind that layer, the compound eye of nocturnal insects—defined as a “superposition” eye—has a transparent region called the clear zone. To decrease the brightness of light, the dark pigment is extruded from the cones into the clear zone. Like clouds blocking the sun, the pigment restricts the amount of light reaching the rhabdoms, photoreceptive structures in a layer at the back of the eye. In darkness, the pigment migrates away from the zone back into the cone layer. In effect, the concentration of pigment granules lessens to permit more light and increases to reduce it.

The migration of pigment is difficult to record because it is a dynamic process, Berry says, and takes place only when a moth is alive. “By necessity, any microscopic examination of the eye requires dissection of a dead insect and will show a snap-shot of the adaptive state at that point in time,” Berry writes his paper. Thus, the fact that OCT is non-invasive is critical to the new method for observing this process.

Moths used in the study were trapped, scanned, and later released. During the experiment, the moths were adapted to darkness in a dark bag for at least an hour. The first scan was completed with the room in darkness to try and ensure the insect stayed dark adapted. A white LED light source was then turned, on and various scans were taken as the insect became light adapted.

Optical coherence tomography is well suited to observing the physiological adaptation process to light in moth eyes because the process is relatively slow, taking approximately 30 minutes to transition between fully dark-adapted to fully light-adapted. (Image originally published in Berry 2022, Environmental Entomology)

Berry found that when a moth is in a dark-adapted state, the clear zone is optically transparent, and light emitted by the OCT passes through it to the rhabdom layer, which serves like the retina of the human eye, resolving wavelengths of light so it can be processed to images by the brain. In a light-adapted state, pigment that has migrated into the clear zone changes its composition so it filters out light.

OCT is well suited to observing the physiological adaptation process to light because the process is relatively slow—circa 30 minutes—says Berry, and during this period the insect’s perception is not optimized for the environmental light levels. For example, if a light source causes an insect to light adapt and then that light source is taken away, it will take a period of time for it to become dark adapted and see effectively in low light levels.

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1. Optical coherence tomography scan: Noctua pronuba, “yellow underwing” moth eye

2. Optical coherence tomography scan: Plusia festucae, “gold spot” moth eye

Optometrist Simon Berry, MCOptom, reports in the journal Environmental Entomology on the use of optical coherence tomography for imaging the eye of a live moth as it adapts for vision in light or dark environments. In two videos here, images from the scans are sequenced to show the process over time. (Videos by Simon Berry, MCOptom)

From the OCT scans, it appears that the beginning of the pigment migration is not instantaneous but rather the pigment migration becomes visible after a short delay. “This may be because it takes time for the pigment to migrate and show in the scan,” says Berry. However, there could possibly be a biological reason why this may occur. The lag before pigment migration means that if the insect encounters a brief flash of bright light, it may be able to recover quickly because the pigment migration has not started. It may not lose its fully dark-adapted state immediately, as humans do, and so its vision not impeded. Conversely, the time lag in transition from light to dark adaption may disadvantage moths with light-adapted eyes for a time period if they move away from a light source into the dark.

“Further research is needed to determine whether the state of light adaption affects moth behavior,” says Berry. “I really do think that OCT can be a useful tool in entomology and could possibly help explain some of moth behaviour around light sources. It opens up another way of examining the compound eye, and because it is non-invasive it can be used to look at dynamic processes like light adaption in ways not previously possible.”

Read More

The Use of Optical Coherence Tomography to Demonstrate Dark and Light Adaptation in a Live Moth

Environmental Entomology

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Study tracks plant pathogens in leafhoppers from natural areas

Date:August 2, 2022Source:University of Illinois at Urbana-Champaign, News BureauSummary:Phytoplasmas are bacteria that can invade the vascular tissues of plants, causing many different crop diseases. While most studies of phytoplasmas begin by examining plants showing disease symptoms, a new analysis focuses on the tiny insects that carry the infectious bacteria from plant to plant. By extracting and testing DNA from archival leafhopper specimens collected in natural areas, the study identified new phytoplasma strains and found new associations between leafhoppers and phytoplasmas known to harm crop plants.Share:

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Phytoplasmas are bacteria that can invade the vascular tissues of plants, causing many different crop diseases. While most studies of phytoplasmas begin by examining plants showing disease symptoms, a new analysis focuses on the tiny insects that carry the infectious bacteria from plant to plant. By extracting and testing DNA from archival leafhopper specimens collected in natural areas, the study identified new phytoplasma strains and found new associations between leafhoppers and phytoplasmas known to harm crop plants.

Reported in the journal Biology, the study is the first to look for phytoplasmas in insects from natural areas, said Illinois Natural History Survey postdoctoral researcher Valeria Trivellone, who led the research with INHS State Entomologist Christopher Dietrich. It also is the first to use a variety of molecular approaches to detect and identify phytoplasmas in leafhoppers.

“We compared traditional molecular techniques with next-generation sequencing approaches, and we found that the newer techniques outperformed the traditional ones,” Trivellone said. These methods will allow researchers to target more regions of the phytoplasma genomes to get a clearer picture of the different bacterial strains and how they damage plants, she said.

“One thing that is really novel about this study is that we’ve focused on the vectors of disease, on the leafhoppers, and not on the plants,” Dietrich said. The standard approach of looking for phytoplasmas in plants is much more labor-intensive, requiring that scientists extract the DNA from a plant that appears to be diseased and checking for phytoplasmas, he said.

“But even when you identify the phytoplasma, you don’t know what leafhopper or other vector transmitted it to the plant,” Dietrich said. “So researchers must go back out into the field to collect all potential insect vectors. Then they do transmission experiments, where they let the leafhoppers feed on an infected plant and then put them on an uninfected plant to see if it catches the disease.”

Because this research is laborious and slow, “we still don’t have a good idea of which insects are spreading most phytoplasmas between plants,” Dietrich said. “That really limits your ability to set up an effective management strategy.”

For the new study, the researchers turned to leafhopper specimens in the INHS insect collection. Dietrich had collected many of these insects over a period of 25 years as part of his work classifying their genetic relatedness and evolution. The researchers examined 407 leafhopper species collected around the world in areas less disturbed by human development. The specimens came from North and South America, Africa, Europe, Asia and Australia.

The team extracted total DNA from the specimens and processed each one, using both traditional and newer sequencing approaches. The latter are less costly and more informative than traditional methods, the researchers report. Of the insects sampled, 41 tested positive for phytoplasmas, and the researchers obtained usable phytoplasma sequence data from 23 leafhoppers. The phytoplasmas included those that cause a disease known as aster yellows, which inhibits photosynthesis and reduces the productivity of several different crop plants. These phytoplasmas were found in several new species of leafhoppers never before identified as vectors of the disease.

“These leafhoppers may transmit the phytoplasmas to wild plants in natural areas,” Trivellone said.

The study found phytoplasmas in regions of the world where such diseases had not been reported and identified several new strains of bacteria. It also found previously unreported associations between some phytoplasmas and species of leafhopper.

Scientists have no tools to target the bacteria in asymptomatic plants to prevent disease outbreaks, so controlling phytoplasmas involves the use of pesticides to kill the insect vectors.

“Because the insecticides are only partially specific to the target insects, they kill a variety of beneficial insects as well, which is not sustainable,” Trivellone said.

“We’re finding that there are lots of new phytoplasmas out there in nature that nobody’s ever seen before,” Dietrich said. “They don’t cause disease symptoms in the native plants they’ve associated with for maybe millions of years. They only start causing disease when they jump to a new host that has not been exposed to the phytoplasma before.”

The new findings parallel those seen in emerging infectious diseases of humans originating in wildlife, Dietrich said. “This is why we need to look more broadly across nature and see what’s out there.”

The National Science Foundation supports this research.

The INHS is a division of the Prairie Research Institute at the University of Illinois Urbana-Champaign.

 Grahame Jackson

 Sydney NSW, Australia

 For your information

 2 days ago

Pacific Pests, Pathogens & Weeds version 11

Dear Everyone

There is a new version of the Pacific Pests, Pathogens & Weeds out for mobile devices – phones and tablets. You can find it for free at the Glogle Play and Apple Stores. There are another 30 fact sheets and some amendments to others. 

If you want to see what’s new go to the About this App on the main page and it tells you.

grahame

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