Tag: biocontrol

From curiosity to control: A new wasp joins the fight against soybean gall midge

Recently, the discovery of the wasp Synopeas ruficoxum parasitizing soybean gall midge in Nebraska offers hope that it could be deployed in biological control efforts.

Guest blog post by Sarah von Gries

Tiny, squishy, and deceptively cute, bright orange maggots tucked inside soybean stems are causing big trouble. Resseliella maxima, better known as the soybean gall midge (SGM), has become a concern for soybean growers, chewing through stems and cutting into yields. Despite several years of efforts, there is still no reliable way to keep SGM populations in check. However, nature may already be offering reinforcements: parasitoid wasps that consume SGM maggots from the inside out.

Three close-up images of a small insect, with scale bars for size reference.
As soybean gall midge (Resseliella maxima) grows as a pest of concern, researchers are searching for ways to keep it in check. Recently, the discovery of the wasp Synopeas ruficoxum parasitizing soybean gall midge in Nebraska offers hope that it could be deployed in biological control efforts. Shown here are lateral views of the 2005 holotype of S. ruficoxum found in New Brunswick, Canada (A), a 2017 unidentified Synopeas found in Ontario, Canada (B), and 2021 Synopeas “Y” (C), illustrating the elongate metasoma. (Image originally published in von Gries et al. 2025, Journal of Hymenoptera Research)

A Lone “Oddball” Wasp

In 2021, Justin McMechan, Ph.D., and his lab team at the University of Nebraska–Lincoln began rearing insects from SGM-infested soybean stems. Among the hundreds of midges and a handful of familiar soybean-associated insects, the team recovered an unusual wasp. It stood out, not just from the known insects, but also from another wasp species discovered around the same time in Minnesota.

This lone wasp was sent to Gloria Melotto, a graduate student at the University of Minnesota studying natural enemies of SGM. At the time, Melotto was working to identify a different wasp species associated with SGM in Minnesota, collaborating with two taxonomists, Elijah Talamas, Ph.D., of the Florida State Collection of Arthropods and Jessica Awad, Ph.D., at Naturalis Biodiversity Center in the Netherlands.

Tiny, bright orange maggots of Resseliella maxima, better known as the soybean gall midge are causing big trouble for soybean growers, chewing through stems and cutting into yields. Despite several years of efforts, there is still no reliable way to keep soybean gall midge populations in check. However, nature may be offering reinforcements: parasitoid wasps that consume soybean gall midge larvae from the inside out. (Adult soybean gall midge shown in inset.) (Image courtesy of Sarah von Gries)

Melotto forwarded the Nebraska specimen, along with her Minnesota parasitoids, to Talamas and Awad for identification. More specimens were available from Minnesota, so the team’s attention focused on that species, now known as Synopeas maximum (family Platygastridae, subfamily Platygastrinae). The Nebraska wasp remained unidentified, waiting patiently in a collection drawer for its time to shine.

By 2023, I had joined McMechan’s team as a graduate student, just in time for a new field season surveying Nebraska soybean fields for natural enemies. That same “oddball” wasp reappeared, only this time it was not alone. We collected 26 more wasps, scattered across multiple sites. Suddenly, the curious singleton revealed itself to be part of a much larger story. It was clear this wasp warranted closer attention, and we published the resulting discovery in August in the Journal of Hymenoptera Research.

The first page of a research article covering Synopeas ruficoxum, a natural enemy of the soybean gall midge.
The first page of the paper in the Journal of Hymenoptera Research.

The Mystery of Synopeas “Y”

Talamas and Awad identified the wasp as a second species in the genus Synopeas, and we began referring to it as Synopeas “Y.” Its elongate metasoma, or tail end of its abdomen, set it apart from most of the 400 described species in the genus, narrowing the possible matches to a subset of 34, which we later named the “craterum group.”

While Talamas and Awad combed the literature for descriptions that matched Synopeas “Y,” we generated genentic barcode sequences from the 26 fresh specimens and queried them against the Barcode of Life Database. Two matches surfaced: unidentified Synopeas specimens from Montreal and Guelph, Canada. Fortunately, voucher specimens were available for closer examination, so Talamas requested them to compare against Synopeas “Y.”

New species of parasitic wasp associated with soybean pest in Minnesota

“The Canadian specimens had more brightly colored appendages [than those from the U.S.], but otherwise they appeared to be conspecific,” says Talamas. The morphological match and a genetic barcode similarity of 99.5% provided strong evidence that the Canadian and U.S. populations were the same species.

Then came a breakthrough. Awad found a potential match with a single female wasp collected in 2005 near Belleville, New Brunswick, Canada, Synopeas ruficoxum, which she had seen during a previous visit to the Natural History Museum of Denmark, Copenhagen.

“I was about 90% confident that Synopeas “Y” was Synopeas ruficoxum,” Awad says. “The morphology was a very close match and the known distribution matched as well. I wanted to double-check the holotype, but I examined it closely when I was in Copenhagen and took detailed notes, so I had a pretty good idea of what it looked like.”

Identity Confirmed

Map showing the distribution of R. maxima in the U.S. Midwest and S. ruficoxum in Canada, marked by orange and blue dots, respectively.
Geographic distribution of soybean gall midge (Resseliella maxima) and the parasitoid wasp Synopeas ruficoxum in the U.S. and Canada. (Figure originally published in von Gries et al. 2025, Journal of Hymenoptera Research)

After borrowing and comparing the museum specimen and two voucher specimens, Talamas and Awad confirmed Synopeas “Y” was indeed Synopeas ruficoxum, expanding the known geographic range of the species.

Using the genetic barcodes, we developed species-specific primers to screen field-collected SGM larvae for parasitism by S. ruficoxum. This method provided DNA evidence for the host-parasitoid relationship, confirming that S. ruficoxum parasitizes SGM.

Although all wasps in Platygastrinae are assumed to parasitize gall midges (family Cecidomyiidae), validated host-parasitoid relationships at the species level remain rare. “Something that’s kind of interesting,” Awad says, “is that other members of the Synopeas craterum group also parasitize species of Resseliella. This is only the third host association known for this group.” The function of the extra-long metasoma remains unknown, but more ecological data could help explain this unusual feature.

Looking Ahead: Biological Control Potential

Close-up of a damaged plant stem, showing brown decay and small reddish insects partially embedded in the wood.
Soybean Gall Midge (Resseliella maxima). Photo by slisak published under a CC BY-NC 4.0 license

With S. ruficoxum now identified as a parasitoid of SGM, it opens the door to more questions. We still do not know much about its basic biology, like how long adults live, or even how they reproduce, since only females have been found. We also lack data on parasitism rates, which is key to evaluating its potential as a biological control agent in integrated pest management. And all of these questions need to be considered alongside the other known SGM parasitoid, S. maximum.

Molecular tools, including DNA barcoding, offer opportunities to advance our understanding of platygastrines and their gall midge hosts, especially in pest management. These techniques can reveal host-parasitoid associations, detect new species, and monitor population dynamics in agriculture. Broader implementation has the potential to enhance biological control strategies but is presently limited by major knowledge gaps about the diversity and life history of gall midges and their parasitoids.

Here, the agricultural significance of the insects helps to provide both the impetus and funding to advance our understanding of their biology, and the tools used to do it. These tools can now be used to study gall midge-parasitoid interactions more broadly, including those in both agricultural and natural ecosystems.

Research article:

von Gries SC, Awad J, Talamas EJ, McMechan AJ, Koch RL, Lindsey ARI (2025) Synopeas ruficoxum Buhl (Hymenoptera, Platygastridae) is a natural enemy of soybean gall midge, Resseliella maxima Gagné (Diptera, Cecidomyiidae). Journal of Hymenoptera Research 98: 721-742. https://doi.org/10.3897/jhr.98.163211

Story originally published on Entomology Today. Republished with permission.

Comprehensive review of Burmese python science released

A USGS-led publication offers a new look at the constrictor that has invaded southern Florida.

The U.S. Geological Survey has released a comprehensive synthesis of Burmese python science, showcasing results from decades of USGS-funded research on python biology and potential control tools. The giant constrictor now represents one of the most challenging invasive species management issues worldwide.

Occurrence records were obtained from a large geospatial database of invasive species reports (Early Detection & Distribution Mapping System) submitted by both researchers and the public. The map illustrates the chronology of python removals across southern Florida and represents the best professional estimate of the invasion front, which is not exact and will change over time.

“For the first time, all the science on python ecology and potential control tools has been consolidated into one document, allowing us to identify knowledge gaps and important research areas to help inform future python management strategies. This synthesis is a major milestone for Burmese python research; six years in the making, it represents the consensus of the scientific community on the python invasion,” said USGS Ecologist Jacquelyn Guzy, lead author for the publication.

Burmese pythons were confirmed to have an established breeding population in Everglades National Park in 2000. The population has since expanded and now occupies much of southern Florida. They consume a wide range of animals and have altered the food web and ecosystems across the Greater Everglades.

Photo by U.S. Geological Survey.
Photo by Conservancy of Southwest Florida.
Photo by U.S. Geological Survey.
Burmese pythons.

The synthesis, which pulled together the expertise of scientists and managers nationwide, provides a breakdown of 76 prey species found in python digestive tracts, which primarily included mammals and birds, as well as two reptile species, American alligator and Green iguana. However, as the scientists noted, the number of animals may increase as the python population expands to new areas.

It also reports new findings including a summary of body sizes of pythons measured by state and federal agencies between 1995 and 2022, as well as descriptions of length-mass relationships, the estimated geographic spread of pythons over time, and a comprehensive assessment of all control tools explored to date.

Illustration by Natalie Claunch demonstrates typical features of the Burmese python.

One of the hallmark issues of the Burmese python invasion has been the difficulty of visually detecting or trapping pythons in an immense natural landscape, Guzy said. Pythons do not readily enter any type of trap, occupy vast stretches of inaccessible habitat, and camouflage extremely well within the subtropical Florida environment.

Examples of cryptic coloration contributing to low detection probability in representative habitat where Burmese pythons have been captured. White circles indicate pythons. Photos by

“Extremely low individual python detection rates hamper our ability to both estimate python abundance and expand control tools across the extensive natural landscape” says USGS Research Ecologist Kristen Hart, an author of the publication.

Because the Burmese python has spread throughout southern Florida, eradication of the population across the landscape is not possible with existing tools, the publication states. However, researchers at USGS and partner institutions are exploring potential novel techniques such as genetic biocontrol, that may one day provide an avenue towards larger-scale population suppression.

In the meantime, important areas of research according to the publication include reproductive life history and estimation of demographic vital rates such as survival, to help managers evaluate and refine existing control tools. With improved control tools managers may be able to reduce population expansion and minimize the future impact of pythons on the environment.

The USGS python research over the past decades has been largely supported by the USGS Greater Everglades Priority Ecosystem Sciences (GEPES) Program with additional support from the USGS Biothreats and Invasive Species program.

Research article:

Guzy JC, Falk BG, Smith BJ, Willson JD, Reed RN, Aumen NG, Avery ML, Bartoszek IA, Campbell E, Cherkiss MS, Claunch NM, Currylow AF, Dean T, Dixon J, Engeman R, Funck S, Gibble R, Hengstebeck KC, Humphrey JS, Hunter ME, Josimovich JM, Ketterlin J, Kirkland M, Mazzotti FJ, McCleery R, Miller MA, McCollister M, Parker MR, Pittman SE, Rochford M, Romagosa C, Roybal A, Snow RW, Spencer MM, Waddle JH, Yackel Adams AA, Hart KM (2023) Burmese pythons in Florida: A synthesis of biology, impacts, and management tools. NeoBiota 80: 1-119. https://doi.org/10.3897/neobiota.80.90439

Story originally published by the USGS. Republished with permission.

Dr Giovanni Vimercati gave the Best Talk at NEOBIOTA 2022

The invasion scientist and NEOBIOTA 2022 awardee shares more about his research on the impact assessment of biological invasions.

Giovanni Vimercati is a postdoctoral researcher at the University of Fribourg, Switzerland, and most recently recipient of the Best Talk award (Early Career Researcher) at the 2022 NEOBIOTA conference held in mid-September in Tartu, Estonia. 

As a sponsor of the event and publisher of the NeoBiota journal, Pensoft granted a complimentary publication in it to the awardee. 

NeoBiota readers might already be familiar with Vimercati, whose name first appeared on its pages in a 2017 paper that used alien amphibians as a case study to identify the differences and potential difficulties with two impact assessment scoring tools: the Environmental Impact Classification of Alien Taxa (EICAT) and the Generic Impact Scoring System (GISS). 

Then, in 2020 and 2021, the researcher had two research articles published in NeoBiota as lead author. The 2020 paper provided a summary of the frameworks assessing beneficial impacts of alien species, while in the 2021 study his team used a spatially-explicit stage-structured model to assess efficacy of past, present and alternative control strategies for invasive guttural toads (Sclerophrys gutturalis) in Cape Town.

Giovanni Vimercati being awarded at NEOBIOTA 2022. Photo by Ana Novoa.

In anticipation of Vimercati claiming the Best Talk award with a forthcoming submission to the journal, we asked him to join us for an interview and share his thoughts on his research.  

Going back to the beginning, what sparked your interest in the study of invasive species in particular? What are the unique aspects of your research?

Like the episodic nature of many biological invasions, my first contact with the study of alien species was quite “unexpected”. Having a strong interest in herpetology, I had the luck to pursue my doctoral research at the Center of Excellence for Invasion Biology (CIB) in Stellenbosch, South Africa, where I studied the invasion of an alien amphibian species. My PhD study, and the highly stimulating community of researchers that characterized the CIB, made me realize not only that invasive species provide an invaluable opportunity to address ecological and evolutionary questions, but also how important it is to study their impact on biodiversity and human communities. 

One unique aspect of my research since then has been its multidisciplinary character, as I have studied biological invasions from multiple angles simultaneously, by using mathematical models, physiological experiments, field surveys, remote sensing, literature reviews, meta analysis, and questionnaires. It seems a paradox, but the uniqueness of my research on biological invasions is that it has never really been unique! 

Are there recent developments in the field that you find particularly interesting to explore?

As many other scientific disciplines, the field of invasion science is highly dynamic, and novel developments emerge every year. However, I find of particular interest the development of new approaches and tools to explore the links between biological invasions and the various socio-economic contexts. The use of online structured and semi-structured interviews, or the development of standardized socio-economic indicators are, for example, particularly promising for future studies. 

In addition, the emergence of novel technological tools, for instance, linked to remote sensing, eDNA, stable isotopes and camera trapping, or the rapid increase in the computational power of modern CPUs, are allowing invasion scientists to collect and analyze data that used to be unaffordable, or simply unavailable. It is certainly an exciting moment to be an invasion scientist. 

What do you find to be the biggest challenges as a researcher in your field?

I find that the proliferation of hypotheses and frameworks that characterize the field of invasion biology are particularly intriguing and challenging. Many of them work extremely well in certain conditions or across specific taxonomic groups, but they often lack generality or are marred by context dependence, which may limit their predictive power. 

Addressing such a context dependence and finding ways to integrate various hypotheses and frameworks in invasion biology will be highly beneficial for understanding and forecasting biological invasions in the next decades. 

Another challenge is to communicate the implications of our research to non-experts. I often wonder how stakeholders and policymakers from different cultural backgrounds or geographic regions perceive alien species and their impacts.  

The theme of this year’s NEOBIOTA conference was “Biological Invasions in a Changing World”. To what extent can changes be anticipated and forecasted in order to make the work of assessing their impacts and mitigating damage easier?

I think that a key point would be to focus on specific indicators or proxies to measure these changes, so that different impacts and species can be quantified, both transparently and consistently. 

In recent years, the field has produced a huge body of literature regarding impacts caused by alien species, but the results of these studies have not always been comparable. I feel that the development of the EICAT framework and its recent adoption by the IUCN as a global standard for measuring the magnitude of environmental impacts of alien species were two very important steps in this direction. 

Your talk at the NEOBIOTA conference focused on the positive socio-economic impacts of invasive species. Why is this important for different stakeholders, including policy makers, but also local communities and individuals?

In my opinion, invasive species, and more generally alien species, can have various positive socio-economic impacts that should be identified and assessed rigorously. These impacts are often anecdotally reported or vaguely stated in the literature, a tendency that hampers our capacity to identify (and forecast) conflicts of interest among different stakeholders or understand their perceptions toward alien species. 

In my talk, I presented the preliminary version of a framework that assesses positive socio-economic impacts. The framework is based on the capability approach, and aims to quantify the degree to which the well-being of certain human communities increases after the introduction of alien species. Of course, the scheme won’t be used in isolation, but rather in combination with other frameworks that assess the negative socio-economic and environmental impacts of alien species, so that their effects can be understood in their full complexity.

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Assessments of alien species impacts are reliable to prioritize resources

Experts are consistent when assessing the economic, health and ecological impacts of alien species, find the scientists.

Original post by EBD-CSIC

An international collaboration led by the Doñana Biological Station (EBD-CSIC) has shown that experts are consistent when assessing the economic, health and ecological impacts of alien species. These assessments are therefore reliable to guide the prioritization of resources invested against biological invasions.

You can find the scientific article published in the open-access, peer-reviewed scholarly journal NeoBiota.

These results have a great impact on the management by national and international institutions, which have limited resources to fight against the growing and worrying increase of alien species invasions and the damage they caused to society and environment. 

Biological invasions annually cause huge food losses, disease transmissions, species extinctions and ecosystem perturbations. For these reasons, it is one of the biggest problems that humankind currently faces, and its relevance will alarmingly increase due to the extreme situations that climate change will expose society to.

The seriousness of this problem lies in the limited human resources available to fight against it, that force to prioritize its management. Here is where tools such as impact assessments play a key role. Assessments report the impact of invasive species in different areas, including economy, health and environment, and allow us to rank the most harmful species.

For instance, in aquatic ecosystems like the Ebro Delta in Spain, there are dozens of invasive alien co-occurring species that cause millions of economic losses and irreparable ecological damage.

Such is the case of the Zebra mussel, which affects irrigation; the apple snail that devours rice fields; and the blue crab causing the local extinction and declines of many native species.

“That’s why it is crucial to ensure that the results are not dependent on the assessors and to understand what factors affect discrepancies among experts,”

explains Rubén Bernardo-Madrid, lead author and researcher at Doñana Biological Station – CSIC.

One of the relevant aspects of this study is the quantification of the consistency of responses across assessors for a large number of invasive species of vertebrates, invertebrates and plants. In addition, the researchers have studied multiple protocols focused on different aspects, providing a global view of this problem.

“The study has shown that the great majority of assessments are consistent and therefore valid to aid in decision-making. These results are encouraging as they suggest that these protocols may be useful when facing the worrying forecasts of increasing biological invasions and their damages,” 

explains Rubén.

On the other hand, the researchers have observed that discrepancies across assessments might be due to multiple factors, such as the type of impact asked or the linguistic formulation used in the protocols.

The results suggest that there is room for improvement in assessments, but it will require more funding for research, and more multidisciplinary collaborations between ecologists and linguists to develop less ambiguous protocols.

As always, the most effective measure against biological invasions turns out to be prevention.

However, given the incapacity to control every voluntary and involuntary introduction, other tools such as impact assessments are essential to reduce as far as possible the damage caused by these species on human welfare and environment. Its continuous improvement and evaluation, such as the one made in this study, are decisive.

***

Research article:

Bernardo-Madrid R, González-Moreno P, Gallardo B, Bacher S, Vilà M (2022) Consistency in impact assessments of invasive species is generally high and depends on protocols and impact types. In: Giannetto D, Piria M, Tarkan AS, Zięba G (Eds) Recent advancements in the risk screening of freshwater and terrestrial non-native species. NeoBiota 76: 163-190. https://doi.org/10.3897/neobiota.76.83028

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Genetically-enhanced biocontrols can help fight large invasive mammals

Genetic biocontrols could rapidly eradicate animals like rats, mice and rabbits. Others – like cats and foxes, would however take a lot longer.

But gene drives are not a one-size-fits-all solution

Invasive alien mammals can have catastrophic impacts on native flora and fauna, causing species extinctions and driving profound environmental change. Classical control methods such as poison baiting, trapping, or hunting are currently not feasible on a large scale, which is why researchers are looking for alternatives.

CRISPR-based genome engineering is often seen as a “silver bullet” for pest control. Despite the increasing interest in the development of this technology for invasive mammals like mice, rats, rabbits, feral cats, and foxes, studies have so far only focused on mice.

Scientists have been pondering whether genome editing technologies could help eradicate larger mammals, and if so, how long it would take.

Rabbit. Photo by Mark Philpott licensed under CC BY-NC 2.0.

In order to address these questions, a team of researchers from the University of Adelaide developed a mathematical model able to simulate the impact of gene drives on mammal populations at a landscape scale. Published in the open-access NeoBiota journal, their study is the first to estimate the time it would take to eradicate long-lived alien mammals.

Using CRISPR-Cas9 technology, the simulated gene drive relies on “molecular scissors” inserted into the Y-chromosome that target and slice up the X-chromosome at the right time during meiosis, so that only Y-chromosome carrying sperms are functional and can successfully fertilize the egg. In this way, the drive carrying males should only produce sons that also carry the molecular scissors on their Y-chromosome. Over multiple generations, females will become rarer and produce fewer offspring; as a result, the population size will fall.

Red fox. Photo by Rylee Isitt licensed under CC BY-SA 2.0.

This “X-shredder” drive has been successfully developed and demonstrated to suppress cage populations of malaria-carrying mosquitos, but has not yet been developed in mammals. The model shows that the X-shredder drive could potentially achieve landscape-scale eradication of mice, rats, rabbits, feral cats, and red foxes, but the probability of success and the time it would take to eradicate them vary greatly.

The researchers investigated the ability of the X-shredder drive to eradicate a population of 200,000 individuals of each species. “CRISPR-based gene drives offer novel solutions for controlling invasive alien species, which could ultimately extend eradication efforts to continental scales,” they concluded.

The method could be effective in small-sized pests, such as rodents and rabbits. The expected time to eradication is 18 years for mice, 19 years for rats, and 48 years for rabbits, with 90% population suppression achieved in around half those times.

However, the results suggest that gene drives are not a one-size-fits-all solution: they might not be so useful in larger species like cats and foxes.

“The probability of eradicating feral cats with gene drives is identical to flipping a coin, 50/50; and provided that the coin lands on the right side, it would take about 140 years to get rid of them,” says Dr. Aysegul Birand, part of the research team. “The probability of eradication is higher for foxes, but the wait is even longer.”

Original source: 

Birand A, Cassey P, Ross JV, Thomas PQ, Prowse TAA (2022) Scalability of genetic biocontrols for eradicating invasive alien mammals. NeoBiota 74: 93-103. https://doi.org/10.3897/neobiota.74.82394

What is the Asian hornet invasion going to cost Europe?

Since its accidental introduction in 2003 in France, the yellow-legged Asian hornet Vespa velutina nigrithorax is rapidly spreading through Europe. In a new paper, published in the open-access journal Neobiota, French scientists try to estimate the costs of the invasion regarding the potential damage to apiculture and pollination services.

Since its accidental introduction in 2003 in France, the yellow-legged Asian hornet (Vespa velutina nigrithorax) is rapidly spreading through Europe. Both experts and citizen scientists keep on identifying the new invader spreading all over the Old Continent in the last decades. 

In a recent study, French scientists led by Prof. Franck Courchamp at the Université Paris-Saclay and the CNRS, tried to evaluate the first estimated control costs for this invasion. Supported by the INVACOST project, their findings are published in the open-access journal Neobiota.

Since its invasion to France in 2004 when it was accidentally introduced from China, the Asian hornet has been spreading rapidly, colonising most of France at an approximate rate of 60-80 km per year, and also invading other European countries: Spain in 2010, Portugal and Belgium in 2011, Italy in 2012, Germany in 2014 and the UK in 2016. In the recent paper, published in the open-access journal Evolutionary Systematics, Dr. Martin Hussemann from CeNaK, University of Hamburg has recorded the northernmost capture of the Asian hornet in Hamburg in September 2019.

These data show that the Asian hornet is spreading all around Europe faster and faster with every year, even in climatically less favourable regions. The rapid invasion of the species is not necessarily caused by human-mediated dispersal, the species can rapidly spread on its own, but nevertheless, it is not uncommon.

Within its native and invasive range, V. velutina nigrithorax actively preys on honeybees, thus, causing harm to apiculture. Due to its active praying on wild insects, the Asian hornet also has a negative impact on ecosystems in general and contributes to the global decline of pollination services and honey production. Furthermore, by nesting in urban areas, the Asian hornet, which is well known for its aggressive behaviour, is a potential threat to human activities.

Currently, the control of the invasion is mainly undertaken by nest destruction and bait trapping, but none of these methods is sufficient enough to achieve complete eradication.

To proceed with the further control of the invasion, there is the need to evaluate economic costs. Those costs are divided into 3 main categories: (1) prevention of the invasion, (2) fighting the invasion and (3) damage caused by the invasion.

The cost of fighting the invasion of the Asian hornet is the cost of nest destruction. To identify those costs, the research team has studied information about the companies providing the services in the nest destruction, extrapolated the cost of nest destruction spatially and modelled the potential distribution of the invasive.


Estimated yearly cost of nest destruction if climatically suitable areas are fully invaded. Grey bars represent countries invasion hasn’t reached yet.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

As the calculations show, at the moment, the estimated yearly costs for eradication would be €11.9M for France, €9.0M for Italy and €8.6M for the United Kingdom.

“In 2006, only two years after the hornet was first observed in France, three departments were already invaded and the cost of nest destruction was estimated at €408k. Since then, the estimated yearly costs have been increasing by ~€450k each year, as the hornet keeps spreading and invades new departments. Overall, we estimated €23M as the cost of nest destruction between 2006 and 2015. If this temporal trend can be extrapolated for the next few years (i.e. if the hornet keeps spreading at a similar rate), we expect the yearly cost of nest destruction to reach an estimated value of €11.9M (given all suitable areas are invaded) in just 12 years,”

shares Prof. Franck Courchamp.

In Japan and South Korea, where the species has already been observed, the total yearly cost of nest destruction is estimated at €19.5M and €11.9M respectively.

So far, nests eradication is the most effective way to fight the invasion, though, it is not sufficient enough. As a result, so far, only 30-40% of the detected nests are destroyed each year in France. Moreover, rather than the result of a controlled strategy, those destroyed nests are only the ones that have been determined of particular potential harm to human or beekeeping activities. The researchers point out that this is not enough.


Estimated yearly cost of nest destruction in France since the start of the invasion given the yearly invasive range.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

In conclusion, the scientists call for more active measures and research, related to the invasion of V. velutina nigrithorax. Provided that other countries, including the USA, Australia, Turkey and Argentina appear to be climatically suitable for the species, they are also in danger (e.g., €26.9M for the USA).

The current study presents only the first estimates of the economic costs resulting from the Asian hornet, but definitely more actions need to be taken in order to handle harmful invasive species – one of the greatest threats to biodiversity and ecosystem functioning.

Consensus climate suitability of the yellow-legged hornet predicted from species distribution modelling.
Credit: Prof. Franck Courchamp
License: CC-BY 4.0

***

Original source:

Barbet-Massin M, Salles J-M, Courchamp F (2020) The economic cost of control of the invasive yellow-legged Asian hornet. NeoBiota 55: 11-25. https://doi.org/10.3897/neobiota.55.38550

All microgastrinae wasps from around the world finally together in a 1,089-page monograph

With 3,000 known species and thousands more left to describe, the wasps of the subfamily Microgastrinae are the single most important group of parasitoids attacking the larvae of butterflies and moths, many of which are economically important pests. Consequently, these wasps have a significant impact on both the world’s economy and biodiversity.

Due to their affinities, these wasps are widely used in biological control programs to manage agricultural and forestry pests around the globe. Further, they have also been prominently featured in many basic and applied scientific research (e.g. chemical ecology, biodiversity studies, conservation biology, genomics, behavioural ecology). However, the information about Microgastrinae species is scattered across hundreds of papers, some of which are difficult to find. To make matters worse, there has never been an authoritative checklist of the group at a planetary scale.

All currently available information about the group is now brought together in a large monograph of 1,089 pages, published in the open-access, peer-reviewed journal ZooKeys. The publication presents a total of 2,999 valid extant species belonging to 82 genera. On top of that, the monograph features fossil species and genera, unavailable names and the institutions that store the primary types of all listed species.

Moreover, the researchers have included extensive colour illustrations of all genera and many species (thousands of images in 250 image plates); brief characterisation and diagnosis of all genera; detailed species distributions (within biogeographical regions and per individual country); synopsis of what is known on host-parasitoid associations; summary of available DNA barcodes; estimations of the group diversity at world and regional levels; as well as notes on individual species upon request.

“Compiling this annotated checklist was, more than anything, a labour of love,”

says Dr. Jose Fernandez-Triana of the Canadian National Collection of Insects, lead author of the paper.

Monograph paper openly published in ZooKeys at
https://doi.org/10.3897/zookeys.920.39128

“For the past six or seven years, we have spent thousands of hours pouring through hundreds of publications, reading original descriptions in old manuscripts, checking type specimens in many collections worldwide, exchanging information with colleagues from all continents. For the past year or so, I basically stopped all other ongoing research projects I was involved with, to focus solely (almost obsessively!) on finishing this manuscript. The work was often tedious and mind-numbing, and many times I had the temptation to delay the completion of the paper for a later time. However, I was lucky that the other co-authors were just as passionate as myself, and we all pushed each other to finish the task when energy ran low.”

Fifteen species of microgastrinae wasps showing the incredible diversity within the subfamily. Note the variety of colours and shapes.
Image by Dr. Jose Fernandez-Triana

“For the past few years, the Microgastrinae wasps have been one of the most intensively studied groups of insects, at least from a taxonomic perspective,” he adds. “Just to give you an idea: between 2014 and 2019 a total of 720 new species of Microgastrinae were described worldwide. That is an average of one new species every three days, sustained over a six-year period and showing no signs of slowing down.”

He also points out that many scientists from many different countries and biogeographical regions have been involved in the description of the new species. The paper recognises them all and their contributions in the Acknowledgements section.

“You could even say that we are witnessing a renaissance in the study of this group of wasps. However, even then, what has been done is only the tip of the iceberg, as we estimated that only 5 to 10% of all Microgastrinae species have been described. That means that we do not have a name, let alone detailed knowledge, for 90-95% of the remaining species out there. Perhaps, there could be up to 50,000 Microgastrinae wasp species worldwide. It is truly humbling when you consider the magnitude of the work that lies ahead.”

Yet, it is not only a matter of counting huge numbers of species. More importantly, many of those species either have already been put in use as biocontrol agents against a wide range of agricultural and forestry pests, or have the potential to be in the future.

For applied scientists, working with hyperdiverse and poorly known groups such as Microgastrinae is even more perplexing. Navigating the maze of old names, synonyms (species described more than one time under different names), homonyms (same names applied to different species), or unavailable names (names that do not conform to the rules of the International Commission of Zoological Nomenclature) is a daunting task. Often, that results in the same species being referred to in several different ways by different authors and academic works. Consequently, many historical references are full of misleading or even plainly wrong information. Meanwhile, it is very difficult to seek out the useful and correct information.

The present annotated checklist could work as a basic reference for anyone working with or interested in the parasitoid wasps of the subfamily Microgastrinae. In the future, the authors hope to produce revised editions, thus continuing to incorporate new information as it is generated, and to also correct possible mistakes.

“We welcome all kinds of criticisms and suggestions. And we hope that biocontrol practitioners will also help us, the taxonomists, to improve future versions of this work. However, for the time being, let me say that it is a tremendous relief to get this first version out!”

concludes Dr. Fernandez-Triana.

***

Original source:

Fernandez-Triana J, Shaw MR, Boudreault C, Beaudin M, Broad GR (2020) Annotated and illustrated world checklist of Microgastrinae parasitoid wasps (Hymenoptera, Braconidae). ZooKeys 920: 1-1089. https://doi.org/10.3897/zookeys.920.39128.

Faster than a speeding bullet: Asian hornet invasion spreads to Northern Germany

Known to prey on many insects, including honey bees and other beneficiary species, the Asian hornet, which had recently invaded parts of Europe, presents a serious threat to apiculture and even to ecosystems. In their paper, published in the open-access journal Evolutionary Systematics, German scientists share concerns about this fast invader spreading to the north. In early September 2019, a single specimen was collected alive in Hamburg (Germany), representing the northernmost find of the species so far.

In early September 2019, an Asian hornet (Vespa velutina nigrithorax) was collected alive in Hamburg, Germany, representing the northernmost find of the species so far in Europe and indicating its further spread to the north. The paper by the research group from Hamburg, which also serves to update the occurrence of the dangerous invader, was published in the open-access journal Evolutionary Systematics. 

Known to prey on many insects, including honey bees and other beneficiary species, the Asian hornet, which had already invaded parts of Southern and Central Europe, is a potential threat to apiculture and even to ecosystems. 

The first specimen was captured in south-western France in 2005 and started to spread quickly. Over the next years, it invaded large parts of France and regions of Spain, Portugal, Belgium, Italy, the Netherlands, Great Britain and south-western parts of Germany. The estimated invasion speed for France has been estimated at around 78 km/year, but in reality, the species spread might be occurring much faster due to anthropogenic factors.

It’s not yet clear if the collected Asian hornet belonged to an already settled population or it’s rather the first record of a new invasion. Nevertheless, considering the fast invasion speed of the species and its relatively high climatic tolerance, it’s quite possible that it had reached Hamburg on natural routes and now reproduces there.

Even though other models suggest that the Hamburg area is not suitable for the species today, the new find might be a sign that the Asian hornet has begun spreading at a speed above that previously known and even in climatically less favourable regions.

“Therefore, the current find needs to be taken seriously, no matter if it is only a single specimen or a member of an established population”, shares the lead researcher Martin Husemann from Centrum für Naturkunde, University of Hamburg.

Invasive species are one of the great challenges in the modern world. Their occurrence can be considered as one of the key important ecological and evolutionary drivers.

***

Original source:
Husemann M, Sterr A, Maack S, Abraham R (2020) The northernmost record of the Asian hornet Vespa velutina nigrithorax (Hymenoptera, Vespidae). Evolutionary Systematics 4(1): 1-4.
https://doi.org/10.3897/evolsyst.4.47358



Non-native pest-controlling wasp identified in Canada prior to formal approval

A samurai wasp (Trissolcus japonicus) lays an egg inside a brown marmorated stink bug (Halyomorpha halys) egg. The samurai wasp’s offspring will develop inside the pest’s egg and emerge as an adult wasp. Photo by Warren Wong.

Thought to be Canada’s most promising potential defense against the brown marmorated stink bug – a globally spreading agricultural pest native to Asia – the samurai wasp (another species from Asia and natural parasitoid of the former) has been considered for future release in the country in recent years.

However, prior to any formal decision and regulatory approval, the parasitoid, which is known to be specialized on stink bug eggs, was identified at a heavily infested site in Chilliwack, British Columbia, during a survey of the local enemies of the bug, conducted by a research team led by Dr. Paul Abram of Agriculture and Agri-Food Canada. Their findings are published in the open-access Journal of Hymenoptera Research.

Native to China, Japan, Taiwan and the Korean peninsula, the brown marmorated stink bug (Halyomorpha halys) has already established in areas of the United States and Europe and continues to spread. It is highly damaging to a wide range of vegetable and fruit crops, including peaches, apples, pears, soybeans, cherries, raspberries and pears. Curiously, those infested areas in both the USA and Europe also saw the arrival of the samurai wasp (Trissolcus japonicus) amid assessments whether releasing samurai wasps in the wild should be warranted.

“Classical (importation) biological control of invasive pests, where natural enemies are imported and intentionally introduced from a pest’s area of origin, involves years of research to assess risks and benefits of proposed introductions, followed by regulatory approval,” explain the researchers in their paper.

“However, there is increasing recognition that unintentional introductions of natural enemies are probably common, introducing a high level of uncertainty to the regulatory process for biological control introductions.”

In two consecutive years (2017 and 2018), the team of Dr Abram placed a total of 1,496 egg masses (41,351 eggs) of brown marmorated stink bugs at 16 field sites in coastal and interior British Columbia – already known to host large and well-established breeding populations of the species – in order to monitor and identify the local enemies of the pest. Later on, when the researchers retrieved the eggs and studied their parasitoids, they found three native wasp species, but their parasitism appeared largely unsuccessful.

Female samurai wasp (Trissolcus japonicus) collected from Chilliwack, British Columbia. Photo by Elijah Talamas.

According to the scientists, as well as previous studies conducted in both the USA and Europe, native wasps would often lay their eggs in those of the brown marmorated stink bug, but their larvae would rarely complete development. Even when they emerged, they were unlikely to produce their own offspring.

In one of the egg masses, however, the scientists noted that all eggs had been parasitized and, moreover, each produced a viable wasp. Later, the offspring would register a success of >90% in parasitizing brown marmorated stink bug eggs. Following these observations, the team identified these parasitoids as samurai wasps.

While the species is currently being redistributed within some US states on purpose, samurai wasp populations advancing to other localities suggest that much like its host, the parasitoid is also becoming a “global invader”. Therefore, it is quite possible that the samurai wasps in British Columbia have simply crossed a distance of >400 km from nearby Washington State, and the wasp is still at the early stages of its establishment in Canada.

“Nonetheless, the detection of this exotic biological control agent in Canada concurrently with regulatory review of its intentional importation and release is emblematic of the current uncertainty around regulatory control on the movement of biological control agents across borders,” comment the authors of the study.

Field surveys and extensive analyses are currently underway to track the establishment and biological control impact of the samurai wasp in Canada and also reveal how the species ended up in British Columbia.

 

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Original source:

Abram PK, Talamas EJ, Acheampong S, Mason PG, Gariepy TD (2019) First detection of the samurai wasp, Trissolcus japonicus (Ashmead) (Hymenoptera, Scelionidae), in Canada. Journal of Hymenoptera Research 68: 29-36. https://doi.org/10.3897/jhr.68.32203

Advanced computer technology & software turn species identification interactive

Important group of biocontrol wasps from Central Europe are used to demonstrate the perks and advantages of modern, free-to-use software

Representing a group of successful biocontrol agents for various pest fruit flies, a parasitic wasp genus remains largely overlooked. While its most recent identification key dates back to 1969, many new species have been added since then. As if to make matters worse, this group of visually identical species most likely contains many species yet to be described as new to science.

Having recently studied a species group of these wasps in Central Europe, scientists Fabian Klimmek and Hannes Baur of the Natural History Museum Bern, Switzerland, not only demonstrate the need for a knowledge update, but also showcase the advantages of modern taxonomic software able to analyse large amounts of descriptive and quantitative data.

Published in the open access Biodiversity Data Journal, the team’s taxonomic paper describes a new species – Pteromalus capito – and presents a discussion on the free-to-use Xper3, developed by the Laboratory of Informatics and Systematics of Pierre-and-Marie-Curie University. The software was used to create an openly available updated key for the species group Pteromalus albipennis.

The fully illustrated interactive database covers 27 species in the group and 18 related species, in addition to a complete diagnosis, a large set of body measurements and a total of 585 images, displaying most of the characteristic features for each species.

“Nowadays, advanced computer technology, measurement procedures and equipment allow more sophisticated ways to include quantitative characters, which greatly enhance the delimitation of cryptic species,” explain the scientists.

“Recently developed software for the creation of biological identification keys like Xper3, Lucid or Delta could have the potential to replace traditional paper-based keys.”

To put the statement into context, the authors give an example with one of the studied wasp species, whose identification would take 16 steps if the previously available identification key were used, whereas only 6 steps were needed with the interactive alternative.

One of the reasons tools like Xper3 are so fast and efficient is that the key’s author can list all descriptive characters in a specific order and give them different weight in species delimitation. Thus, whenever an entomologist tries to identify a wasp specimen, the software will first run a check against the descriptors at the top, so that it can exclude non-matching taxons and provide a list of the remaining names. Whenever multiple names remain, a check further down the list is performed, until there is a single one left, which ought to be the one corresponding to the specimen. At any point, the researcher can access the chronology, in order to check for any potential mismatches without interrupting the process.

Being the product of digitally available software, interactive identification keys are not only easy, quick and inexpensive to publish, but they are also simple to edit and build on in a collaborative manner. Experts from all around the world could update the key, as long as the author grants them specific user rights. However, regardless of how many times the database is updated, a permanent URL link will continue to provide access to the latest version at all times.

To future-proof their key and its underlying data, the scientists have deposited all raw data files, R-scripts, photographs, files listing and prepared specimens at the research data Zenodo, created by OpenAIRE and CERN.

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Original source:

Klimmek F, Baur H (2018) An interactive key to Central European species of the Pteromalus albipennis species group and other species of the genus (Hymenoptera: Chalcidoidea: Pteromalidae), with the description of a new species. Biodiversity Data Journal 6: e27722. https://doi.org/10.3897/BDJ.6.e27722