January 2024
It’s a Plant move Bug World

How do insects spread across the world? Why does it seem like some areas are more susceptible to invasive/non-native introduction than others? Are there different geographical or environmental pressures? Are the biological traits of the invasive organism the cause, and everything else is coincidence? Researchers have proposed several hypotheses in an attempt to explain the asymmetry that occurs during the geographic exchange of invasive species.

For example, a recent study looked closely at the asymmetrical exchange of non-native insects that has occurred between Europe, North America, and Australia since the early 1800s. The study took regional trade and source species (invader) pool into account. European insects were found to be highly successful invaders and were more numerous compared to North American and Australian invasives. What was causing this asymmetry? At first it was suspected that North American and Australian habitats may be easier to invade compared to Europe. However, this was quickly ruled out. Europe has been invaded by many Asian invasive insects, which suggests that it is no more resilient to invasives than any other continent.

Further evidence suggests historical plant introduction may be the true culprit behind the asymmetry. In the historical records, most of the asymmetry arises prior to 1950, suggesting settlers likely played a heavy role in the movement of these plants. Plants infested with hitchhikers that were introduced to the European colonies could have promoted the spread of insects throughout the other continents. These plants would have provided a sustainable food source and habitat. Researchers are still examining the vast archives and historical records for more information that shed light on other examples of geographic exchange and asymmetry of invasive species.

Read the research: Isitt et al., 2024



 european-insects-spreaFlows of non-native insects between North America, Europe, and Australasia. Numbers indicate the total count of species established from donor to recipient, with flow widths being proportional to these counts. Overlapping flows on the donor side indicate the fraction of species that established in both recipient regions. Credit: Isitt et al., 2024.


Can’t Fool Me with Your Treats

Ants are highly diverse, exhibit a variety of specialized behaviors, and are important for the functionality of a healthy ecosystem. However, invasive ants can pose a severe economic and ecological threat for many of the same reasons that make them unique (regardless of where they are). Ants can “listen” with their feet (vibrations), “smell” with their antennae, and “speak” with chemical signals (pheromones and allomones) released through the body. Some colonies have also exhibited a behavioral immunity against pathogens. A colony can deploy behavioral strategies to collectively respond to a toxin or dangerous situations in order to avoid it. This behavior is making toxic ant bait traps less effective which could explain some of the challenges that occur within the management of invasive species.

To learn more, Argentine ant (Linepithema humile) colonies were observed during a laboratory study to determine if the colonies would actively abandon ‘palatable’ yet toxic food bait, and to what degree. Two baits were placed and examined: a sucrose-only and a sucrose-toxicant. After many hours, the researchers started to see a decline in the activity of ant activity at the sucrose-toxicant, while the activity at the other bait remained consistent throughout. At the end of the observation time, the toxicant showed an approximate 75% decline in activity. Upon further examination, it was found this was not due to ant death by the consumption of poison, i.e. not due to a decrease in population size, or lack of motivation to forage. The researchers observed that the accumulation results demonstrate the colony that was presented with the toxicant was exhibiting behavioral abandonment. These results could help us gain a deeper understanding of pest bait avoidance, along with implications that can be used toward future control efforts and monitoring.

Read the research: Zanola et al., 2024

Argentine ant. Eli Sarnat. PIAkey Invasive Ants of the Pacific Islands. USDA APHIS PPQ. Bugwood.org
Argentine ant (Linepithema humile). Credit: Eli Sarnat, PIAkey Invasive Ants of the Pacific Islands, USDA APHIS PPQ, Bugwood.org

ants and bait
Ant activity (measured as the mean number) crossing a line on the bridge (foraging trail) toward the foraging arena (bait) over a period of hours. Blue indicates ant activity at the sucrose bate and red at the toxicant. Credit: Zanola et al., 2024

CABI Digital Library

CABI is an international, inter-governmental, non-profit organization that supports research, community, and professional development. The CABI scientific staff provides a variety of information, support tools, and research services that assist with solving problems in agriculture and the environment.

The digital library offers a database, literature collection, compendium, books, and more. The large database is made up of millions of research records, and is categorized into areas of interest that include global health, agriculture, abstracts, and others. The Collections, books, journals, and cases are made up of an assortment of bibliographies, research articles, and full texts. However, a subscription or purchase is required for access.

The Compendiums are albums that bring together data and research of species, pests, and disease into one comprehensive resource. Each album includes images, maps, diagnostic, and decision support tools, such as The Horizon Scanning Tool, Pest Risk Analysis Tool, and the Invasive Species Discovery Tool. There are many albums to choose from: animal health and production, aquaculture, forestry, horticulture, seedborne pests, crop protection, food safety and quality, and the CABI Invasive Species Compendium. It includes an easily searchable database with images, taxonomic information, distribution, descriptions, and more.

The Invasive Species Discovery Tool is like a digital key that can help the user move through the database by filtering through select search parameters: distribution, organism type, taxonomy, habitat, risk and impact factors, and pathways. This tool can be useful in a variety of ways. For example, it can to narrow down your search radius for hosts affected by a target, or estimate pathways and distributions.

Search the CABI Library.



CABI invasive species discovery tool
Example of CABI Invasive Species Discovery Tool in use. Credit: Screen shot of CABI.org

Keep Your Citrus Healthy

TISI is offering FREE diagnostic services if you suspect your citrus has either the psyllid pest or the Citrus Greening pathogen, or you would like your citrus plants to be part of our screening survey.

The Asian citrus psyllid (Diaphorina citri) and the Citrus Greening pathogen (Candidatus liberibacter asiaticus) are threatening citrus in multiple Texas counties. By taking samples and monitoring the spread, it is easier to ensure that you and your neighbors are not affected. This pest and pathogen are extremely detrimental to Texas citrus, both economically and agriculturally. The presence of either can greatly affect citrus yield.

If you are interested in having your citrus trees checked or being part of the survey, please contact invasives@shsu.edu. If you are located within 200 miles of our headquarters, we can collect samples and/or provide traps and monitoring services. Otherwise, we will send you easy step-by-step instructions so you can do it yourself. Not only will we share the results and management strategies (where applicable), but you will become part of a multi-county monitoring survey that is striving to improve the health of Texas citrus!

Also Available: TISI offers educational workshops that highlight information about the Asian citrus psyllid, the pathogen Citrus Greening, and what you need to look out for in your own backyard. If you are interested in this, TISI will provide trapping materials, assist with management strategies, and more.

Don’t waste another moment. Help stop the spread!

symptoms of citrus greening. Jeffrey W. Lotz. Florida Department of Agriculture and Consumer Services. Bugwood.org
Symptoms of citrus greening bacterium. Credit: Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, bugwood.org

citrus greening
Leaf mottle on grapefruit, a characteristic symptom caused by citrus greening bacterium but also seen on trees infected by Spiroplasma citri. Credit: J.M. Bove.

North American Invasive Species Management Association Training Webinars

This program is designed to provide the education needed for professionals and students who are managing or learning to manage invasive species. The courses include the most current invasive species identification, control, and management techniques, and how to comply with local and federal regulations.

Participants may register and enroll at any time, and will receive a certificate of invasive species management from NAISMA upon completion of the program.

All live webinars are open to the public. Recorded webinars are available to members of NAISMA.

NAISMA 2020 Webinar Schedule:

  • February 26, 1pm CDT- Annual USGS Invasive Species Research Forum. REGISTER.
  • February 28, 1pm CST- The Federal Interagency Committee on the Management of Noxious and Exotic Weeds. REGISTER.
  • February 29, 1pm CST- Opportunities and Challenges for Preventing the Next Plant Invasion. REGISTER.
  • March 1, 1pm CST- Protecting North American Biodiversity from Invasive Species. REGISTER.



Lure Them with Buzzzing

The spotted lanternfly (Lycorma delicatula) is an invasive species that has now spread to 13 states along the eastern coast of the U.S. This herbivorous beauty feeds on over 70 different host plants (over 100 plant species), many of which are economically important crops, making it a priority threat. Fortunately, scientists may have found a potential weakness that could be utilized for mitigation.

Recent research has revealed that 4th instar nymphs and adults responded to and walked toward a 60-cycle (60Hz) vibration stimulus during experimental conditions. These findings, although preliminary, suggest there is potential for using vibration stimulus for management of this invasive possibly with some kind of lure or trap. Research also mentions that other Hemiptera are known to communicate using some form of ‘substrate-borne vibrational signals,’ which leads one to wonder if vibration stimulus could be used when dealing with other Hemipteran invasives... it’s too soon to tell, but not too soon to hope.

Read the research: Rohde et al., 2022

Bug Zapper. Credit: Public Domain, Free access image.

CWMA Whooping Crane Festival and Spring Workday

The Texas Gulf Coast CWMA is ready to celebrate at the annual Whooping Crane Festival in Port Aransas. We would like to have volunteers out at the Port Aransas Nature Preserve sites to help visitors, answer questions, and make visitors feel welcome!

If you would like to volunteer at one of our Port Aransas Nature Preserve sites or at our Nature Preserve and Texas Gulf Region CWMA booth for the Whooping Crane Festival: February 22-25, 2024- please register HERE.

To sign up for the Spring Workday and Meeting, February 22, 2024- please register HERE.

WhoopingCraneFest2024 2
Credit: CWMA

InvasivesU NAISMA Webinars

InvasivesU is NAISMA’s exclusive online learning library intended to provide professionals, students, and interested individuals with the knowledge and tools necessary to prevent and manage invasive species. There are multiple certified courses available in a number of different fields and areas of interest. Some examples are:

Biocontrol 101: Provides individuals with knowledge about the science, application, and regulation of classical weed biological control. REGISTER.

Certified Weed Free Products Inspector Training: Provides professionals working under a NAISMA MOU with the information necessary to serve as an inspector certifying forage, gravel, and/or mulch to the science-based international standards. REGISTER.

There are other courses available, but registration fees apply. For additional information and to see a list of all courses, online learning library.



Invasive Spotlight:

Giant Salvinia
(Salvinia molest)

Giant salvinia (Salvinia molesta) is a rootless, floating fern. Emergent groups of leaves (fronds) are oblong and flat or semi-cupped and grow in chains. Leaves grow in pairs and are approximately 1/2 inches wide and 1 inch long. The upper surface of the green leaves is covered with rows of white, coarse hairs, acting as a water repellent. It is an aquarium fern that was first discovered in South Carolina in 1995, and has made itself at home in Texas since 1997. It has become one of the most destructive aquatic invasive plants listed on the Federal and TDA Noxious Weeds list, as well as the TPWD Prohibited Exotic species and Invasive Plant Atlas of the US. Quite a feat for a rootless, free-floating fern.

It thrives in slow moving warm bodies of water, quickly creating dense mats that cover the surface. These mats can grow large enough to deplete oxygen levels and block sunlight from areas of the water system. It can quickly choke out the native vegetation and harm other organisms supported in the ecosystem. Salvinia mainly reproduces by the budding off of nodes or broken stems. It can then go wherever the water leads. Salvinia has infested 17 states, including Texas, since its introduction.

There is some research to suggest that this invasive fern has some resilience toward extreme temperatures, both hot and cold, though on-going research is underway. Salvinia weevils (Cyrtobagous salviniae) are the current approved biocontrol for salvinia. Find more information at the TexasInvasives.org, HERE. These weevils have shown to be effective upon release in many areas.

Learn more about giant salvinia, how it threatens Texas waterways, and where it's found at the 'Protect the lakes you love' information page. If you believe you have spotted giant or common salvinia, please REPORT IT HERE!.

Salvinia infestation. Mic Julien. Commonwealth Scientific and Industrial Research Organization. Bugwood.org 
Giant salvinia (Salvinia molesta) infestation. Credit: Mic Julien, Commonwealth Scientific and Industrial Research Organization, Bugwood.org
Giant salvinia. Keith Bradley. Botanist Conservation Biologist. Bugwood.org 2
Giant salvinia. Credit: Keith Bradley, Botanist Conservation Biologist, Bugwood.org

Salvinia weevil. Richard Chan. Commonwealth Scientific and Industrial Research Organization. Bugwood.org
Salvinia weevil (Cyrtobagous salviniae). Credit: Richard Chan, Commonwealth Scientific and Industrial Research Organization, Bugwood.org

Get Involved Today!!

The Texas Invasive Species Institute (TISI) and The Texas Research Institute for Environmental Studies (TRIES) have many surveys and projects underway. These facilities strive to provide yearly invasive species presence and absence data to the authorities. Pre-screening is one of the first lines of defense in the war against invasives. However, sometimes it is hard to do it alone.

With the aid of the public and citizen scientists, we could cover a much wider area, and gather a more substantial amount of data. When it comes to protecting our environment, there is an opportunity for everyone! Together we can make a difference, one research project at a time.

See how you can get involved by reading the projects listed below or see all the available projects on the Texas Invasives website HERE.


Air Potato Survey

Help Texas Research Institute for Environmental Studies conduct an air potato survey by actively reporting any infestations seen in your area. The air potato (Dioscorea bulbifera) is a fast growing, high climbing vine. Potato-like tubers are the primary means of reproduction for this vine. They can be as small as a marble or as large as a softball. Native yams are often confused for air potatoes. To avoid this confusion, please refer to the key below:

- Plants rhizomatous; bulbils never produced in leaf axils; petiole base never clasping the stem; Native D. villosa
- Plants tuberous; bulbils produced in leaf axils; petiole base sometimes clasping the stem; Invasive D. bulbifera

For additional information, please refer to the TexasInvasives information page.

If you believe you have identified an air potato vine, please email invasives@shsu.edu and include the following information: an image, an approximate number of vines present, the location (including whether it is on public or private land), and if bulbils are present (the potato-like tubers that emerge from the stem).

Participation opportunities

Participation Opportunities. Credit: KNKleiner, TRIES.


air-potato (Dioscorea bulbifera)2 bulbil. credit Karen Brown

Air-potato (Dioscorea bulbifera), bulbil emerging from leaf axil. Credit: Karen Brown.  


Video Invasion

Monthly video picks about invasive species or the people that want to tell us more about them. There are some amazing citizens and professionals around the world that poke, prod, chase, dive, and investigate everything they can about these alien invaders. Jump into this cinematic rabbit hole. You never know what you may learn.

FIELD NOTES: Weevils Fight Invasive Giant Salvinia on Texas Lakes. TPWD

Weevils are an effective biocontrol of Giant Salvinia (Salvinia molesta). Texas Parks & Wildlife has constructed giant salvinia weevil rearing facilities at the Jasper State Fish Hatchery and the Caddo Lake National Wildlife Refuge. Giant salvinia is harvested from the affected reservoir or lake, inoculated with weevils, and reintroduced into the lake after weevils have matured. Biocontrol options are important to keep pesticide use and pesticide resistance at a minimum where possible.

The Impact of Climate Change On Invasive Species And Ecosystems. CBSN

This video may be a bit old, but it is just as relevant as the day it was recorded. CBSN team investigates invasive species and the role climate change plays in altering ecosystems. People vs. climate vs. others.

Uninvited: The Spread of Invasive Species. NYSDEC

One of the biggest ways you can help stop invasive species is by educating friends, family, and neighbors about the small choices they can make. Starting small can make a big difference, such as: using local firewood, cleaning, draining, and drying your watercraft, and brushing mud/debris off your outdoor gear.

More News

Over 2,000 Giant Invasive Snails Removed from San Antonio River Walk
Thousands of invasive apple snails (Pomacea maculata) were found and removed during this year’s biennial downtown San Antonio River draining. mysanantonio.com

Space Invaders: Solving The Invasive Species Explosion
Humans have reshaped environments and changed ecosystems by moving species across their natural boundaries. We have had the greatest impact on our planet. Now we must do something about it. nationalgeographic.com

Pflugerville Parks And Recreation Uses Goats to Clear Parks of Weeds
Pflugerville Park is allowing goats roam and graze as an environmentally friendly way to clean up the weeds and invasive vegetation around the recreation areas. mysanantonio.com

What’s Keeping Invasive Species Out of Hawaii? Inspections, Programs And Plans, And Finally, You
Hawaii is under threat by many different invasive species. Unfortunately, there is no single organization that can tackle all the invasive species challenges. An alert system of organizations with the help of an aware community is required. mauinews.com

New Gene-Editing Tools May Help Wipe Out Mosquito-Borne Diseases
Gene editing has allowed researchers to develop select Aedes aegypti male mosquitoes to produce females that do not survive development to adulthood. npr.org

African Smallholder Farmers Benefit from Reduced Crop Losses and Higher Incomes from A Novel Pest Alert Service
A project that has been providing smallholder farmers with a pest alert service, called CABI-led Pest Risk Information Service (PRISE), have benefited from a reduced crop loss and higher income compared to farmers who did not have access to the alert service. phys.org

A Monkey, A Mussel, and A Crayfish: No Joke, But Likely the Next Florida Invasive Species
A recent study conducted in Florida evaluated over 400 species on features that could make them adept at becoming successful invasive species. Thanks to the results, experts may be able to prepare for the potential threats. news-press.com

Colony Spawning and Enhanced Brood Protection in Invasive Bluegill Found to Facilitate Their Spread
Bluegills (Lepomis macrochirus) have been introduced to aquatic ecosystems worldwide. The males construct nests in social clusters, while aggressively guarding their own brood. The lack of natural predators plus this behavior may explain some of their invasive abilities. phys.org

Human Activity Facilitates Invasive Plants' Colonization in Mediterranean Ecosystems
Some invasive plants can form persistent seed banks that remain under the soil for years, and this makes eradication very difficult. Eventually, these buried seedbanks will reoccupy ecosystems and displace the native flora. sciencedaily.com

Revolutionizing Plastics: Upcycling Agricultural Waste Boosts Performance and Sustainability
Researchers have developed a composite matrix that combines the conservation of waste milk bottles and eco-friendly sustainability of waste pineapple leaves to create strong, flexible materials. phys.org

Sentinel Pest Network and Invaders of Texas Workshops

Invaders of Texas workshops train volunteers to detect and report invasive species as citizen scientists. Workshops, which are free, are designed to introduce participants to invasive species and the problems they cause, cover aspects of invasive species management, teach identification of local invasive plants, and train participants to report invasive plants using the TX Invaders mobile application. The workshop is 7 hours long (usually on a Saturday, but scheduling is arranged with each individual host group). The workshop satisfies Master Naturalist training requirements.

Sentinel Pest Network workshops serve to increase the awareness and early detection of a set of particularly important invasive species to help prevent their spread into Texas or their further spread within Texas. Participants learn to identify species such as the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance, and to report them. The workshop is 3.5 hours long. The workshop satisfies Master Naturalist training requirements.

Upcoming Workshops:

Citizen Scientist Training, Woodlands Invasive Species Task Force
February 17th, 2024
Time: 8:30-12:30pm
Woodlands Emergency Training Center, 16135 Interstate 45 S, Conroe, TX 77385 Contact: Terrilyn MacArthur (TMacArthur@thewoodlandstownship-tx.gov)

Invasive Species Presentation, Burnet Master Gardeners
February 28th, 2024
Time: 12:30-2:30pm
Marble Falls, TX
Contact: Joan Altobelli

CITRUS WORKSHOPS: Stay tuned for upcoming 2023 virtual weekend presentations about Citrus diseases and FREE testing we offer at Texas Invasive Species Institute.