November 2022
Genetic Biocontrol in Mice

Genetic biological technology has been targeted on invasive insect control, mainly mosquitos, in an attempt to prevent the spread of malaria or other transmittable diseases that endanger humans, livestock, and wildlife. Genetic biocontrol can be described as the release of a genetically modified organism through the alteration of gene drives with the intent to disrupt the reproduction of invasive populations. Recently, a new gene drive technological strategy, called t-CRISPR, has been developed to control invasive mice, the first ever vertebrate gene drive to be created.

Invasive vertebrate pests can be just as detrimental as invasive invertebrates. Invasive rodents are a major cause of biodiversity loss and environmental damage, especially throughout island ecosystems. Control strategies for invasive rodents usually rely on anticoagulant rodenticides, which are not species specific and can be damaging to humans, livestock, and native species. With little other options in the way of control, researchers turned to genetic biocontrol as a possible solution, which has been difficult to develop until now. Researchers set up a prototype called t-CRISPR, which utilizes a gene drive strategy of DNA editing technology to make alterations to the female fertility gene. A spatially explicit computer model determined that the population would be saturated with the modified gene, and all females that are generated will be infertile. The model determined that the release of 250 gene-modified mice could eradicate an island population of 200,000 in approximately 20 years. New versions of t-CRISPR are being developed to target specific mouse pest populations to prevent the unwanted spread of the gene drive, and to prevent failed eradication due to the emergence of gene resistance in future generation. This prototype is currently highly specific to mice, but researchers believe there is potential for this technology to be developed for use with other invasive pest animals.

Although this line of research can be controversial, it is an innovative step toward understanding genetic biocontrol as an option, especially when other options are environmetaly damaging.

Read the research: Gierus et al., 2022



 house mouse (Mus musculus)House mouse (Mus musculus), which is invasive in many areas on the world, especially on islands. Credit: Ed Feytag, City of New Orleans.

Hole and fecal dropping left behind by Mus musculu or house mouse. Liz KasameyerExample of Mus musculu damage: Hole in basement wall and fecal dropping. Credit: Liz Kasameyer.

Gierus et al 2022 figure 1Overview of t haplotype modification strategies for population suppression. Credit: Gierus et al., 2022. Figure 1.

The Males Have No Chance

Many different insects use pheromones for habitat selection, mate competition, courtship, and mate selection. Most insects excrete pheromones from specific gland tissues; however, female spiders deposit pheromones directly onto the silk of their web. Web-building spiders disseminate pheromone from their webs to attract males over long distances and deposit contact pheromone components on their webs that induce courtship once a mate-seeking male arrives. Yet, there has been much about this process that was not previously known. To learn more, researchers focused their attention on Steatoda grossa, also referred to as a cupboard spider, a globally invasive false widow spider that is known to reproduce year-round.

There are six species of false widow spider that are found around the world, many of which can be classified as either native or invasive, depending on where you are looking. All six species have a similar web formation, as well as body size and color, but each have a distinctive set of markings on their abdomen. When researchers examined female Steatoda grossa spiders, they found that not only did they produce three new contact pheromone components that induce courtship by males, but that the pheromone was disseminated from the posterior aggregate silk gland. This has often been hypothesized but has remained unknown until now. The study also found that Steatoda grossa might be able to adjust their webs’ attractiveness by manipulating the mate attractant pheromone components on the web. They do this by fluctuating the pH balance of the web, as there are three carboxylic acids that attract males that are present on the web that are pH dependent. With the combination of these web alterations and manipulations, false widow spiders can perform an almost constant mate call by slowly breaking down courtship-inducing pheromone components into sex attractant pheromone components. Male false widow spiders will die shortly after mating. The female will lay three or more egg sacs, each containing 200 eggs that will hatch within two to four months. The female false widow spider will then repeat the process, reproducing all year long.

Read the research: Fischer et al., 2022

steatoda-grossa-male-femaleSteatoda grossa or cupboard spider. (Top) Male, (Bottom) Female. Credit: Top)Algirdas, CC BY-SA 3.0, Bottom) Dariusz Kowalczyk, CC BY-SA 4.0.

Fischer et al 2022 figure 3Origin of contact pheromone components produced by female Steatoda grossa. Credit: Fischer et al., 2022. Figure 3

Can Lab-Reared Beetles Stop Wilt?

Ambrosia beetles are burrowing beetles that drill their way through the bark and create galleries throughout the wood of the tree where they deposit eggs and rear young. The galleries provide a low nutrient environment, causing ambrosia beetles to rely on fungus, yeast, bacteria, and virus symbionts for essential nutrients. During the construction of these galleries, female ambrosia beetles introduce many different types of symbiotic fungi; however, they can also introduce fungi that can be detrimental to the tree host. A well-known example of this is Laurel wilt (Raffaelea lauricola) which is introduced to several different tree hosts by the invasive redbay ambrosia beetle (Xyleborus glabratus). But why are these problematic fungi produced and how is the beetle-fungus symbiotic relationship involved?

A recent study examined the symbiotic fungi produced by lab reared Euwallacea interjectus in order to compare them to the fungi found in the wild. Euwallacea interjectus is a species of ambrosia beetle found in poplar trees (Argentina and China), and box elder trees (US). In Japan, this species of ambrosia beetle is a vector of Ceratocystis ficicola, a pathogenic fungus that causes wilt disease in fig trees. Researchers wanted to see if being reared in an artificial environment, on an artificial diet, affected symbiotic fungal production of this species of beetle.

Upon reviewing the results, nine filamentous fungi and one yeast were identified as symbionts, including a previously undescribed species of Fusarium fungi. The research found that the dominant symbiotic fungi produced by the reared beetles was different than that of the wild beetles. The dominant symbiont in wild ambrosia beetles was Fusarium kuroshium, while for reared beetles it was Neocosmospora metavorans. These results suggest that the symbiotic relationship between beetle and fungi is dynamic and could be altered by their diet or nesting place. Based on these new findings, researchers believe it may one day be possible to replace an insect's symbiotic fungi with a species-specific strain that would cause less damage to the host plant.

There are about 3,000 species of ambrosia beetles (subfamilies Scolytinae and Platypodinae, Family Curculionidae) but there is still a lot about their cryptic lifestyle we do not know, mainly because it happens inside the bark of a tree. Studying wild populations is difficult, but lab-reared ambrosia beetles can provide us with a bit more information. Although this research is in its beginning stages, it already introduces many possibilities for artificial control methods of wilt or similar fungal pathogens. Could these lab-reared beetles help us stop wilt? Mayby.

Read the research: Zi-Ru Jiang et al., 2022

Zi-Ru Jiang et al 2022 figure 1
Typical reproduction of an ambrosia beetle, Euwallacea interjectus, on a semi-artificial diet. Credit: Zi-Ru Jiang et al., 2022. Figure 1. Note: the mycangium is what carries the symbiotic ambrosia fungus throughout the galleries.

Zi-Ru Jiang et al 2022 figure 2
Morphological characteristics of Fusarium sp., Neocosmospora metavorans, and Meyerozyma guilliermondii. Credit: Zi-Ru Jiang et al., 2022. Figure 2.


Texas Citrus Need Your Help

The Asian citrus psyllid (Diaphorina citri) and the Citrus Greening pathogen (Candidatus liberibacter asiaticus) are threatening citrus in multiple Texas counties, and we need your help and samples to monitor the spread. This pest and pathogen are extremely detrimental to Texas citrus, both economically and agriculturally. The presence of either can greatly affect citrus yield.

TISI is offering diagnostic services if you suspect your backyard citrus has either the psyllid pest or the Citrus Greening pathogen.

Contact for instruction to send a plant or pest sample. If you are located within 200 miles of our headquarters, we can collect samples, and/or provide traps and monitoring services. 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 back yard. Your citrus can also become part of a TISI survey that is monitoring Texas citrus for pests and pathogens. If you are interested in this, TISI will providing trapping materials, assist with management strategies, and more.

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

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.

The Government eDNA Working Group

The 6th annual Environmental DNA Technical Exchange Workshop will be a FREE virtual workshop hosted and coordinated by the Government eDNA Working Group (GEDWG). GEDWG focuses on bringing together scientists, natural resources managers, and other stakeholders interested in eDNA and related fields for the purposes of sharing technical expertise and experience. Participants from outside federal, state, provincial, municipal, and other government agencies are welcome to join.

There are three available dates: January 24, 25, or 26, from 10am-6pm EST.

For more information on GEDWG, please contact: Richard Lance or Katy Klymus. Submit your Abstract submission here. Click HERE for Registration and additional information.

 6eDTEW copy
Credit: Government Environmental DNA Working Group.

2023 Annual Invasive Species Forum

The virtual 2023 Invasive Species Forum is an annual event that brings attention to invasive species issues, research, and advances in prevention and management occurring across Canada, and in neighboring U.S. States.

Date: February 7-9, 2023

The theme is “Invasive Species Action in a Changing Climate” The event will feature may dedicated sessions such as Vectors, Ecosystem Resilience Developments in Research and Management, Municipalities, Indigenous Communities, Outreach, and more. Registration is free!

 invasive species forum 
Credit: Invasive Species Centre.

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:

  • December 21, 1pm- Understanding ISPM 15 to reduce the risk of pests in wood packaging. REGISTER.
  • January 18, 1pm – Miller Creek Watershed Restoration: The value of partnership during a pandemic. REGISTER


Spongy Invasives Found on Ship

An agricultural specialist with US Customs and Border Protection found the egg cases of Asian spongy moths (Lymantria dispar, previously known as Asian Gypsy moth) on a Panamanian bulk carrier trying to make port in Laplace, Louisiana. Authorities found four egg masses on the exterior surface of the vessel and railing on the upper and lower decks. These egg masses could yield hundreds of larvae once hatched. The vessel was targeted for inspection because it had previously docked at spongy moth high-risk areas in China. The Asian spongy moth is considered a major invasive pest in the northern US and southeastern Canada. The ship was required to leave port and anchor outside of US waters for cleaning and disinfection. A follow up inspection was conducted, and no additional egg masses were found. The ship was then allowed to proceed with cargo operations.


Asian spongy moths (<em>Lymantria dispar</em>) egg sacks
Asian spongy moths (Lymantria dispar, previously known as Asian Gypsy moth) egg sacks found on ship. Credit: US Customs and Border Protection.

Invasive Snail Stopped by Beagles

A pair of invasive giant African snails (Achatina fulica) were found in the luggage of a passenger at an international airport, according to US Customs and Border Protection. A K-9 team of beagles at Hartsfield-Jackson International Airport detected the invasive species during a routine luggage search. The snails were found in a checked bag coming from Nigeria. Giant African snails are problematic because they reproduce rapidly and can cause damage to over 500 variations of host plants and crops. This situation serves as an example of the vital service these surveillance dogs provide at both the airports and ports. The snails were turned over to the USDA for evaluation and the traveler was warned about properly declaring pests and agriculture.


CBP Beagle Brigade intercepts Giant African Snails at ATLairport. CBP Southeast
US Customs and Border Protection Beagle Brigade intercepts Giant African Snails (Achatina fulica) at Hartsfield-Jackson International Airport. Credit: CBP Southeast.

Invasive Spotlight:

European Starling
(Sturnus vulgaris)

European starling, also known as the common starling (Sturnus vulgaris), is a stocky blackbird with a short tail and a long slender beak. In flight, their wings are short and pointed, giving them a star-like appearance, which is where they received their name. During the summer months, they turn iridescent purplish green with a yellow beak. During the winter, they are brown and covered in brilliant white spots. Their eggs are a pale glossy blue or greenish white. Both parents take turns incubating the eggs. The females will lay 4-6 eggs in mid-April. The eggs hatch after 12 days. These birds can adapt to a variety of habitats and have diverse dietary preferences. These characteristics allow them to expand quickly and produce two broods per season.

Since their introduction to the US, the European starling has competed aggressively with blue birds (Sialia spp.), purple martins (Progne subis), red-headed woodpeckers (Melanerpes erythrocephalus), and other cavity nesting birds. European starlings often expel the occupants of native bird nests and take possession of them. This can be problematic to native bird populations as they are often outnumbered by European starlings. European starlings prefer urban, suburban, and rural areas. They are ground feeders of lawns, fields, sidewalks, and parking lots. They perch and roost high on wires, trees, and buildings. These birds are widespread throughout Texas and much of the US.

There are several species that are similar in appearance to the European starling. These species include the Rusty Blackbird (Euphagus carolinus), Brewer's Blackbird (Euphagus cyanocephalus), Red-winged Blackbird (Agelaius phoeniceus), Common Grackle (Quiscalus quiscula), and Brown-headed Cowbird (Molothrus ater).

For information about the European starling management, visit the TexasInvasives species info page.

Sturnus vulgaris. John Gould 
European starling (Sturnus vulgaris). Credit: John Gould.
European starling eggs. Chris Evans. University of Illinois
European starling eggs. Credit: Chris Evans, University of Illinois.

european starling distribution
Map depicting distribution of European starling throughout the US. Credit: National Audubon Society.

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 scientist, 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.

Aquarium Watch: Looking for Prohibited Invasive Aquatic Species

Please help and natural habitats by looking for 14 prohibited invasive aquatic species being sold in your local aquarium store. With just one photo you can assist us in finding and documenting which stores are selling prohibited species. will contact the appropriate Texas institutions to remove the species for sale.

If you would like more information please email, and mention you want to assist with our Aquarium Watch.

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 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.

Armorded catfish. Photographer United States Geological Survey
Armored catfish (Hypostomus plecostomus). Credit: United States Geological Survey.

air-potato (Dioscorea bulbifera)2 bulbil. credit Karen Brown
Air-potato (Dioscorea bulbifera), bulbil emerging from leaf axil. Credit: Karen Brown.

More News

King Ranch Is Turning Its Invasive Mesquite Problem into Bourbon
Kentucky's Old Forester Distilling released King Ranch bourbon, which is currently only available in Texas. This bourbon is aged and passed through layers of mesquite charcoal. The process was created to make use of invasive mesquite trees that have been growing on the property.

Report Says Native Fish Overlooked as Invaders in US Waters
Some scientists want to document the positive impacts of alien species. The development of the EICAT+ system is helping that happen. However, this topic has been a hotbed for debate for a long time and some scientists think it is a waste of time and resources. What do you think?

Scientists Find Intact 5-Foot Alligator Inside 18-Foot-Long Burmese Python in Florida
Fieldworker sent a group of researchers a deceased 18-Foot-Long Burmese Python (Python molurus bivittatus) in Florida and performed a necropsy after something large was felt inside the snake's body during a cursory examination.

Commission Approves Drone Use to Aid Feral Hog Hunters
The use of drones to aid in visual surveillance of feral hogs to aid in control has been approved for Texas landowners. If certain parameters are met, a permit to use a drone can be requested and issued by TPWD. Drone mounted weapons have not been legalized.

Invasive Plant Species Are Increasing Exponentially, But No One Knows How Many Species There Are
Existing lists of global invasive species are often incomplete, missing recent invasion records, missing species that are yet to be recorded, but it is unclear how many species are not accounted for.

Millions Of Fire Ants Threaten To 'Rain Down' On Hawaii Residents and Sting Them in Their Sleep, Officials Say
Kauai, Hawaii, is experiencing one of the worst infestations of invasive little fire ants (Wasmannia auropunctata) since its introduction. The ants are infesting homes and can fall from the trees that they inhabit. These fire ants are a different species from the ones we have in Texas (Solenopsis invicta), but their stings are similarly bad.

Invasive Fruit Fly May Pose Threat to Forest Ecosystems
The invasive spotted wing drosophila (SWD, Drosophila suzukii) can cause massive amounts of economical and agricultural damage. However, researchers are just starting to understand the impact this invasive fly have on natural forest ecosystems.

Entomologists Issue Warning About Effects of Climate Change on Insects
The effects of climate change are often compounded with habitat loss, pollution, and introduction of invasive species, and could drastically reduce insect populations. Recent research looks at the long-term and short-term effects this will have on sustainable ecosystems.

How Telephone Poles Could Help Stop the Spotted Lanternfly
Spotted lanternflies (Lycorma delicatula) are attracted to tall structures. Researchers are utilizing telephone poles by turning them into monitoring devices to test different eradication methods.

Plant Roots Change Shape and Branch Out for Water
Researchers were able to reveal that plant roots can alter their shape in response to external moisture availability. This ability is key for adaptation in times of limited water or in dry areas.


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: