Researchers have engineered a robot to scare invasive mosquitofish (Gambusia holbrooki) away, revealing how fear alters its behavior, physiology, and fertility. Inspired by the main natural enemy to mosquitofish, the largemouth bass (Micropterus salmoides), the robot mimics the appearance and movements of a real predator.

Eastern mosquitofish (Gambusia holbrooki) were introduced in many parts of the world to eat mosquito larvae and keep mosquito populations under control. However, there have been negative consequence on local fauna since their introduction. Mosquitofish chew the tails off native freshwater fish and tadpoles, leaving them to die, and eat the eggs of fishes and amphibians. In a controlled laboratory setting, a testing arena was created where a high-precision robotic manipulator was placed below a container which held the robotic predator, mosquitofish, and tadpoles. A webcam was installed above the arena to acquire real time video for the multi-species tracking system that was used to quantify interactions. Tadpoles used were of the native Australian frog (Litoria moorei), which is negatively impacted by mosquitofish in the wild.

Data revealed that brief exposure to the robotic predator altered mosquitofish behavior, increasing fear and stress responses, and reduced the impact of mosquitofish on tadpoles. When the robotic fish was present, the mosquitofish stayed closer to each other, spent more time in the center of the testing arena, and swam more frequently with repeated sharp turns, compared to those who had not been introduced to the robotic predator. Effects of predation risk resulted in altered behavior for weeks after exposure. Routine activity and feeding rate of mosquitofish was altered because the fish spent more energy toward escape than anything else, resulting in weight loss, variation in body shape, and reduction in the fertility of both sexes. The behavior of the tadpoles was also affected. Since tadpoles have poor eyesight, they do not see the robot well and did not seem affected by its presence. With the absence of mosquitofish predation, the tadpoles ventured out and swam more freely around the arena with less fear. Results suggest the presence of an artificial predator could impair mosquitofish survival, reproduction, and ecological success. More research is required before robotic predators are applicable for field trials.

Click here to see a video that shows the robotic fish, mosquitofish, and tadpoles in a testing arena where computer vision guides the robot’s movements and attacks.

To read the research: Polverino et al., 2021.

The tree of heaven (Ailanthus altissima) is a fast-growing deciduous tree, native to Taiwan and northeast and central China, that can grow up to 80 feet in height. These trees are prolific seed producers and can quickly outgrow and overrun native vegetation by forming an impenetrable thicket. They are tolerant of extreme environmental conditions and there are limited herbivorous insects capable of suppressing growth. Ailanthus trees also produce toxins that prevent the establishment of other plant species. The root system is aggressive enough to cause damage to pavement, sewers, and foundations. These trees are a particular nuisance in vineyards, where mechanical control and herbicides can damage the grapevines. The tree of heaven is widely distributed across the U.S. (occurring in 42 states) and Europe.

As a part of an ongoing pursuit of USDA Agriculture Research Service (ARS) to identify natural enemies of tree of heaven, field observations were carried out in a recreative park in the city of Colombes, near Paris, where a population of Eriophyid mites (Aculus mosoniensis) were found on an Ailanthus tree. There are four species of Eriophyid mites that feed on the tree of heaven: Aculops ailanthic, Aculops taihangensis, Aculus altissimae, and Aculus mosoniensis. Aculus mosoniensis is considered one of the most promising biological controls agents of the tree of heaven in Europe. These mites form dense populations on the undersurface of young compound leaves, causing the edges to curl and turn yellow. Heavily infested plants reveal drying of the upper parts of the stem, and younger plants can desiccate and permanently loose leaves. Aculus mosoniensis is always associated with the tree of heaven, indicating host specificity.

Further investigation found these mites in four other locations around France. This is the first time these mites have been found outside of Hungry and Italy, where it first originated. These findings indicate that Aculus mosoniensis is already established and distributed within France and provides encouraging evidence that the geographic occurrence of this species is expanding in Europe.

To read more about Aculus mosoniensis and the tree of heaven: Kashefi et al., 2021.

Giant salvinia, Salvinia molesta, is an extremely invasive, free-floating fern that has developed sophisticated structures to allow water to roll off its leaves quickly. The fern consists of a trifoliate whorl, two floating leaves that lie on the water’s surface and one root-like leaf extending downward. The fern forms thick, dense matts along the surface of the water. The upper surface of each leaf is covered in water repellant hairs, called trichomes, that resemble tiny eggbeaters. The hairs are coated with hydrophobic wax crystals, while the area at the terminal ends of the hairs lack wax crystals and are hydrophilic. These features make the air-water interface more stable and ensure the leaves do not become waterlogged. The trichomes also help relieve the pressure on the leaves floating on the water surface, and allows the plant to keep the stomata open for air exchange.

Researchers set up experiments to simulate rainfall, and used high-speed cameras to track the path of water droplets slapping onto the fern's leaves. They found the combination of the trichomes, and the elasticity of the leaves allow for the water to be shaken off rather quickly when water droplets of various sizes were dropped onto both fixed and free-floating leaves. The trichomes are efficient at keeping the base of the leaf free of water. The researchers say the energy state of a droplet is more favorable on the trichomes than between them due to the water-repelling effect of the whisks. When a drop of water rolls over the trichomes of the leaf, its strong surface forces cause it to suck up the residual water trapped between the trichomes. This keeps water off the stomata at the base of the floating fern's leaves where the gas exchange for the plant takes place.

Read the research: Konrad et al., 2021.

Are You Eating My Crops? 8 of 12

Rice blast (Magnaporthe oryzae- Triticum pathogen), sometimes also referred to a wheat blast, has been reported in 85 countries around the world, where rice is grown. We are passed the halfway mark with the eighth headliner in our 12-month series called ‘Are you eating my crops?’ Individual pests chosen for this series have not yet been reported in Texas, but are on the ‘Watch List’ due to their high level of pest importance or risk due to host availability. So far during this series, we have covered several different crop pests, what they look like, and where you can find more information about them. To read more about previous headliners, visit the TexasInvasives.org iWire page.

Rice blast is caused by a fungus and is one of the most devastating cereal diseases worldwide, resulting in 10-30% losses of the global yield of rice. It can be identified by characteristic oval or diamond shaped spots with dark borders that occur on the leaves, collar – junction of the leaf blade and leaf sheath, nodes, neck, and panicle. These spots develop quickly under moist conditions, can seriously impair grain development, and develop large numbers of spores on both sides of the leaves. The spores infect leaf sheath, stem, and panicle, and cause rot. There are several different types of rot that can occur, such as collar rot, neck rot, panicle rot, and node rot. Approximately 20,000 spores are produced from one lesion. Spore release is triggered by a 1–2 hr period of darkness. The fungus can sporulate repeatedly for around 20 days. The disease has multiple infection cycles in a growing season (polycyclic) with 7 days between spore germination and production of conidia (an asexual reproductive spore of fungi).

This disease is particularly serious in areas that experience frequent and prolonged showers, with temperatures in the range of 75-82 degrees Fahrenheit. The pathogen has jumped hosts to wheat, and is now an urgent problem in South America. The most preferred and cost-effective way of managing rice blast disease is by growing high yielding cultivars with dominant resistance genes. Over 70 blast resistance (R) genes have been identified, however, the problem with single-locus resistance is that it often only lasts for a few years.

If you believe you have identified a wheat/rice blast infestation, please send a picture to invasives@shsu.edu.

To read more about the rice blast, see the USDA fact sheet.

Come join the Texas Gulf Region Cooperative Weed Management Area (CWMA) for an all-hands meeting and workday to help remove Brazilian peppertrees from Port Aransas, TX.

February 24, 2022- 9am to 12pm. Meeting place TBA

The CWMA is also looking for volunteers to help with outreach during the 2022 Whooping Crane Festival, February 25-27th, where they will have a booth.

For more information, contact Christina Marconi.

Participate in the largest invasive species awareness effort! National Invasive Species Awareness Week is right around the corner. This event is so full of great opportunities and advice, we are celebrating twice! Go to NISAW website for more information.

NISAW 2022 Part I: February 28 - March 4, 2022– Information and Advocacy

Watch Webinar Recordings: March 1-4, 2022

• Invasive Species Management Priorities and Opportunities for the Biden-Harris Administration and Members of the 117th Congress
• U.S. Federal Agency Updates
• Aquatic Nuisance Species Priorities for Prevention and Management
• Science, Policy, and Solutions for Invasive Species
• Show Me the Money!

NISAW 2021 Part II – Outreach and Education

Watch Webinar Recordings: May 15-22, 2022

• The Climate Crisis and Invasive Species
• Biological Threat Surveillance Tools (US Geological Survey Special Event)
• The Model Legislative Framework for State Aquatic Nuisance Species (ANS) Programs and Resource Toolkit for Local Governments
• The Regulatory Process for Classical Weed Biological Control Aquatic Plant Management Priorities
• A Comparison of State Noxious Weed Lists and The Western Weed Action Plan

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:

• January 19, 1pm- History and effectiveness of injurious wildlife listing under the “Lacey Act”. REGISTER.
• February 16, 1pm- The Power of Ethical Framing. REGISTER.

The United States Register of Introduced and Invasive Species (US-RIIS) is comprised of three lists, one each for Alaska (AK, with 532 records), Hawaii (HI, with 6,075 records), and the conterminous United States (L48, with 8,657 records). Each list includes introduced (non-native), established (reproducing) taxa that: are, or may become invasive (harmful) in the locality, are not known to be harmful there, and/or have been used for biological control in the locality.

Each record has information on taxonomy, dates of introduction (where available; currently for 38%), invasion status (invasive or introduced), and citations for the authoritative sources from which this information is drawn. The US-RIIS builds on a previous dataset, A Comprehensive List of Non-Native Species Established in Three Major Regions of the U.S.: Version 3.0 (Simpson et al., 2020, https://doi.org/10.5066/p9e5k160).

There are 15,264 records in the master list and 12,981 unique scientific names. The list is derived from 5,951 authoritative sources, was reviewed by or based on input from 30 invasive species scientists, and continues to be updated. Publication of version 2.0 of the US-RIIS is anticipated (but not guaranteed) in approximately 12 months.

Click HERE to see US-RIIS version 3.0.

Invasive Spotlight:

Armored Catfish
(Hypostomus Plecostomus and Pterygoplichthys spp.)

Armored Catfish (Family: Loricariidae) are also commonly referred to as plecos, algae-eaters, and suckermouth catfish. They are predominantly algae eaters with a noticeable sucker located ventrally on the head. Loricariids are mostly nocturnal and can range in size from 3 inches to over 3 feet. Their flattened ventral surface allows the fish to use their suckers on most substrates. The adipose fin has a spine, and the pectoral fins have thick toothed spines that are used for locomotion and male-male competition. Hypostomus plecostomus (Common Pleco) and Pterygoplichthys anisitsi (Paraná Sailfin Catfish) are Loricariids that are well established in Texas. They are often confused with one another because the black-lined patterns can vary significantly in both species and can resemble one another.

Loricariids are cavity builders and can lay more than 300 eggs in their nests, which are guarded by the males. This burrowing behavior can lead to bank erosion and collapse. This increases turbidity, which can increase water temperature and decrease oxygen levels. Their successful breeding can cause native fish populations to be outcompeted and become reduced. Loricariids can also withstand a wide range of ecological conditions. For example, their large vascular stomach allows the fish to gulp in air and survive out of water for more than 20 hours.

Loricariids can be found in most freshwater habitats in tropical Costa Rica, Panama, and South America, but many species have small natural ranges. They can also be found in some brackish water habitats. Armored Catfishes are now established in many spring-influenced habitats in Texas, including: San Antonio River (Bexar County), Comal Springs (Comal County), San Marcos River (Hays County), San Felipe Creek (Val Verde County), and in the bayou and canal systems in the Houston area. It is believed that these fish were purchased from pet stores and dumped into local creeks or rivers when the fish grow too large for the aquarium.

For more information regarding management and removal, see the texasinvasives.org info page here. If you believe you have found armored catfish of any kind, please email a picture and the location it was found to invasives@shsu.edu.

Opportunities To Get Involved
Looking for participants for the following surveys: 

Citrus Greening Workshops

We need your help to safeguard Texas Citrus, and it can start in your backyard!

TISI is offering educational workshops focused on the Asian citrus psyllid and the pathogen Citrus Greening. The Asian citrus psyllid and the Citrus Greening pathogen is threatening citrus in multiple Texas counties, and we need your help to monitor the spread. The workshop will highlight what you need to look out for, address USDA-APHIS Citrus Quarantines, and offer diagnostic services if you suspect your backyard citrus has either the psyllid pest or Citrus Greening pathogen. This includes providing trapping materials, assisting with management strategies, and more.

Please contact invasives@shsu.edu so we can schedule a workshop (virtual or in-person) for you or your group this year!

Aquarium Watch: Looking for Prohibited Invasive Aquatic Species

Please help texasinvasives.org 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. Texasinvasives.org will contact the appropriate Texas institutions to remove the species for sale.

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

Lake Murvaul to Benefit from Texas Parks Grants
The Texas Parks and Wildlife Department’s (TPWD) Inland Fisheries Division has selected 21 projects to be supported by the new Habitat and Angler Access Program (HAAP), including one for Lake Murvaul. panolawatchman.com

Invasive Grasses Are Taking Over the American West’s Sea of Sagebrush
Invasive annual grasses, such as cheatgrass (Bromus tectorum), now dominate one-fifth of the Great Basin, a stretch of land that includes portions of Oregon, Nevada, Idaho, Utah, and California. sciencenews.org

The Sky's the Limit: Using Airborne DNA to Monitor Insect Biodiversity
Scientists have discovered for the first time that it is possible to detect insect DNA in the air. Sampling DNA from the air offers benefits over traditional sampling methods. phys.org

Goldzilla: This is What Happens If You Set Your Pet Goldfish Free
Photos showing enormous goldfish (Family: Cyprinidae) caught in a harbor in Canada have been released by wildlife authorities, warning people that this is what can happen when pets are released into the country's waterways. newsweek.com

Finding New Channels to Selectively Target Pest Insects
Researchers have revealed the structure and function of a potassium ion channel in fruit flies. The research could help pesticide manufacturers design new drugs apt to specifically kill pest insects and parasites without affecting other animals like bees and mammals. sciencedaily.com

Public Awareness and Perceptions of Invasive Alien Species in Small Towns
A study in small towns of South Africa was conducted to assess awareness of invasive alien species (IAS) by the public, local perceptions of the impacts associated with IAS, if awareness of IAS is associated with demographic covariates and IAS density, and people’s willingness to detect, report, and support IAS management. mdpi.com

Staying a Step Ahead of Invasive Insect Species with Computer Simulations
Researchers have developed a simulation predicting the spread of an invasive beetle species harming local flora. They tried models based on road lengths, river lengths and recorded cherry tree numbers in square "cells" over Saitama Prefecture, Tokyo. phys.org

Invasive Snake in Gran Canaria Has Killed Off Most Native Reptiles On the Island
A pair of researchers has found that the California kingsnake (Lampropeltis californiae) has killed off nearly all the reptile’s native to Gran Canaria, California, as they analyze the habitats impacted by these invasive snakes. phys.org

Biodiversity Loss in Plants Worldwide
Naturalized alien plants are causing a worldwide decline in the uniqueness of regional floras in a process called naturalization, according to the results of a global research project. sciencedaily.com

Invasive Ants Can Threaten Ecosystems by Damaging Plants at the Roots
A new study is the first of its kind to find that invasive ants can disrupt plants' growth and photosynthesis by nesting at their roots, potentially threatening plants in tropical and subtropical regions around the globe. phys.org

If you would like to highlight a successful invasive species project or nominate a special person to be highlighted in an upcoming iWire, please send the details to iwire@texasinvasives.org.
 

Citizen Scientists Spotlight
Special thanks to Master Naturalists and Master Gardeners

The Texas Master Naturalists and Master Gardeners include multiple groups of well-informed, trained volunteers that provide education, outreach, and service dedicated to the management of natural resources within their communities. They give lectures, create gardens, conduct research, and organize/participate in invasive species removal workshops.

Texas Master Naturalists, along with Texas Master Gardeners, have been a vital aspect of the texasinvasives.org program and we want to express our deep gratitude for all that you do to protect our state’s natural habitats. Texasinvasives.org was able to present at the Texas Master Naturalist’s Annual Meeting in October, and we received an outpour of support and engagement. Many groups have attributed to the success of texasinvasives.org, but to see two groups who have continued the battle against Invasive Species since the inception of our program 15 years ago is truly heartwarming. Thank you for all that you do; please keep up the great work, our state needs it!

Always remember you can email invasives@shsu.edu to schedule an invasive species presentation or workshop today!