Rat lungworm (Angiostrongylus cantonensis) larvae were recently recovered from the hind leg muscles of invasive Cuban treefrogs (Osteopilus septentrionalis) in Florida. Not only is this the first time an anuran (frog or toad) has been identified as a host in the state, but it’s the first time the rat lungworm has been detected in Volusia County, FL.

Angiostrongylus nematodes are zoonotic parasites that require a mammal host (primary/definitive) and a gastropods host (secondary/intermediate) to complete its lifecycle. When a nematode reaches their larval stage (L3) within the secondary host, they are excreted. Angiostrongylus cantonensis relies predominantly on rats as the primary host, and mollusk/flatworm as a secondary host. The infectious L3 stage is then excreted in the host’s slime trails. The ingestion of an intermediate host, such as freshwater shrimp, crabs, anurans, lizards, and flatworms, containing L3 nematodes has led to human infections in many areas around the world. Infections in human result in angiostrongyliasis, a common cause of eosinophilic meningitis.

Cuban treefrogs have become abundant in Florida. They can be found in natural and man-made habitats like swamps, pine forests, or residential areas. Cuban treefrogs are frequently seen around houses, sheds, and ornamental ponds. The close proximality to humans increases potential for these frogs to become agents of zoonotic transmission, as well as enable infection in pets if consumed. The wide distribution of Cuban treefrogs across Florida, and into nearby states, could geographically spread the parasite.

Angiostrongylus cantonensis is not native to the United States, but has been found in Alabama, California, Florida, Hawaii, Louisiana, Mississippi, and Oklahoma. The Cuban treefrog has established populations in Florida, Louisiana, Puerto Rico, and U.S. Virgin Islands, with documented cases in Alabama, Mississippi, South Carolina, and Texas.

Read the research: "Rat Lungworm (Angiostrongylus cantonensis) in the Invasive Cuban Treefrog (Osteopilus septentrionalis) in Central Florida, USA." - PDF available at allenpress.com

Learn more about A. cantonensis: CDC graphic video.

Biological invasions have been known to cause behavior modifications of vulnerable native species as an attempt to reduce their exposure to a harmful invasive. An example of this is when a predator adapts its foraging or hunting tactics to avoid invasives that are detrimental to their survival. In areas invaded by toxic cane toads (Rhinella marina, formerly Bufo marinus), Australia’s freshwater crocodiles (Crocodylus johnstoni) have shown a shift in foraging tactics. The cane toad is toxic and can be fatal to predators when ingested. The toad’s introduction has led to a high mortality rate in freshwater crocodiles. However, the increased mortality rate was more evident in some populations, but not others. Research and observations suggest that the location of crocodile-toad encounters play a critical role in this oddity.

To determine the degree of foraging adaptation, an experiment was set up to observe crocodiles foraging in locations with and without cane toads, foraging from the water and water’s edge, and bait preference/avoidance between a control (chicken) and a slightly toxic toad bait. The research found that crocodiles in areas without cane toads did not show a significant preference between the control and the toad bait, suggesting they were naive to the risk of toxicity. The crocodiles also foraged equally from the water and the water’s edge. Conversely, crocodiles in toad abundant areas significantly preferred the control, and even if the toad bait was selected, it was often actively rejected and not consumed, even though the toxic parts of the toad that would cause a taste aversion were removed. Also, crocodiles in these areas took the bait almost exclusively from the water compared to bait offered at the water’s edge. The results supported the reasoning that terrestrial foraging posed an increased risk since predators that seize a cane toad on land cannot wash away the toxin before it is absorbed into the bloodstream. Whereas a predator that seizes a toad in the water might be able to flush the toxin away before it is absorbed, and predators that have not been exposed to this toxic invader are unlikely to have adapted an avoidance behavior.

Read the research: Aiyer et al, 2022
 

Plants use sunlight, water, and atmospheric carbon dioxide to produce oxygen and carbohydrates vital for plant growth. Plants absorb 1/3 of the yearly carbon dioxide emitted by humans through tiny pores on the leaf surface, called stomata. Plants, soil, and the ocean are important carbon sinks (remove more CO2 from the atmosphere than they release). As climate change worsens, atmospheric carbon dioxide levels increase, and temperatures warm, causing some plants to go into overtime.

Increased levels of atmospheric CO2 can increase photosynthesis activity, an effect know as carbon fertilization. Keenan et al. (2021) found that carbon fertilization increased global annual photosynthesis by 12% compared to the 17% global increase of atmospheric CO2 between 1981 and 2020. De Graaff et al., 2006 examined the effects of changing atmospheric CO2 levels on nutrient cycling. They found that some above and below ground plants exhibited an increase in growth rate as a result of increased photosynthetic activity. They also saw an elevated yield in some crop plants, as well as an increase in microbial carbon content and soil respiration. Higher CO2 concentrations also cause less water to be used during photosynthesis and less water to be released into the atmosphere because of partially closed stomata.

These benefits are short lived and there reaches a point when plants no longer benefit from carbon fertilization, like when other nutrients are used up. Nitrogen and soil carbon quickly become limiting factors. Availability of additional nutrients dictates how long increased productivity will last. A plant cannot process the excess CO2 in the atmosphere if there isn’t enough nitrogen (Read more). Increased temperatures caused by climate change can also affect plant productivity. As temperatures increase, nitrogen fixation decreases, resulting in lower plant productivity and the removal of less CO2 from the atmosphere. Higher temperatures can affect the efficacies of enzymes vital for photosynthesis, causing them to become misshapen or completely deactivated, lowering the efficacy of photosynthesis. Rising temperatures result in longer growing seasons. This will cause plants to grow more and for longer, requiring more water, offsetting the benefits of partially closed stomata.

These are but a few examples of how elevated atmospheric CO2 can affect plants. A much longer article would be necessary to discuss them all. As of now, researchers do not know how long plants will be able to keep up increased CO2 absorption. Research does suggest that plants in the future may become more stressed and less productive. One thing seems clear, plants are not stopping climate change, even with the increased absorption of atmospheric CO2, but they are helping to slow it down.

Are You Eating My Crops 10 of 12

The false codling moth (Thaumatotibia leucotreta) has been recorded feeding on over 50 different plant species, and if established in the US, it would be a significant production and quarantine issue for numerous agricultural commodities. We are reaching the end of our 12-month series called ‘Are you eating my crops?’. Individual pests highlighted in 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 damage they cause, what they look like, and where you can find more information about them. To read about previous headliners, visit the TexasInvasives.org iWire page.

Thaumatotibia leucotreta is an internal fruit-feeding moth that does not undergo diapause (a period of suspended development), and may be found all year round in warm climates where suitable hosts are present. These moths have been recorded on many different host plants, including commonly grown agricultural crops like apricot, avocado, beans, cherry, citrus, corn, English walnut, grapes, olive, peach, pepper, persimmon, plum, pomegranate, and tomato.

Females lay eggs at random along the host fruit. They prefer prematurely ripened fruit or wounded fruit. Females can lay up to 800 eggs in one lifetime, and a population can go through 4-10 generations per year. Once hatched, the larvae will penetrate the fruit, where they stay until pupation, when they will leave the fruit and spin cocoons near the soil or bark crevices. The boring hole is small (1mm diameter) and is conspicuous due to the presence of frass and discoloration around the rind. Entry wounds can provide an entrance for infections by bacteria and other organisms. Younger larvae feed near the surface of the fruit, while older larvae bore closer to the center. Larval feeding and development can affect fruit development at any stage, causing premature ripening and fruit drop. Infested fruit typically drops before harvest. Larval entries can take a few days to become visible. Infestations that occur near fruit harvest are often not detected by the packing house fruit graders, resulting in the inadvertent packaging and export of infested fruit.

Eggs are flat, oval discs (< 1mm in length and width) with a granulated surface. They are initially white to cream, but change to a reddish color prior to hatching. Eggs can be distributed in small groups or individually on the host. First instar larvae (1 to 1.2 long) have a spotted appearance, while fifth instar larvae (12 to 18 mm long) are orangey-pink with a brown head capsule and prothoracic shield. An important larval identifier is the anal comb found on the last abdominal segment (see USDA fact sheet linked below for more details). Adults are grayish brown to dark brown with an average forewing length of 7 to 10 mm and a body length of 6 to 20 mm (size is variable by sex). Males have a semicircular pocket of opalescent scales on the distal end of the hindwing that form a distinct circular mark. This character can be used to separate T. leucotreta males from all other North American moths in this family (Torticidae).

Thaumatotibia leucotreta has been intercepted at ports in California many times over the last two decades, but it is not known to be established in the US. If you believe you have identified a false codling moth infestation, please send a picture and location to invasives@shsu.edu.

Read more about false codling moths: USDA fact sheet.

The University of Georgia - Center for Invasive Species and Ecosystem Health in collaboration with its partner organizations is providing a one-day training and update. This free summit is open to everyone from beginners to experienced users. The Summit will have presentations that cover EDDMapS’ smartphone apps, website, tools, and projects.

Date: Wednesday, March 23
Time: 11:00 am - 3:00 pm EST

Register HERE.

“Introduced” is a podcast that dives into stories of the aquatic invasive species (AIS) that are costing millions of dollars and altering lakes, streams, and wetlands ecosystems. This weekly podcast covers a wide range of topics, from Asian carp to trade in invasive species on the Internet. Created by the Wisconsin Sea Grant Institute. Subscribe for free on Google Play, Spotify, or iTunes.

“Introduced” by Sea Grant

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:

• March 16, 1pm- Invasive reptiles and amphibians. REGISTER.
• April 20, 1pm- A Biocultural Approach to Integrating Indigenous Knowledge with Western Science for Invasive Species Management and Policy. REGISTER.
• May 18, 1pm- Using Community Based Social Marketing to Prevent the Spread of Invasive Species. REGISTER.
• June 15, 1pm- Spotted Lanternfly Ecology and Biocontrol Efforts. REGISTER.

Invasive quagga mussels (Dreissena bugensis) have been detected for the first time in Texas. National Park Services (NPS) discovered the mussels at the International Amistad Reservoir (Lake Amistad) in the Rio Grande basin along the Texas-Mexico border near Del Rio. In addition to this first time detection in Texas waters, this is also the first finding of any invasive mussel species in the Rio Grande basin.

Amistad Reservoir early detection surveys resulted in a single quagga mussel larva that was detected and confirmed by DNA testing at Diablo East in June 2021. In May, August, and September, single quagga mussel larvae were detected at a second site in Rough Canyon. TPWD has designated the reservoir as “positive” for quagga mussels. Positive status indicates invasive mussel larvae have been repeatedly detected, but no juveniles or adults have been found and there is not yet evidence of an established population. TPWD press release.

Quagga mussels are closely related to zebra mussels (D. polymorpha), and cause many of the same problems. They are present in other areas of the US, so there is a risk that boats can transport them to Texas lakes. The department emphasized the importance of continued help from boaters, marina operators, and others to Clean, Drain and Dry all boats and water craft equipment before moving them, and remain vigilant to stop the spread of aquatic hitchhikers.

Anyone who spots quagga or zebra mussels should immediately Report It! here.

Invasive Spotlight:

Quagga Mussel
(Dreissena bugensism)

Quagga mussels (Dreissena bugensis) are closely related to zebra mussels (D. polymorpha). They resemble each other in size and shape; however, quaggas are generally rounder with a shell that appears asymmetrical when viewed from the front. The size can range from ¼ to 1.5 inches. The shell pattern is variable, but typically bares dark bands that fade near the hinge. The bands can be black, cream, or white. Individuals reproduce externally by releasing eggs and sperm into the water column. In a few days, microscopic larvae will begin to develop tiny bivalve shells as they drift in the plankton. Three to four weeks later, juveniles will settle down and attach to various substrates with strong byssal threads. Juveniles are generally fixed to one place, but adults can detach and settle in new areas. These mussels can form colonies up to 4-12 inches thick.

Quagga mussels can negatively impact native species by out-competing them for resources and space. The mussel’s high rate of filtration decreases the level of beneficial phytoplankton, like diatoms and green algae from the water column, subsequently reducing food for zooplankton eaters and freshwater macro-invertebrates. The reduction of algae can change water clarity and affect the composition of aquatic plant, like floating plants nursery areas vital to aquatic organisms. Also, much like the zebra mussel, quagga mussels clog pipes and foul different aquatic structures, which reduces the pumping capacity and damages equipment, which costs industries millions of dollars to fix.

In December 2021, quagga mussels were found in Lake Amistad in the Rio Grande basin. Experts fear they could spread to many other bodies of water in Texas. Texas Parks and Wildlife Department and partners are monitoring many high-risk water bodies in Texas for the presence of invasive mussels.

Because of its negative impacts, quagga mussels are part of the Sentinel Pest Network, a component of Texasinvasives.org. Please Report It! here. For more information regarding management and removal, see the Texas Invasive Species Institute info page here.

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.

Officials Removed Hundreds of Giant Invasive Snails from San Antonio River Walk
During a routine draining of the San Antonio River, more than 500 apple snails (Pomacea maculata) were pulled from the river along with other trash and debris. mysanantonio.com

Study shows plant diversity declining due to invasive species’ success
Globalization means it’s easier for invasive plants to infiltrate and establish in a new habitat, causing homogenization. Here are some examples of this happening in Texas. texasstandard.org

Tiny Mite Shows Promise as Control Agent to Fight Australian Swamp Stonecrop in UK And Europe
A tiny mite (Aculus crassulae) could soon be used as a more environmentally friendly biological control agent against the invasive aquatic weed known as Australian swamp stonecrop or New Zealand pigmyweed (Crassula helmsii) that is found in the UK and Europe. phys.org

Opportunities For Natural Enemy to Fight Devastating Fall Armyworm
An evaluation of mass rearing techniques, costs of mass production, and release strategies for the natural enemy Telenomus remus suggests it could be an effective biocontrol against fall armyworm (Spodoptera frugiperda). phys.org

Innovative battles against park invaders
Problems with invasive plants and animal species in the National Park System is not unique in one park over another, especially in those along the continental southwest and Hawaii. nationalparkstraveler.org

Two New Species of Potentially Invasive Hammerhead Flatworms from Europe and Africa
An international team of researchers describes two new species of potentially invasive hammerhead flatworm, Humbertium covidum (found in France and Italy) and Diversibipalium mayottensis (found on a French island in the Indian Ocean). phys.org

Prevention Strategies for Invasive Species Could Save Trillions
Since 1960, damage costs by invasive species have cost up to $95 billion worldwide, at least ten times the management expenditure. Invasive species prevention could save trillions. Recent research reveals insufficient proactive management worldwide. qub.ac.uk

Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species
Analysis of data from tourism accommodations and exotic organism detections shows that levels of detection are significantly related to international and domestic tourist movement. sciencedaily.com

How Climate Change Can Worsen Impact of Invasive Plants
A study tested the effects of prescribed fire on long-leaf pines grown under drought conditions, colonization by the invasive plant cogongrass (Imperata cylindrica), and a combination of the two. sciencedaily.com

eDNA- A Useful Tool for Early Detection of Invasive Green Crab
Invasive green crabs (Carcinus maenas) can be a nightmare for wildlife managers to control in Washington’s marine waters. A combination between labor intensive trap deployment and DNA-based water testing techniques could be the answer. sciencedaily.com

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
Hwang Eco-friendly Development for Green Environment

A research and innovation partnership called Hwang Eco-friendly Development for Green Environment (HEDGE) has come together with a combined focus of repurposing or upcycling various invasive species into sustainable and functional materials. The group is predominantly made up of Texas State students and was created by Professor Hwang from the Texas State Ingram School of Engineering. They also partnered with many local organizations.

One of their main projects involves creating plant-based, chemical-free menstrual pads out of common water hyacinth (Eichhornia crassipes). This invasive aquatic plant grows in thick matts along the water’s surface which reduces light penetration and dissolved oxygen levels in the water, altering native vegetation and fish communities. By joining forces with a local canoeing company, Texas State students were able to go out on the San Marcos River and carefully remove sections of water hyacinth. They were taught how to do this by the San Marcos River Foundation, to ensure native microorganisms were not removed from the river. Collected batches of the plant were returned to the HEDGE lab for processing. A prototype pad is produced by first removing hyacinth roots and cleaning the stem/leaves with water. The remaining hyacinth is dried using sunlight and industrial ovens. A blender is then used to turns it into a fibrous substance before added it to raw cotton and water. The resulting product is absorbent, bio-degradable, and without the chemicals found in many over the counter brands.

In selecting water hyacinth for this project, their product is made from a plant that is prolific and easily accessible in many areas around the world. The process used to create the menstrual pads is inexpensive and easily replicated, making it not only an environmentally friendly product but a cost-efficient one. Upon the project’s completion, HEDGE hopes to combat "period poverty," a term used to describe inadequate access to menstrual products, experienced by women all over the world.