Brown widow spiders (Latrodectus geometricus) are an urban invasive species that have spread to multiple locations worldwide. They are known for their neurotoxic venom and can outcompete native spider species found in warm climates. As organisms move around, they often do not do so alone. A new study has investigated what these spiders packed with them for their travels.

Researchers compared endosymbiont diversity and prevalence in brown widow spiders from South Africa (their likely native range) and invasive populations in Israel and the United States. The study looked for two variant strains of Rhabdochlamydia and several Wolbachia, Spiroplasma and Enterobacteriaceae strains. They found the brown widow spiders across all three continents are highly infected with a single strain of Rhabdochlamydia, a bacterium related to major human and animal pathogens like chlamydia. It is important to note that despite the infection, bites from these spiders do not transmit chlamydia to humans.

Rhabdochlamydia has only been found in a few other organisms, including a species of tick, an isopod, a cockroach, and one other spider. Rhabdochlamydia was present in 86% of the brown widows and in their eggs surveyed during this project. Finding the bacteria in the eggs suggesting mother-to-offspring transmission. Wolbachia was found to have a 14% prevalence and was represented in all countries, but not all populations. The study highlights the potential ecological significance of Rhabdochlamydia in these spiders. The high prevalence of the bacterium suggests it might play an important functional role and could contribute to the spiders' invasive success. Inherited endosymbionts can affect traits that are important to dispersal, fecundity, predator defense, and invasive potential. The study also found that South African brown widow spiders had more diverse bacterial strains compared to those in Israel and the United States, supporting the theory of the spider’s origin. There has been expressed interest in continuing this research to test the functional role of this bacteria and the fitness effects of this endosymbiotic relationship.

Read the research: Mowery et al., 2024

Fungus Destructans

White-nose syndrome (WNS) is a disease caused by an invasive cold-loving fungus called Pseudogymnoascus destructans that infects the skin of the ears, muzzle, and wings of several species of hibernating bats. The fungus causes bats to wake from hibernation and often results in dehydration, starvation, and death.

Researchers are still trying to learn all they can about the invasive fungus. However, new information may help us understand how the fungus gains entry into skin cells and initiates infection. The study was conducted by creating a keratinocyte cell line from the skin of a little brown bat (Myotis lucifugus) and keeping it housed in the mimicked conditions of hibernation, i.e. torpor and arousal. This is critical for testing and understanding P. destructans as the period of torpor is typically when the fungus is very successful. It was found that P. destructans take shelter in the cells they infect and prevent those cells from dying. This hinders the immune system, which allows for more fungal pathogens to grow and invade more skin cells.

During periods of arousal, the body experiences higher temperatures and reactivated immune system but the fungus has counter measures to ensure it can continue to infect its host. Instead of penetrating the cells with hyphae, the fungus manipulates the cells into engulfing the fungus. This process is called endocytosis. During arousal, the fungal spores are covered by protective coating of melanin. The spores can survive inside the bat until the bat returns to a period of torpor, when the spores in cells will start to germinate again.

Overall, the fungus initial ‘stealth’ entry into cells co-opting a protein on their surface by two epidermal growth factor receptors, or EGFR- dependent mechanisms: active penetration during torpor and induced endocytosis during arousal. FDA tested drugs, used for human cancer treatment have been applied to the EGFR receptors with encouraging results. Researchers hope this new information may lead one step closer to a treatment of white-nose syndrome.

Read the research: Isidoro-ayza et al., 2024

Add a Caffeine Kick to That Bait

There is nothing like a fresh cup of coffee in the morning, a calming sip of black tea in the evening, or a nice kick from that energy drink to get you through the rest of the workday. For many of us, reaching for a caffeinated beverage is almost second nature. In moderation, it has been found to reduce drowsiness and depression, while enhancing alertness, cognitive function, and physical performance. Caffeine has even been given to honeybees and bumble bees with many of the same positive and negative results. A group of researchers took what we knew about caffeine and bees and decided to see what would happen if we incorporated the addictive, delicious chemical into ant bait.

The study was conducted on Argentine ants (Linepithema humile). These ants are globally invasive and ecologically harmful. Their ability to spread quickly has much to do with their ability to develop enormous populations (super-colonies) comprised of hundreds of queens and individual colony members that can move freely between and within multiple nests. These large colonies are exceptionally hard to control and manage but they are particularly attracted to sweet baits. Researchers suggest that incorporating caffeine into ant bait could improve control efforts by increasing bait consumption and navigation.

Ants walked into a testing platform where researchers placed a drop of sucrose solution with either 0, 25, 250, or 2,000 ppm of caffeine. Ants given low or intermediate doses of caffeine became more efficient at relocating the reward, indicating signs of enhanced learning ability. Foraging time decreased by 28% per visit for ants with 25 ppm of caffeine and by 38% for those with 250 ppm, showing significant improvements. This effect was not seen at the highest caffeine dose. Overall, the caffeine did not increase ant speed, only quickened their arrival time to the reward via a more direct path, a more “focused path”. Without caffeine, ants did not learn to navigate to the reward location more quickly on subsequent trips, suggesting they did not remember its location. Too much caffeine was found to be hermetic, in this instance meaning it is toxic in too high of a dose but beneficial in lower doses.

Researchers are hopeful that caffeine can aid in controlling Argentine ants, but further studies are needed. They are currently testing caffeine-laced baits in natural settings in Spain and plan to explore interactions between caffeine and bait poison.

Read the research: Galante et al., 2024

Don’t Mess With Texas Citrus

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 second.
Help us stop the spread!

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 2024 Webinar Schedule:

• August 21, 1pm CST- Dutch Elm Disease and Resistance. REGISTER.
• September 18, 1pm CST- Stony Coral Tissue Loss Disease. REGISTER.
• October 16, 1pm CST- White-Nose Syndrome and Bats. REGISTER.

Join the Woodlands Township and help keep the beautiful landscapes native. The Woodlands Invasives Task Force monitors, controls, and removes invasive species so pathways, green spaces, and habitats can thrive. Learn how you can help our dedicated volunteer group by attending this workshop. Participants under the age of 16 must be accompanied by a legal guardian. Registration is required and free. Visit HERE for more information.

Aug. 17, 8:30 a.m. - 12:30 p.m.
The Woodlands Township, 2801 Technology Forest Blvd., The Woodlands
Register HERE.

Invasive organisms come in all shapes and sizes. I’m sure we can all agree that it would be a little bit easier to dislike them, fight against them, or learn more about them if they were easier to dislike, such as mosquitoes or fire ants. Unfortunately, a lot of invasive species are beautiful varietal plants, radiantly colored insects, or adorable animals. This is one of the ways they end(ed) up getting traded around. However, it’s okay to have an Awww moment when you see a cute invasive, and for guilty pleasure here is a link just for that. Let us indulge in the cute, while we learn about invasive species.

12 Very Cute, Very Invasive Species that May or May Not Be in your area but are still good to know about (and fun to look at).

Help TCA and Trinity River Audubon Center remove Alligator Weed (Alternanthera philoxeroides) and Common Cattail (Typha latifolia) overgrowth. Removals will occur on wetland banks and from kayaks. For more information, visit the website.

When: August 3rd, 8-11am
Where: Trinity River Audubon Center, Dallas, Tx
Register HERE

Invasive Spotlight:

Tropical Soda Apple
(Solanum viarum)

Tropical soda apple ( Solanum viarum), is native to Argentina and Brazil. This upright, thorny perennial subshrub, or shrub, grows from 3 to 6 feet (1 to 2 m) in height with prickly stems and leaves that produce clusters of tiny white flowers. The fruit is green-and-white mottled when young and yellow golf-ball sized when mature. Its sweet-smelling fruit is attractive to livestock and wildlife, which spread the seeds through consumption. Tropical soda apples remain green over winter in most southern locations. It is typically found in open semi-shaded areas such as pastures, ditch banks, roadsides, recreational areas, citrus groves, sugar cane fields, and wet areas of rangeland. It is usually found in poorly drained and sandy soils but cannot survive in extremely wet soils.

Tropical soda apples cause several problems as they grow and spread quickly. Each plant can produce approximately 50,000 seeds. Ecologically, it reduces biological diversity in natural areas by displacing native plants and disrupting ecological integrity. Its prickles can restrict wildlife grazing and create a physical barrier to animals, preventing movement through infested areas. Agriculturally, tropical soda apples can infest crop fields and reduce the usability of pastureland, which can prevent cattle from reaching shade. Tropical soda apples can also play host to several viruses and insect pests that attack important vegetable crops. The fruit contains solasodine, which is poisonous to humans. Because of these threats, tropical soda apples are on the Texas Department of Agriculture and Federal Noxious Weed Lists. Tropical soda apples have been reported in East Texas, as well as eight additional U.S states.

For more information, see the TexasInvasives.org species page. If you believe you have seen any tropical soda apples, please REPORT IT!. We will review your report and get back to you as swiftly as possible. Citizen Scientists are often our first line of defense. We appreciate your diligence and dedication.

Get Involved Today!!

The Texas Invasive Species Institute (TISI) and The Texas Research Institute for Environmental Studies (TRIES) has 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 early detection.

With the aid of the public and citizen scientists, we could cover a much wider area, and gather more substantial amounts 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.
 

Enjoy monthly videos about invasive species and/or people willing to teach 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 new wonders you may discover.

Webxtra: How East Texans Can Help Prevent Spread of Invasive Species

District supervisor for the Inland Fisheries Tyler District spoke about invasive species in East Texas and how people can stop the spread going into summer.

Parasitoid Wasps as Biocontrol. SLF Summit 2024

An expert speaker from the USDA APHIS gives updates on the research validating the release of a parasitoid wasp Dryinus sinicus as a classical biocontrol agent for spotted lanternfly (Lycorma delicatula).

Invasive Species Habitat Tool from USGS. Catherine Jarnevitch

Research Ecologist with the USGS shares the uses of INHABIT, a habitat suitability tool for over 100 terrestrial invasive species across the continental U.S.

Giant Australian Lizards May Help Protect Sheep from Deadly Fly-Borne Diseases
Scavenging by heath goannas (Varanus rosenbergi) plays an underappreciated role in reducing carcasses, and their maggots, when compared to birds, foxes, and cats. science.org

Invasive Coral Making Its Way Towards South Florida Waters
A new invasive soft coral, or pulse coral (Family: Xeniidae), is moving its way toward Florida waters but isn’t officially there yet. Officially are partnering up with other agencies and putting the word out to be ready. islandernews.com

How Artificial Intelligence Can Help Prevent Illegal Wildlife Trade
White-eyes (Zosteropidae) are popular songbirds foreign markets that include prohibited trade species. It can often be difficult for law enforcement to distinguish between legal and illegal trade birds. A new AI tool might be able to help professionals distinguish certain birds using voice recognition. Phys.org

Invasive Ants Spread by Hitchhiking on Everyday Vehicles
Ants might be progressing spreading to new locations by stowing away on everyday vehicles. This was previously thought to occur mainly via agricultural goods and equipment. sciencedaily.com

Are Invasive Spotted Lanternflies Hitching Rides Across State Lines?
A new study has found that invasive spotted lanternflies (Lycorma delicatula) can hold onto moving vehicles and withstand wind speeds up to 62 miles per hour. Their strong spindly legs are allowing them to move through public transport. science.org

Pest Predictor Identifies Ingredients for Ecological Recipe for Destruction
The development of a tool to predict the probability of a non-native insect becoming a high-impact pest. Researchers compiled factors that may affect non-native insects’ ability to reshape a forest to create the tool. phys.org

Invasive Fruit Fly Quarantine Lifted in Contra Costa County, Sacramento, CA
After the diligent cooperation of multiple agencies and officials, Contra Costa County, Sacramento, CA, has declared the end of the Oriental fruit fly (Bactrocera dorsalis) quarantine following the eradication of the invasive pest. morningagclips.com

No More Invasive Species Planting Along State Highways, Pennsylvania
A new law now requires the Pennsylvania Department of Transportation to plant native species along state highways. This came about because of the growing concern of non-native species impact on the ecosystem. thecentersquare.com

BLM Issues Decision on Herbicides to Control Noxious and Invasive Weeds
The Bureau of Land Management and the U.S Environmental Protection Agency is approving seven herbicide active ingredients to control noxious weeds and invasive species on public lands in rangelands and forests. thecheyennepost.com

Scientists Scramble to Put Animals on Birth Control After Harmful Species Threaten Entire Ecosystems: 'We Are Running Out of Options'
Researchers say unconventional methods, such as birth control, may be the only alternative to lethal control of harmful invasive and pest populations. thecooldown.com

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.