Tick-borne disease is a significant public health concern in the U.S. Ticks, such as the black-legged tick, dog tick, and Lone Star tick, can transmit a variety of bacteria, viruses, or parasites. The most common tick-borne pathogens include Lyme disease and Rocky Mountain spotted fever, both of which can be transmitted by multiple tick species. Many native ticks found in and around the U.S. are expanding into new areas, which increases animal and human exposure to newly established tick habitats.

The results of a recent study could provide a greater understanding of tick genetics and a foundation for new control methods. The research focused on cattle fever ticks (Rhipicephalus microplus), one of two invasive cattle fever tick species found in northern Mexico that are a constant threat to U.S. re-establishment. These ticks are vectors of bovine babesiosis, also known as Texas cattle fever, a disease known to devastate whole livestock populations. The Texas A&M Department of Entomology and the U.S. Department of Agriculture’s collaborative efforts aimed to identify the specific genetic markers for sex determination in (R. microplus). The identification and understanding of these mechanisms are essential for future genetic control strategies, such as manipulating sex ratios to prevent or mitigate tick reproduction, which could drastically reduce populations. Genetic control methods could have significant impacts on preventing tick-borne diseases in both livestock and humans. With ticks becoming increasingly resistant to traditional methods (pesticides), new strategies are urgently needed. Similar techniques have already successfully been used for controlling mosquito species like Aedes aegypti, which can transmit Zika and dengue fever.

Foundational research that identified the genetic markers for sex determination, such as this, could pave the way for broader applications in controlling other disease-carrying arthropods. Researchers say the next phase will involve mapping the genomes of local tick populations in Texas and Mexico, to help better understand genetic variation and refine control strategies.

Read the Research: Tidwell et al., 2024

Assigned at Birth

An ant colony is a fascinating example of complex social structures and fluid community behavior. A typical colony is comprised of three distinct adult castes: queens (or gynes) and short-lived males (or drones) responsible for reproduction, and female workers responsible for non-reproductive roles such as foraging, defense, and brood care. Caste determination between reproductive and non-reproductive roles in most social insects occurs during the larval stage. Cast assignments are typically irreversible.

Ants are extremely diverse organisms. With over 12,000 known species in the world, it is not surprising this ‘typical rule’ does not apply to the whole Formicidae family. Some ant colonies determine cast assignments early- during the embryonic (egg) stage.

As part of a new study, researchers questioned whether early embryonic determination in ants would result in fixed/irreversible caste determination, similar to cell determination in animals. This referred to germline (reproductive) and somatic (body) cells developed into fixed roles from early development.

The invasive pharaoh ant (Monomorium pharaonis) colonies can vary in size between those that have a single queen with a few hundred workers and those with hundreds of queens and several thousand workers. Also, the caste differentiation in pharaoh ant begins at the egg stage. This combination made them a perfect subject for the study. Pharaoh ant worker larvae were fed controlled doses of juvenile hormone (JH) analog during the 3rd larval instar, which is the final stage of larval development. Results reveal that caste development was surprisingly flexible when exposed to JH. Treated workers developed physical traits normally seen in queens. Traits included increased body size, the appearance of wings and flight muscles, the development of extra frontal eyes, and the formation of a sperm storage organ. These are all traits’ workers typically lack. Hormone-treated workers never develop ovaries, the key reproductive feature of queens.

This suggests that while JH can trigger some aspects of gyne-like development in workers, the full transformation to a reproductive gyne is irreversibly constrained by the timing of hormonal sensitivity, which in this case is the time of embryonic development. This research highlighted the plasticity of caste development in ants, while representing how caste differentiation at the colony level may have similar constraints as animals when it comes to somatic cell developmental factors. This study also introduced an interesting perspective on how the evolutionary processes may shape complex social structures in insect colonies.

Read the research: R. Li et al., 2024

EXTRA: The pharaoh ant measures from 1/12 to 1/16 inchs long (2mm). All workers are the same size, but color can vary from golden-yellow to reddish-brown. Reproductive males are the same size as the workers but are black in color. The queens are 4mm in length and slightly darker than the workers. They are found throughout the U.S., especially in the south. They are most often found nesting inside buildings and cracks.

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 strives 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:

• December 5, 1pm CST- Annual Biocontrol Summit: Aquatic Weed Biocontrol- Project Progress and Innovative Tools. REGISTER.
• December 18, 1pm CST- Canadian Biocontrol Experience: Past, Present and Future. REGISTER.

Do you live in or around Hays County, Tx? Would you like to help remove invasive species and help promote the beautification of your area with like-minded people? Below are three volunteer organizations in Hays County that could provide that opportunity .

San Marcos Greenbelt Alliance
This nonprofit organization aims to protect quality of life through interconnected parks and natural areas through conservation, stewardship and education outreach for community members in the San Marcos area.

• Sample activities: remove invasive species, build and install trail markers, host educational activities, fundraise
• Donations accepted: monetary
• 107 E. Hopkins St., San Marcos
• www.smgreenbelt.org

The Eyes of the San Marcos River
This nonprofit organization strives to protect the quality of the San Marcos River by hosting volunteer-based river cleanups.

• Sample activities: river and land cleanups
• Donations accepted: monetary, trash grabbers, gloves
• No physical address
• www.eyesofthesanmarcosriver.org

San Marcos River Foundation
This nonprofit organization aims to preserve and protect the San Marcos River.

• Sample activities: become a member, trash cleanups, tree-planting, invasive species removals, water quality monitoring, monthly newsletter
• Donations accepted: monetary
• 604 W. Hopkins St., San Marcos
• www.sanmarcosriver.org

The emerald ash borer (Agrilus planipennis, EAB) have been particularly active this year. Tedious monitoring and survey work have provided real time reports as these pests move through Texas. As of August 2024, EAB has been detected in 27 counties since the original Harrison County (2016) detection. The recent jump southward to Hood, Hill, McLennan, etc. confirms that the EAB will continue to move within and spread out from these areas.

INFESTED & QUARANTINED COUNTIES: Bosque, Bowie, Camp, Cass, Collin, Cooke, Dallas, Denton, Ellis, Franklin, Grayson, Harrison, Hill, Hood, Hopkins, Johnson, Lamar, Marion, McLennan, Morris, Palo Pinto, Parker, Red River, Rusk, Tarrant, Titus and Wise Counties.

**Authorities strongly discourage the movement of firewood across county lines, even if your area is not subject to quarantine. The spread of invasive pests and pathogens can be prevented if you remember to Buy it where you burn it (learn more here).

The emerald ash borer is a metallic emerald-green iridescence beetle that displays an almost brassy to coppery or reddish reflection. The adult beetle is bullet shaped (10-13 mm) and has a characteristically bright red to purple coloration on its abdominal surface under its wings (elytra). One external sign of EAB infestation is the distinctive D-shaped hole adult EABs leave in the trees upon emergence. The larvae are white, and slightly flattened, with a pair of brown pincer-like appendages on the last abdominal segment. The larvae (~1.5 inches long) feed on the phloem and outer sapwood of ash trees, leaving S-shaped galleries that cut off the circulation of the phloem to the tree, resulting in tree death.

If you believe you have found an emerald ash borer or suspect an ash tree of being infested, please immediately Report It! HERE, and contact your local AgriLife Extension agent, Texas A&M Forest Service agent, and/or contact your city Arborist.

Invasive Spotlight:

Redbay Ambrosia Beetle
(Xyleborus glabratus)

The redbay ambrosia beetle (Xyleborus glabratus, RAB) is a dark colored, bullet shaped beetle that measures approximately 2 mm long. RAB can be identified by the small puncture-like dents covering the elytra and the characteristic snout, called mycangia, which are modified mandibles used to take up nutrients and carry fungal spores. Positive identification of X. glabratus is almost impossible without the help of a professional, but the ‘hair-less’ upper surface and abrupt apical declivity may help distinguish this invasive beetle from other native species. Adult males are slightly smaller and flightless. RAB larvae are legless, white grubs with an amber colored head capsule.

RAB is a known vector of the vascular fungus Raffaelea lauricola. Once introduced, the fungus moves rapidly through the xylem, plugging the flow of water, which causes the host plant to wilt and die within a matter of months or even weeks. Female beetles have a specialized organ that carries the fungus which allows them to inoculate healthy trees as they bore and lay eggs. The larvae feed on the fungal growth in boring chambers beneath the surface of the bark, not on the tree itself. This insect-disease complex is referred to as ‘laurel wilt’. Infested trees typically have a dark discoloration to the outer sapwood, have strings of sawdust that spill out around the trunk, and display red to purplish wilted foliage. Flight allows the adult females to transfer the fungus from host to host rapidly.

The laurel wilt pathogen has been spreading since its introduction in Georgia in 2004 and in Texas since 2013. Trees in the family Lauraceae, including redbay (Persea borbonia), silk bay (P. borbonia var. humbles), swamp bay (P. palustris), sassafras (Sassafras album), and avocado (P. americana) are susceptible. The pathogen has also been recovered in the southeastern U.S. from diseased pond berry (Lindera melissifolia), camphor tree (Cinnamomum camphora), and pond spice (Litsea aestivates) trees. The pathogen has been found AL, AR, FL, GA, LA, MS, NC, SC, and 14 East Texas counties.

For more information about the redbay ambrosia beetle, click HERE. If you believe you have identified a suspected redbay ambrosia beetle, please take a picture and REPORT IT! HERE. If you believe you have a tree(s), on your property dying of laurel wilt, it is recommended to contact International Society of Arboriculture certified arborist to make a assessment before removing any trees.

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.

A Tree-Killing Disease Is Spreading Through Harris County. KHOU-11 News

Texas A&M is tracking a disease called Laurel Wilt that is spread through red bay ambrosia beetles (Xyleborus glabratus). Researchers say there is no cure, and most infested trees die within a year. Because of how quickly and easily an infestation can spread, experts stress the importance of vigilance and action.

Managing Invasive Plants in Texas Rivers and Creeks: Arundo And Elephant Ear. Hill Country Alliance.

The Texas Hill Country is home to both native and invasive plants. Watch this video to learn about two invasive plant species that have become common on Hill Country waterways and what we can do to minimize their negative impacts.

TFB Resolutions Committee Considers Issues Facing Agriculture
The Texas Farm Bureau (TFB) Resolutions Committee convened to review over 280 policy proposals, addressing critical agricultural issues such as predator control, foreign ownership of land, and feral hog population management. morningagclips.com

Waterfowl Hunters Play a Critical Part in Preventing the Spread Of Invasive Species
TPWD urges waterfowl hunters to take simple steps to prevent the spread of invasive species between lakes. These actions are critical in protecting waterfowl habitats, maintaining water recreation areas, and avoiding the legal consequences of transporting invasive species. ntxe-news.com

Invasive Zebra Mussels Are Associated with Elevated Mercury Levels in Fish, Study Finds
Invasive zebra mussels (Dreissena polymorpha) significantly alter aquatic ecosystems and are associated with elevated mercury concentrations in fish. Mercury is a potent neurotoxin which can pose a serious threat to aquatic life and human health. phys.org

Officials Host Competition to Battle Fish Species Capable of Wiping Out Ecosystems: 'Get Rid of Them as Quickly as Possible'
Invasive fish species can wreak havoc on an entire ecosystem, so officials in San Marcos, Tx, hosted its semiannual tournament for spearfisherman to go up against invasive suckermouth armored catfish (Hypostomus plecostomus, Pterygoplichthys spp.). thecooldown.com

Scientists Develop Groundbreaking Method for Detecting DNA Of Invasive Snakes in Florida
Scientists have developed a DNA-based environmental monitoring tool that can pinpoint where invasive species have been. This testing tool will aid in early detection and eradication efforts. sciencedaily.com

Migrating Birds Have Stowaways: Invasive Ticks Could Spread Novel Diseases Around the World, Say Scientists
Migrating birds can transport ticks across vast distances, potentially introducing novel tick-borne pathogens to new regions. Climate change is creating conditions that allow some tick species to establish themselves in previously unsuitable areas, raising concerns about the spread of emerging diseases. phys.org

Crayfish Map Gives Conservation a Helping Claw
A new mapping project puts 427 crayfish taxa and over 100,000 observation records on the first searchable global atlas: World of Crayfish. The resource will help protect vulnerable crayfish species and manage invasive species worldwide. sciencedaily.com

Researchers Study Effect of Phosphorous and Irradiance on The Invasive Plant Chromolaena Odorata
A recent study examined how phosphorus levels and irradiance influence the competitive dynamics between the invasive plant Chromolaena odorata and two native species in China. The findings suggest the competitive performance was highly dependent on environmental factors and identity of native competitors. phys.org

Invasive Fruit Fly Species Puts Parts of Southern California's Orange County Under Quarantine
Parts of Orange County, CA, have imposed a quarantine to address a recent infestation of the oriental fruit fly (Bactrocera dorsalis), an invasive species that poses a significant threat to agriculture fruits, vegetables, and nuts. Officials are taking measures to contain the spread. phys.org

Texas Land Commissioner Buckingham Redraws Texas-Oklahoma State Boundary, Ensuring Safe and Secure Water for Two Million North Texans
The discovery of zebra mussels (Dreissena polymorpha) in Lake Texoma in North Texas several decades ago set off a chain of events that resulted in not only the security of water to Texans but the redrawing of the Texas-Oklahoma border. glo.texas.gov

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.