February 2021
Go, Go, Evolution!

Species-species and organism-environment interactions are fascinating, full of mystery and intrigue. My personal favorites have always been examples of coevolution, such as how ants and carnivorous pitcher plants co-evolved to form symbiotic relationships (Read more here). In the last decade, researchers started to notice that the calculated rates of changes in natural populations seemed very fast relative to what was considered the ‘normal’ rate of evolution; thus, the term ‘rapid evolution’ was born. It was soon noted that coexistence and competition where the main driving force behind rapid evolution, and rapid trait changes occur quickly enough to potentially affect the outcome of simultaneous ecological changes. A resent publication, Grainger et al. (2021), took a closer look at how competition with invasive species and climate may affect the way species evolve rapidly in their environment.

The first thing one needs to know: evolution is the change in the heritable characteristics of biological populations over successive generations. An organism’s generation may be different than ours; therefore, we must alter our perception of thinking when we look at evolution on a time scale. Elephants, humans, plants, and fruit flies will all evolve at a different rate, for example, and rapid evolution can occur quickly enough to be observed in real time.

Grainger et al., (2021) conducted a field-based experiment with common laboratory fruit flies (Drosophila melanogaster). The populations were either exposed or not exposed to interspecific levels of competition with invasive African fig flies (Zaprionus indianus) over the summer. The D. melanogaster populations where then removed from any competitive scenarios, and exposed to cooling fall climates. The researchers found that the fruit flies that were exposed to interspecific competition evolved under fall conditions to be larger, had lower cold fecundity (reproduction), and faster development than those not exposed to levels of competition. They also found that an evolutionary response to climate occurred even after competition pressures had ceased. The paper demonstrates how the interactions with competitors, including invasive species, can shape a species' evolution in response to climate.

Credit: Kylee N. Kleiner, TRIES.

Drosophila melanogaster
Laboratory fruit fly (Drosophila melanogaster). Credit: Sanjay Acharya, CC BY-SA 4.0
Zaprionus indianus
African fig fly (Zaprionus indianus),  identified with the even number of white longitudinal stripes along the head and thorax. Native to Africa and South Asia. Credit: Doug Pfeiffer, Virginia Tech.

Ouch! Those Darn Mosquitos

You see a mosquito and you squish it before it sucks your blood, right? Yes. But have you ever thought about what kind of mosquito lies dead in your palm? Turns out there are several species of invasive and non-native mosquitos buzzing around in the U.S. Here are a few in the news recently:

While counting, sorting, and identifying the specimens from regularly monitored traps, the Miami-Dade Mosquito Control Division, FL, found Aedes scapularis, a non-native species of mosquito, which has not been found in South Florida since the 1940s. The identification was confirmed at the end of 2020 using molecular sequencing (Reeves et al., 2020). Aedes scapularis doesn't usually live in densely populated areas, but is known as a more aggressive bitter than other species. It is a vector of diseases such as yellow fever and Venezuelan equine encephalitis in its native range. However, there is no evidence that it poses any risk to human health or to animals in South Florida. The geographic spread and disease transmission of the new species will be monitored closely. Florida has 16 established non-native mosquitoes, 10 of which have been detected since 2000. Aedes scapularis is predominantly found in neo-tropical regions of the Americas, including the southern-most part of Texas.

The yellow fever mosquito (Aedes aegypti) is an invasive species to North America that is becoming widespread throughout the eastern U.S. It is a vector for dengue fever, chikungunya, yellow fever, and Zika in humans. A group of researchers from the University of California, Davis, is using a new machine-learning approach to map landscape connectivity to integrate genetic and environmental data (Pless et al., 2021). This allows them to examine the genetic connectivity of Aedes aegypti as it adapts to humam-impacted areas, new landscapes, and as it expands its range across North America. Mosquitoes are evolving an increased resistance to pesticides, many of which cause environmental harm. Current methods focus more on biotechnological solutions, including various genetic modification techniques, such as the release of sterile males into the population. Researchers hope with the aid of these new mapping tools and other techniques, invasive populations can be better targeted and kept small enough to avoid human disease transmission.

Please try to remember: Native species of mosquitos pose an important role in the food chain.

Aedes scapularis- Reeves et al., (2020) map
Modification of Figure 1) Female Aedes scapularis. Map of Broward and Miami-Dade Counties, Florida, U.S., where Ae. scapularis were collected in 2006–2020. Number of Ae. scapularis collected represented by points: White) 1-2; Gray) 2–19; Black) 20. Credit: Reeves et al., (2020)

Aedes aegypti- Muhammad Mahdi Karim- GFDL 1.2
Yellow fever mosquito (Aedes aegypti). Credit: Muhammad Mahdi Karim, CC GFDL 1.2
Aedes aegypti  Pless et al. 2021 map
Optimized connectivity map using CSE full dataset. The black points show collection sites for Aedes aegypti (genetic data). Credit: Pless et al., (2021)

Cactus Moth: Tale of the Ages

The Cactus moth (Cactoblastis cactorum) was first introduced to the Texas Gulf Coast around 2018. They can quickly spread and eliminate prickly pear cacti (Opuntia sps.) populations, disturbing the ecosystem the cacti support. Native Lepidoptera, such as the endangered Schaus swallowtail (Papilio aristodemus ponceanus), birds, reptiles, and other insects that rely on the cactus as a source of food and shelter. But what kind of impact has this moth-cactus duo had throughout the ages, and how did the moth get to Texas?

Thousands of years ago, the Aztecs, and others throughout Mesoamerica, cultivated prickly pear cacti to selectively breed cochineal bugs (Dactylopius coccus). They created superior, vivid red dyes for painting, clothing and textiles that were highly sought after and traded. By the mid-1500s, cochineal bugs and the dye were the second most profitable commodity in Spain. Failed efforts to steal, smuggle, or create cochineal populations elsewhere only succeeded in spreading prickly pear cacti throughout the world. In the 1800, synthetic dyes made the cultivation of prickly pear cactuses and cochineal insects obsolete. However, by that point the cacti had become an established invasive in many areas, such as South and East Africa, and Australia.

The non-descript, gray-brown Cactus moth was found to be a natural occurring, biological pest to prickly pear cacti in South America, the native home to both. The caterpillars will bore into the cacti pads and consume it from the inside as the larvae matures. The caterpillars will often leave the pads hollow/partially hollow, paper thin and see-through, killing the pad. The larvae are pink and cream during the early instars (stages), and grow to become black with red dots on the dorsal (top) surface.

Armed with the perfect tool to fight the invasive cacti, cactus moths were introduced to Australia, New Caledonia, South Africa and Hawaii, with successful results. The moth larvae are still used today as a prickly pear biological control agent in some areas. In 1957, cactus moth larvae were introduced on the island of Nevis, Caribbean. Researchers believe this single introduction event marks the beginning of the moth invasive infestation into the rest of the Caribbean and the Americas. From 1987-89, the cactus moths were reported in Florida, where prickly pears are native. Soon after, the entire peninsula was infested, and the prickly pears where devastated. The invasive moths began to work their way up the east coast to Charleston County, North Carolina, and across the Gulf coasts. Researchers believe the spread is caused by a combination of human mediation, island hopping, and climatic events (such as hurricanes). Nonetheless, by 2018, the moths were in Brazoria County, Texas.

Read about ‘Local dispersal pathways during the invasion of the cactus moth: Guadalupe et al. (2020).

Cactus moth on prickly pear
Third instar larvae of cactus moth (Cactoblastis cactorum) moving to a new cladode (cactus pad) on prickly pear species, Opuntia stricta. Credit: Ignacio Baez, USDA Agricultural Research Service.
Cochineal bugs (Dactylopius coccus), on a prickly pear, used for red dyes. Credit: Credit: GFDL, CC BY-SA 3.0

cactus moth
Cactus moth (Cactoblastis cactorum). Credit: Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services

Extreme Weather Effects on Native vs Invasive Species

Studies show that climate change has increased the likelihood of severe weather and climate events. It could lead to longer-lasting heat waves, stronger hurricanes, increased wildfire risk, longer wildfire seasons, heavy rain events, severe droughts, and yes, extreme freeze events like many Texas counties experienced in February. Plants and organisms/wildlife have adapted to deal with natural disturbances, but not those of such a ‘grand-scale’ like the 22 record breaking weather and climate disasters that we saw during 2020 (read more at climate.gov). Extreme weather can kill both directly and indirectly. It can eliminate food sources, contaminate water, or alter habitat. It can force species to move into areas of increased competition, fewer resources, or greater predatory risk. It can kill migratory animals that are already exhausted from travel. Most native species are able to recover from extreme weather events; however, it can sometimes take years or decades. More temperature tolerant invasives can take advantage of the niche space availability, pushing out the native species, especially in areas where the invasive was already a problem.

There is some good news regarding the cold snap! The recent freeze pushed back against some of the Texas invasive species. There are reports that the freeze left some of the invasive Brazilian pepper trees (Schinus terebinthifolia) in Port Aransas, TX, looking burnt and damaged, which may help with die back and make them more vulnerable to herbicide treatments. In the Brazos Valley, reports say they lost several invasive Axis deer (Axis axis) and blackbuck antelope (Antilope cervicapra), as they are not adapted to the cold.

What Can you do to help?

Scientist and TPWD have observed a high level of mortality and injury rate in wildlife throughout Texas. TPWD is asking the public to make reports on deceased animals through iNaturalist.org so researchers can collect data and monitor the effects of the storm. Please do not touch the deceased animals. If you see any animals that seem new to your area, please share this information on the iNaturalist app, as these individuals may have migrated to a new area due to the ice storm. TPWD authorities believe the natives affected by winter storm Uri should bounce back and continue to thrive.

In 2020, the United States experienced record-smashing 22 weather or climate disasters that each resulted in at least $1 billion in damages. NOAA map by NCEI, climate.gov
Brazilian peppertree (Schinus terebinthifolia)
Brazilian peppertree (Schinus terebinthifolia). Credit: Amy Ferriter, State of Idaho
Adult male blackbuck (Antilope cervicapra)
Adult male blackbuck (Antilope cervicapra). Credit: Sagar735, CC BY-SA 3.0

Book: Invasive Species in Forests and Rangelands of the U.S.

This open access, multi-disciplinary, well-illustrated book describes the serious threat of invasive species to native ecosystems. This book presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands, and grasslands of the United States.

Access to book here: fs.usda.gov

IS forest book

2021 25th Annual Great Texas Birding Classics

The 25th Annual Great Texas Birding Classics welcomes all levels of birders and those of all ages to join this Texas birdwatching event during the amazing spring migration. There's a tournament category for everyone - from the beginning backyard birder to the competitive lister! In 24 years, the birding classic donated over $1 million in conservation funding to nature tourism and avian habitat restoration, enhancement, and acquisitions projects throughout Texas.

Conservation, habitat restoration, and invasive species removal grant project rewards are available!
Grant Proposals Deadline: May 1, 2021

Registration Deadline: April 1, 2021
Registration fees raise money for Texas bird and birding conservation project grants

Tournament Date: April 15- May 15, 2021

Birding classic

National Invasive Species Awareness Week

With the conclusion of another successful National Invasive Species Awareness Week, we would like to thank all of those who participated, whether by tuning in online or by venturing out into the world!

**Did you or someone you know do something to commemorate NISAW? We would like to hear all about it!**
Email: invasives@shsu.edu and tell us your story!

Don’t forget, NISAW will be back in May with new materials over Outreach and Education!

The NISAW 2020 webinar series are still available to watch on YouTube here.


North American Invasive Species Management Association Training Webinars

The 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 17, 1pm- Non-native Invasive Earthworms 101: From the Nightcrawler to the Jumping Worm. REGISTER
  • April 21, 1pm- Emerald Ash Borer Deregulation and Programs Going Forward. REGISTER
  • May 5, 1pm- PlayCleanGo Awareness Week and How to Integrate the New PlayCleanGo Outreach Tools. REGISTER



Invasive Spotlight:
Asian Swamp Eel
(Monopterus albus)

The Asian swamp eel (Monopterus albus) lacks fins, and has a long cylindrical, scaleless body. They have a distinctive V-shaped gill on the throat, with a mouth containing bristle-like teeth, and tails that taper at the rear end of the body. The coloration can vary between green, brown, and olive, with a lighter underside. They can grow up to 100 cm (39 inches) in length. In the U.S., Asian swamp eels are commonly mistaken for the native American eel (Anguilla rostrata) and lampreys (Ichthyomyzon, Lampetra, Lethenteron, or Petromyzon spp.); however, the Asian swamp eel is not a true eel. It belongs to the fish family Synbranchidae. True eels have small pectoral fins and paired gills on each side of the head. Lampreys have an ovoid oral disc with embedded teeth, and 7 small, pore-like gills.

Swamp eels are generally found in slowly moving freshwater regions, such as shallow wetlands, marshes, swamps, streams, ditches, and ponds. They are nocturnal and will often burrow into soft sediments, hide in thick aquatic vegetation, or occupy small crevices. They are highly adaptable, able to tolerate extreme conditions, and go weeks to months without food. They consume a wide variety of invertebrate, organic and plant material, and vertebrate prey, including fishes and fish eggs, amphibians, reptiles, and turtles. All Asian swamp eels are born female. It is not until maturation that some eels later transform into males; this is called sequential hermaphroditism. They breed year-round, with one eel laying as many as 1,000 eggs at a time. This species can breathe air using atmospheric oxygen absorbed via a vascularized breathing apparatus at the rear of the mouth. They use this air breathing ability to move short distances over dry land, from one water source to another, primarily during heavy rains.

Although the impact of their introduction is unknown, this species is considered a potential threat to native fishes, frogs, and aquatic invertebrates because of their generalized predatory behavior. In some areas where high populations have been established, habitats have shown a high level of disturbance. Researchers are concerned for the possible harm to recreational fishing, and the potential introduction of microparasites. Asian swamp eels are a known host of multiple Gnathostoma spp., nematodes which are a potential source of gnathostomiasis in humans.

Asian swamp eels seem unaffected by traditional nuisance and invasive fish eradication methods: concussion sampling/explosives and poisons. The eels lack the large air bladder that make fishes susceptible to concussion sampling. One common poison prevents fishes from using oxygen in the water, but the eels simply raise their snout above water and use their vascularized breathing apparatus. Researchers and managers believe dispersal may be controlled through a combination of electric barriers, vegetation removal, and trapping.

If you believe you have identified a suspected Asian swamp eel, please take a picture and REPORT IT! to invasives@shsu.edu.

Asian swamp eel (Monopterus albus)
Asian swamp eel (Monopterus albus). Notice V-shaped gill on throat. Credit: Florida Fish and Wildlife Conservation Commission.
Monopterus albus
Asian swamp eel (Monopterus albus) breathing atmospheric oxygen. Credit: Kim Hyun-tae, iNaturalist.org. License- CC by Attribution.
Distibution of Asian swamp eel DiscoverLife
World distribution of Asian swamp eel (Monopterus albus). Credit: DiscoverLife.org


Emerald Ash Borer Watch

Status of emerald ash borer (EAB, Agrilus planipennis) is classified as infestation in the following Texas Counties: Bowie, Cass, Denton, Harrison, Marion, and Tarrant. The EAB was first detected in 2016 in Harrison County, TX, and was found through trapping efforts in Cass and Marion Counties the following year, with all 3 counties upgraded to infested level by 2018. By 2020, Bowie County was also added to the list of infested Northeastern Texas Counties. While EAB was spreading in northeast Texas, it jumped to Tarrant County with the first confirmed report in 2018 posted by a young student through iNaturalist. Since its initial sighting in Tarrant County, the beetles were subsequently found in Denton County, May 2020. The infestation has caused millions of dollars of damage to ash trees annually.

The Dallas Environment and Sustainability Committee met early February to discuss potential action plans that could slow the spread of EAB before it reaches the Dallas County area. The beetle could cause significant damage to the Great Trinity Forest in Dallas, where nearly 40% of forest canopy is ash trees. The Environmental and Sustainability Committee aims to develop a task force by April 2021, which will create a management plan to be implemented by December 2021. More about Dallas Plan.

The emerald ash borer is a metallic emerald-green beetle with iridescence that creates 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 their 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 pincher-like appendages on the last abdominal segment. The larvae (1.5 in) feed on the phloem and outer sapwood of ash trees, leaving S-shaped galleries that cut off the circulation of phloem to the tree, resulting in tree death.

If you believe you have seen an emerald ash borer, please take a picture and REPORT IT!

EAB Watch- KK
Credit: Kylee N. Kleiner, TRIES.

More News

TTU Researcher Receives Grant to Sniff Out Invasive Pests, Species in Agriculture
Texas Tech University and the director of the Canine Olfaction Research and Education Laboratory received a grant to train detection dogs to finding agricultural pests and plant pathogens, such as laurel wilt disease (Raffaelea lauricola) and citrus greening disease (caused by the bacteria Candidatus Liberibacter spp., spread by Asian citrus psyllid, Diaphorina citri, and the African citrus psyllid, Trioza erytreae). everythinglubbuck.com

Global Fight Against Fall Armyworm Gets Texas Boost
Texas A&M AgriLife Research scientists have declared war on the fall armyworm (Spodoptera frugiperda), with the help of a grant. Researchers aim to determine the behaviors and genomic traits in order to assistance in controlling the agricultural pests. today.tamu.edu

Invasive Flies Prefer Untouched Territory When Laying Eggs
A recent study finds that the invasive spotted wing drosophila (Drosophila suzukii) prefers to lay its eggs in places that no other spotted wing flies have visited. The finding raises questions about how the flies can tell whether a piece of fruit is virgin territory and what that might mean for pest control. sciencedaily.com

Starling Success Traced to Rapid Adaptation
Cornell examines non-native European Starling (Sturnus vulgaris) to see what happened at the genetic level as the population increased from 80 birds released in New York City's Central Park in 1890, to an estimated 200 million spread across North America. phys.org

Invasive Lizards Spotted in the Midlands Could Soon Be Outlawed In SC, Officials Say
There is growing concern about the increased sightings of invasive Argentine black and white tegu lizard (Salvator merianae) across South Carolina. The Department of Natural Resources is taking action to stop the spread. thestate.com

International News

Eco-Fusion is the New Normal, As Native and Non-Native Species Mix Together!
Species have moved, or have been moved, around the planet recombining to establish "novel" mixes of native and non-native species in a process is called eco-fusion or ecological hybridization. These hybrid ecosystems are increasing around the globe, turning sone non-natives non-threatening. phys.org

The Great Extermination: How New Zealand Will End Alien Species
New Zealand's unique fauna are under threat from and virtually all mammals have been eradicated by alien invaders. However, they have an ambitious plan to remove the invasive predators by 2050. newscientist.com

Ten Conservation Success Stories When Species Came Back from the Brink
Most successful conservation efforts involve big “charismatic” species that readily attract attention and funding. However, Bolam and Butchart’s team identified a number of recurring and widely applicable themes in successful conservation work: removal of invasive species, management of hunting and protection of important habitats. newscientist.com

Fear and Love Surround Escobar's Hippos Thriving In Colombia
Pablo Escobar’s hippopotamuses (Hippopotamus amphibius) once held in his private zoo, now thrive in the tropical countryside and wetlands in and around the palace-turned-theme park. The hippos are still an endless source of controversy as the population continues to increase. phys.org

Invasive Evergreen Acutely Reduces Water Resources in Ethiopia, Costing Rural Livelihoods
New research revealed how an invasion of the evergreen tree Prosopis juliflora diminishes water resources in the Afar Region, Ethiopia, consuming already scarce resource used to irrigate cotton and sugarcane. 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

An iNaturalist Post That Helped Stop the Spread!

iNaturalist started in 2008 as a master's degree project at the University of California, Berkeley. It was set up as a social networking site to get people to pay more attention to the world around them and share/upload images of the living things they come across. Since its launch, the site has almost 1.4 million registered "observers" worldwide who have collectively uploaded more than 52 million photos of 300,000 species. Since research finding is often restricted, observation databases such as iNaturalist have been very helpful to researchers by having more feet on the ground and more eyes in the field, gathering information and collecting data points.

One botanist for the San Diego County Natural History Museum, Jon Redman, was going through iNaturalist posts, helping people identify their plant photos, when he spotted something out of place: invasive alligatorweed (Alternanthera philoxeroides) which has not been documented in San Diego County, CA, for nearly 146 years. Redman contacted the person who posted the photo, and asked for more information, additional pictures, and a sample of the specimen. It was confirmed as Alternanthera philoxeroides! Officials at Otay Lakes, CA, were immediately contacted and informed of the invasive species presence so it could be removed before it became established or had a chance to spread further.

Citizen scientist observations made in iNaturalist have led to multi-year studies, and led to new location records, assisted in publications, species diversity surveys, and so much more.

About Alligatorweed: It is a rooted floating invasive plant that often forms very dense stands (1.5 ft) along shorelines. The stems are hollow, grow in the water, and can be single or branched. Its leaves (3/4 inch wide and 5 inches long) are opposite and non-succulent, elliptical or lance-shaped, with a prominent midrib. Soft, whitish hairs are found along the leaf axis. The white flowers occur in short, head-like spikes, and resemble white clover. Alligatorweed can be mistaken for native Water willow (Justicia americana). Water willow grows taller (1.5 to 3 ft tall), have longer leaves (minimum 3 inch), and the flowers are more orchid-like, with purple and white coloration. Learn more at texasinvasives.org

Alligatorweed is present in Texas. If you believe you have identified suspected alligatorweed, please take a picture and REPORT IT! to invasives@shsu.edu.

Alligatorweed (Alternanthera philoxeroides) on a shoreline. Credit: Chris Evans, University of Illinois.

alligatorweed flower and leaves
Alligatorweed's small white flower and elliptical leaves. Note the soft whitish hairs on the leaf axis. Credit: Chris Evans, University of Illinois.


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, and teach identification of local invasive plants, and to 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:

Saturday, March 27, 2021 (9:00am-1:00pm)
Invaders of Texas Workshop
Location: Virtual
Contact: Terrilyn MacArthur

For more information or to register to attend a free workshop, please visit the Workshop Page.