Ecology and Evolutionary Biology Commons^™

Potential Landscape Connectivity For Invasive Wild Pigs (Sus Scrofa) Across The Northern Prairies Of North America, Corey J. Kramer, Melanie R. Boudreau, Ryan Powers, Kurt C. Vercauteren, Ryan S. Miller, Ryan K. Brook

United States Department of Agriculture Wildlife Services: Staff Publications

Understanding landscape scale connectivity is an essential component in the management of invasive species since connectivity facilitates their invasion potential. Invasive wild pigs (Sus scrofa) are among the most prolific invaders on the planet, causing billions of dollars in agricultural and environmental damage annually. Newly introduced to Canada in the 1980s, we examined wild pig invasion potential across the northern prairies from western Canada into the currently wild pig-free northern U.S. states. We used GPS collar data collected in the Canadian prairies to quantify resource selection and incorporated results into an electric circuit theory framework to evaluate potential …

Eradication Of Feral Swine From A Barrier Island In Florida, Usa: An Examination Of Effort And Multi-Method, Multi-Species Population Indexing, Richard M. Engeman, Eric A. Tillman, Betsy A. Evans, John C. Griffin, Garrison Grobaski, Bradley S. Smith, John Stark, Bryan M. Kluever

United States Department of Agriculture Wildlife Services: Staff Publications

Feral swine (Sus scrofa) were targeted for and successfully eradicated from Saint Vincent Island (SVI), a National Wildlife Refuge (NWR) along the coast of Florida’s panhandle to protect its habitats and uncharacteristically high diversity of wildlife species for barrier islands in the region, including federal and state-listed threatened and endangered species. The eradication effort was initiated in early 2015 and concluded in 2019. A total of 438 feral swine were removed from the Island, 417 by federal control experts and 21 by recreational hunters. In general, the amount of effort needed to eradicate each feral swine slowly increased …

Effects Of Ungulate‐Proof Fencing On Space Use By Wild Pigs, Kelly Koriakin, D. Buck Jolley, Benjamin Smith, Kurt C. Vercauteren, Nathan P. Snow

United States Department of Agriculture Wildlife Services: Staff Publications

Wild pigs (Sus scrofa) are a highly adaptable species that have invaded many regions and cause significant damage throughout the world. Ungulate‐proof fencing is increasingly used in conjunction with other control techniques to manage wild pig populations. However, little is known about how fencing affects wild pig space use behaviors and whether any changes may be exploited to increase efficacy of control activities. Our goal was to understand how wild pigs altered their space use behaviors in response to newly constructed fencing. Specifically, we examined for changes in space use area (home range and core area), increases in …

Relief Displacement Of Airborne Objects, Esteban Fernández-Juricic, Joe Crumpton, Morgan B. Pfeiffer, Sathishkummar Saiappan, Jared A. Elmore, Landon R. Jones, B. Santhana Krishnan, Raymond B. Iglay, Bradley F. Blackwell

United States Department of Agriculture Wildlife Services: Staff Publications

The increasing availability of unoccupied aircraft systems (UAS, also referred to as drones) has led to their use in taking vertical aerial photographs at relatively small spatial scales. These photographs can be used to measure the distances between objects appearing in the photographs. However, relief displacement can cause an object above or below ground level to appear at a point in a vertical aerial photograph that is not directly in-line with the object’s actual location, causing a measurement error. A UAS was used in this study as a photographed airborne object because its location and altitude could be controlled. We …

Efficacy Of Gonacon Fertility Control Against Prairie Dogs And Potential For Uses On Other Rodent Species, Aaron B. Shiels, Emily W. Ruell, Jason E. Bruemmer

United States Department of Agriculture Wildlife Services: Staff Publications

Use of a contraceptive (i.e., fertility control) is attractive for rodent management where lethal control is unwanted. Although population reduction is generally unachievable with small-scale, short-term contraceptive use, reduced juvenile recruitment is achievable. The injectable immunocontraceptive vaccine GonaCon (active ingredient: gonadotropin releasing hormone [GnRH]) was registered in 2022 by the United States Environmental Protection Agency (EPA) for controlling fertility of female prairie dogs (Cynomys, a type of ground squirrel) in urban/suburban settings. Here we: 1) describe past research, including a replicated field study in Colorado (GonaCon treatment vs. control sites) testing efficacy of GonaCon in prairie dogs, which …

Herbicide Management Alters Fungal Biomass And Community Composition In Great Lakes Coastal Wetlands, Erica Danae Lathers

Master's Theses and Doctoral Dissertations

Wetlands provide many ecosystem services, and invasive species and their management can alter these services. Plant responses to wetland management actions are typically monitored, but less is known about how soils respond. Phragmites australis, an invasive wetland plant, can alter soil conditions, potentially impacting soil microbial structure and function. We sampled soil communities in Great Lakes coastal wetlands in southeastern Michigan dominated by Phragmites and sites that had been previously invaded by Phragmites then treated with herbicide from 2011-2017, to understand how herbicide management alters soil fungal communities. We assessed microbial and fungal biomass, fungal community composition, greenhouse gas emissions, …

Evaluating The Trojan Y Chromosome Strategy For The Removal Of Invasive Sacramento Pikeminnow From The Eel River, Ca, Alexander W. Juan

Cal Poly Humboldt theses and projects

The recent introduction and spread of Sacramento Pikeminnow (Ptychocheilus grandis) in Northern California’s Eel River Basin represents a significant threat and impediment to the recovery of several threatened native fish species. This study was undertaken to evaluate the Trojan Y Chromosome Strategy (TYC) for the extirpation of pikeminnow from the basin. TYC is a genetic biocontrol method that relies on the production and stocking of fish with YY sex chromosomes, which may be phenotypically male (YY male) or female (YY female). These YY fish produce all-male offspring when mating with their wild conspecifics and TYC can lead to …

Barn Owls Exert Top-Down Effects On The Abundance And Behavior Of Rodent Pests, Katherine C. Larson

Cal Poly Humboldt theses and projects

Predators can exert top-down effects on their prey by direct consumption, by imposing risk of predation, or a combination of both. However, empirical evidence for these effects is mixed and inconsistent. Barn owls in agriculture present a system with attributes that should, according to theory, lead to strong top-down effects, but research is limited and the distinction between effects on prey abundance and behavior remains unresolved. Understanding the top-down effect of predators on pests is a cornerstone of integrated pest management and important where barn owls may contribute to the control of rodents on farms. Vegetation can mediate the top-down …

Season Influences Interspecific Responses Of Canopy-Forming Kelps To Future Warming And Acidification At High Latitude, Lauren E. Bell, Lily Westphal, Evan O' Brien, Jason A. Toy, Haleigh Damron, Kristy J. Kroeker

Biological Sciences Faculty Publications

Variability in primary producers' responses to environmental change may buffer higher trophic levels against shifts in basal resource composition. Then again, in instances where there is a lack of functional redundancy because consumers rely on a few species to meet their energetic requirements at specific times of the year, altered community production dynamics may significantly impact food web resilience. In high-latitude kelp forests, a complementary annual phenology of seaweed production supports coastal marine consumers' metabolic needs across large seasonal variations in their environment. Yet, marine consumers in these systems may face significant metabolic stress under the pronounced low pH conditions …

Deconstructing The Mangrove Carbon Cycle: Gains, Transformation, And Losses, M. F. Adame, N. Cormier, P. Taillardat, N. Iram, A. Rovai, T. M. Sloey, E. S. Yando, J. F. Blanco-Libreros, M. Arnaud, T. Jennerjahn, C. E. Lovelock, D. Friess, G. M. S. Reithmaier, C. A. Buelow, S. M. Muhammad-Nor, R. R. Twilley, R. A. Ribeiro

Biological Sciences Faculty Publications

Mangroves are one of the most carbon-dense forests on the Earth and have been highlighted as key ecosystems for climate change mitigation and adaptation. Hundreds of studies have investigated how mangroves fix, transform, store, and export carbon. Here, we review and synthesize the previously known and emerging carbon pathways in mangroves, including gains (woody biomass accumulation, deadwood accumulation, soil carbon sequestration, root and litterfall production), transformations (food web transfer through herbivory, decomposition), and losses (respiration as CO₂ and CH₄, litterfall export, particulate and dissolved carbon export). We then review the technologies available to measure carbon fluxes in …

State Of Coastal And Marine Resources: Lian, Batangas, Joseph Benedict T. Garcia, Mary Joyce P. Velos, Jemelyn Grace P. Baldisimo, Joey P. Cabasan, Ma Celina J. Añonuevo, Denmark B. Recamara, Hazel O. Arceo

Biological Sciences Faculty Publications

[Introduction] Lian (13.9852° N, 120.6545° E) is a third-class municipality in the northwestern part of the province of Batangas. It is bounded on the north by the municipality of Nasugbu, on the east by the municipalities of Tuy and Balayan, on the west by the WPS, and on the south by the municipality of Catatagan (Figure 2.7-1). It has a total land area of 76.80km² that is divided into 19 barangays, six of which are coastal and two are integrated coastal barangays (LGU-Lian 2013). Its total population is 56,280 individuals in 15,991 households as of 2020 (PSA 2020).

The main …

Better Understanding The Barred Owl, Adam Lee Potts

Graduate Student Theses, Dissertations, & Professional Papers

This thesis research presents an analysis of barred owl nest site selection in an understudied region of their expanded range. The barred owl has dramatically expanded its range westwards over the last 150 years, prompting multiple conflicting reinterpretations of their species account. Hypotheses of range expansion are reviewed to provide context for this study’s research. This study gathers empirical data on nest site selection in the mixed conifer forests of Montana’s Seeley-Swan and Mission Valleys. Eight barred owl nests were located following extensive territory surveys. Field measurements of tree height and diameter using USFS Forest Inventory and Analysis (FIA) plot …

Soil Responses To Eastern Redcedar (Juniperus Virginiana L.) Afforestation And Prescribed Fire In South-Central South Dakota, Robert Schaefer

Electronic Theses and Dissertations

Research was conducted in 2019 and 2020 on rangelands located in south-central South Dakota assessing a number of physical, chemical, and biological properties of mineral ustepts and ustents soils associated with eastern redcedar (ERC) (Juniperus virginiana) afforestation and prescribed fire. ERC afforestation appeared to be associated with significantly higher field-condition soil aggregate stability, cation exchange capacity (CEC), soil pH, and fungi:bacteria (F:B) as well as significantly lower soil moisture, nitrate-N, phosphorus, bacteria biomass, and Gram-positive:Gram-negative (GP:GN) bacteria compared to native grassland conditions, while other mineral soil properties appeared relatively unaffected. Compared to soil conditions under dense, living ERC canopies, prescribed …

Fire Severity Mediates Marten And Fisher Occurrence: Impacts Of The Dixie Fire On A Carnivore Community, Christopher James Collier

Cal Poly Humboldt theses and projects

The consumption of an astounding one million acres resulted from California’s largest single fire to date, the 2021 Dixie Fire. The social and economic losses associated with the fire were immediately apparent, but the effects on wildlife remained unknown. While previous research has suggested mixed or low severity fire may be beneficial to certain wildlife species, the responses to megafires are poorly understood for many carnivores. To better understand these responses to severe fire, I used a random sampling design stratified by burn severity to survey in and around the Dixie Fire footprint using baited camera stations. This allowed me …

Recent Beak Evolution In North American Starlings After Invasion, Julia M. Zichello, Shelagh T. Deliberto, Paul Shrewsbury, Agnieszka A. Pierwola, Scott J. Werner

United States Department of Agriculture Wildlife Services: Staff Publications

European starlings are one of the most abundant and problematic avian invaders in the world. From their native range across Eurasia and North Africa, they have been introduced to every continent except Antarctica. In 160 years, starlings have expanded into different environments throughout the world, making them a powerful model for understanding rapid evolutionary change and adaptive plasticity. Here, we investigate their spatiotemporal morphological variation in North America and the native range. Our dataset includes 1,217 specimens; a combination of historical museum skins and modern birds. Beak length in the native range has remained unchanged during the past 206 years, …

Oral Rabies Vaccination Of Raccoons (Procyon Lotor) Across A Development Intensity Gradient In Burlington, Vermont, Usa, 2015–2017, Emily M. Beasley, Kathleen M. Nelson, Dennis Slate, Amy T. Gilbert, Frederick E. Pogmore, Richard B. Chipman, Amy J. Davis

United States Department of Agriculture Wildlife Services: Staff Publications

Management of the raccoon rabies virus variant in North America is conducted primarily using oral rabies vaccination (ORV). When a sufficient proportion of the population is vaccinated (60%), rabies transmission can be eliminated. To date, ORV programs have successfully controlled and eliminated raccoon rabies in rural areas, but there has been less success in urban areas. We studied the proportions of rabies virus neutralizing antibodies (RVNA) in a raccoon (Procyon lotor) population during a 3-year ORV trial in developed areas of Burlington, Vermont, United States. We used a modified N-mixture model to estimate raccoon abundance, RVNA seroprevalence, and …

Assessing The Efficiency Of Local Rabies Vaccination Strategies For Raccoons (Procyon Lotor) In An Urban Setting, Guillaume Bastille-Rousseau, Nicole T. Gorman, Katherine M. Mcclure, Larissa Nituch, Tore Buchanan, Richard B. Chipman, Amy T. Gilbert, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Raccoon rabies virus (RRV) has been managed using multiple vaccination strategies, including oral rabies vaccination and trap-vaccinate-release (TVR). Identifying a rabies vaccination strategy for an area is a nontrivial task. Vaccination strategies differ in the amount of effort and monetary costs required to achieve a particular level of vaccine seroprevalence (efficiency). Simulating host movement relative to different vaccination strategies in silico can provide a useful tool for exploring the efficiency of different vaccination strategies. We refined a previously developed individual-based model of raccoon movement to evaluate vaccination strategies for urban Hamilton, Ontario, Canada. We combined different oral rabies vaccination baiting …

Limitations Of Invasive Snake Control Tools In The Context Of A New Invasion On An Island With Abundant Prey, Shane R. Siers, Melia G. Nafus, Jereid E. Calaor, Rachel M. Volsteadt, Matthew S. Grassi, Megan Volsteadt, Aaron F. Collins, Patrick D. Barnhart, Logan T. Huse, Amy A. Yackel Adams, Diane L. Vice

United States Department of Agriculture Wildlife Services: Staff Publications

In October 2020, a new population of invasive brown treesnakes (Boiga irregularis) was discovered on the 33-ha Cocos Island, 2.5 km off the south coast of Guam, United States. Cocos Island is a unique conservation resource, providing refuge for many lizards and birds, including endangered species, which were extirpated from mainland Guam by invasive predators including brown treesnakes. We sought to evaluate the usefulness of toxic baiting with acetaminophen-treated carrion baits and cage trapping, common tools for the control of brown treesnakes on mainland Guam, as potential eradication tools on Cocos Island. We evaluated multiple bait types and …

Site-Specific Space Use And Resource Selection By Black Vultures (Coragyps Atratus) In The Southeastern Usa, Betsy Evans, John S. Humphrey, Eric A. Tillman, Michael L. Avery, Bryan M. Kluever

United States Department of Agriculture Wildlife Services: Staff Publications

North American populations of Black Vultures Coragyps atratus have increased and expanded their distribution in the southern and eastern USA. In conjunction with these patterns has been a rise in human–vulture conflicts. To improve our understanding of space use patterns and better inform management, we evaluated the movements of Black Vultures (n = 23) in the southeastern USA using a long-term GPS tracking database. Our specific objectives were to: (1) quantify home-range sizes in relation to season and geographical study location and (2) examine within-home-range resource selection to identify landscape and anthropogenic factors influencing roost and diurnal space use. …

Treatment With The Immunocontraceptive Vaccine, Gonacon, Induces Temporary Fertility Control In Free-Ranging Prairie Dog Populations In Colorado, Usa, Aaron B. Shiels, Jackson Runte, Emily W. Ruell, Douglas C. Eckery, Gary W. Witmer, Daniel J. Salkeld

United States Department of Agriculture Wildlife Services: Staff Publications

Context

Prairie dogs (Cynomys spp.) are rodents enjoyed by some humans; yet, they cause crop and property damage, and carry zoonotic disease. Non-lethal control of prairie dogs is of interest in urban/suburban settings. The injectable immunocontraceptive vaccine GonaCon (active ingredient is gonadotropin-releasing hormone [GnRH]) has been shown to be effective at reducing fertility in equine and deer, and is a US EPA-registered vaccine for use in these ungulate species.

Aims

To conduct a replicated field study to test efficacy of GonaCon in black-tailed prairie dogs (C. ludovicianus), and if found to be efficacious, to help facilitate …

Comparison Of Ketamine-Xylazine, Butorphanol-Azaperone-Medetomidine, And Nalbuphine-Medetomidine-Azaperone For Raccoon (Procyon Lotor) Immobilization, Shylo R. Johnson, Christine K. Ellis, Chad Wickham, Molly R. Selleck, Amy T. Gilbert

United States Department of Agriculture Wildlife Services: Staff Publications

Raccoons (Procyon lotor) are frequently handled using chemical immobilization in North America for management and research. In a controlled environment, we compared three drug combinations: ketamine-xylazine (KX), butorphanol-azaperone-medetomidine (BAM), and nalbuphinemedetomidine- azaperone (NalMed-A) for raccoon immobilization. In crossover comparisons, raccoons received a mean of the following: 8.66 mg/kg ketamine and 1.74 mg/kg xylazine (0.104 mL/kg KX); 0.464 mg/kg butorphanol, 0.155 mg/kg azaperone, and 0.185 mg/kg medetomidine (0.017 mL/kg BAM); and 0.800 mg/kg nalbuphine, 0.200 mg/kg azaperone, and 0.200 mg/kg medetomidine (0.020 mL/kg NalMed-A). Induction time was shortest with KX (mean6SE, 10.060.7 min) and longest with NalMed-A (13.061.3 min). …

Distribution And Prevalence Of Antibodies To Trichinella Spp. And Toxoplasma Gondii In Wild Pigs (Sus Scrofa) In The United States, Christopher A. Cleveland, Ellen Haynes, Katherine C. Callaghan, Alinde Fojtik, Sarah Coker, Emily Doub, Vienna R. Brown, Ania A. Majewska, Michael J. Yabsley

United States Department of Agriculture Wildlife Services: Staff Publications

Invasive wild pigs (Sus scrofa) are a reservoir for over 100 viral, bacterial, and parasitic pathogens that are transmissible to humans, livestock, domestic animals, and wildlife in North America. Numerous historical local surveys and results from a nation-wide survey (2006–2010) indicated that wild pigs in the United States act as reservoirs for Trichinella spp. and Toxoplasma gondii, two zoonotic pathogens of importance for human and animal health. Since that time, wild pig populations have expanded and increased in density in many areas. Population expansion of wild pigs creates opportunities for the introduction of pathogens to new areas …

Use Of Rhodamine B As A Biomarker In A Simulated Oral Vaccine Deployment Against Bovine Tuberculosis In White-Tailed Deer, David Dressel, Kurt Vercauteren, Michael Lavelle, Nathan P. Snow, Henry Campa Iii

United States Department of Agriculture Wildlife Services: Staff Publications

Introduction Free-ranging white-tailed deer (Odocoileus virginianus) in northeastern lower Michigan, United States are a self-sustaining reservoir for bovine tuberculosis (bTB). Farm mitigation practices, baiting bans, and antlerless deer harvests have been ineffective in eliminating bTB in white-tailed deer and risks to cattle. The apparent prevalence has remained relatively constant in deer, prompting interest among wildlife researchers, managers, and veterinarians for an effective means of vaccinating deer against bTB. The commonly used human vaccine for bTB, Bacillus Calmette Guerin (BCG), is the primary candidate with oral delivery being the logical means for vaccinating deer.

Materials and methods We developed …

Identifying Priority Mitigation Areas For Human–Osprey Conflict, Natasha K. Murphy, Melanie R. Boudreau, Brian S. Dorr, Kate Slankard, Scott A. Rush

United States Department of Agriculture Wildlife Services: Staff Publications

Raptor nests on human‐built structures represent a significant source of conflict, as they can result in bird mortality, fires, or power outages due to falling nest materials or animals connecting with energized conductors. Power companies typically try to mitigate these conflicts to avoid service disruptions. Performing mitigation measures across all potentially problematic power infrastructure is generally not a practical solution given logistical, time, or budgetary constraints. Therefore, there is a need for quantitative, landscapescale tools to identify conflict risk and prioritize mitigation. We examined the influence of habitat and transmission infrastructure distribution on the potential risk of osprey (Pandion …

Estimating Landscape Spread Of A Low-Prevalence Disease Using Multiple Surveillance Methods, Abigail Feuka, Aakash Pandey, Melinda Cosgrove, Megan Moriarty, Anthony Duffiney, Henry Campa Iii, Kurt C. Vercuteren, Kimberly M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

1. Diseases occurring at low prevalence in free-ranging wildlife can be difficult to study and predict at a landscape scale. This problem is compounded by imperfect pathogen detection.

2. We used data from multiple surveillance methods to determine factors influencing spread of a low-prevalence disease, bovine tuberculosis (bTB), among white-tailed deer (Odocoileus virginianus) in a bTB endemic area over a 10-year period. We fit dynamic occupancy models to predict spatial spread of bTB through a county in Michigan, USA, within the bTB endemic area, while accounting for imperfect detection and a suite of ecological processes potentially driving bTB …

Efficacy Of An Inflatable Deterrent For Reducing New World Vulture Human‑Wildlife Conflict, Bryan M. Kluever, Betsy A. Evans, Noah M. Osterhoudt, Eric A. Tillman

United States Department of Agriculture Wildlife Services: Staff Publications

Increasing urbanization coupled with spatial expansion and numerical increase of New World vulture populations has engendered a rise in human-vulture conflict, creating a need for effective tools to mitigate vulture-related damage. Visual frightening devices that mimic the presence of human or other predators can be employed in human-vulture conflict scenarios to increase perceived risk by the pest species, thereby eliciting an antipredator behavioral response, such as fleeing. One visual frightening device, inflatable scarecrows, recently proved effective at reducing passerine attendance at feral swine feeders, but their effectiveness when directed at other species and conflict scenarios has varied. Our primary objective …

Using Prescribed Fire And Biosolids Applications As Grassland Management Tools: Do Wildlife Respond?, Brian E. Washburn, Michael J. Begier

United States Department of Agriculture Wildlife Services: Staff Publications

Prescribed burning is a management tool commonly used in forested ecosystems in the southeastern United States, but the influence of this method on grassland vegetation and wildlife in this geographic region is unknown. During 2009–2015, we conducted a study to determine if the application of prescribed burning and/or long-term biosolid applications alter plant communities and/or wildlife use of grassland areas at Marine Corps Air Station Cherry Point, Havelock, North Carolina. We monitored vegetation growth, measured plant community composition, and documented wildlife activity in four study plots for 3 years after the implementation of annual winter prescribed burns. Prescribed burning reduced …

Effects Of Pregnancy Prevention On Brucella Abortus Shedding In American Bison (Bison Bison), Pauline Nol, Rebecca Frey, Morgan Wehtje, Jack C. Rhyan, Patrick Ryan Clarke, Matthew Mccollum, Christine Quance, Douglas C. Eckery, Suelee Robbe-Austerman

United States Department of Agriculture Wildlife Services: Staff Publications

Products of parturition are the predominant source of Brucella abortus for transmission in bison (Bison bison). Our objective was to assess whether preventing pregnancy in Brucella-seropositive bison reduced B. abortus shedding. Brucella-seropositive and -seronegative bison from Yellowstone National Park, Wyoming, USA were used in a replicated experiment. Each of two replicates (rep1, rep2) included a group of seropositive females treated with a single dose of gonadotropin-releasing hormone-based immunocontraceptive (Treatment rep1, n = 15; Treatment rep2, n = 20) and an untreated group (Control rep1, n = 14; Control rep2, …

Effects Of The Immunocontraceptive Gonacon On Pregnancy In Brucella-Seropositive American Bison (Bison Bison), Rebecca K. Frey, Morgan E. Wehtje, Pauline Nol, Patrick R. Clarke, Jack C. Rhyan, Matthew P. Mccollum, Lowell A. Miller, Douglas C. Eckery

United States Department of Agriculture Wildlife Services: Staff Publications

The purpose of this study was to determine if the number of pregnancies in naturally infected Brucella abortus-positive bison (Bison bison) cows would be reduced over a period of 5 yr after one treatment with 3000 mg gonadotropin-releasing hormone immunocontraceptive (GonaCon) compared to a similar group of naturally infected B. abortus-positive bison cows not treated with GonaCon. In each of the 5 yr, GonaCon-treated cows produced fewer offspring in relation to number of cows than the nontreated cows. Fisher’s Exact test comparing offspring produced during the first reproductive season showed a significant difference between the …

Antipredator Blood-Squirting Defense In Horned Lizards (Phrynosoma): Chemical Isolation Of Plasma Component(S), Pogonomyrmex Ant Dietary Origin, And Evolution, Wade C. Sherbrooke, Bruce A. Kimball

United States Department of Agriculture Wildlife Services: Staff Publications

North American horned lizards of the genus Phrynosoma are largely myrmecophagous and squirt systemic blood from circumocular sinuses during encounters with certain mammalian predators. The predators react with distinct revulsion. Using bioassay-guided fractionation of blood plasma, we endeavored to identify the source and characteristics of the active chemical compound(s) responsible for this negative oral response. Our results of coyote bioassays and a series of novel mouse bioassay experiments were largely concordant. The active compound(s) was likely plasma-borne with a molecular weight (mw) of between 800 and 1,600. To identify the source of the active compound(s), we noted bioassay responses …