About

Susan Paskewitz is a professor in the Department of Entomology at the University of Wisconsin-Madison. Her research centers on the management of arthropods involved in disease transmission, with a particular focus on mosquitoes and ticks. Her work investigates the basis for compatibility versus incompatibility between various mosquito species and malaria parasite strains or species, emphasizing the immune responses of mosquitoes and parasite evasion mechanisms. Key contributions include identifying enzymes involved in the melanization immune response through gene silencing studies, developing a model Sephadex bead system for molecular and ecological immune response investigations, and discovering a mosquito protein that facilitates parasite development. Her ongoing NIH-funded research explores the mosquito lysozyme gene family and their interactions with parasites, as well as efforts to control mosquito populations and disease transmission through integrated mosquito management strategies. This includes identifying major human-biting mosquito species, diagnosing West Nile virus in pooled samples, characterizing aquatic breeding sites, and testing biological control methods such as native fish species and predatory microcrustaceans. Additionally, her work addresses tick-borne diseases like Lyme disease, focusing on risk assessment in urban forests and the expansion of tick ranges in Wisconsin. She has contributed to understanding how changes in forest structure influence tick populations and Lyme disease infection rates. Dr. Paskewitz is actively involved in teaching courses related to medical and global health entomology and is a member of professional societies including the American Mosquito Control Association, the American Society of Tropical Medicine and Hygiene, and the Entomological Society of America.

Research topics

• Environmental health
• Immunology
• Veterinary medicine
• Demography
• Medicine
• Geography
• Biology

Selected publications

• Description of all stages of a new tick species from California, Haemaphysalis vespertina (Acari: Ixodidae), with redescription of H. leporispalustris Packard, 1869 adults and phylogenetic relationships among related U. S. taxa

  The Catalogue of Life · 2026-02-16

  datasetOpen access
  PublisherDOI

• Survey of tick control practices on public lands across 4 states reporting high incidence of Lyme disease

  Journal of Medical Entomology · 2026-01-20

  articleSenior author

  Ticks and tick-borne diseases pose a significant public health threat in the United States, particularly in the Northeast and Upper Midwest. Tick control operations are predominately focused on private residential properties. Surveys of publicly funded vector control programs have indicated that high use public lands may be viable targets for future tick control activities if funding is available. However, little is known about the feasibility of implementing tick control activities on these properties. We administered a survey to understand current tick control and tick bite prevention educational practices and potential barriers to future tick control on public lands. The survey was distributed to public land managers in Minnesota, New York, Pennsylvania, and Wisconsin and we received 129 responses. The responses indicated that tick control was undertaken on only 10% of the public lands that respondents managed. Landscape management was the most common intervention. Some (40%) of the public land managers indicated interest in using tick control methods in the future, again with landscape management being the preferred intervention. Respondents indicated that there may be significant barriers for the use of acaricides and host-targeted interventions. Currently, tick bite prevention education appears to be the primary protective measure utilized on public land, with 63% of responding land managers offering education to staff or visitors. Our survey indicates that high use public lands may present potential targets for limited tick control operations, but the potential barriers must be addressed and additional evaluation of these interventions on high use public land is required.

  PublisherDOI

• Description of all stages of a new tick species from California, Haemaphysalis vespertina (Acari: Ixodidae), with redescription of H. leporispalustris Packard, 1869 adults and phylogenetic relationships among related U. S. taxa

  Open MIND · 2025-01-01

  datasetOpen access

  This dataset contains the digitized treatments in Plazi based on the original journal article Egizi, Andrea, Nava, Santiago, Nakano, Angie, Saunders, Megan E. M., Maestas, Lauren P., Angelus, Autumn D., Noden, Bruce, Nadolny, Robyn M., Bajwa, Waheed I., Lubelcyzk, Charles, Bhosale, Chanakya R., Paskewitz, Susan, Gaff, Holly D., Beati, Lorenza (2025): Description of all stages of a new tick species from California, Haemaphysalis vespertina (Acari: Ixodidae), with redescription of H. leporispalustris Packard, 1869 adults and phylogenetic relationships among related U. S. taxa. Zootaxa 5719 (1): 49-72, DOI: 10.11646/zootaxa.5719.1.2, URL: https://doi.org/10.11646/zootaxa.5719.1.2AbstractAll active stages of Haemaphysalis vespertina sp. nov. (Acari: Ixodidae), a tick previously identified as H. leporispalustris Packard, 1869, are described from specimens collected on the vegetation and from leporids in California and Oregon. The adults of H. leporispalustris Packard, 1969 are redescribed based on type material. Adults of the two species can be distinguished by their overall size, the dorsal shape of palpal segment II, the number and shape of dorsal and ventral setae on palpal segment II, the number of spurs on coxae II, the length of setae on scutum, legs and coxae, and the pattern of scutal punctations. Phylogenetic analyses support H. vespertina as a distinct taxonomic lineage. Additional unresolved lineages within H. leporispalustris s.l. were identified, suggesting a need for further taxonomic study of leporid-associated Haemaphysalis ticks in North America.

  OA PDFDOI

• Haemaphysalis Koch 1844

  Zenodo (CERN European Organization for Nuclear Research) · 2025-11-11

  articleOpen access

  Genus Haemaphysalis Koch, 1844 Haemaphysalis leporispalustris (Packard, 1869) Female— Figs. 7A–7G; based on 14 specimens, some partially engorged, from Packard’s type series deposited at the Harvard Museum of Comparative Zoology (MCZ IZ 47339) Body of unfed specimens dorsally suboval, longer (1.27–1.65; 1.54 ± 0.10) than wide (0.87–1.14; 1.00 ± 0.07); widest posterior to mid-length. Scutum (Fig. 7C) oval, longer (0.86–0.96; 0.91 ± 0.03) than wide (0.63–0.806; 0.74 ± 0.05), with posterior margin rounded; cervical grooves deep and broad, converging posteriorly to almost mid-length of scutum, then diverging; scapulae with scattered fine, punctations, bearing very short, fine setae, lateral fields and posterior border with few inconspicuous punctations and glabrous; median field with homogeneously distributed, scattered, small, shallow punctations all bearing very short, fine setae (0.001–0.003; 0.002 ± 0.001) (Fig. 7C). Alloscutum (Fig. 7D) with deep, uniformly distributed, small punctations all bearing short setae (0.002– 0.004; 0.003±0.001); marginal groove complete, lining 11 festoons, reaching scutum at level of coxa II; festoons and marginal folds with numerous deep, small, punctations bearing short fine setae. Venter (Figs. 7E–G): genital aperture at level of coxae III, U-shaped, with almost parallel lateral margins (Fig. 7G); anal groove posterior to anus joining anterolaterally genital groove; bean-shaped areas posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove; ventral grooves more distinct in unfed specimens; punctations dense, fine, deep, uniformly distributed, bearing fine setae (0.001–0.003; 0.002 ± 0.001) (Fig. 7E); spiracular plates almost round with inconspicuous, blunt, dorsal projection, with 3–5 rows of small goblet cells, slightly smaller along periphery. Capitulum (Figs 7A–B). Dorsal (Fig. 7A): length from palpal apices to tip of cornuae (0.49–0.58; 0.53 ± 0.03); basis capituli broader (0.39–0.44; 0.41 ± 0.01) than long (0.15–0.19; 0.17 ± 0.01), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae wider at insertion than long, rounded; porose areas narrowly flattened and oval (0.07–0.11; 0.09 ± 0.01) long and (0.04–0.09; 0.06 ± 0.01) wide, placed in deep depressions of basis capituli, diverging posteriorly, inter-porose area concave; ventrally (Fig. 7B), basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short rounded, posteriorly directed processes, almost as wide at insertion than at apex. Palps dorsal (Fig. 7A): palpal segment I inconspicuous; palpal segment II length (0.21–0.28; 0.24 ± 0.01), palpal segment II width at level of lateral projection (0.13–0.18; 0.15 ± 0.01), distance between apices of lateral projections (0.54–0.65; 0.60 ± 0.03); internal edge of palpala segment II markedly concave ending in conspicuous medially directed anterior lobe, with approx. 3 fine, barbed setae; palpal segment III approximately as long (0.13–0.18; 0.14 ± 0.01) as wide (0.09–0.12; 0.11 ± 0.01); lateral length of palpal segments II and III measured from apex of palpal segment III to tip of angle with lateral projection (0.29–0.35; 0.33 ± 0.02). Palps ventral (Fig. 7B): palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 8 fine, barbed, flattened, median setae (damaged in Fig. 7B, but basal insertion holes are clearly visible, and confirmed by the examination of other type specimens); palpal segment III with rounded ventral spur; hypostome clavate, with homogeneous 3:3 dental formula excepted crown, approx. 9 denticles per file. Legs. Coxa I (Fig. 7F) with short, wide, rounded internal spur, wider than long; distinct, smaller, rounded, external spur; coxa II with internal, round, posteriorly directed spur and external very small, rounded spur; coxa III–IV with single, triangular spur, as long as wide at insertion, directed posteriorly, inserted at mid-width in coxa III, inserted more medially in coxa IV. Trochanter I with ventral rounded spur; coxae and legs with scattered, long, fine setae. Male— Figs. 8A–8G; based on 2 specimens, some partially engorged, from Packard’s type series deposited at the Harvard Museum of Comparative Zoology (MCZ IZ 47339); therefore, standard deviation values are missing when only 2 measurements were available. Scutum (Fig. 8C) oval, longer (1.33–2.12; 1.73) than wide (0.95–1.43; 1.19); with lateral edges convex, widest posterior to mid-length; cervical grooves very deep, short, almost parallel, reaching level of coxa II; scapulae round with scattered fine punctations, bearing short, fine setae as in female; marginal grooves starting anteriorly at approx. mid length of scutum, deep, reaching and lining first festoon, absent along other 9 festoons; festoons with scattered punctations and inconspicuous short, fine setae; median field with unevenly distributed, medium sized shallow punctations, all bearing very short, fine setae (0.004–0.011; 0.008 ± 0.003), glabrous crescent outlining pseudoscutum and glabrous median longitudinal line reaching central festoon, interrupting punctation pattern, lateral fold anterior to festoons with single, lateral, almost linear line of punctations reaching almost level of coxa II (Fig. 8C). Venter: genital aperture at level of coxa II, covered by oval apron as in Fig. 8E; anal groove posterior to anus joining genital groove anterolaterally, bean-shaped areas posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove; punctations dense, fine, shallow, and uniformly distributed, bearing fine, very short setae (0.006–0.009; 0.008 ± 0.001) (Fig. 8F); spiracular plates almost round with blunt, inconspicuous, dorsal projection, with 4–5 lines of small goblet cells, smaller along periphery. Capitulum (Figs. 8A–B). Dorsal: length from palpal apices to tip of cornuae (0.33–0.35; 0.34); basis capitula broader (0.23–0.24; 0.235) than long (0.13–0.14; 0.135), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae at least as long as wide, bluntly rounded (Fig. 8A); ventrally basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short rounded, posteriorly directed processes as wide at insertion as long (Fig. 8B). Palps dorsal: palpal segment I inconspicuous; palpal segment II length (0.13–0.14; 0.13 ± 0.005), width at level of lateral projection (0.10–0.13; 0.11 ± 0.01), distance between apices of lateral projections (0.39–0.41; 0.40); lateral length of palpal segments II and III combined measured from apex of palpal segment III to tip of angle with lateral projection (0.18–0.19; 0.18 ± 0.006); internal margin concave ending in conspicuous medially directed lobe, with 2–3 fine, barbed setae (visible in specimen not used for SEM); palpal segment III approximately as long (0.06– 0.1; 0.08 ± 0.02) as wide (0.07–0.08; 0.08 ± 0.002) (Fig. 8A). Palps ventral: palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 5, lanceolate, barbed, fine, median setae; palpal segment III with rounded ventral spur. Hypostome clavate, with homogeneous 3:3 dental formula excepted crown, approx. 8 denticles per file (Fig. 8B). Legs. Coxa I (Fig. 8D) with short, rounded internal spur, wider than long, external spur shorter and round; coxa II with round almost ridge-like internal spur and pointed short external spur; coxa III with round, very short, internal spur, coxa IV with inconspicuous barely noticeable internal ridge. Trochanter I with ventral rounded ridge-like spur; coxae and legs with scattered, long, and fine setae (Fig. 8D). Diagnostic characters The diagnostic characters unique for the female of H. vespertina are a combination of the following characters: palpal segment II with pointed lateral projection and 6 dorsal, flattened, barbed setae inserted on an almost straight internal margin, with approximately 11–12 ventral, lanceolate, long, barbed medially inserted setae, palpal segment III with a rounded ventral spur; ventral process of basis capituli short, subtriangular with rounded anterior apex. Hypostome clavate with homogeneous 3:3 dental formula except crown; scutum with lateral fields and posterior border almost devoid of punctations and glabrous, median field with homogeneously distributed very large, shallow, somewhat confluent punctations; coxa I with internal short and rounded spur and external spur as a triangular ridge, coxae II–IV with a single triangular spur, coxae and other leg segments with numerous, long, and fine setae; genital aperture round with small lateral chitinous flaps, and spiracular plate with 3–4 rows of goblet cells, the central ones being much larger than those of the marginal row. Males of H. vespertina can be diagnosed by the following combination of characters: basis capituli with rounded, triangular, and short cornuae; palpal segment II with pointed lateral projection and with 4 dorsal barbed setae inserted medially into concave internal margin and with approximately 9 ventral, barbed, long and lanceolate setae; ventral process of basis capituli short and triangular, hypostome clavate with homogeneous 3:3 dental formula except crown; scutum with homogeneously distributed, very large, shallow, and somewhat confluent punctations; coxa I with 2 spurs, the internal short and rounded spur, the external ridge-like, coxae II–IV with a single triangular spurs; coxae and other segments of legs with very numerous, long, and fine setae; spiracular plate as in female. The diagnostic morphological characters for the female of H. leporispalustris are as follows: palpal segment II with pointed lateral projection, with 3 dorsal, fine, barbed setae inserted along the concave internal margin, posterior to the conspicuous anterior lobe, and with approximately 8 ventral fine barbed setae; palpal segment III with a rounded ventral spur; ventral

  PublisherDOI

• Genetic and landscape connectivity of blacklegged ticks during range expansion in select states of the Midwestern U.S.

  2025-05-19

  preprintOpen access

  Since the 1970s, the Midwestern USA has experienced an expansion of blacklegged ticks ( Ixodes scapularis ), the primary vector of Lyme disease caused by Borrelia burgdorferi , leading to increased Lyme disease incidence. Public health surveillance indicates that Northwestern Wisconsin has served as refugia for these ticks, seeding an expansion into neighboring states such as Michigan. However, the process of re-emergence and invasion remains unclear. To improve tick management, we examine whether environmental variables in the Midwestern (eastern North Central) region have constrained tick dispersal and whether connectivity corridors can be identified. By developing fine-scale spatial population genomic data, our analyses reveal genetically diverse populations in Wisconsin, with northern populations contributing to recent expansions within the state. We identify several east-west gene flow corridors facilitating tick dispersal in Wisconsin. An independent dispersal network exists along Wisconsin’s Mississippi River, extending southwards. In contrast, Michigan populations exhibit sharp genetic divergence from Wisconsin and Indiana populations, with low genetic diversity and high in-state gene flow. We also identified high landscape connectivity in the region connecting the Michigan Peninsulas and significant gene flow at the landmass near southern Lake Michigan. Geographical isolation, as well as landscapes with low soil humidity during summer and high human disturbance, were found to limit gene flow across the region, although these effects were minor. Management of blacklegged ticks in the region can be enhanced by recognizing that landscape connectivity has influenced the dispersal of distinct genetic populations, and targeted interventions in seemingly less tick-favorable landscapes may help mitigate the spread.

  PublisherOA PDFDOI

• Haemaphysalis vespertina Beati, Egizi & Nava 2025, new species

  Zenodo (CERN European Organization for Nuclear Research) · 2025-11-11

  articleOpen access

  Haemaphysalis vespertina Beati, Egizi & Nava, new species (Figs. 3–6) ZooBank registration: Details of the new species have been submitted to ZooBank (http://zoobank.org/). The Life Science Identifier (LSID) for the new name Haemaphysalis vespertina is B61B3440-02C5-4944-9221-7B2E703EA237. Etymology: The specific epithet is derived from the Latin ‘vesper’ in reference to the evening or the evening star and, by extension, to the West. This species is described from the western coast of North America. Type-locality: USA: California, San Mateo County, Costanoa (coordinates: 37.154342, -122.341978). Collected from vegetation. Known hosts for all stages are Lepus californicus Gray, 1837 and Sylvilagus sp. Gray, 1867; avian hosts such as Melanerpes sp. Swainson, 1832 and Toxostoma sp. Wagler, 1831 have been found infested with immatures. Female— Figs. 3A–3I HOLOTYPE: USNMENT1785003 (USA, California, San Mateo County, Costanoa, 37.154342, -122.341978, 9 VII 2024; from vegetation, coll. Tara Roth and Arielle Crews). PARATYPES: USNMENT1510975, 5 females (USA, California, San Mateo County, Costanoa, 37.154342, -122.341978, 9 VII 2024; from vegetation, coll. Tara Roth and Arielle Crews); USNEMNT1510966, 1 female (USA, California, San Mateo County, Costanoa, 37.154342, -122.341978, 15 VI 2021; from vegetation, coll. Angie Nakano). Other material examined: USNEMNT1510970, 22 females (USA, California, Mendocino County, Hopland, 38.9729541, -123,1163918, 15 VI 1965, ex. L. californicus); USNMENT1510977, 7 females (USA, California, Mendocino County, Hopland, 38.9729541, -123.1163918); USNMENT1510986, 1 female (USA, California, San Benito County, 22 III 1932, ex. L. californicus); USNMENT1510974, 6 females (USA, California); USNMENT1510976, 1 female (USA, Oregon, Harney County, Burns, 43.588333, -119.061389, ex. Sylvilagus sp.). Body (Fig. 3A) of unfed specimens dorsally suboval, longer (1.30–1.49; 1.36 ± 0.06) than wide (0.86–0.95; 0.93 ± 0.03); with lateral edges slightly concave at level of coxa II, widest posterior to mid-length. Scutum oval, (Fig. 3A, Fig. 3G) longer (0.79–0.84; 0.82 ± 0.02) than wide (0.62–0.68; 0.64 ± 0.02), with posterior margin rounded; cervical grooves very deep and broad, converging posteriorly to almost mid-length of scutum, broadening posteriorly into shagreened triangular shallower area (Fig. 3G); scapulae round, with scattered fine punctations, bearing short, fine setae (0.017–0.027; 0.024 ± 0.003), lateral fields and posterior border with few punctations and glabrous; median field with homogeneously distributed, dense, larger, shallow punctations, all bearing fine setae (0.014–0.025; 0.018 ± 0.003), central punctations sometimes confluent producing rugose effect (Fig. 3G). Alloscutum (Fig. 3A) with deep, uniformly distributed, very small punctations, all bearing short setae, slightly shorter (0.011–0.022; 0.015 ± 0.003) than scutal setae; marginal groove complete, lining 11 festoons, reaching scutum at level of coxa II; festoons and marginal fold with numerous deep, small, punctations bearing setae. Venter: genital aperture at level of coxae II–III (Fig. 3E, Fig. 3H), U-shaped, with almost parallel lateral margins, lined by very narrow sclerotized flaps; anal groove posterior to anus joining genital groove anterolaterally (Fig. 3C); in unfed specimens, bean-shaped areas posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove; ventral grooves more distinct in unfed specimens; punctations dense, fine, deep, uniformly distributed, bearing fine setae (0.011–0.022; 0.016 ± 0.003); spiracular plates almost round with inconspicuous, blunt, dorsal projection, with 2–4 lines of goblet cells, larger in center, slightly smaller along periphery (Fig. 3F). Capitulum (Figs. 3B, Fig. 3D). Dorsal (Fig. 3B): length from palpal apices to tip of cornuae (0.35–0.41; 0.39 ± 0.02); basis capituli broader (0.31–0.35; 0.34 ± 0.01) than long (0.18–0.19; 0.19 ± 0.004), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae wider at insertion than long, rounded; porose areas as narrow flattened ovals (0.050–0.063; 0.055 ± 0.004 long and 0.020–0.035; 0.029 ± 0.04 wide), placed in deep depressions of basis capituli, diverging posteriorly; ventrally (Fig. 3D) basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short, triangular, rounded, posteriorly directed processes, wider at insertion than long. Palps dorsal (Fig. 3B): palpal segment I inconspicuous; palpal segment II length (0.16–0.17; 0.16 ± 0.02), palpal segment II width at level of lateral projection (0.13–0.15; 0.14 ± 0.01), distance between apices of lateral projections (0.48–0.54; 0.50 ± 0.02), internal edge of palpal segment II almost straight, with 6 flattened, barbed setae; palpal segment III approximately as long (0.09–0.10; 0.10 ± 0.01) as wide (0.10–0.10; 0.10 ± 0.01); lateral length of palpal segments II and III measured from apex of palpal segment III to tip of angle with lateral projection (0.24–0.26; 0.25 ± 0.001). Palps ventral (Fig. 3D): palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 11–12 lanceolate, barbed, flattened median setae, palpal segment III with rounded ventral spur; hypostome clavate, with homogeneous 3:3 dental formula except at crown, approx. 6–7 denticles per file. Legs. Coxa I (Fig. 3E) with short, rounded internal spur, wider than long, external spur as triangular ridge, shorter than internal spur, concealed by tuft of long fine, setae; coxa II, III, and IV with single, rounded, triangular spurs, as long as wide at insertion, directed posterolaterally and inserted at mid-width in coxa II and III, directed posteriorly and inserted more medially in coxa IV. Trochanter I with ventral rounded spur; coxae and legs with numerous, very long, fine setae. Haller’s organ as in Fig. 3I. Male— Figs. 4A–4H ALLOTYPE: USNMENT1785004 (USA, California, San Mateo County, Costanoa, 37.154342, -122.341978, 9 VII 2024; from vegetation, coll. Tara Roth and Arielle Crews). PARATYPES: USNMENT1510975, 4 males (USA, California, San Mateo County, Costanoa, 37.154342, -122.341978, 9 VII 2024; from vegetation, coll. Tara Roth and Arielle Crews); USNEMNT1510966, 2 males (USA, California, San Mateo County, Costanoa, 37.154342, - 122.341978, 15 VI 2021; from vegetation, coll. Angie Nakano). Other material examined: USNEMNT1510970, 12 males females (USA, California, Mendocino County, Hopland, 38.9729541, -123,1163918, 15 VI 1965, ex. L. californicus); USNMENT1510977, 12 males (USA, California, Mendocino County, Hopland, 38.9729541, -123,1163918); USNMENT1510986, 2 males (USA, California, San Benito County, 22 III 1932, ex. L. californicus); USNMENT1785016; 23 males (USA, California, Bernardino County, 5 IX 1936, ex. L. californicus); USNMENT1510976, 4 males (USA, Oregon, Harney County, Burns, 43.588333, -119.061389, ex. Sylvilagus sp.). Body: conscutum (Fig. 4A) distinctly oval, longer (1.16–1.30; 1.21 ± 0.04) than wide (0.72–0.90; 0.80 ± 0.04); with lateral edges slightly convex, widest posterior to mid-length; cervical grooves very deep, short, almost parallel, reaching level of coxa II; scapulae round with scattered fine punctations, bearing short, fine setae as in female; marginal grooves starting anteriorly at approx. mid length of scutum, deep, reaching and lining first festoon, fragmented along other 9 festoons; festoons with scattered punctations and inconspicuous short, fine setae; median field with homogeneously distributed, dense, large, shallow punctations, all bearing short fine setae (0.012–0.019; 0.015 ± 0.002), central punctations sometimes confluent producing distinct rugose effect; lateral fold anterior to festoons with single, lateral, almost linear line of punctations reaching level of coxa II. Venter (Figs. 4D–F): genital aperture at level of coxa II, covered by oval apron as in Fig. 4E; anal groove posterior to anus joining anterolaterally genital groove, bean-shaped areas, posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove (Fig. 4D); punctations dense, fine, deep, uniformly distributed, bearing fine setae (0.014–0.028; 0.020 ± 0.007); spiracular plates almost round with blunt, dorsal projection, with 2–4 lines of goblet cells, larger in center, slightly smaller along periphery (Fig. 4H). Capitulum (Figs. 4B–C). Dorsal (Fig. 4B): length from palpal apices to tip of cornuae (0.25–0.29; 0.27 ± 0.01); basis capituli broader (0.19–0.22; 0.21 ± 0.01) than long (0.10–0.12; 0.11 ± 0.01), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae triangular, wider at insertion than long, rounded; ventrally basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short rounded, posteriorly directed processes, twice as wide at insertion as long (Fig. 4C). Palps dorsal (Fig. 4B): palpal segment I inconspicuous; palpal segment II length (0.09–0.10; 0.10 ± 0.001), width at level of lateral projection (0.11–0.12; 0.12 ± 0.001), distance between apices of lateral projections (0.33–0.35; 0.34 ± 0.01); lateral length of palpal segments II and III measured from apex of palpal segment III to tip of angle with lateral projection (0.15–0.16; 0.15 ± 0.004); internal margin concave ending anteriorly with inconspicuous medially directed lobe, with 4 flattened, barbed setae; palpal segment III approximately as long (0.07–0.08; 0.07 ± 0.002) as wide (0.08–0.09; 0.08 ± 0.002). Palps ventral (Fig. 4C): palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 9 lanceolate, barbed, flattened median setae; palpal segment III with rounded ventral spur. Hypostome clavate, with homogeneous 3:3 dental formula excepted crown, approx. 6–7 denticles per file. Legs. Coxa I with short, rounded internal spur, wider than long, external spur as rounded ridge, shorter than internal spur

  PublisherDOI

• Tick spotting: using mannequins to evaluate individual efficacy at detecting <i>Ixodes scapularis</i> (Acari: Ixodidae)

  Journal of Medical Entomology · 2025-05-19 · 1 citations

  articleOpen accessSenior author

  Tick checks are a free and accessible personal protection measure used to prevent tick bites and are frequently recommended by public health institutions and vector-borne disease researchers. However, little is known about how successful people are at detecting ticks on themselves or others when using this method. We developed a tool for evaluating factors affecting the efficacy of tick checks using mannequins. In 2022 and 2023, we recruited 207 participants to complete a brief survey and perform a tick check on a mannequin, where dead Ixodes scapularis Say larvae, nymphs, and adults had been glued at various locations. None of the survey results (demographics, knowledge, attitude, and concerns about ticks and tick-borne disease) were associated with likelihood of tick detection. On average, participants detected 42% of nymphs on the mannequin. Adult females were 3 to 4 times more likely to be detected than nymphs. Ticks above the waistline were detected 3 times more frequently than ticks below. Ticks that were on white-colored clothing were 3 times more likely to be detected than those on dark-colored clothing. Ticks that were not covered by hair or clothing were 2 times more likely to be detected than covered ticks. These findings show that there are multiple factors that may limit tick detection during a tick check. Outreach should emphasize the importance of awareness of size variation between stages, completing a thorough whole-body examination including the lower limbs and covered locations, and wearing light-colored clothing.

  PublisherOA PDFDOI

• Genetic and Landscape Connectivity of Blacklegged Ticks During Range Expansion in Select States of the Midwestern USA

  Ecology and Evolution · 2025-10-01 · 2 citations

  articleOpen access

  , leading to increased Lyme disease incidence. Public health surveillance indicates that Northwestern Wisconsin has served as refugia for these ticks, seeding an expansion into neighboring states such as Michigan. However, the process of re-emergence and invasion remains unclear. To improve tick management, we examine whether environmental variables in the Midwestern (eastern North Central) region have constrained tick dispersal and whether connectivity corridors can be identified. By developing fine-scale spatial population genomic data, our analyses reveal genetically diverse populations in Wisconsin, with northern populations contributing to recent expansions within the state. We identify several east-west gene flow corridors facilitating tick dispersal in Wisconsin. An independent dispersal network exists along Wisconsin's Mississippi River, extending southwards. In contrast, Michigan populations exhibit sharp genetic divergence from Wisconsin and Indiana populations, with low genetic diversity and high in-state gene flow. We also identify high landscape connectivity in the region connecting the Michigan Peninsulas and significant gene flow at the landmass near southern Lake Michigan. Geographical isolation, as well as landscapes with low soil humidity during summer and high human disturbance, were found to limit gene flow across the region, although these effects were minor. Management of blacklegged ticks in the region can be enhanced by recognizing that landscape connectivity has influenced the dispersal of distinct genetic populations, and targeted interventions in seemingly less tick-favorable landscapes may help mitigate the spread.

  PublisherOA PDFDOI

• Description of all stages of a new tick species from California, Haemaphysalis vespertina (Acari: Ixodidae), with redescription of H. leporispalustris Packard, 1869 adults and phylogenetic relationships among related U.S. taxa

  Zootaxa · 2025-11-11 · 1 citations

  articleOpen access

  All active stages of Haemaphysalis vespertina sp. nov. (Acari: Ixodidae), a tick previously identified as H. leporispalustris Packard, 1869, are described from specimens collected on the vegetation and from leporids in California and Oregon. The adults of H. leporispalustris Packard, 1969 are redescribed based on type material. Adults of the two species can be distinguished by their overall size, the dorsal shape of palpal segment II, the number and shape of dorsal and ventral setae on palpal segment II, the number of spurs on coxae II, the length of setae on scutum, legs and coxae, and the pattern of scutal punctations. Phylogenetic analyses support H. vespertina as a distinct taxonomic lineage. Additional unresolved lineages within H. leporispalustris s.l. were identified, suggesting a need for further taxonomic study of leporid-associated Haemaphysalis ticks in North America.

  PublisherOA PDFDOI

• Haemaphysalis Koch 1844

  Zenodo (CERN European Organization for Nuclear Research) · 2025-11-11

  articleOpen access

  Genus Haemaphysalis Koch, 1844 Haemaphysalis leporispalustris (Packard, 1869) Female— Figs. 7A–7G; based on 14 specimens, some partially engorged, from Packard’s type series deposited at the Harvard Museum of Comparative Zoology (MCZ IZ 47339) Body of unfed specimens dorsally suboval, longer (1.27–1.65; 1.54 ± 0.10) than wide (0.87–1.14; 1.00 ± 0.07); widest posterior to mid-length. Scutum (Fig. 7C) oval, longer (0.86–0.96; 0.91 ± 0.03) than wide (0.63–0.806; 0.74 ± 0.05), with posterior margin rounded; cervical grooves deep and broad, converging posteriorly to almost mid-length of scutum, then diverging; scapulae with scattered fine, punctations, bearing very short, fine setae, lateral fields and posterior border with few inconspicuous punctations and glabrous; median field with homogeneously distributed, scattered, small, shallow punctations all bearing very short, fine setae (0.001–0.003; 0.002 ± 0.001) (Fig. 7C). Alloscutum (Fig. 7D) with deep, uniformly distributed, small punctations all bearing short setae (0.002– 0.004; 0.003±0.001); marginal groove complete, lining 11 festoons, reaching scutum at level of coxa II; festoons and marginal folds with numerous deep, small, punctations bearing short fine setae. Venter (Figs. 7E–G): genital aperture at level of coxae III, U-shaped, with almost parallel lateral margins (Fig. 7G); anal groove posterior to anus joining anterolaterally genital groove; bean-shaped areas posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove; ventral grooves more distinct in unfed specimens; punctations dense, fine, deep, uniformly distributed, bearing fine setae (0.001–0.003; 0.002 ± 0.001) (Fig. 7E); spiracular plates almost round with inconspicuous, blunt, dorsal projection, with 3–5 rows of small goblet cells, slightly smaller along periphery. Capitulum (Figs 7A–B). Dorsal (Fig. 7A): length from palpal apices to tip of cornuae (0.49–0.58; 0.53 ± 0.03); basis capituli broader (0.39–0.44; 0.41 ± 0.01) than long (0.15–0.19; 0.17 ± 0.01), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae wider at insertion than long, rounded; porose areas narrowly flattened and oval (0.07–0.11; 0.09 ± 0.01) long and (0.04–0.09; 0.06 ± 0.01) wide, placed in deep depressions of basis capituli, diverging posteriorly, inter-porose area concave; ventrally (Fig. 7B), basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short rounded, posteriorly directed processes, almost as wide at insertion than at apex. Palps dorsal (Fig. 7A): palpal segment I inconspicuous; palpal segment II length (0.21–0.28; 0.24 ± 0.01), palpal segment II width at level of lateral projection (0.13–0.18; 0.15 ± 0.01), distance between apices of lateral projections (0.54–0.65; 0.60 ± 0.03); internal edge of palpala segment II markedly concave ending in conspicuous medially directed anterior lobe, with approx. 3 fine, barbed setae; palpal segment III approximately as long (0.13–0.18; 0.14 ± 0.01) as wide (0.09–0.12; 0.11 ± 0.01); lateral length of palpal segments II and III measured from apex of palpal segment III to tip of angle with lateral projection (0.29–0.35; 0.33 ± 0.02). Palps ventral (Fig. 7B): palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 8 fine, barbed, flattened, median setae (damaged in Fig. 7B, but basal insertion holes are clearly visible, and confirmed by the examination of other type specimens); palpal segment III with rounded ventral spur; hypostome clavate, with homogeneous 3:3 dental formula excepted crown, approx. 9 denticles per file. Legs. Coxa I (Fig. 7F) with short, wide, rounded internal spur, wider than long; distinct, smaller, rounded, external spur; coxa II with internal, round, posteriorly directed spur and external very small, rounded spur; coxa III–IV with single, triangular spur, as long as wide at insertion, directed posteriorly, inserted at mid-width in coxa III, inserted more medially in coxa IV. Trochanter I with ventral rounded spur; coxae and legs with scattered, long, fine setae. Male— Figs. 8A–8G; based on 2 specimens, some partially engorged, from Packard’s type series deposited at the Harvard Museum of Comparative Zoology (MCZ IZ 47339); therefore, standard deviation values are missing when only 2 measurements were available. Scutum (Fig. 8C) oval, longer (1.33–2.12; 1.73) than wide (0.95–1.43; 1.19); with lateral edges convex, widest posterior to mid-length; cervical grooves very deep, short, almost parallel, reaching level of coxa II; scapulae round with scattered fine punctations, bearing short, fine setae as in female; marginal grooves starting anteriorly at approx. mid length of scutum, deep, reaching and lining first festoon, absent along other 9 festoons; festoons with scattered punctations and inconspicuous short, fine setae; median field with unevenly distributed, medium sized shallow punctations, all bearing very short, fine setae (0.004–0.011; 0.008 ± 0.003), glabrous crescent outlining pseudoscutum and glabrous median longitudinal line reaching central festoon, interrupting punctation pattern, lateral fold anterior to festoons with single, lateral, almost linear line of punctations reaching almost level of coxa II (Fig. 8C). Venter: genital aperture at level of coxa II, covered by oval apron as in Fig. 8E; anal groove posterior to anus joining genital groove anterolaterally, bean-shaped areas posterolateral to anus, delimited by posteromedian groove, festoons, posterior part of genital groove, and anal groove; punctations dense, fine, shallow, and uniformly distributed, bearing fine, very short setae (0.006–0.009; 0.008 ± 0.001) (Fig. 8F); spiracular plates almost round with blunt, inconspicuous, dorsal projection, with 4–5 lines of small goblet cells, smaller along periphery. Capitulum (Figs. 8A–B). Dorsal: length from palpal apices to tip of cornuae (0.33–0.35; 0.34); basis capitula broader (0.23–0.24; 0.235) than long (0.13–0.14; 0.135), subrectangular, with convex, rounded, lateral edges, posterior margin straight, cornuae at least as long as wide, bluntly rounded (Fig. 8A); ventrally basis capituli subrectangular, with lateral edges slightly diverging anteriorly, with short rounded, posteriorly directed processes as wide at insertion as long (Fig. 8B). Palps dorsal: palpal segment I inconspicuous; palpal segment II length (0.13–0.14; 0.13 ± 0.005), width at level of lateral projection (0.10–0.13; 0.11 ± 0.01), distance between apices of lateral projections (0.39–0.41; 0.40); lateral length of palpal segments II and III combined measured from apex of palpal segment III to tip of angle with lateral projection (0.18–0.19; 0.18 ± 0.006); internal margin concave ending in conspicuous medially directed lobe, with 2–3 fine, barbed setae (visible in specimen not used for SEM); palpal segment III approximately as long (0.06– 0.1; 0.08 ± 0.02) as wide (0.07–0.08; 0.08 ± 0.002) (Fig. 8A). Palps ventral: palpal segment I inconspicuous, palpal segment II with no spurs, with approx. 5, lanceolate, barbed, fine, median setae; palpal segment III with rounded ventral spur. Hypostome clavate, with homogeneous 3:3 dental formula excepted crown, approx. 8 denticles per file (Fig. 8B). Legs. Coxa I (Fig. 8D) with short, rounded internal spur, wider than long, external spur shorter and round; coxa II with round almost ridge-like internal spur and pointed short external spur; coxa III with round, very short, internal spur, coxa IV with inconspicuous barely noticeable internal ridge. Trochanter I with ventral rounded ridge-like spur; coxae and legs with scattered, long, and fine setae (Fig. 8D). Diagnostic characters The diagnostic characters unique for the female of H. vespertina are a combination of the following characters: palpal segment II with pointed lateral projection and 6 dorsal, flattened, barbed setae inserted on an almost straight internal margin, with approximately 11–12 ventral, lanceolate, long, barbed medially inserted setae, palpal segment III with a rounded ventral spur; ventral process of basis capituli short, subtriangular with rounded anterior apex. Hypostome clavate with homogeneous 3:3 dental formula except crown; scutum with lateral fields and posterior border almost devoid of punctations and glabrous, median field with homogeneously distributed very large, shallow, somewhat confluent punctations; coxa I with internal short and rounded spur and external spur as a triangular ridge, coxae II–IV with a single triangular spur, coxae and other leg segments with numerous, long, and fine setae; genital aperture round with small lateral chitinous flaps, and spiracular plate with 3–4 rows of goblet cells, the central ones being much larger than those of the marginal row. Males of H. vespertina can be diagnosed by the following combination of characters: basis capituli with rounded, triangular, and short cornuae; palpal segment II with pointed lateral projection and with 4 dorsal barbed setae inserted medially into concave internal margin and with approximately 9 ventral, barbed, long and lanceolate setae; ventral process of basis capituli short and triangular, hypostome clavate with homogeneous 3:3 dental formula except crown; scutum with homogeneously distributed, very large, shallow, and somewhat confluent punctations; coxa I with 2 spurs, the internal short and rounded spur, the external ridge-like, coxae II–IV with a single triangular spurs; coxae and other segments of legs with very numerous, long, and fine setae; spiracular plate as in female. The diagnostic morphological characters for the female of H. leporispalustris are as follows: palpal segment II with pointed lateral projection, with 3 dorsal, fine, barbed setae inserted along the concave internal margin, posterior to the conspicuous anterior lobe, and with approximately 8 ventral fine barbed setae; palpal segment III with a rounded ventral spur; ventral

  PublisherDOI

Recent grants

• NIH Grant R01AI046031

  NIH · $1.4M · 2006

• NIH Grant P01AI028781

  NIH · $5.4M · 1999

• Evaluation of a novel mosquito repellent isolated from bacteria

  NIH · $400k · 2016–2019

• NIH Grant R01AI037083

  NIH · $2.6M · 2012

Frequent coauthors

• Lyric C. Bartholomay

  University of Wisconsin–Madison

  36 shared

• Frank H. Collins

  University of Notre Dame

  33 shared

• Gebbiena M. Bron

  29 shared

• Xia Lee

  Wisconsin Department of Health Services

  27 shared

• David W. Severson

  Indiana University

  21 shared

• Weiqi Wei

  20 shared

• Fotis C. Kafatos

  Imperial College London

  19 shared

• Bruce M. Christensen

  University of Wisconsin Health

  18 shared

Labs

• Paskewitz LabPI

Education

• Ph.D., Entomology

  University of California, Berkeley

  1990

• M.S., Entomology

  University of California, Berkeley

  1986

• B.S., Entomology

  University of California, Davis

  1984

Awards & honors

• Vilas Associate Award, University of Wisconsin-Madison (2006…
• Pound Research Award, University of Wisconsin-Madison (1998)