Rowland, A. C.

Wicht, M. C., Jr.

English

UARK (University of Arkansas )

Journal of the Arkansas Academy of Science Volume 41 Article 44 1987 Fauna and Distribution of Free Living Chiggers (Acarina: Trombiculidae) in Arkansas M. C. Wicht Jr. Lyon College A. C. Rowland Lyon College Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Zoology Commons Recommended Citation Wicht, M. C. Jr. and Rowland, A. C. (1987) "Fauna and Distribution of Free Living Chiggers (Acarina: Trombiculidae) in Arkansas," Journal of the Arkansas Academy of Science: Vol. 41 , Article 44. Available at: https://scholarworks.uark.edu/jaas/vol41/iss1/44 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. Arkansas Academy of ScienceAPPLICATION OF GELIGAM SOFTWARE TO THE ANALYSISOF X-RAY SPECTRAIn1986 a feasibility study (H. B. Eldridge, "Testing Treated Posts Using X-Ray Fluorescence- AFeasibility Study." Paper presented at theForty-Second Arkansas Transportation Research Committee Meeting April1986.) was conducted to determine ifX-ray fluorescence energy disper-sive techniques could be used as a timely and nondestructive means of testing the quality of treatment of wood products. This project was of interestto and was funded by The Arkansas Highway and Transportation Department (AHTD), which uses the preservative Copper-Chrominum Arsenate(CCA). „ _ . . ..„ ...The X-ray fluorescence energy dispersive techniques currently being investigated uses an "'Amisotopic X-ray source withan ADCAMsystemconsisting of a model 918 Multichannel Buffer, and Lithium-Drifted Silicon X-ray Detector. The software used for analysis of the spectrum col-ected with this system was the Geligam Gamma-ray Analysis (Geligam is a Software program developed by EG&G ORTEC 100 Midland Road,Oak Ridge, TN 37831-0895) package. Geligam is a modular software package designed for analysis of Gamma-ray spectra collected with a ger-manium gamma radiation detector. The modules of Geligam which were used for the X-ray analysis project were A18-BIApplication Managerand A30-BI Gamma-Ray Analysis. A18-BI Application Manager program allows the user to collect data with the ADACAM, transfer spectraldata, create, modify, delete or transfer bookkeeping data, print spectral orbookkeeping data, or convert emulator output files to the form neededfor the analysis program to be able to use them. The emulator program is the software part of the ADCAMsystem which allows the PC to beused to collect spectra.The A30-BI Gamma-ray analysis module is designed to analyze Gamma-ray spectra collected witha germanium solid state detector. Thegamma analysis software is designed to work with files produced by the A18-BIapplication manager, in order to produce a report containing theintensities of Gamma-rays found and the concentrations of the radioactive nuclide present.The first program to be run from the Geligam software package is the Gerpar file. This file allows the user to set initial parameters. Themost important of these parameters are the MCA number, which makes sure the same set-up is used during the entire analysis, and the analysisversion number, which tells the type of analysis to be performed. The only other parameters changed from the program defaults were the startand stop channels (200 and 500 respectively) and the intermediate print-out.The next program run should be the library program which creates, modifies, or prints a library of the nuclide that the user would like theanalysis program to find. Inour case, the elements were Copper, Chromium and Arsenic. Only Copper and Chromium were entered into the library,due to the effect of the Compton edge of "'Am on the counting statistics ofArsenic. There are three possible types of libraries which may beused. These are GAMMA,NAAA,and NAAC. The type of library used was the GAMMAsimply because it fitthe needs of the analysis performed.The GAMMAlibrary needs the following information; the half life, which was chosen to be large enough so as not to interfere with thecalculations, the branching ratios, determined to be the fractional area under each of the peaks as compared to the total area of the peaks in thelibrary. The Gammas/ 100D were chosen to be 100 times the branching ratio. Alldata entered into the library was taken from experimental data.The Convert filemust then be run inorder to change the CHN file into a spectrum file and combine the outputs of the library and analysisparameter files with the spectrum. Next tocalibration filemust be run. This fileserves three purposes. One, to calibrate the file, secondly, to adjustfor the detector's efficiency knee, and third, to find the efficiency ofthe spectrum. The calibration fileproduced is then combined with the spectrumfile with the use of the Convert file. The first analysis file (AN1)is then run. This file produces a UFO file which is needed in the final analysis.Italso allows the user to modify any parameters set inGerpar. The second analysis file (AN2) analyzes the UFO file formed by the first analysisprogram and makes a report which is placed in this file. The final program to be run is the report file, which willprint a report of the file tothe monitor, printer, or save it as a disk file. The report this file creates shows the energy of the peak found, the corresponding channel, the cor-responding nuclide, and the peaks found that are not in the library.As stated, the Geligam analysis software package is for the analysis of Gamma-ray spectra collected with a germanium solid state detector.The X-ray spectra which is analyzed with this study is collected with a Silicon lithium solid state detector using a "'Am isotopic X-ray source.The spectra which has been collected thus far is from liquid CCA. There were 10 samples made. The samples ranged from 10% CCA to pureCCA at 10% increments. The samples were then placed in standard liquidsample containers that provided a 0.15 mil thick Mylar entrance windowto the incident X-ray beam.The background continuum and Compton edge of "'Am interfered with the counting statistics of the Cr and As peaks at low concentrationsof CCA. The Compton edge of "'Am is approximately 9 Kev. Another X-ray (109Cd) source, which is being purchased, has no appreciable Com-pton edge, and should not interfere with any of the peaks. However, since the As peak has good counting statistics through the range of CCAconcentrations, a graph was constructed of the concentration of As versus its activity. The resulting curve was linear, as was expected.Geligam Gamma-ray analysis program found the peaks in the X-ray spectra ofthe elements in the library and reported their activity. Althoughthis is not a true activity, as in Gamma-ray analysis itmay be used to find the amounts of elements in a sample. Inthe study underway, Geligamwillbe used to find the amount of CCA in a sample and the concentrations of the elements involved.R. S. SAUNDERS, H. L.PRAY, and H. B. ELDRIDGE, University of Central Arkansas, Conway, Arkansas 72032.FAUNA AND DISTRIBUTION OF FREE LIVINGCHIGGERS (ACARINA:TROMBICULIDAE) INARKANSASIn the southern United States, the pest chigger Eutrombicula alfreddugesi (Oudemans), is widely distributed and medically important (Jenkins,1949; Crossley and Proctor, 1971). Infestive larvae of this mite cause dermatitis in man and some animals, resulting in economic losses (Whartonand Fuller, 1952). Dense populations of this chigger may have an adverse effect on forestry operations, recreation, and military training (Martinko,1974; Anonymous, 1976). In the Pacific, other Trombiculid mites have long been known to transmit scrub typhus or Tsutsugamushi disease. E.olfreddugesi is the most common and abundant chigger on the Georgia piedmont (Ludwig, et ai, 1984). No previous extensive survey in the state°fArkansas has been undertaken.A three year study of the fauna and distribution of the free living Trombiculidae ofArkansas was initiated in the fall of 1984. Atthis date,the authors feel that the survey has been fairly complete, but some additional work needs to be done.Free living chiggers were collected throughout the state using "chigger samplers" as described by Wicht and Crossley (inmanuscript). Thismethod consists of placing 7 x 14 centimeter (about 100 cm 2)black vinylbaseboard rectangles on objects and placed where chiggers might occur.Fromprevious experience in the field, the authors have learned that chiggers are most likely to be found on logs, stumps, and rocks, where lizardsmight sun themselves, where birds might land, or where some mammal might walk.Proceedings Arkansas Academy of Science, Vol. 41, 1987 115115Journal of the Arkansas Academy of Science, Vol. 41 [1987], Art. 44Published by Arkansas Academy of Science, 1987116Proceedings Arkansas Academy of Science, Vol. 41, 1987General Notes>Localities were sampled in all hours of daylight, in temperatures ranging from 22 to 40 degrees Celsius, and in a wide variety of weatherconditions including overcast, partly cloudy, and sunny. The earliest successful sampling date was May 4 and the latest successful sampling datewas September 28. Even though sampling was conducted under various weather conditions, previous experience has also taught the authors thatchiggers are most apt to respond to the chigger sampler ifit is placed on an object, partially shaded, on a bright sunny day (Wicht and Crossley;field notes, summer of 1982) with the incident sunlight being on the order of 1000 foot candles.Others have used small black objects to collect unengorged chiggers. Wharton and Fuller (1952) used black bakelite caps removed from reagentbottles. Loomis (1956) used rigid black plexiglass-acrylic rectangles to locate chiggers. Using his type of "chigger sampler," Loomis recoverd atotal of eight different species of chigger in the state of Kansas (Eutrombicula alfreddugesi, Trombicula sylvilagi, and Trombicula gurneyi beingcommon; Eutrombicula lipovskyana, Trombicula lipovskyi, and Neoschongastia americana in small numbers; Euschongastia diversa and Euschongastiajonesi, a single specimen each). Crossley and Proctor (1970) reported the use of small rectangles of prepainted masonite material.Mounted specimens were identified using taxonomic keys provided by Brennan and Jones (1959). Further identifications were confirmedby D. A. Crossley (personal communication).To date, 124 localities in 55 of Arkansas' counties have been identified in which chiggers occur. Over 2500 specimens have been collectedfrom these localities and over 1500 of these specimens have been mounted and identified to species. Three species thus far have been identified.They are Eutrombicula alfreddugesi, Eutrombicula splendens, and what appears to be a new species heretofore not described.Eutrombicula alfreddugesi is by far the most pominent species in the state. Itis the most prevalent and occurs in greatest numbers inhabitatswhere a mixture of oak-hickory pre-climax forest exists mixed with conifers. This species appears throughout all parts of the state but occurs inmuch less numbers and is much harder to find inareas of poor drainage and little forest such as in the delta and eastern counties. There appearsto be a definite association between pine and the occurrence ofthis species. Boone County, for example, has a significant amount ofoak, hickory,and other hardwoods, but much less than a county such as Cleburne. E. alfreddugesi also occurs inmuch greater numbers in Cleburne and likecounties than in Boone County; however, there was also a great deal of variation in numbers of chiggers found in the individual sampling sites.A woods environment is not the only habitat in which chiggers were found, however. Numerous specimens were collected from such examplesas stumps instate parks, logs and boards near pasture fence lines, large stones in the middle of fields oron road banks, and in one instance, froma slab of concrete in a grassy area in the middle of town.Eutrombicula splendens is the second most prevalent free living chigger in the state. Numerous specimens of this species were recovered,but itis much less prevalent than alfreddugesi. Itis concentrated, likealfreddugesi, mostly in the central and western counties. The authors believethat succinct populations of splendens occur; however, numbers of this species were never collected without alfreddugesi being found within afew meters. Both these chiggers, in fact, have been collected from the same spot on the same log at the same time. This is not to suggest thatthey are the same species or that they are two different species occupying the same ecological niche.According to Jenkins (1949), E. alfreddugesi and E. splendens have sympatric ranges but tend to be concentrated in different habitats. E.alfreddugesi is more abundant in drier, upland habitats, while E. splendens is more abundant inmesic to moist situations. Our observations supportthose of Jenkins'.Numerous specimens which we are calling "variants" were collected from Perry, Marion, Searcy, Pulaski, and White Counties. These chig-gers keyed out to be either alfreddugesi or splendens but had either unusual or uneven setation. Both arrangement and numbers of setae in par-ticular are important taxonomic characteristics in this family. The cause of the variation in these specimens needs to be investigated further.A single specimen of an unknown species was taken from Scott County. Personal communication with D. A. Crossley indicates that thisis probably a new species. Regrettably, efforts to obtain additional specimens from this site have proven unsuccessful.LITERATURE CITEDBRENNAN, J. M. and E. K. JONES. 1959. Keys to the chiggers ofNorth America withsynonymic notes and descriptions of two newgenera (Acarina: Trombiculidae). Ann. Entomol. Soc. Amer.52:7-16.CROSSLEY, D. A., JR. and C. W. PROCTOR, JR. 1970. A noteon a sampling technique for unengorged chiggers (Trombiculidae).J. Georgia Entomol. Soc. 5:22.CROSSLEY, D. A.,JR. and C. W. PROCTOR, JR. 1971. New recordsofchigger species (Acarina: Trombiculidae) in Georgia. J. GeorgiaEntomol. Soc. 6:185-7.JENKINS, D. W. 1949. Trombiculid mites affecting man. IV.Revision of Eutrombicula in the American hemisphere. Ann.Entomol. Soc. Amer. 42:289-318.LOOMIS, R. B. 1956. The chigger mites of Kansas (Acarina:Trombiculidae). Univ. Kan. Sci. Bull. 37:1195-1443.LUDWIG, D. F., D. A. CROSSLEY, JR., M. J. HAYES, D.MALLOW,and M.C. WICHT, JR. 1984. Pest chigger, Eutrom-bicula alfreddugesi, infestation of small mammals in piedmonthabitats of Georgia (Acarina: Trombiculidae). J. Georgia Entomol.Soc. 20:1-8.MARTINKO, E. A. 1974. Chiggers in Kansas: Their habits andeffects on man. Bull. State Bio. Surv. Kan. 1:1-9.SOUTHERN REGIONAL AGRICULTURAL RESEARCHSERVICE. 1976. Controlling chiggers. U.S. Gov. Print. Off.,Wash., DC.WHARTON, G. W. and H. S. FULLER. 1952. A manual of thechiggers. Mem. Entomol. Soc. Wash. 4:1-185.M. C. WICHT, JR. and A. C. ROWLAND, Department ofMedical Technology, Arkansas College, Batesville, AR 72501.116Journal of the Arkansas Academy of Science, Vol. 41 [1987], Art. 44https://scholarworks.uark.edu/jaas/vol41/iss1/44

Fauna and Distribution of Free Living Chiggers (Acarina: Trombiculidae)  in Arkansas

ScholarWorks@UARK

Journal of the Arkansas Academy of ScienceVolume 41 Article 441987Fauna and Distribution of Free Living Chiggers(Acarina: Trombiculidae) in ArkansasM. C. Wicht Jr.Lyon CollegeA. C. RowlandLyon CollegeFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Zoology CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the ArkansasAcademy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu, ccmiddle@uark.edu.Recommended CitationWicht, M. C. Jr. and Rowland, A. C. (1987) "Fauna and Distribution of Free Living Chiggers (Acarina: Trombiculidae) in Arkansas,"Journal of the Arkansas Academy of Science: Vol. 41 , Article 44.Available at: http://scholarworks.uark.edu/jaas/vol41/iss1/44Arkansas Academy of ScienceAPPLICATION OF GELIGAM SOFTWARE TO THE ANALYSISOF X-RAY SPECTRAIn1986 a feasibility study (H. B. Eldridge, "Testing Treated Posts Using X-Ray Fluorescence- AFeasibility Study." Paper presented at theForty-Second Arkansas Transportation Research Committee Meeting April1986.) was conducted to determine ifX-ray fluorescence energy disper-sive techniques could be used as a timely and nondestructive means of testing the quality of treatment of wood products. This project was of interestto and was funded by The Arkansas Highway and Transportation Department (AHTD), which uses the preservative Copper-Chrominum Arsenate(CCA). „ _ . . ..„ ...The X-ray fluorescence energy dispersive techniques currently being investigated uses an "'Amisotopic X-ray source withan ADCAMsystemconsisting of a model 918 Multichannel Buffer, and Lithium-Drifted Silicon X-ray Detector. The software used for analysis of the spectrum col-ected with this system was the Geligam Gamma-ray Analysis (Geligam is a Software program developed by EG&G ORTEC 100 Midland Road,Oak Ridge, TN 37831-0895) package. Geligam is a modular software package designed for analysis of Gamma-ray spectra collected with a ger-manium gamma radiation detector. The modules of Geligam which were used for the X-ray analysis project were A18-BIApplication Managerand A30-BI Gamma-Ray Analysis. A18-BI Application Manager program allows the user to collect data with the ADACAM, transfer spectraldata, create, modify, delete or transfer bookkeeping data, print spectral orbookkeeping data, or convert emulator output files to the form neededfor the analysis program to be able to use them. The emulator program is the software part of the ADCAMsystem which allows the PC to beused to collect spectra.The A30-BI Gamma-ray analysis module is designed to analyze Gamma-ray spectra collected witha germanium solid state detector. Thegamma analysis software is designed to work with files produced by the A18-BIapplication manager, in order to produce a report containing theintensities of Gamma-rays found and the concentrations of the radioactive nuclide present.The first program to be run from the Geligam software package is the Gerpar file. This file allows the user to set initial parameters. Themost important of these parameters are the MCA number, which makes sure the same set-up is used during the entire analysis, and the analysisversion number, which tells the type of analysis to be performed. The only other parameters changed from the program defaults were the startand stop channels (200 and 500 respectively) and the intermediate print-out.The next program run should be the library program which creates, modifies, or prints a library of the nuclide that the user would like theanalysis program to find. Inour case, the elements were Copper, Chromium and Arsenic. Only Copper and Chromium were entered into the library,due to the effect of the Compton edge of "'Am on the counting statistics ofArsenic. There are three possible types of libraries which may beused. These are GAMMA,NAAA,and NAAC. The type of library used was the GAMMAsimply because it fitthe needs of the analysis performed.The GAMMAlibrary needs the following information; the half life, which was chosen to be large enough so as not to interfere with thecalculations, the branching ratios, determined to be the fractional area under each of the peaks as compared to the total area of the peaks in thelibrary. The Gammas/ 100D were chosen to be 100 times the branching ratio. Alldata entered into the library was taken from experimental data.The Convert filemust then be run inorder to change the CHN file into a spectrum file and combine the outputs of the library and analysisparameter files with the spectrum. Next tocalibration filemust be run. This fileserves three purposes. One, to calibrate the file, secondly, to adjustfor the detector's efficiency knee, and third, to find the efficiency ofthe spectrum. The calibration fileproduced is then combined with the spectrumfile with the use of the Convert file. The first analysis file (AN1)is then run. This file produces a UFO file which is needed in the final analysis.Italso allows the user to modify any parameters set inGerpar. The second analysis file (AN2) analyzes the UFO file formed by the first analysisprogram and makes a report which is placed in this file. The final program to be run is the report file, which willprint a report of the file tothe monitor, printer, or save it as a disk file. The report this file creates shows the energy of the peak found, the corresponding channel, the cor-responding nuclide, and the peaks found that are not in the library.As stated, the Geligam analysis software package is for the analysis of Gamma-ray spectra collected with a germanium solid state detector.The X-ray spectra which is analyzed with this study is collected with a Silicon lithium solid state detector using a "'Am isotopic X-ray source.The spectra which has been collected thus far is from liquid CCA. There were 10 samples made. The samples ranged from 10% CCA to pureCCA at 10% increments. The samples were then placed in standard liquidsample containers that provided a 0.15 mil thick Mylar entrance windowto the incident X-ray beam.The background continuum and Compton edge of "'Am interfered with the counting statistics of the Cr and As peaks at low concentrationsof CCA. The Compton edge of "'Am is approximately 9 Kev. Another X-ray (109Cd) source, which is being purchased, has no appreciable Com-pton edge, and should not interfere with any of the peaks. However, since the As peak has good counting statistics through the range of CCAconcentrations, a graph was constructed of the concentration of As versus its activity. The resulting curve was linear, as was expected.Geligam Gamma-ray analysis program found the peaks in the X-ray spectra ofthe elements in the library and reported their activity. Althoughthis is not a true activity, as in Gamma-ray analysis itmay be used to find the amounts of elements in a sample. Inthe study underway, Geligamwillbe used to find the amount of CCA in a sample and the concentrations of the elements involved.R. S. SAUNDERS, H. L.PRAY, and H. B. ELDRIDGE, University of Central Arkansas, Conway, Arkansas 72032.FAUNA AND DISTRIBUTION OF FREE LIVINGCHIGGERS (ACARINA:TROMBICULIDAE) INARKANSASIn the southern United States, the pest chigger Eutrombicula alfreddugesi (Oudemans), is widely distributed and medically important (Jenkins,1949; Crossley and Proctor, 1971). Infestive larvae of this mite cause dermatitis in man and some animals, resulting in economic losses (Whartonand Fuller, 1952). Dense populations of this chigger may have an adverse effect on forestry operations, recreation, and military training (Martinko,1974; Anonymous, 1976). In the Pacific, other Trombiculid mites have long been known to transmit scrub typhus or Tsutsugamushi disease. E.olfreddugesi is the most common and abundant chigger on the Georgia piedmont (Ludwig, et ai, 1984). No previous extensive survey in the state°fArkansas has been undertaken.A three year study of the fauna and distribution of the free living Trombiculidae ofArkansas was initiated in the fall of 1984. Atthis date,the authors feel that the survey has been fairly complete, but some additional work needs to be done.Free living chiggers were collected throughout the state using "chigger samplers" as described by Wicht and Crossley (inmanuscript). Thismethod consists of placing 7 x 14 centimeter (about 100 cm 2)black vinylbaseboard rectangles on objects and placed where chiggers might occur.Fromprevious experience in the field, the authors have learned that chiggers are most likely to be found on logs, stumps, and rocks, where lizardsmight sun themselves, where birds might land, or where some mammal might walk.Proceedings Arkansas Academy of Science, Vol. 41, 1987 115115Journal of the Arkansas Academy of Science, Vol. 41 [1987], Art. 44Published by Arkansas Academy of Science, 1987116Proceedings Arkansas Academy of Science, Vol. 41, 1987General Notes>Localities were sampled in all hours of daylight, in temperatures ranging from 22 to 40 degrees Celsius, and in a wide variety of weatherconditions including overcast, partly cloudy, and sunny. The earliest successful sampling date was May 4 and the latest successful sampling datewas September 28. Even though sampling was conducted under various weather conditions, previous experience has also taught the authors thatchiggers are most apt to respond to the chigger sampler ifit is placed on an object, partially shaded, on a bright sunny day (Wicht and Crossley;field notes, summer of 1982) with the incident sunlight being on the order of 1000 foot candles.Others have used small black objects to collect unengorged chiggers. Wharton and Fuller (1952) used black bakelite caps removed from reagentbottles. Loomis (1956) used rigid black plexiglass-acrylic rectangles to locate chiggers. Using his type of "chigger sampler," Loomis recoverd atotal of eight different species of chigger in the state of Kansas (Eutrombicula alfreddugesi, Trombicula sylvilagi, and Trombicula gurneyi beingcommon; Eutrombicula lipovskyana, Trombicula lipovskyi, and Neoschongastia americana in small numbers; Euschongastia diversa and Euschongastiajonesi, a single specimen each). Crossley and Proctor (1970) reported the use of small rectangles of prepainted masonite material.Mounted specimens were identified using taxonomic keys provided by Brennan and Jones (1959). Further identifications were confirmedby D. A. Crossley (personal communication).To date, 124 localities in 55 of Arkansas' counties have been identified in which chiggers occur. Over 2500 specimens have been collectedfrom these localities and over 1500 of these specimens have been mounted and identified to species. Three species thus far have been identified.They are Eutrombicula alfreddugesi, Eutrombicula splendens, and what appears to be a new species heretofore not described.Eutrombicula alfreddugesi is by far the most pominent species in the state. Itis the most prevalent and occurs in greatest numbers inhabitatswhere a mixture of oak-hickory pre-climax forest exists mixed with conifers. This species appears throughout all parts of the state but occurs inmuch less numbers and is much harder to find inareas of poor drainage and little forest such as in the delta and eastern counties. There appearsto be a definite association between pine and the occurrence ofthis species. Boone County, for example, has a significant amount ofoak, hickory,and other hardwoods, but much less than a county such as Cleburne. E. alfreddugesi also occurs inmuch greater numbers in Cleburne and likecounties than in Boone County; however, there was also a great deal of variation in numbers of chiggers found in the individual sampling sites.A woods environment is not the only habitat in which chiggers were found, however. Numerous specimens were collected from such examplesas stumps instate parks, logs and boards near pasture fence lines, large stones in the middle of fields oron road banks, and in one instance, froma slab of concrete in a grassy area in the middle of town.Eutrombicula splendens is the second most prevalent free living chigger in the state. Numerous specimens of this species were recovered,but itis much less prevalent than alfreddugesi. Itis concentrated, likealfreddugesi, mostly in the central and western counties. The authors believethat succinct populations of splendens occur; however, numbers of this species were never collected without alfreddugesi being found within afew meters. Both these chiggers, in fact, have been collected from the same spot on the same log at the same time. This is not to suggest thatthey are the same species or that they are two different species occupying the same ecological niche.According to Jenkins (1949), E. alfreddugesi and E. splendens have sympatric ranges but tend to be concentrated in different habitats. E.alfreddugesi is more abundant in drier, upland habitats, while E. splendens is more abundant inmesic to moist situations. Our observations supportthose of Jenkins'.Numerous specimens which we are calling "variants" were collected from Perry, Marion, Searcy, Pulaski, and White Counties. These chig-gers keyed out to be either alfreddugesi or splendens but had either unusual or uneven setation. Both arrangement and numbers of setae in par-ticular are important taxonomic characteristics in this family. The cause of the variation in these specimens needs to be investigated further.A single specimen of an unknown species was taken from Scott County. Personal communication with D. A. Crossley indicates that thisis probably a new species. Regrettably, efforts to obtain additional specimens from this site have proven unsuccessful.LITERATURE CITEDBRENNAN, J. M. and E. K. JONES. 1959. Keys to the chiggers ofNorth America withsynonymic notes and descriptions of two newgenera (Acarina: Trombiculidae). Ann. Entomol. Soc. Amer.52:7-16.CROSSLEY, D. A., JR. and C. W. PROCTOR, JR. 1970. A noteon a sampling technique for unengorged chiggers (Trombiculidae).J. Georgia Entomol. Soc. 5:22.CROSSLEY, D. A.,JR. and C. W. PROCTOR, JR. 1971. New recordsofchigger species (Acarina: Trombiculidae) in Georgia. J. GeorgiaEntomol. Soc. 6:185-7.JENKINS, D. W. 1949. Trombiculid mites affecting man. IV.Revision of Eutrombicula in the American hemisphere. Ann.Entomol. Soc. Amer. 42:289-318.LOOMIS, R. B. 1956. The chigger mites of Kansas (Acarina:Trombiculidae). Univ. Kan. Sci. Bull. 37:1195-1443.LUDWIG, D. F., D. A. CROSSLEY, JR., M. J. HAYES, D.MALLOW,and M.C. WICHT, JR. 1984. Pest chigger, Eutrom-bicula alfreddugesi, infestation of small mammals in piedmonthabitats of Georgia (Acarina: Trombiculidae). J. Georgia Entomol.Soc. 20:1-8.MARTINKO, E. A. 1974. Chiggers in Kansas: Their habits andeffects on man. Bull. State Bio. Surv. Kan. 1:1-9.SOUTHERN REGIONAL AGRICULTURAL RESEARCHSERVICE. 1976. Controlling chiggers. U.S. Gov. Print. Off.,Wash., DC.WHARTON, G. W. and H. S. FULLER. 1952. A manual of thechiggers. Mem. Entomol. Soc. Wash. 4:1-185.M. C. WICHT, JR. and A. C. ROWLAND, Department ofMedical Technology, Arkansas College, Batesville, AR 72501.116Journal of the Arkansas Academy of Science, Vol. 41 [1987], Art. 44http://scholarworks.uark.edu/jaas/vol41/iss1/44

https://scholarworks.uark.edu/cgi/viewcontent.cgi?article=2391&amp;context=jaas

Fauna and Distribution of Free Living Chiggers (Acarina: Trombiculidae) in Arkansas

Abstract

Similar works

Full text

Available Versions

UARK (University of Arkansas )

ScholarWorks@UARK