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Faculty Publications: Department of Entomology Entomology, Department of
2010
Morphological and genetic analyses in the Melanoplus packardii group (Orthoptera: Acrididae)
Mathew L. Brust University of Nebraska-Lincoln, [email protected]
Erica J. Lindroth University of Nebraska-Lincoln, [email protected]
W. Wyatt Hoback University of Nebraska at Kearney, [email protected]
Robert Wright University of Nebraska--Lincoln, [email protected]
Kathryn J. Hanford University of Nebraska, [email protected]
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Brust, Mathew L.; Lindroth, Erica J.; Hoback, W. Wyatt; Wright, Robert; Hanford, Kathryn J.; and Foster, John E., "Morphological and genetic analyses in the Melanoplus packardii group (Orthoptera: Acrididae)" (2010). Faculty Publications: Department of Entomology. 331. https://digitalcommons.unl.edu/entomologyfacpub/331
This Article is brought to you for free and open access by the Entomology, Department of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications: Department of Entomology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Mathew L. Brust, Erica J. Lindroth, W. Wyatt Hoback, Robert Wright, Kathryn J. Hanford, and John E. Foster
This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/ entomologyfacpub/331 Journal of Orthoptera Research 201 0, 19(2): 281-288
Morphological and genetic analyses in the Melanoplus packardii group (Orthoptera: Acrididae)
Submitted January 18, 201 0, accepted December 5, 201 ° MATHEW L. BRUST, ERICA J. LINDROTH, W. WYATI HOBACK, ROBERT J. WRIGHT, KATHY HANFORD AND JOHN E. FOSTER (MLB, EJL RJW, JEF; all based Nebraska USA) Department of Entomology, University of Nebraska Lincoln, 202 Entomology Hall, Lincoln, NE 68583-0816. Email: elindro [email protected], [email protected], jfoster1 @unl.edu (MLB) Present address: Department of Biology, Chadron State College, 1000 Main Street. Chadron, NE 69337. Email: [email protected] (WWH) Department of Biology, University of Nebraska at Kearney, 905 W 25th Street. Kearney, NE 68849. Email: [email protected] (KH) Department of Statistics, University of Nebraska Lincoln, 340 Hardin Hall North, Lincoln, NE 68583-0963. Email: [email protected] Abstract and subspecies in the packardii group: Melanoplus packardii, Melano Melanoplus packardii Scudder was described in 1897. Three additional plus foedus foedus, Melanoplus foedus fluviatilis, Melanoplus foedus isleyi, closely-related species were later described and their status as species has and Melanoplus stonei (Eades & OUe 2009). The ranges of M. foedus been questioned on numerous occasions. We examined morphology from foedus and M. foedus fluviatilis overlap across a large portion of the specimens collected in Nebraska which fit descriptions of three of the United States, and yet no apparent hybrids have been mentioned four forms and specimens that appeared to be hybrids. We found distinct in the literature. In addition, the range of M. foedus isleyi appears to morphological characters suggesting species status for M. foedus and M. overlap the range of M. foedus fluviatilis over a smaller area (Eades packardii, but not for M. foedus fluviatilis. Examination of aedeagi of these & Otte 2009). three forms suggests that M. foedus and M. packaTdii are each distinct, but All forms within this group are very difficult to differentiate that the aedeagi of M. f fluviatilis and M. f foedus cannot be distinguished. Molecular analyses ofthe three groups did not produce clear separations and because few morphological characters consistently differ between suggest gene exchange between these three forms may be ongoing. Together, them and even the genitalic differences are few. The cerci of the these data suggest that M. foedus and M. packardii should be recognized as males of all forms are virtually identical; however, the aedeagus of sibling species, butM. foedus fluviatilis is best considered a form ofM. foedus, M. packardii differs from that of M. foedus (Brooks 1958). typically found in low lying areas. Chapco et al. (1999) conducted mitochondrial DNA analyses on several North American Melanoplus species and determined that Keywords M. packardii and M. foedus were distinct, but closely related, species. However, genetic analysis of members of the group has also been Melanoplus packardii, morphometric, genetic, grasshopper, inconclusive and a later study by Chapco and Litzenberger (2002) systematics determined thatM. packardii andM. foedus had some genetic overlap among individuals. Together, these results suggest that these species Introduction either represent a variable single species or they represent a very recent evolutionary radiation with hybridization possible. More The taxonomic status of members of the Melanoplus packardii detailed studies on the genetic relationships between described group (Orthoptera: Acrididae) has been changed numerous times. species and subspecies within the M. packardii group are needed Melanoplus packardii packardii Scudder was described in 1897 to clarify these relationships. (Scudder 1897) and its taxonomic status has not shifted since Collections oflarge series from this group across Nebraska from (pfadt 2002, Capinera et al. 2004). Melanoplus foedus Scudder was 2005 to 2007 show trends that raise questions on the taxonomic described in 1897 (Scudder 1897), but was considered a subspe status of forms currently recognized as subspecies of M. foedus and cies of M. packardii for five years (Blatchley 1920, Hebard 1925). for M. packardii. This study scores morphological traits and uses It is currently recognized as a full species (Vickery & Kevan 1985, molecular analyses to test three hypotheses: 1) Melanoplus foedus Pfadt 2002, Capinera et al. 2004). Melanoplus packardii brooksi and M. packardii are distinct species; 2) Melanoplus foedus fluviatilis Vickery was described from Canada in 1979 (Vickery 1979) and represents a full species; and 3) local hybridization occurs between it remains recognized as a subspecies of M. packardii. Melanoplus M. packardii and M. foedus. fluviatilis Bruner was described as a species in 1897 (Bruner 1897), but without an extensive description. It was formally described in Methods 1920 (Blatchley 1920), but was later placed as a subspecies of M. foedus (Hebard 1931). Its taxonomic status has remained unchanged Large series of the forms M. packardii, M. foedus foedus, and M. since 1931 (Helfer 1987, Kirk & Bomar2005).Melanoplus foedus isleyi foedus fluviatilis were collected from across Nebraska, as well as from Hebard was described as a subspecies of M. foedus and remains as a single site in South Dakota, during the summers of 2005-2007. a subspecies under current classification (Hebard 1936a, Capinera Specimens were identified to species using a variety of resources, et al. 2004). Finally, Melanoplus stonei Rehn was described in 1904 including Bruner (1897), Scudder (1897), Helfer (1987), and Pfadt (Rehn 1904) and has since been recognized as a subspecies of M. (2002). foedus (Cantrall 1968) or M. packardii (Hebard 1928), but is now All specimens used for morphological studies were then pinned considered distinct [Hebard 1932 (1931), Vickery & Kevan 1985, and placed in the collection at USDA-APHIS in Lincoln, Nebraska. Kirk & Bomar 2005]. Specimens representing potential hybrids between M. foedus foedus In summary, the current literature recognizes the following species and M. packardii were grouped with the species or subspecies with
JOURNAL OF ORTHOPTERA RESEARCH 201 0, 19(2) -, "2534 %* ,).$2/4( 77 (/"!#+ 2* 72)'(4 + (!.&/2$ !.$ *% &/34%2
4ABLE .UMBER OF SPECIMENS OF EACH -ELANOPLUS TAXON BY COUNTY WHICH THEY SHARED THE GREATEST SIMILARITY 'ENETIC EXAMINATION WAS OF COLLECTION EXAMINED IN MORPHOMETRIC STUDY THEN USED TO DETERMINE THE IDENTITY OF THESE POSSIBLE HYBRIDS SEE 3PECIES #OUNTY 1UANTITY BELOW ! TOTAL OF - FOEDUS mUVIATILIS - FOEDUS FOEDUS AND - FOEDUS mUVIATILIS "UFFALO - PACKARDII WERE EXAMINED MORPHOLOGICALLY 4ABLE - FOEDUS mUVIATILIS $AWSON .ONMEASUREMENT DATA INCLUDED SPECIES DETERMINATION DATE - FOEDUS mUVIATILIS &URNAS COUNTY LOCALITY SEX HIND TIBIAL COLOR POSTOCULAR BAR DEVELOPMENT - FOEDUS mUVIATILIS (UGHES 3$ AND PREDOMINANT COLOR CONSISTENCY OF DORSAL PRONOTAL COLOR SOLID OR - FOEDUS mUVIATILIS +EARNEY STRIPED PREDOMINANT DORSAL PRONOTAL COLOR AND SECONDARY PRONOTAL - FOEDUS mUVIATILIS +EITH COLOR -EASUREMENT DATA WERE OBTAINED FOR TEGMEN LENGTH FROM - FOEDUS mUVIATILIS ,INCOLN LOWEST INSERTION ALONG LOWER PRONOTUM TO TIP NARROWEST DORSAL - FOEDUS FOEDUS !RTHUR DISTANCE BETWEEN EYES AND LENGTH OF MALE FURCULAE -EASUREMENTS - FOEDUS FOEDUS "ANNER OF TEGMEN LENGTH WERE DONE USING A VERNIER CALIPER AND ESTIMATED - FOEDUS FOEDUS "LAINE TO THE NEAREST MM WHILE MEASUREMENTS OF THE INTEREYE DISTANCE - FOEDUS FOEDUS "OX "UTTE AND LENGTH OF FURCULAE WERE TAKEN WITH AN OPTICAL MICROMETER 3COPE - FOEDUS FOEDUS "ROWN /LYMPUS 3: 343 X X X -ICROMETER /LYMPUS !8 - FOEDUS FOEDUS #HERRY /" - MM -ELANOPLUS F mUVIATILIS AND - F FOEDUS WERE - FOEDUS FOEDUS #USTER SEPARATED BASED ON THE CHARACTERS LISTED IN 4ABLE - FOEDUS FOEDUS $EUEL #HARACTERS WERE THEN ANALYZED USING 02/# ',)--)8 3!3 - FOEDUS FOEDUS $UNDY )NSTITUTE )NC -EASUREMENT DATA TEGMEN LENGTH DISTANCE - FOEDUS FOEDUS 'ARDEN BETWEEN EYES AND MALE FURCULA LENGTH WERE ANALYZED UNDER A NOR - FOEDUS FOEDUS 'RANT MAL DISTRIBUTION WHILE CATEGORICAL VARIABLES TIBIAL COLOR POSTOCULAR - FOEDUS FOEDUS (ALL BAR DEVELOPMENT AND POSTOCULAR COLOR WERE ANALYZED UNDER A - FOEDUS FOEDUS (OLT MULTINOMIAL DISTRIBUTION "ECAUSE OF DISTINCT DIFFERENCES IN SIZE - FOEDUS FOEDUS (OOKER BETWEEN SEXES MALES AND FEMALES WERE COMPARED SEPARATELY FOR - FOEDUS FOEDUS +EITH MEASUREMENT VARIABLES - FOEDUS FOEDUS +EYA 0AHA - FOEDUS FOEDUS ,INCOLN %XAMINATION OF !EDEAGI!EDEAGI FROM THREE MALES OF SPECIMENS - FOEDUS FOEDUS ,OGAN IDENTIlED AS - FOEDUS mUVIATILIS - FOEDUS FOEDUS AND - PACKARDII - FOEDUS FOEDUS ,OUP WERE EXAMINED FOR STRUCTURAL DIFFERENCES )N EACH CASE THE TERMINAL - FOEDUS FOEDUS -C0HERSON PART OF THE ABDOMEN OF THREE MALES WAS SEVERED INTESTINAL CONTENTS - FOEDUS FOEDUS -ORRILL REMOVED AND THE REMAINING STRUCTURE SOAKED IN A SOLUTION OF +/( - FOEDUS FOEDUS 2ED 7ILLOW FOR APPROXIMATELY H !FTER H THESE WERE TRANSFERRED TO - FOEDUS FOEDUS 2OCK ETHANOL AND THE AEDEAGUS THEN REMOVED !EDEAGI WERE CLEANED - FOEDUS FOEDUS 3COTTS "LUFF UNDER A DISSECTING SCOPE TO REMOVE BITS OF CONNECTIVE TISSUE 4HEY - FOEDUS FOEDUS 3HERIDAN WERE PLACED IN ETHANOL UNTIL EXAMINATION 0HOTOGRAPHS OF THE - FOEDUS FOEDUS 3IOUX AEDEAGI WERE TAKEN THROUGH A DISSECTING SCOPE AND DRAWN USING A - FOEDUS FOEDUS 4HOMAS CAMERA LUCIDA ! COMPARISON WAS MADE OF THE GENERAL STRUCTURE OF - PACKARDII "ANNER THE TERMINAL END OF THE AEDEAGUS ESPECIALLY IN REGARD TO PARAMERE - PACKARDII "UFFALO STRUCTURE - PACKARDII #HASE - PACKARDII #HERRY 'ENETIC !NALYSES - PACKARDII #USTER - PACKARDII $UNDY $.! )SOLATION AND 1UANTIlCATION$.! WAS ISOLATED FROM THE HIND - PACKARDII &RANKLIN LEGS OF INDIVIDUALS OF EACH FORM FOLLOWING A MODIlED $OYLE - PACKARDII &URNAS AND $OYLE #4!" EXTRACTION PROTOCOL 0ELLETED $.! WAS - PACKARDII 'AGE SUSPENDED IN «L X 4% BUFFER M- 4RIS (#, M- %$4! - PACKARDII 'ARDEN 4HE LOCATIONS DATES OF COLLECTION AND THE NUMBER OF SPECIMENS - PACKARDII 'OSPER USED IN THE GENETIC ANALYSES ARE PRESENTED IN 4ABLE - PACKARDII 'REELEY - PACKARDII (ARLAN !&,0 0#2'ENETIC VARIATION WAS ANALYZED USING A MODIlED !&,0 - PACKARDII (AYES AMPLIlED FRAGMENT LENGTH POLYMORPHISM PROCEDURE BASED ON - PACKARDII (ITCHCOCK 6OS ET AL - PACKARDII (OWARD - PACKARDII +EITH 4EMPLATE PREPARATION!PPROXIMATELY «L OF NG«L $.! TEMPLATE - PACKARDII +NOX WAS INCUBATED WITH «L %CO2) «L -SE) .EW %NGLAND - PACKARDII ,OUP "IOLABS «L /NE 0HOR !LL BUFFER '% (EALTHCARE «L - PACKARDII -ORRILL BOVINE SERUM ALBUMIN .EW %NGLAND "IOLABS AND NANOPURE WATER - PACKARDII 0AWNEE FOR TOTAL VOLUME OF «L AT ª# FOR H IN A 04# 0ELTIER - PACKARDII 3COTTS "LUFF 4HERMAL #YCLER -* 2ESEARCH )NC 7ALTHAM -! 4HE RESULTING - PACKARDII 3HERIDAN FRAGMENTS WERE THEN INCUBATED AT ª# FOR H WITH A LIGATION - PACKARDII 3HERMAN MIXTURE OF «L 4 $.! LIGASE X 4 $.! LIGASE BUFFER .EW - PACKARDII 3IOUX %NGLAND "IOLABS &OSTER #ITY #! «L %CO2) ADAPTER «L -SE)
*/52.!, /& /24(/04%2! 2%3%!2#( -, "2534 %* ,).$2/4( 77 (/"!#+ 2* 72)'(4 + (!.&/2$ !.$ *% &/34%2 4ABLE #HARACTERS FOR DIFFERENTIATING - FOEDUS mUVIATILIS AND - FOEDUS FOEDUS - FOEDUS FOEDUS - FOEDUS mUVIATILIS (IND TIBIA COLOR 0INKISH RED RARELY BLUE 0INKISH RED PURPLE OR BLUE #OLOR OF DORSAL /RANGE BROWN WITH LIGHT STRIPES LATERALLY 3OLID glLLg WITH SPECKLED APPEARANCE WOODY BROWN PRONOTUM 0OSTOCULAR BARS ,ACKING OR POORLY DEVELOPED BROWN TO BLACK 3TRONGLY DEVELOPED BLACK TO RARELY BROWN -ALE FURCULA LENGTH 5SUALLY MM RARELY UNDER MM 5SUALLY MM RARELY OVER MM #OLOR INNER HIND ,IGHT YELLOWISH TO LIGHT ORANGE BROWN /RANGE TO RED MAY HAVE HEAVY BLACKISH SUFFUSION RARELY ORANGE FEMUR BROWN ADAPTER /PERON 4ECHNOLOGIES AND «L NANOPURE WATER ! $ATA SCORING AND ANALYSIS/NE MICROLITER SAMPLES WERE ELECTRO DILUTION WAS THEN PERFORMED ON THE LIGATION PRODUCT USING X PHORESED THROUGH A +"0LUS POLYACRYLAMIDE GEL ,) #/2 AND 4% BUFFER THE BANDS DETECTED VIA INFRARED mORESCENCE USING A LASER SCANNING MACHINE ,) #/2 -ODEL 3 !N )2$ LABELED BP 0REAMPLIlCATION «L OF THE LIGATION MIXTURE WAS INCUBATED WITH SIZE STANDARD WAS USED TO ESTIMATE FRAGMENT SIZE 3IXTY TWO MARK «L 0REAMPLIlCATION 0RIMER -IX )) )NVITROGEN «L X 0#2 ERS WERE SELECTED BASED ON CLARITY AND BANDS WERE SCORED USING THE
BUFFER )) «L -G#L AND «L !MPLITAG $.! POLYMERASE PROGRAM 3!'! -8 ,) #/2 4HE DATA WERE CONVERTED TO MATRIX !PPLIED "IOSYSTEMS 4HE 0#2 PROGRAM CONSISTED OF CYCLES FORM FOR FURTHER ANALYSIS WITH A INDICATING BAND PRESENCE AND A S AT ª# MIN AT ª# MIN AT ª# ! DILUTION WITH INDICATING ABSENCE $ATA WERE ANALYZED USING 0!50 B 3WOF NANOPURE WATER WAS PERFORMED ON THE PRODUCT FORD $ISTANCE ANALYSIS WAS PERFORMED USING NEIGHBOR JOINING AND MINIMUM EVOLUTION WHILE UNWEIGHTED MAXIMUM PARSIMONY 3ELECTIVE AMPLIlCATION2EACTION VOLUMES CONTAINING «L NANO WAS PERFORMED USING A HEURISTIC SEARCH "OOTSTRAP ANALYSES OF
PURE WATER «L X 0#2 BUFFER )) «L -G#L «L !M REPLICATES WERE PERFORMED TO ASSESS CLADE SUPPORT !RPHIA XANTHOP PLITAG $.! POLYMERASE !PPLIED "IOSYSTEMS «L -SE) PRIMER TERA "URMEISTER SERVED AS AN OUTGROUP TAXON /NE SPECIMEN OF ,) #/2 «L %CO2) )2$ LABELED PRIMER ,) #/2 AND THE OUTGROUP AND A TOTAL OF SPECIMENS OF THE SELECTED TAXA WERE «L OF THE PREAMPLIlCATION TEMPLATE WERE AMPLIlED VIA 0#2 0RIM USED IN THE ANALYSES 4WO SPECIMENS OF THE SELECTED TAXA DID NOT ERS WERE SCREENED AND CHOSEN BASED ON THE NUMBER AND CLARITY OF DEMONSTRATE MARKERS DISTINCT ENOUGH FOR ANALYSIS BANDS PRODUCED 4HE 0#2 PROGRAM CONSISTED OF ONE CYCLE S AT ª# S AT ª# MIN AT ª# CYCLES S AT ª# 2ESULTS MIN AT ª# AND CYCLES S AT ª# S AT ª# MIN AT ª# 4HE REACTION WAS STOPPED BY ADDING «L STOP SOLUTION $ISTRIBUTION- FOEDUS FOEDUS AND - FOEDUS mUVIATILIS WERE ONLY FOUND ,) #/2 4HE PRODUCT WAS THEN DENATURED FOR MIN AT ª# AND TO CO OCCUR AT A SINGLE SITE APPARENT INTERGRADES WERE EXTREMELY RARE STORED AT ª# AND ONLY FOUND AT THAT SITE %LSEWHERE IN .EBRASKA EACH OF THESE TWO FORMS OCCUPIED DISTINCT HABITATS WITH - F FOEDUS OCCURRING IN DRY
&IG #OUNTY LEVEL DISTRIBUTION OF SPECIMENS COLLECTED FOR MOR PHOMETRIC ANALYSES ACROSS .EBRASKA ,IGHT GRAY INDICATES -ELANOPLUS FOEDUS MEDIUM GRAY INDICATES - mUVIATILIS AND DARK GRAY INDICATES - PACKARDII #OUNTIES WITH CHECKERED PATTERN HAD MORE THAN ONE SPECIES ANALYZED
*/52.!, /& /24(/04%2! 2%3%!2#( -, "2534 %* ,).$2/4( 77 (/"!#+ 2* 72)'(4 + (!.&/2$ !.$ *% &/34%2
4ABLE #OLLECTION INFORMATION FOR SPECIMENS USED IN GENETIC ANALYSES 3PECIES 3TATE #OUNTY ,OCATION LAT . LONG 7 $ATE 1UANTITY !RPHIA XANTHOPTERA .EBRASKA ,ANCASTER ,INCOLN 7ILDERNESS 0ARK 3EPTEMBER OUTGROUP -ELANOPLUS FOEDUS mUVIATILIS .EBRASKA $AWSON KM 3 OF ,EXINGTON *ULY -ELANOPLUS FOEDUS FOEDUS .EBRASKA ,INCOLN KM ..7 OF .ORTH 0LATTE *ULY -ELANOPLUS PACKARDII .EBRASKA 0AWNEE KM . OF $U"OIS *ULY - FOEDUS X PACKARDII .EBRASKA -ORRILL KM 37 OF "RIDGEPORT *ULY - FOEDUS X PACKARDII .EBRASKA 'ARDEN KM 33% OF ,EWELLEN *ULY SANDY UPLANDS AND - F mUVIATILIS IN OPEN SANDY WOODLANDS AND SPECIMEN MAY BE AN INTERGRADE WITH - FOEDUS FOEDUS !LL - FOEDUS THE UPPER REACHES OF SANDBARS ALONG MAJOR RIVERS &IG FOEDUS AND - PACKARDII HAD THE DORSAL PRONOTUM DISTINCTLY STRIPED %XTENSIVE SAMPLING SHOWED - FOEDUS AND - PACKARDII CO OCCUR 7HILE - FOEDUS FOEDUS AND - PACKARDII WERE GENERALLY SIMILAR IN ONLY RARELY IN .EBRASKA (OWEVER IN SOME AREAS OF CO OCCURRENCE HAVING A STRIPED DORSAL PRONOTUM THE COLOR OF THE DARK STRIPES APPARENT HYBRIDS BETWEEN - FOEDUS AND - PACKARDII WERE COLLECTED TENDED MORE STRONGLY TOWARD RED BROWN IN SPECIMENS IDENTIlED AS FAIRLY COMMONLY AND AT THESE SITES hHYBRIDv FORMS TENDED TO PRE - FOEDUS FOEDUS AND DARK OLIVE BROWN IN - PACKARDII DOMINATE OVER EITHER OF THE TWO PARENT SPECIES MAKING THE SPECIE (IND FEMUR AND TEGMEN LENGTHS WERE SIMILAR WITHIN SEXES FOR DIFlCULT TO DISTINGUISH !T ONE SITE IN +EITH #OUNTY .EBRASKA BOTH ALL THREE FORMS 4ABLE "OTH SEXES OF - F mUVIATILIS AND - PACK SPECIES CO OCCURRED IN LARGE NUMBERS AND NO APPARENT HYBRIDS WERE ARDII DIFFERED FROM - F FOEDUS IN THE MINIMUM DISTANCE BETWEEN OBSERVED 4HIS SUGGESTS THAT THESE TWO SPECIES MAY BE HYBRIDIZING THE EYES BUT WERE SIMILAR TO EACH OTHER 4ABLES AND -ALES OF IN SOME AREAS AND THAT THE HYBRIDIZATION MIGHT BE AT LEAST PARTIALLY -ELANOPLUS F mUVIATILIS AND - PACKARDII DIFFERED FROM - F FOEDUS DRIVEN BY LOW ABUNDANCE OF THE TWO FORMS AT THESE SITES IN THE LENGTH OF THE MALE FURCULAE 4ABLE %XAMINATION OF THE AEDEAGI OF MALES SHOWED STRONG DIFFERENCES -ORPHOLOGICAL EXAMINATION/NCE SEPARATED BASED ON ORIGINAL SPE IN THE SHAPE AND ANGLE OF THE BASAL RING AS WELL AS IN THE SHAPE AND CIES DESCRIPTIONS SEE %ADES AND /TTE EACH OF THE THREE FORMS LENGTHWIDTH RATIO OF THE PARAMERES AMONG ADEAGI OF - PACKARDII WERE FOUND TO DIFFER STATISTICALLY IN SEVERAL CHARACTERS !LL THREE FORMS AND - FOEDUS 4HERE WERE NO DISTINCT OR CONSISTENT DIFFERENCES BE DIFFERED SIGNIlCANTLY IN TIBIAL COLOR FREQUENCY P 4IBIAL TWEEN - FOEDUS mUVIATILIS AND - FOEDUS FOEDUS IN AEDEAGAL STRUCTURE COLOR OF - FOEDUS WAS NEARLY ALWAYS RED TO PINKISH RED AND THAT OF !LTHOUGH THE MIDDLE TOOTH OF THE INNER SIDE OF THE PRIMARY VENTRAL - PACKARDII WAS MOST OFTEN BLUE &IG 4HE TIBIAL COLOR OF - F PARAMERE APPEARED TO BE SLIGHTLY MORE PRONOUNCED IN - F FOEDUS mUVIATILIS WAS VARIABLE BEING RED PURPLE OR BLUE OR MORE RARELY THIS TRAIT WAS NOT CONSISTENT &IG PALLID &IG 7ITH THE EXCEPTION OF A SINGLE SPECIMEN FROM ,AKE -C#ONAUGHY +EITH #OUNTY .EBRASKA ALL - FOEDUS mUVIATILIS HAD 'ENETIC ANALYSES! TOTAL OF CHARACTERS BOTH MONOMORPHIC AND THE DORSAL PRONOTUM SOLIDLY COLORED USUALLY BROWN AND THIS SINGLE POLYMORPHIC WERE USED IN THIS STUDY &IFTY TWO OF THE CHARACTERS
&IG 0ROPORTIONS HIND TIBIAL COLORS AMONG THE SPECIES .UMBER OF SPECI MENS EXAMINED - FOEDUS mUVIATILIS N - FOEDUS FOEDUS N AND - PACK ARDII N
*/52.!, /& /24(/04%2! 2%3%!2#( -, "2534 %* ,).$2/4( 77 (/"!#+ 2* 72)'(4 + (!.&/2$ !.$ *% &/34%2 4ABLE -EANS AND STANDARD ERRORS OF MEASUREMENT DATA MM FROM ANALYZED SPECIMENS &OREWING LENGTH $ISTANCE BETWEEN EYES &URCULA LENGTH 3PECIES BY )$ 3EX -EAN 3TANDARD ERROR 3EX -EAN 3TANDARD ERROR 3EX -EAN 3TANDARD ERROR -ELANOPLUS FOEDUS mUVIATILIS FEMALE FEMALE FEMALE .! .! -ELANOPLUS FOEDUS FOEDUS FEMALE FEMALE FEMALE .! .! -ELANOPLUS PACKARDII FEMALE FEMALE FEMALE .! .! -ELANOPLUS FOEDUS mUVIATILIS MALE MALE MALE -ELANOPLUS FOEDUS FOEDUS MALE MALE MALE -ELANOPLUS PACKARDII MALE MALE MALE WERE PARSIMONY INFORMATIVE ! LARGE NUMBER OF POLYMORPHIC BANDS SEVERAL CHARACTERISTICS (OWEVER THE AEDEAGUS OF - F mUVIATILIS IS WERE FOUND BOTH BETWEEN AND WITHIN SPECIES .EITHER DISTANCE NOR VIRTUALLY INDISTINGUISHABLE FROM THAT OF - F FOEDUS 4HE SHAPE AND PARSIMONY ANALYSIS RESOLVE THIS SPECIES COMPLEX &IGS SUGGEST ANGLE OF THE BASAL RING AS WELL AS THE FORM OF THE PARAMERES APPEAR ING THAT THERE MAY BE FREQUENT HYBRIDIZATION )T IS UNCLEAR WHETHER TO BE IDENTICAL &IG EACH OF THESE FORMS IS A DISTINCT SPECIES OR IF HYBRIDIZATION AND 4HE LACK OF ANY DISTINCT CLADES IN THE GENETIC ANALYSES &IGS RESULTANT INTROGRESSION OCCURS 4HESE RESULTS ARE SIMILAR TO THOSE SUPPORTS - FOEDUS FOEDUS AND - FOEDUS mUVIATILIS AS BEING THE SAME OBTAINED BY #HAPCO AND ,ITZENBERGER WHEN THEY ANALYZED SPECIES AND THAT FREQUENT INTERBREEDING OR HYBRIDIZATION OCCURS BE NUMEROUS SPECIES IN THE GENUS -ELANOPLUS USING MITOCHONDRIAL TWEEN THESE TAXA AND - PACKARDII /UR RESULTS ARE SIMILAR TO THOSE $.! 4HESE AUTHORS WERE ALSO UNABLE TO DISTINGUISH BETWEEN - OBTAINED BY #HAPCO AND ,ITZENBERGER WHEN THEY ANALYZED PACKARDII AND - FOEDUS NUMEROUS SPECIES IN THE GENUS -ELANOPLUS USING MITOCHONDRIAL $.! AND WERE UNABLE TO DISTINGUISH BETWEEN - PACKARDII AND - FOEDUS $ISCUSSION BASED ON GENETIC CRITERIA -ORPHOLOGICAL DIFFERENCES IN THE ABSENCE OF CLEAR GENETIC DIF !S ANTICIPATED BASED ON DESCRIPTIONS OF THE FORMS -ELANOPLUS F FERENCES SUGGEST SEVERAL POSSIBILITIES - FOEDUS AND - PACKARDII FOEDUS - F mUVIATILIS AND - PACKARDII EACH DISPLAY MORPHOMETRIC ARE ENVIRONMENTALLY INDUCED FORMS OF THE SAME SPECIES THEY ARE DIFFERENCES #OMPARED TO - F FOEDUS - F mUVIATILIS IS DISTINGUISHED SPECIES THAT WERE PREVIOUSLY SEPARATED BUT HAVE RETAINED THE ABILITY BY HAVING A SOLID COLOR ON THE DORSAL PRONOTUM AND USUALLY HAV TO INTERBREED WHERE POPULATIONS MEET OR THEY ARE SUBSPECIES IN ING LARGE DARK POSTOCULAR BARS 4HE MINIMUM DISTANCE BETWEEN THE PROCESS OF BECOMING FULL SPECIES !LTHOUGH OUR DATA DO NOT AL THE EYES WAS SIGNIlCANTLY DIFFERENT BETWEEN - F FOEDUS AND - F LOW RESOLUTION OF THESE OR OTHER POSSIBILITIES THE FORMS IN .EBRASKA mUVIATILIS DESPITE THE FACT THAT TEGMEN LENGTHS DID NOT DIFFER 4HE OCCUR MOST OFTEN IN DISTINCT HABITATS STRUCTURE OF THE AEDEAGUS DID NOT DIFFER BETWEEN THE SUBSPECIES )N .EBRASKA - F FOEDUS OCCURS IN UPLAND SANDY AREAS WITH SPARSE BUT DIFFERED BETWEEN - FOEDUS AND - PACKARDII (IND TIBIAL COLOR VEGETATION AND IS ESPECIALLY COMMON IN THE .EBRASKA 3ANDHILLS COULD ALSO BE USED TO DIFFERENTIATE - F FOEDUS AND - PACKARDII IN -ELANOPLUS F mUVIATILIS OCCURS IN LOWLAND AREAS NEAR RIVERS ESPECIALLY .EBRASKA APPROXIMATELY OF THE TIME - F mUVIATILIS APPEARS TO ALONG THE HIGHER AREAS OF SANDBARS AND IN OPEN WOODLAND WHERE BE INTERMEDIATE IN THIS CHARACTER WITH INDIVIDUALS EXHIBITING BROAD THERE IS MORE GROWTH OF WEEDY VEGETATION -ELANOPLUS PACKARDII IS VARIATION IN COLOR 7HILE - STONEI WAS NOT ANALYZED IN THIS STUDY MOST COMMON IN AREAS WITH SOMEWHAT SPARSE VEGETATION ON GENERALLY ALL SPECIMENS COLLECTED BY THE SENIOR AUTHOR FROM NORTHWESTERN HEAVY SOILS SUCH AS CLAY OR LOESS 0OPULATIONS OF SUSPECTED HYBRIDS /NTARIO #ANADA HAVE RED HIND TIBIAE 4O FURTHER COMPLICATE IDEN BETWEEN - FOEDUS AND - PACKARDII HAVE BEEN FOUND MOSTLY IN TIlCATION WITHIN THIS GROUP OCCASIONAL SPECIMENS RESEMBLING - SPARSELY VEGETATED AREAS ON HETEROGENEOUS SOILS ESPECIALLY IN AREAS FOEDUS ISLEYI OCCUR IN .EBRASKA 4HIS SUBSPECIES IS DIFFERENTIATED BY WHERE CLAYS ARE MIXED WITH SMALL STONES OR GRAVEL 4HESE OBSERVATIONS POORLY DEVELOPED POSTOCULAR BARS AND PALLID HIND TIBIAE SUGGEST THAT EACH FORM MAY DIFFER IN SOIL ANDOR PLANT PREFERENCE %XAMINATION OF THE MALE AEDEAGUS REVEALED THAT IN - FOEDUS BUT MAY HYBRIDIZE WHERE MULTIPLE HABITATS MIX IT IS CLEARLY AND CONSISTENTLY DISTINCT FROM THAT OF - PACKARDII IN )N AREAS WITH HETEROGENEOUS SOILS APPARENT HYBRIDS BETWEEN
4ABLE 3PECIES AND SUBSPECIES COMPARISONS OF TEGMEN LENGTH MINIMUM DISTANCE BETWEEN EYES AND MALE FURCULA LENGTH 3IGNIlCANT DIFFERENCES ARE INDICATED BY AN ASTERISK AND BOLD TYPE 3PECIES #OMPARISON 3EX #HARACTER P - FOEDUS mUVIATILIS VS - FOEDUS FOEDUS FEMALE TEGMEN LENGTH - FOEDUS mUVIATILIS VS - PACKARDII FEMALE TEGMEN LENGTH - FOEDUS FOEDUS VS - PACKARDII FEMALE TEGMEN LENGTH - FOEDUS mUVIATILIS VS - FOEDUS FOEDUS MALE TEGMEN LENGTH - FOEDUS mUVIATILIS VS - PACKARDII MALE TEGMEN LENGTH - FOEDUS FOEDUS VS - PACKARDII MALE TEGMEN LENGTH - FOEDUS mUVIATILIS VS - FOEDUS FOEDUS FEMALE DISTANCE BETWEEN EYES - FOEDUS mUVIATILIS VS - PACKARDII FEMALE DISTANCE BETWEEN EYES - FOEDUS FOEDUS VS - PACKARDII FEMALE DISTANCE BETWEEN EYES - FOEDUS mUVIATILIS VS - FOEDUS FOEDUS MALE DISTANCE BETWEEN EYES - FOEDUS mUVIATILIS VS - PACKARDII MALE DISTANCE BETWEEN EYES - FOEDUS FOEDUS VS - PACKARDII MALE DISTANCE BETWEEN EYES - FOEDUS mUVIATILIS VS - FOEDUS FOEDUS MALE FURCULA LENGTH - FOEDUS mUVIATILIS VS - PACKARDII MALE FURCULA LENGTH - FOEDUS FOEDUS VS - PACKARDII MALE FURCULA LENGTH
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OF A CLOSELY RELATED SPECIES IF FEMALES OF THE SAME SPECIES ARE SCARCE 0LATT ET AL 4HE LACK OF GENETIC DIFFERENTIATION SUGGESTS THAT - FOEDUS AND - PACKARDII ARE ACTUALLY ONE SPECIES (OWEVER WE FEEL THAT DIFFERENCES IN AEDEAGAL STRUCTURE AND HABITAT OCCURRENCE SHOULD BE RECOGNIZED AND THAT THE SPECIES DESIGNATION SHOULD REMAIN UNTIL ADDITIONAL GENETIC OR BEHAVIORAL TESTS CAN BE PERFORMED 4HE LACK OF RESOLUTION IN THE GENETIC TESTS COULD BE THE RESULT OF OCCASIONAL HYBRIDIZATION 7HILE WE CONCLUDE THAT - PACKARDII AND - FOEDUS ARE DISTINCT MORPHOLOGICALLY INCLUDING IN MALE GENITALIA WE SUGGEST THAT - F mUVIATILIS SHOULD BE SYNONYMIZED UNDER - FOEDUS &URTHER RESEARCH IS NEEDED TO VERIFY OUR CONCLUSIONS BUT WE SUSPECT THAT - F mUVIATILIS IS AN ENVIRONMENTALLY INDUCED VARIANT OF - FOEDUS AND DOES NOT QUALIFY AS A VALID SUBSPECIES BASED ON DISTRIBUTION "OTH FORMS CAN BE FOUND THROUGHOUT .EBRASKA IN SUITABLE HABITAT 4HUS ONE COULD FEASIBLY CONSIDER THEM ECOTYPES HOWEVER SOME OF THE EXTERNAL TRAITS MAY BE INDISCRETE OR SUBJECT TO ENVIRONMENTAL INmUENCE 3HELFORD /TTE AND 7ILLIAMS 3UCH ENVIRONMENTAL FACTORS HAVE BEEN SHOWN TO EXERT A STRONG INmUENCE ON ADULT COLORATION IN OTHER GRASSHOPPER SPECIES /TTE 7ILLIAMS &URTHERMORE COLLEC TIONS OF A RELATED SPECIES -ELANOPLUS ANGUSTIPENNIS $ODGE HAVE SHOWN DARKER INDIVIDUALS MORE PREDOMINANT IN PARTIALLY WOODED RIVERINE AREAS COMPARED TO IN ADJACENT UPLANDS ALTHOUGH NOT AS DARK AS - FOEDUS mUVIATILIS SOMETIMES WITH THIS CHANGE NOTED OVER A DISTANCE OF LESS THAN KM -, "RUST UNPUB
!CKNOWLEDGEMENTS
7E WOULD LIKE TO THANK THE 53 $EPARTMENT OF !GRICULTURE !NIMAL AND 0LANT )NSPECTION 3ERVICE 7E ALSO THANK 4HOMAS (UNT FOR PROVIDING FUNDING FOR PART OF THIS STUDY 4HANKS TO 3TEVEN 2 3KODA FOR HIS ASSISTANCE EDITING THE MANUSCRIPT
2EFERENCES
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