Effective rearing methods are needed to recover the federally endangered Salt Creek tiger beetle, Cicindela (Ellipsoptera) nevadica lincolniana Casey, a subspecies that occurs exclusively in saline wetlands and seeps along Little Salt Creek in Lancaster County, Nebraska. Experiments were initiated to determine soil type and salinity concentrations appropriate for stimulating female oviposition in laboratory settings to produce larvae and/or adults for reintroduction to native habitats. In 2013, there were highly significant differences between native soil and a sand/loess soil mixture, but no differences between two salinity levels, 0.354 M and 0.5 M. In 2014, using only a sand/loess soil mixture, there were again no differences between the test salinity levels. A sand/loess soil mixture of either 0.354M or 0.5M salinity was determined to be optimum for egg production

Brewer, Gary J.

Crosier, Sarah A.

Fritz, Michael I.

Harms, Robert R.

Johns, Aimee M.

Klatt, Kay A.

Palmer, Joseph A.

Spomer, Stephen M

English

DigitalCommons@University of Nebraska

University of Nebraska - LincolnDigitalCommons@University of Nebraska - LincolnFaculty Publications: Department of Entomology Entomology, Department of2015Determining Optimum Soil Type and Salinity forRearing the Federally Endangered Salt Creek TigerBeetle, Cicindela (Ellipsoptera) nevadica lincolnianaCasey (Coleoptera: Carabidae: Cicindelinae)Stephen M. SpomerUniversity of Nebraska-Lincoln, sspomer1@unl.eduGary J. BrewerUniversity of Nebraska-Lincoln, gbrewer2@unl.eduMichael I. FritzNebraska Game & Parks CommissionRobert R. HarmsU. S. Fish & Wildlife ServiceKay A. KlattHenry Doorly ZooSee next page for additional authorsFollow this and additional works at: http://digitalcommons.unl.edu/entomologyfacpubPart of the Entomology CommonsThis Article is brought to you for free and open access by the Entomology, Department of at DigitalCommons@University of Nebraska - Lincoln. It hasbeen accepted for inclusion in Faculty Publications: Department of Entomology by an authorized administrator of DigitalCommons@University ofNebraska - Lincoln.Spomer, Stephen M.; Brewer, Gary J.; Fritz, Michael I.; Harms, Robert R.; Klatt, Kay A.; Johns, Aimee M.; Crosier, Sarah A.; andPalmer, Joseph A., "Determining Optimum Soil Type and Salinity for Rearing the Federally Endangered Salt Creek Tiger Beetle,Cicindela (Ellipsoptera) nevadica lincolniana Casey (Coleoptera: Carabidae: Cicindelinae)" (2015). Faculty Publications: Department ofEntomology. 489.http://digitalcommons.unl.edu/entomologyfacpub/489AuthorsStephen M. Spomer, Gary J. Brewer, Michael I. Fritz, Robert R. Harms, Kay A. Klatt, Aimee M. Johns, SarahA. Crosier, and Joseph A. PalmerThis article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/entomologyfacpub/489Determining Optimum Soil Type and Salinity for Rearing the FederallyEndangered Salt Creek Tiger Beetle, Cicindela (Ellipsoptera) nevadicalincolniana Casey (Coleoptera: Carabidae: Cicindelinae)STEPHEN M. SPOMER,1 GARY J. BREWER,1 MICHAEL I. FRITZ,2 ROBERT R. HARMS,3KAY A. KLATT,4 AIMEE M. JOHNS,5 SARAH A. CROSIER,6 AND JOSEPH A. PALMER7ABSTRACT: Effective rearing methods are needed to recover the federally endangered SaltCreek tiger beetle, Cicindela (Ellipsoptera) nevadica lincolniana Casey, a subspecies that occursexclusively in saline wetlands and seeps along Little Salt Creek in Lancaster County,Nebraska. Experiments were initiated to determine soil type and salinity concentrationsappropriate for stimulating female oviposition in laboratory settings to produce larvae and/oradults for reintroduction to native habitats. In 2013, there were highly significant differencesbetween native soil and a sand/loess soil mixture, but no differences between two salinity levels,0.354 M and 0.5 M. In 2014, using only a sand/loess soil mixture, there were again nodifferences between the test salinity levels. A sand/loess soil mixture of either 0.354 M or 0.5 Msalinity was determined to be optimum for egg production.KEY WORDS: Cicindelidae, breeding, husbandry, Endangered Species ActThe Salt Creek tiger beetle, Cicindela (Ellipsoptera) nevadica lincolniana Casey, isone of the rarest insects in North America. Limited to a single stream system andadjacent saline seeps and wetlands near Lincoln, Lancaster Co. Nebraska, estimatednumbers are precipitously low. Estimates of adults have been taken yearly since1991, and numbers have fluctuated from a low of 115 in 1993 to a high of 777 in2002. The 2014 estimate was 143 adults. The Salt Creek tiger beetle (SCTB) waslisted as state endangered in 2000 (Nebraska Game and Parks Commission, 2000),federally endangered in 2005 (U. S. Fish and Wildlife Service, 2005), and criticalhabitat was designated in 2014 (USFWS, 2014a).A goal of the Endangered Species Act is to protect threatened and endangeredspecies and pursue their recovery. An objective toward achieving this goal is toincrease numbers and populations of the species to levels where it is no longerthreatened or endangered. One method of doing this is by breeding individuals in thelab and introducing their progeny into new suitable habitats or by reintroductionsinto presently- or previously-occupied habitats. Several endangered and threatenedinsects, including the American burying beetle, Nicrophorus americanus (Olivier),and the Oregon silverspot butterfly, Speyeria zerene hippolyta (W. H. Edwards), arebeing reared by zoos and universities and reintroduced into the wild with somepositive results (Amaral et al., 1997; USDA, 2011; USFWS, 2014b; WAZA, 2015).In addition, the Northeastern Beach tiger beetle, Cicindela (Habroscelimorpha)1 Department of Entomology, 103 Entomology Hall, University of Nebraska, Lincoln, Nebraska68583-0816, E-mail: sspomer1@unl.edu2 Nebraska Game & Parks Commission, 2200 N. 33rd St., Lincoln, Nebraska 68503.3 U. S. Fish & Wildlife Service, 9325 S. Alda Road, Wood River, Nebraska 68883.4 Henry Doorly Zoo, 3701 S. 10th St., Omaha, Nebraska 68107.5 Lincoln Children’s Zoo, 1222 S. 27th St., Lincoln, Nebraska 68502.6 5641 S. 91st Avenue, Omaha, Nebraska 68127.7 2299 N. Silverbell Road, Tucson, Arizona 85745.Received 26 May 2015; Accepted 20 August 2015E 2015 Kansas Entomological SocietyJOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY88(4), 2015, pp. 444–449dorsalis dorsalis Say has been successfully reintroduced into the wild (Kapitulik,2012). In 2011, a coalition composed of the City of Lincoln, Lower Platte SouthNatural Resource District, U. S. Fish and Wildlife Service, Nebraska Game andParks Commission, Lincoln Children’s Zoo, Omaha’s Henry Doorly Zoo, and theUniversity of Nebraska set out to rear the SCTB with the goal of reintroductions andincreased number of wild populations on multiple streams and saline wetlandsystems where suitable habitat is available.Attempts by other researchers to get tiger beetles to oviposit have been somewhatsuccessful. Palmer (1979) used several types of containers as oviposition chambers:plastic shoeboxes, bread boxes, and glass terraria. She used tops of canning jars, withthe metal plates replaced with window screen, and filled them with soil from thespecies’ native habitat. Gwiazdowski et al. (2011) used sterilized native soil at a depthof 7 cm in polystyrene containers. They placed one pair of adults in each containerand kept a 14:10 L:D schedule with a temperature of 17–18uC, provided humiditywith a pan of water, and fed crickets. Brust et al. (2012) also used plastic containerswith a native soil depth of 7–13 cm and fed the adults termites or Tribolium. Knisleyand Schultz (1997), in their review of rearing methods, noted that some species mayhave very specific conditions for oviposition that may be difficult to duplicate in thelaboratory.One problem to overcome in rearing saltmarsh-dwelling tiger beetles is de-termining what type of soil and salinity is required for the female to oviposit. Allgeier(2005) and Brosius (2010) previously determined that sifted topsoil (commerciallyavailable), saturated with either a 0.5 M or 0.354 M NaCl solution was sufficient toinduce oviposition. Prior to Allgeier’s work, we had extracted soil from actual SCTBhabitat and used that to induce oviposition and rear larvae. However, the clay-saturated habitat soil created problems with uneven moisture gradients and wettopsoil often promoted mold growth. Lab mortality was sometimes quite high. Ourgoal in these experiments was to determine the best soil type and salt concentrationto maximize oviposition potential.Materials and MethodsIn 2011, we began preliminary experiments with soil types and determined thata mixture of topsoil and sand appeared superior to topsoil alone for egg production,although statistically, it was significantly different at only the 0.10 level ofprobability. In 2012, we used a higher sand ratio and females laid almost no eggs.Topsoil from commercial sources was found to be inconsistent in texture andcontent. In 2013, we reduced the sand ratio and added native loess soil (from a bluffat Henry Doorly Zoo in Omaha) rather than topsoil from commercial sources. Inaddition, we used soil from SCTB habitat along the banks of Little Salt Creek. Weused the following treatments in 2013: (1) habitat soil + 0.354 M NaCl solution, (2)habitat soil + distilled water, (3) 50/50 loess:sand (by weight) + 0.354 M NaClsolution, and (4) 50/50 loess:sand (by weight) + 0.5 M NaCl solution. In 2014, weused only treatments 3 and 4 above. Soils were added to square plastic dishes (2.16cm high 3 10.16 cm2) lined with plastic wrap and solutions were added until soilswere saturated. Each of the four treatments were set into a layer of small, naturalstone aquarium gravel so the tops of the square dishes were level with the gravel, andrandomized within a clear plastic shoe box (31.1 cm long 3 23.5 cm wide 3 12.7 cmVOLUME 88, ISSUE 4 445tall; glassy shoe box, Nam Ngai Hong Co., Thailand) with a lid. Shoe boxes camepre-drilled with five, 0.3 cm diam. holes on each side. These holes were covered with51 3 21 mesh plastic screen (Farm Tek, Dyersville, IA) to prevent fly or parasiteinfestation. Fifteen pairs of SCTB were collected as soon as possible after emergencein the field (13–18 June 2013; 11–18 June 2014) and transferred to the 15 shoe boxes(one pair per box) containing the four soil treatments described above. Males werekept with the females for two days to ensure mating, then removed and released intothe habitat where they were collected. Females were allowed to remain in the box forten days; they were then also removed and returned to the wild. Captive adults werefed a mixed diet of crickets, mealworms, and Drosophila melanogaster every otherday and moisture was provided using Cricket Quencher (Fluker Farms, Port Allen,LA). Soils were kept moist (but not wet) by misting daily with distilled water.Temperature was room temperature (25–28uC) and light was ambient (sunlight andfluorescent).Because eggs are very fragile and will often burst when handled, fecundity wasdetermined by counting first instars. After eggs hatched, soil dishes were allowed todry a few days then turned upside down. The plastic wrap was removed, and the soilwas teased apart and the larvae were counted and transferred to overwinteringplastic tubes for continual rearing. Data were analyzed using PROC GLIMMIX(SAS Institute, 2001) and mean treatment means were separated using LSD (leastsquare differences) at P # 0.01 and 0.05.Results and DiscussionIn 2013, there were significant differences in numbers of larvae between treatments(F 5 6.54, d.f. 5 3, 56; P , 0.001) (Fig. 1). The two native habitat soil treatmentsFig. 1. Total 6 SE number of SCTB larvae produced in ten days by 15 females with two soil types andtwo salinity concentrations, 2013.446 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETYwere not significantly different from each other, but were both different from the50/50 loess/sand mixtures.The loess/sand mixture was superior for oviposition; however, there were nosignificant differences in larval numbers between the 0.5 M (n 5 112) and 0.354 M(n 5 148) saline solution additions to the loess/sand. Likewise, there were nodifferences between native soil (n 5 1) and native soil plus 0.354 M (n 5 0) salinesolution. An additional 52 larvae were obtained from the loess/sand mixtures, but norecord of molarity was recorded, so these were not included in the statistical analysis.These additional larvae were counted in overall numbers obtained however,producing a total of 313 larvae/15 females with a mean of 20.9 larvae/female.Individual females produced from 0–85 larvae.In 2014, as in 2013, there were no significant differences in numbers of larvaebetween 0.5 M (n 5 81) and 0.354 M (n 5 154) saline solution additions to the loess/sand mixture (F 5 0.99, d.f. 5 1, 28; P , 0.3274) (Fig. 2). An additional 11 larvaewere found underneath the soil dishes, so molarity could not be confirmed and thesewere not included in the statistical analyses. Fifteen females produced a total of 246larvae with a mean of 16.4 larvae/female. Individual females produced from 0–66larvae.Based on these results, the potential for high fecundity is present, although it isunknown why some females laid many eggs while others refused to lay any eggs.Allgeier (2005) observed that captive SCTB females laid from 0 to 35 eggs in sevendays in the laboratory. Pearson and Vogler (2001) stated that female tiger beetles canlay from 10 to 20 eggs a day in captivity. Shelford (1908) estimated that fecundityranged from 10 to 50 eggs for a few North American tiger beetle species, and Knisley(unpublished) reported 20 to 50 eggs for several Arizona species. Mating was assuredin our studies because males were not separated from the females until actual mating(not just mate guarding) was witnessed by an observer, and mating always occurredat least once by the end of the second day. Lighting was from ambient sources toassure that there was no light during nighttime hours when females oviposit.Fig. 2. Total 6 SE number of SCTB larvae produced by 15 females in ten days using a 50/50 loess/sandsoil mixture and two salinities, 2014.VOLUME 88, ISSUE 4 447According to Allgeier (2005), SCTB only oviposits at night, and the senior author’sobservations for 25 years agree with this. Nighttime temperatures in the laboratorywere probably slightly higher than field temperatures, but field temperatures alsovary greatly, and this still would not explain why some females produced many eggswhile other produced zero.Another interesting observation is the almost complete lack of oviposition innative soil. The soil used was taken directly from a site where SCTB occurs. Inprevious years, we had used native soil for oviposition, sometimes with good results.However, at that time, the females were not given a choice of soils and salinities. Wemay have had better results with the native soil if the females were not given a choice.But the question remains: why do females prefer a loess/sand mixture when thenative soil contains much more clay? In nature, SCTB females are very specific wherethey lay their eggs, but salinity may be a more important cue than soil composition.In conclusion, these experiments provided some essential information necessaryfor lab propagation of SCTB. Future experiments will focus on refining thesetechniques.AcknowledgmentsWe thank past and present workers at both zoos: Traci Clevenger, Sarah Jenkins,Trace Hardin, Isaac Powell, Trevor Henderson, Devin Krafka, Jessica Mascarello,Dan Cassidy, Jessie Edgar, and Stephy Hanigan. Natalie Matz helped feed the larvaeafter they hatched as well as having many other duties. We also thank directors JohnChapo (LCZ) and Dennis Pate (HDZ) for allowing us to work in their facilities.Nebraska Master Naturalist program provided volunteers. Travis Prochaska wasespecially helpful with statistics.The findings and conclusions in this publication are those of the authors and donot necessarily represent the views of the U. S. Fish and Wildlife Service.Literature CitedAllgeier, W. J. 2005. The behavioral ecology and abundance of tiger beetles inhabiting the eastern salinewetlands of Nebraska. Master’s Thesis, University of Nebraska-Lincoln, Lincoln, NE.Amaral, M., A. Kozol, and T. French. 1997. Conservation status and reintroduction of the endangeredAmerican burying beetle. Northeastern Naturalist 4(3):121–132.Brosius, T. R. 2010. Niche specialization and conservation biology of Cicindela nevadica lincolniana. Ph.D.dissertation, University of Nebraska-Lincoln, Lincoln, NE.Brust, M. L., C. B. Knisley, S. M. Spomer, and K. Miwa. 2012. Observations of oviposition behavioramong North American tiger beetle (Coleoptera: Carabidae: Cicindelinae) species and notes onmass rearing. The Coleopterists’ Bulletin 66(4):309–314.Gwiazdowski, R. A., S. Gillespie, R. Weddle, and J. S. Elkinton. 2011. Laboratory rearing of common andendangered species of North American tiger beetles (Coleoptera: Carabidae: Cicindelinae). Annalsof the Entomological Society of America 104(3):534–542.Kapitulik, N. 2012. Northeastern beach tiger beetle, Cicindela dorsalis dorsalis, monitoring of adult beetlesat Monomoy National Wildlife Refuge and South Beach, 2012. Unpublished report to U. S. Fishand Wildlife Service, Concord, NH and Monomoy National Wildlife Refuge, Chatham, MA.Knisley, C. B., and T. D. Schultz. 1997. The Biology of Tiger Beetles and a Guide to the Species of theSouth Atlantic States. Virginia Museum of Natural History, Special Publication No. 5,Martinsville, VA.Nebraska Game and Parks Commission. 2000. Regulations, Title 163, Chapter 4, Section 4, Sub-section004.01; August 17, 2000, Lincoln, NE.Palmer, M. 1979. Rearing tiger beetles in the laboratory. Cicindela 11(1):1–11.448 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETYPearson, D. L., and A. P. Vogler. 2001. Tiger Beetles: The Evolution, Ecology, and Diversity of theCicindelids. Cornell University Press, Ithaca, NY.SAS Institute. 2001. PROC User’s Manual, version 6th edition. Cary, NC.Shelford, V. E. 1908. Life histories and larval habits of tiger beetles (Cicindelidae). Journal of the LinnaeanSociety of London 30:157–184.U. S. Department of Agriculture. 2011. Endangered species return to the Wayne NF. http://www.fs.usda.gov/detail/wayne/home/?cid5stelprdb5310535. Accessed February, 2015.U. S. Fish and Wildlife Service. 2005. Final rule to list the Salt Creek tiger beetle (Cicindela nevadicalincolniana) as endangered. Federal Register 70:58335–58351.U. S. Fish and Wildlife Service. 2014a. Revision of critical habitat for Salt Creek tiger beetle; final rule.Federal Register 79:26014–26038.U. S. Fish and Wildlife Service. 2014b. American burying beetle reintroduction in Missouri. http://www.fws.gov/midwest/endangered/insects/ambb/mo2012release.html. Accessed February, 2015.World Association of Zoos and Aquariums. 2015. Oregon silverspot butterfly recovery programme. http://www.waza.org/en/site/conservation/waza-conservation-projects/overview/oregon-silverspot-butterfly-recovery-programme. Accessed February, 2015.VOLUME 88, ISSUE 4 449

Determining Optimum Soil Type and Salinity for Rearing the Federally Endangered Salt Creek Tiger Beetle, \u3ci\u3eCicindela (Ellipsoptera) nevadica lincolniana\u3c/i\u3e Casey (Coleoptera: Carabidae: Cicindelinae)

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University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Faculty Publications: Department of Entomology Entomology, Department of
2015
Determining Optimum Soil Type and Salinity for
Rearing the Federally Endangered Salt Creek Tiger
Beetle, Cicindela (Ellipsoptera) nevadica lincolniana
Casey (Coleoptera: Carabidae: Cicindelinae)
Stephen M. Spomer
University of Nebraska-Lincoln, sspomer1@unl.edu
Gary J. Brewer
University of Nebraska-Lincoln, gbrewer2@unl.edu
Michael I. Fritz
Nebraska Game & Parks Commission
Robert R. Harms
U. S. Fish & Wildlife Service
Kay A. Klatt
Henry Doorly Zoo
See next page for additional authors
Follow this and additional works at: http://digitalcommons.unl.edu/entomologyfacpub
Part of the Entomology Commons
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.
Spomer, Stephen M.; Brewer, Gary J.; Fritz, Michael I.; Harms, Robert R.; Klatt, Kay A.; Johns, Aimee M.; Crosier, Sarah A.; and
Palmer, Joseph A., "Determining Optimum Soil Type and Salinity for Rearing the Federally Endangered Salt Creek Tiger Beetle,
Cicindela (Ellipsoptera) nevadica lincolniana Casey (Coleoptera: Carabidae: Cicindelinae)" (2015). Faculty Publications: Department of
Entomology. 489.
http://digitalcommons.unl.edu/entomologyfacpub/489
Authors
Stephen M. Spomer, Gary J. Brewer, Michael I. Fritz, Robert R. Harms, Kay A. Klatt, Aimee M. Johns, Sarah
A. Crosier, and Joseph A. Palmer
This article is available at DigitalCommons@University of Nebraska - Lincoln: http://digitalcommons.unl.edu/entomologyfacpub/
489
Determining Optimum Soil Type and Salinity for Rearing the Federally
Endangered Salt Creek Tiger Beetle, Cicindela (Ellipsoptera) nevadica
lincolniana Casey (Coleoptera: Carabidae: Cicindelinae)
STEPHEN M. SPOMER,1 GARY J. BREWER,1 MICHAEL I. FRITZ,2 ROBERT R. HARMS,3
KAY A. KLATT,4 AIMEE M. JOHNS,5 SARAH A. CROSIER,6 AND JOSEPH A. PALMER7
ABSTRACT: Effective rearing methods are needed to recover the federally endangered Salt
Creek tiger beetle, Cicindela (Ellipsoptera) nevadica lincolniana Casey, a subspecies that occurs
exclusively in saline wetlands and seeps along Little Salt Creek in Lancaster County,
Nebraska. Experiments were initiated to determine soil type and salinity concentrations
appropriate for stimulating female oviposition in laboratory settings to produce larvae and/or
adults for reintroduction to native habitats. In 2013, there were highly significant differences
between native soil and a sand/loess soil mixture, but no differences between two salinity levels,
0.354 M and 0.5 M. In 2014, using only a sand/loess soil mixture, there were again no
differences between the test salinity levels. A sand/loess soil mixture of either 0.354 M or 0.5 M
salinity was determined to be optimum for egg production.
KEY WORDS: Cicindelidae, breeding, husbandry, Endangered Species Act
The Salt Creek tiger beetle, Cicindela (Ellipsoptera) nevadica lincolniana Casey, is
one of the rarest insects in North America. Limited to a single stream system and
adjacent saline seeps and wetlands near Lincoln, Lancaster Co. Nebraska, estimated
numbers are precipitously low. Estimates of adults have been taken yearly since
1991, and numbers have fluctuated from a low of 115 in 1993 to a high of 777 in
2002. The 2014 estimate was 143 adults. The Salt Creek tiger beetle (SCTB) was
listed as state endangered in 2000 (Nebraska Game and Parks Commission, 2000),
federally endangered in 2005 (U. S. Fish and Wildlife Service, 2005), and critical
habitat was designated in 2014 (USFWS, 2014a).
A goal of the Endangered Species Act is to protect threatened and endangered
species and pursue their recovery. An objective toward achieving this goal is to
increase numbers and populations of the species to levels where it is no longer
threatened or endangered. One method of doing this is by breeding individuals in the
lab and introducing their progeny into new suitable habitats or by reintroductions
into presently- or previously-occupied habitats. Several endangered and threatened
insects, including the American burying beetle, Nicrophorus americanus (Olivier),
and the Oregon silverspot butterfly, Speyeria zerene hippolyta (W. H. Edwards), are
being reared by zoos and universities and reintroduced into the wild with some
positive results (Amaral et al., 1997; USDA, 2011; USFWS, 2014b; WAZA, 2015).
In addition, the Northeastern Beach tiger beetle, Cicindela (Habroscelimorpha)
1 Department of Entomology, 103 Entomology Hall, University of Nebraska, Lincoln, Nebraska
68583-0816, E-mail: sspomer1@unl.edu
2 Nebraska Game & Parks Commission, 2200 N. 33rd St., Lincoln, Nebraska 68503.
3 U. S. Fish & Wildlife Service, 9325 S. Alda Road, Wood River, Nebraska 68883.
4 Henry Doorly Zoo, 3701 S. 10th St., Omaha, Nebraska 68107.
5 Lincoln Children’s Zoo, 1222 S. 27th St., Lincoln, Nebraska 68502.
6 5641 S. 91st Avenue, Omaha, Nebraska 68127.
7 2299 N. Silverbell Road, Tucson, Arizona 85745.
Received 26 May 2015; Accepted 20 August 2015
E 2015 Kansas Entomological Society
JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY
88(4), 2015, pp. 444–449
dorsalis dorsalis Say has been successfully reintroduced into the wild (Kapitulik,
2012). In 2011, a coalition composed of the City of Lincoln, Lower Platte South
Natural Resource District, U. S. Fish and Wildlife Service, Nebraska Game and
Parks Commission, Lincoln Children’s Zoo, Omaha’s Henry Doorly Zoo, and the
University of Nebraska set out to rear the SCTB with the goal of reintroductions and
increased number of wild populations on multiple streams and saline wetland
systems where suitable habitat is available.
Attempts by other researchers to get tiger beetles to oviposit have been somewhat
successful. Palmer (1979) used several types of containers as oviposition chambers:
plastic shoeboxes, bread boxes, and glass terraria. She used tops of canning jars, with
the metal plates replaced with window screen, and filled them with soil from the
species’ native habitat. Gwiazdowski et al. (2011) used sterilized native soil at a depth
of 7 cm in polystyrene containers. They placed one pair of adults in each container
and kept a 14:10 L:D schedule with a temperature of 17–18uC, provided humidity
with a pan of water, and fed crickets. Brust et al. (2012) also used plastic containers
with a native soil depth of 7–13 cm and fed the adults termites or Tribolium. Knisley
and Schultz (1997), in their review of rearing methods, noted that some species may
have very specific conditions for oviposition that may be difficult to duplicate in the
laboratory.
One problem to overcome in rearing saltmarsh-dwelling tiger beetles is de-
termining what type of soil and salinity is required for the female to oviposit. Allgeier
(2005) and Brosius (2010) previously determined that sifted topsoil (commercially
available), saturated with either a 0.5 M or 0.354 M NaCl solution was sufficient to
induce oviposition. Prior to Allgeier’s work, we had extracted soil from actual SCTB
habitat and used that to induce oviposition and rear larvae. However, the clay-
saturated habitat soil created problems with uneven moisture gradients and wet
topsoil often promoted mold growth. Lab mortality was sometimes quite high. Our
goal in these experiments was to determine the best soil type and salt concentration
to maximize oviposition potential.
Materials and Methods
In 2011, we began preliminary experiments with soil types and determined that
a mixture of topsoil and sand appeared superior to topsoil alone for egg production,
although statistically, it was significantly different at only the 0.10 level of
probability. In 2012, we used a higher sand ratio and females laid almost no eggs.
Topsoil from commercial sources was found to be inconsistent in texture and
content. In 2013, we reduced the sand ratio and added native loess soil (from a bluff
at Henry Doorly Zoo in Omaha) rather than topsoil from commercial sources. In
addition, we used soil from SCTB habitat along the banks of Little Salt Creek. We
used the following treatments in 2013: (1) habitat soil + 0.354 M NaCl solution, (2)
habitat soil + distilled water, (3) 50/50 loess:sand (by weight) + 0.354 M NaCl
solution, and (4) 50/50 loess:sand (by weight) + 0.5 M NaCl solution. In 2014, we
used only treatments 3 and 4 above. Soils were added to square plastic dishes (2.16
cm high 3 10.16 cm2) lined with plastic wrap and solutions were added until soils
were saturated. Each of the four treatments were set into a layer of small, natural
stone aquarium gravel so the tops of the square dishes were level with the gravel, and
randomized within a clear plastic shoe box (31.1 cm long 3 23.5 cm wide 3 12.7 cm
VOLUME 88, ISSUE 4 445
tall; glassy shoe box, Nam Ngai Hong Co., Thailand) with a lid. Shoe boxes came
pre-drilled with five, 0.3 cm diam. holes on each side. These holes were covered with
51 3 21 mesh plastic screen (Farm Tek, Dyersville, IA) to prevent fly or parasite
infestation. Fifteen pairs of SCTB were collected as soon as possible after emergence
in the field (13–18 June 2013; 11–18 June 2014) and transferred to the 15 shoe boxes
(one pair per box) containing the four soil treatments described above. Males were
kept with the females for two days to ensure mating, then removed and released into
the habitat where they were collected. Females were allowed to remain in the box for
ten days; they were then also removed and returned to the wild. Captive adults were
fed a mixed diet of crickets, mealworms, and Drosophila melanogaster every other
day and moisture was provided using Cricket Quencher (Fluker Farms, Port Allen,
LA). Soils were kept moist (but not wet) by misting daily with distilled water.
Temperature was room temperature (25–28uC) and light was ambient (sunlight and
fluorescent).
Because eggs are very fragile and will often burst when handled, fecundity was
determined by counting first instars. After eggs hatched, soil dishes were allowed to
dry a few days then turned upside down. The plastic wrap was removed, and the soil
was teased apart and the larvae were counted and transferred to overwintering
plastic tubes for continual rearing. Data were analyzed using PROC GLIMMIX
(SAS Institute, 2001) and mean treatment means were separated using LSD (least
square differences) at P # 0.01 and 0.05.
Results and Discussion
In 2013, there were significant differences in numbers of larvae between treatments
(F 5 6.54, d.f. 5 3, 56; P , 0.001) (Fig. 1). The two native habitat soil treatments
Fig. 1. Total 6 SE number of SCTB larvae produced in ten days by 15 females with two soil types and
two salinity concentrations, 2013.
446 JOURNAL OF THE KANSAS ENTOMOLOGICAL SOCIETY
were not significantly different from each other, but were both different from the
50/50 loess/sand mixtures.
The loess/sand mixture was superior for oviposition; however, there were no
significant differences in larval numbers between the 0.5 M (n 5 112) and 0.354 M
(n 5 148) saline solution additions to the loess/sand. Likewise, there were no
differences between native soil (n 5 1) and native soil plus 0.354 M (n 5 0) saline
solution. An additional 52 larvae were obtained from the loess/sand mixtures, but no
record of molarity was recorded, so these were not included in the statistical analysis.
These additional larvae were counted in overall numbers obtained however,
producing a total of 313 larvae/15 females with a mean of 20.9 larvae/female.
Individual females produced from 0–85 larvae.
In 2014, as in 2013, there were no significant differences in numbers of larvae
between 0.5 M (n 5 81) and 0.354 M (n 5 154) saline solution additions to the loess/
sand mixture (F 5 0.99, d.f. 5 1, 28; P , 0.3274) (Fig. 2). An additional 11 larvae
were found underneath the soil dishes, so molarity could not be confirmed and these
were not included in the statistical analyses. Fifteen females produced a total of 246
larvae with a mean of 16.4 larvae/female. Individual females produced from 0–66
larvae.
Based on these results, the potential for high fecundity is present, although it is
unknown why some females laid many eggs while others refused to lay any eggs.
Allgeier (2005) observed that captive SCTB females laid from 0 to 35 eggs in seven
days in the laboratory. Pearson and Vogler (2001) stated that female tiger beetles can
lay from 10 to 20 eggs a day in captivity. Shelford (1908) estimated that fecundity
ranged from 10 to 50 eggs for a few North American tiger beetle species, and Knisley
(unpublished) reported 20 to 50 eggs for several Arizona species. Mating was assured
in our studies because males were not separated from the females until actual mating
(not just mate guarding) was witnessed by an observer, and mating always occurred
at least once by the end of the second day. Lighting was from ambient sources to
assure that there was no light during nighttime hours when females oviposit.
Fig. 2. Total 6 SE number of SCTB larvae produced by 15 females in ten days using a 50/50 loess/sand
soil mixture and two salinities, 2014.
VOLUME 88, ISSUE 4 447
According to Allgeier (2005), SCTB only oviposits at night, and the senior author’s
observations for 25 years agree with this. Nighttime temperatures in the laboratory
were probably slightly higher than field temperatures, but field temperatures also
vary greatly, and this still would not explain why some females produced many eggs
while other produced zero.
Another interesting observation is the almost complete lack of oviposition in
native soil. The soil used was taken directly from a site where SCTB occurs. In
previous years, we had used native soil for oviposition, sometimes with good results.
However, at that time, the females were not given a choice of soils and salinities. We
may have had better results with the native soil if the females were not given a choice.
But the question remains: why do females prefer a loess/sand mixture when the
native soil contains much more clay? In nature, SCTB females are very specific where
they lay their eggs, but salinity may be a more important cue than soil composition.
In conclusion, these experiments provided some essential information necessary
for lab propagation of SCTB. Future experiments will focus on refining these
techniques.
Acknowledgments
We thank past and present workers at both zoos: Traci Clevenger, Sarah Jenkins,
Trace Hardin, Isaac Powell, Trevor Henderson, Devin Krafka, Jessica Mascarello,
Dan Cassidy, Jessie Edgar, and Stephy Hanigan. Natalie Matz helped feed the larvae
after they hatched as well as having many other duties. We also thank directors John
Chapo (LCZ) and Dennis Pate (HDZ) for allowing us to work in their facilities.
Nebraska Master Naturalist program provided volunteers. Travis Prochaska was
especially helpful with statistics.
The findings and conclusions in this publication are those of the authors and do
not necessarily represent the views of the U. S. Fish and Wildlife Service.
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https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1497&amp;context=entomologyfacpub

Determining Optimum Soil Type and Salinity for Rearing the Federally Endangered Salt Creek Tiger Beetle, \u3ci\u3eCicindela (Ellipsoptera) nevadica lincolniana\u3c/i\u3e Casey (Coleoptera: Carabidae: Cicindelinae)

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