Allen L. Szalanski's Presentations

Recent Presentations

Petersen, J. R. Bischof, and A.L. Szalanski. 2000. Population genetics of mid-continental sandhill cranes. To be presented at the Eighth North American Crane Workshop, Albuquerque, NM.

The Mid-Continent sandhill crane population is comprised of three subspecies, lesser (Grus canadensis canadensis), Canadian (G. c. rowani), and greater (G. c. tabida). Currently, the population genetic structure of these subspecies is unknown. In conjunction with the USGS Northern Prairie Wildlife Research Center, a study was undertaken to investigate the extend of intra and inter specific genetic variation of the Mid-Continent sandhill crane population. DNA was extracted from 150 feather and dried blood samples collected from 1995 to 1999 from the Nebraska central Platte River valley, including 16 birds tagged and released for GPS monitoring. Approximately 675 bp of the mtDNA D-loop region was amplified using PCR. Parsimony and maximum likelihood analysis of the mtDNA D-loop sequences from 29 sandhill cranes and three other crane species revealed two distinct clades within Grus canadensis. Using known morphological data, these two clades represented G. c. canadensis, and G. c. rowani. Genetic divergence was between from 6.6 to 9.4% between the two subspecies, 0.1 to 6.0 within G. c. candensis, and 0.1 to 6.1% within G. c. rowani. From the DNA sequence data, PCR-RFLP analysis was conducted on all 150 sandhill cranes using four restriction enzymes. PCR-RFLP revealed x haplotypes and was able to differentiated subspecies. Based on the levels of mtDNA D-loop variation observed, this marker will be useful for genetic monitoring of these subspecies. In addition, the ability to use feather samples for genetic analysis will facilitate monitoring of cranes from the central Platte River valley, and the use of museum specimens.

R. Bischof, and A.L. Szalanski. 1999. Species Identification of North American Wildlife using PCR-RFLP of Cytochrome B. Annual Meeting, Northwest Association of Forensic Scientists, Cheyenne, WY.

Mammal and avian DNA samples from various North American species were obtained from blood, tissue, hair and feathers. Polymerase Chain Reaction (PCR) was used to amplify a region of the mitochondrial DNA cytochrome B gene. DNA Sequences of cytochrome B amplicons revealed sufficient genetic polymorphism for discrimination of most species examined. PCR – restriction fragment length polymorphism (PCR-RFLP) was conducted in conjunction with polyacrylamide gel electrophoresis (PAGE) resulting in species specific banding patterns. Once samples have been analyzed over the geographical range of each species, we believe that this technique will provide a robust, efficient and economical species identification for wildlife forensic purposes.

Szalanski, A.L., and R.L. Roehrdanz. 1999. Genetic demarcation of northern corn rootworm populations revealed by DNA markers. To be presented at the Annual Meeting, Entomological Society of America, Atlanta, Georgia, 1999

The genetic variation of local and dispersed geographical populations of northern corn rootworms (NCR)(Diabrotica barberi), has been examined using mitochondrial DNA and nuclear ribosomal intergenic transcribed spacer (ITS1). NCR were collected at various sites across the corn belt (KS, NE, SD, IA, WI, IL, IN, OH). Long-PCR was used to amplify DNA segments comprising about 75%of the mtDNA. The mtDNA amplicons were screened for restriction fragment polymorphisms. Approximately 70 restriction fragments per individual have contributed to the RFLP comparisons and numerous mtDNA haplotypes have been identified. Polymorphism has been observed both within populations and between collection sites. A phylogeographic pattern of genetic diversity appears to be emerging with a genetic demarcation zone in east central Illinois. Distinct differences in haplotype frequencies occur on either side of the boundary. The nuclear rDNA ITS1 region has been examined for many of the same individuals. DNA sequence of a 644-646 bp amplicon from several individuals revealed four polymorphic sites. PCR-RFLP analysis with the restriction enzyme Bcl I on many of the same individuals used for mtDNA, detected two haplotypes. Many beetles had both BclI haplotypes present, which is indicative of heterogeneity. The eastern Illinois populations were fixed for haplotype "B", while South Dakota, Nebraska, and Kansas populations were predominately haplotype "A" or "A/B". Both mtDNA and ITS1 support an historic genetic boundary in Illinois.

Szalanski, A.L., and R.L. Roehrdanz. 1999. Genetic variability in populations of northern corn rootworm. Annual Meeting, Kansas (Central States) Entomological Society, Manhattan, KS.

We have begun to examine genetic variation of the nuclear rDNA ITS1 region in local and dispersed geographical populations of northern corn rootworm. Populations from Illinois, Iowa, South Dakota, Nebraska and Kansas were examined. Sequencing of the 644-646 bp amplicon revealed four polymorphic sites. PCR-RFLP analysis with the restriction enzyme Bcl I, detected two haplotypes. Interestingly, many beetles had both Bcl I haplotypes present, indicative of hetergeneity. The Illinois populations were fixed for haplotype “B”, while South Dakota, Nebraska, and Kansas populations were predominately haplotype “A” or “A/B”. A phylogeographic pattern of genetic diversity appears to be emerging.

Clark, B., D.B. Taylor, A.L. Szalanski, and T.O. Powers. 1999. Pathogenicity of entomopathogenic nematodes towares house fly maggots, Musca domestica, of different ages. Annual Meeting, Kansas (Central States) Entomological Society, Manhattan, KS.
Szalanski, A.L., R. Bischof, and M. Fritz. 1999. Population genetics of the endangered American burying beetle (Coleoptera: Silphidae) based on nuclear rDNA ITS1 sequence variation. Annual Meeting, Kansas (Central States) Entomological Society, Manhattan, KS.

Genetic variation within and among seven Nicrophorus americanus populations, collected from South Dakota, Nebraska, Oklahoma, Arkansas, and Rhode Island was studied. Ribosomal DNA ITS1 sequences from 16 beetles revealed 35 polymorphic sites. Genetic divergence ranged from 0.16 to 4.76%. The sequences formed two distinct clades based upon parsimony and distance analysis. Based on this data, genetic variation is being maintained within and among several N. americanus populations. We recommended that reintroduction of N. americanus should proceed with caution until the extent of genetic variation within this species is further quantified.

Szalanski, A.L., D. Sikes, M. Fritz, and D.B. Taylor. 1998. Phylogenetic analysis of burying beetles (Coleoptera: Silphidae) based on nuclear rDNA ITS1 sequences. Entomological Society of America, Las Vegas, NV.

Nuclear ribosomal DNA sequences were used to infer phylogenetic relationships among 12 species of Silphidae in this preliminary study. Sequences were aligned and optimized based on pairwise genetic distance and parsimony criteria. Because of the amplicon size polymorphims observed within Silphinae, 448 to 2500 bp, the 18S and internal transcribed spacer 1 (ITS1) DNA sequences were analyzed independently. The trees estimated from parsiomony and neighbor-joining analysis of the 18S sequences indicated that Silphidae may not be monophyletic. Parsimony and neighbor-joining analysis of the ITS1 sequences of Nicrophorus revealed three distinct clades and supported several of the species groups proposed by Peck and Anderson (1985). The endangered American burying beetle, Nicrophorus americanus, is genetically distinct from most other burying beetles. The nuclear rDNA 18S and ITS1 markers appear to be suitable for species to family level studies of Silphidae.

Taylor, D.B., and A.L. Szalanski. 1998. Molecular diagnostics and phylogenetics of Muscidifurax. Entomological Society of America, Las Vegas, NV.

Wasps in the genus Muscidifurax are pupal parasites of house flies (Musca domestica) and stable flies (Stomoxys calcitrans) and are among the most promising biocontrol agents for flies associated with confined livestock. Polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing analyses were used to detect species diagnostic and phylogenetically informative characters in the mitochondrial (mtDNA) and nuclear intergenic transcribed spacer 1 (ITS-1) DNA of 4 of the 5 species of Muscidifurax. The ITS-1 region proved most useful for diagnostic purposes while both regions were phylogenetically informative.

Taylor, D.B., A.L. Szalanski, and B. Clark. 1998. Entomopathogenic nematodes for the control of flies in beef cattle feedlots. Entomological Society of America, Las Vegas, NV.

The virulence of 40 strains of entomopathogenic nematodes, 27 Heterorhabditis and 13 Steinernema, towards 3rd instar larvae of house fly, Musca domestica, was evaluated with a filter paper assay. Although 22 of the 27 strains of Heterorhabditis infected house fly larvae, none resulted in mortality significantly greater than the control. Ten of the 13 strains of Steinernema infected house fly larvae and 7 strains, 4 S. carpocapsae, 2 S. feltiae, and 1 S. scapterisci caused significant mortality. Ten Heterorhabditis strains and 10 Steinernema strains successfully reproduced 2 or more generations in house fly larvae. No difference was observed between 72 h survival of house fly larvae and adult emergence. Six strains of Steinernema were selected for 10 generations on house fly larvae and then compared with unselected lines. No difference in pathogenicity between selected and unselected lines was observed. Two strains of S. feltiae, SN and UNK-36, and 2 of the best Heterorhabditis strains, H. bacteriophora OSWEGO and H. megidis HF-85 were tested in a fresh bovine manure substrate. All 4 strains produced significant fly mortality in the manure substrate, although the S. feltiae strains had significantly lower LC50 values than did the Heterorhabditis spp. The most promising strain, S. feltiae SN, gave LC50 and LC99 values of 4 and 82 infective juveniles per host larvae, respectively. These doses were equivalent to 2.7 and 55 infective juveniles per gram of manure, and 5.1 and 104 infective juveniles per cm2 of surface area. Infective juveniles capable of infecting wax moth larvae, Galleria mellonella survived in manure for up to 10 wk without hosts.

Roehrdanz, R. L., Szalanski, A. L. Chandler, L. and Powers T. O. 1998. Genetic variation in western, Mexican and northern corn rootworms, Diabrotica sp. (Coleoptera: Chrysomelidae). Keystone Symposia: Toward The Genetic Manipulation of Insects. Taos, NM.

Genetic variation in western (WCR), Diabrotica virgifera virgifera, Mexican (MCR), D. v. zeae, and northern corn rootworm (NCR), D. barberi was studied. PCR-RFLP of mtDNA amplicons, DNA sequencing and PCR-RFLP of nuclear regions, and RAPD-PCR were used to examine interspecific variation and intraspecific variation of geographic populations. WCR and MCR are generally considered to be subspecies. PCR-RFLP of 75% of the mt genome from 13 WCR populations detected 1 poly-morphic site out of >100 sites and no geographic pattern. 3 or 4 poly-morphic sites were observed between WCR and 2 populations of MCR. DNA sequence of a portion of the nuclear 18S ribosomal internal transcribed spacer 1 (ITS1) and a 5' portion of the 5.8S gene uncovered 2 polymorphic sites between WCR and MCR in the ITS1 region. No polymorphism was found with PCR-RFLP of the same region. RAPD-PCR revealed significant polymorphism within each population but no distinctive geographical differences between populations. The very low variability between WCR populations and between WCR and MCR suggests either high levels of gene flow among populations or a recent geographical expansion from a relatively small base. Several of the WCR populations have been identified as resistant to some current use insecticides. High gene flow could facilitate the spread of insecticide resistance which would be a cause for concern. RFLP analysis of the NCR mtDNA found much more variation than in WCR. Some of the polymorphisms show a geographic distribution being present in one population and absent or rare in another population. All of the techniques tried revealed useful diagnostic markers for WCR, NCR and southern corn rootworm (D. undecimpunctata howardi).

Roehrdanz, R.L., A.L. Szalanski, and L. Chandler. 1998. Different levels of genetic variability in western and northern corn rootworms. Annual Meeting of the North Central Branch of the Entomological Society of America, Sioux Falls, SD.
Powers, T.O., J.A. Griesbach, A.L. Szalanski and B.A. Adams. 1998. Molecular identification of Anguinid quarnatinable nematode species. Society of Nematologists, St. Louis, MO.

PCR-RFLP and nucleotide sequencing of the ITSI region have been used to evaluate isolates of Anguina, Ditylenchus, and related nematodes. Distinct restriction patterns have been recorded for each isolate associated with a unique plant host, supporting views of strong host-specificity among anguinid nematodes. Anguina agrostis isolated from bentgrass is readily discriminated from A. funesta isolated from annual rye-rass, as well as Afrina wevelli from weeping lovegrass. The latter two species have been considered in several taxonomic treatments as synonyms of A. agrostis. Other anguinids producing unique ITS1 restriction patterns include Anguina tritici from wheat A. agropyronifloris from western wheatgrass, A. graminis from hard fescue, A. pacijicae from annual bluegrass, and an undescribed species from orchard grass. This method provides a rapid means to assess anguinid species identity in shipments of nematode-contaminated seed.

Taylor, D.B., and A.L. Szalanski. 1998. Entomopathogenic nematodes for the control of filth flies. 42nd Annual Livestock Insect Workers Converence, Lethbridge, AB.