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Telenomus podisi: one species, or more?

Bowers, Kelsey Rae

Abstract Details

2015, Master of Science, Ohio State University, Evolution, Ecology and Organismal Biology.
Parasitoid wasps are a collection of hymenopterans whose larvae feed on the body of a host, eventually killing it (Godfray 1994). The parasitoid wasp Telenomus podisi Ashmead (Hymenoptera: Platygastridae, Telenominae) parasitizes the eggs of both phytophagous and predaceous pentatomids, including a number of important agricultural pests (e.g., Temerak and Whitcomb 1984, Schaefer and Panizzi 2000). Comparisons of strains from Maryland and Brazil has begun to raise questions as to whether T. podisi is a single species (Borges et al. 2003). This study considers populations of T. podisi throughout the species range to determine if there is evidence to support the hypothesis of T. podisi as more than one species. Cytochrome oxidase I is sequenced for 50 specimens of T. podisi from North and South America, along with one specimen each of Telenomus sechellensis Kieffer, Telenomus grenadensis Ashmead, and Trissolcus basalis Wollaston. A number of species delimitation methods are considered, including DNA barcoding with pairwise distances, the General Mixed Yule Coalescent Model (GMYC) and Poisson Tree Process Model (PTP) (Fujisawa and Barraclough 2013, Zhang et al. 2013). DNA barcoding attempts to detect the transition between interspecific and intraspecific variation by a gap in the distribution of genetic distances, and this gap is clear in the histogram of p-distances (Hebert et al., 2004). Mean p-distances between specimens from Ohio and Brazil fall within the rightmost curve in the distribution, suggesting that these populations may be separate species. A maximum likelihood tree and the results from GMYC and PTP suggest that the situation may be even more complicated. Both support the hypothesis of T. podisi as more than one species; PTP identifies 16 different species and GMYC 14. While a clade consisting of the majority of specimens from the continental US is identified as one species in both methods (support=0.905 in bPTP), so is a clade of two Ohio specimens (0.927), a clade consisting of two Ohio specimens and one from Texas (0.859) and a clade of 2-4 specimens from Texas, delimited differently depending on the method (0.247). Other potential species identified corresponded with geographic region, including a clade from Panama (0.944), a clade formed by two individuals from Brazil (0.801), and one by the two specimens from the Dominican Republic (0.898). A number of amino acid changes unique to these clades are identified, including a number of changes that distinguish the specimens from Ohio and Texas that are not included in the continental US clade. Results from pairwise distance data, GMYC, PTP and analysis of fixed sites all suggest that Telenomus podisi may include more than one species. Increased sampling, introduction of multiple loci, and further study of morphological differences within the group is necessary.
Norman Johnson, PhD (Advisor)
Marymegan Daly, PhD (Committee Member)
John Freudenstein, PhD (Committee Member)
55 p.

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Citations

  • Bowers, K. R. (2015). Telenomus podisi: one species, or more? [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431004147

    APA Style (7th edition)

  • Bowers, Kelsey. Telenomus podisi: one species, or more? 2015. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1431004147.

    MLA Style (8th edition)

  • Bowers, Kelsey. "Telenomus podisi: one species, or more?" Master's thesis, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1431004147

    Chicago Manual of Style (17th edition)