Genetic Similarities Among Geographic Isolates of Lysiphlebus testaceipes (Hymenoptera: Aphidiidae) Differing in Cold Temperature Tolerances

Lysiphlebus testaceipes (Cresson) is a solitary endoparasitoid of aphids and is the primary parasitoid attacking cereal aphids in the Great Plains, especially Schizaphis graminum (Rondani). In a previous study, it was found that a Lincoln, NE, isolate of L. testaceipes had a much higher survivorship at cold temperatures than isolates from Stillwater, OK, and Corpus Christi, TX. This suggested that the Nebraska isolate was locally adapted to the northern environment and perhaps genetically divergent from southern populations. We tested for genetic differentiation of the above isolates by sequencing portions of the COI and 16S mtDNA genes. We also examined a Florida isolate reared from Toxoptera citricida (Kirkaldy) and L. fabarum Marshall as an outgroup. The Great Plains isolates (Nebraska, Oklahoma, and Texas) were homogeneous with 0% and 0Ð0.2% sequence divergence in the COI and 16S gene fragments, respectively. The Florida isolate differed from the Great Plains isolates in nucleotide sequence by 1.4% (COI) and 0.5Ð0.7% (16S). Phylogenetic analysis placed the Florida isolate of L. testaceipes basal to the Great Plains isolates with L. fabarum, suggesting a possible species complex within L. testaceipes

Russian wheat aphids (Diuraphis noxia) in China: Native range expansion or recent introduction?

In this study, we explore the population genetics of the Russian wheat aphid (RWA) (Diuraphis noxia), one of the world’s most invasive agricultural pests, in north-western China. We have analysed the data of 10 microsatellite loci and mitochondrial sequences from 27 populations sampled over 2 years in China. The results confirm that the RWAs are holocyclic in China with high genetic diversity indicating widespread sexual reproduction. Distinct differences in microsatellite genetic diversity and distribution revealed clear geographic isolation between RWA populations in northern and southern Xinjiang, China, with gene flow interrupted across extensive desert regions. Despite frequent grain transportation from north to south in this region, little evidence for RWA translocation as a result of human agricultural activities was found. Consequently, frequent gene flow among northern populations most likely resulted from natural dispersal, potentially facilitated by wind currents. We also found evidence for the longterm existence and expansion of RWAs in China, despite local opinion that it is an exotic species only present in China since 1975. Our estimated date of RWA expansion throughout China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. We conclude that western China represents the limit of the far eastern native range of this species. This study is the most comprehensive molecular genetic investigation of the RWA in its native range undertaken to date and provides valuable insights into the history of the association of this aphid with domesticated cereals and wild grasses

Preparing Teachers to Teach the Language of History

The preparation of history teachers has not traditionally included a focus on teaching the language of history. However, in order to think like historians, students in middle and high school history classrooms must learn to read and write like historians. This article describes how two preservice history teachers identified and taught language in fieldwork placements. Their experiences illustrate the challenges that history teachers face in incorporating meaningful language instruction. The findings suggest that training preservice and in-service teachers to identify and teach the language of history would be necessary to ensure that language instruction is implemented in history classrooms

Preparing secondary teacher candidates to teach academic English

In this qualitative study, mainstream teacher candidates in a secondary teacher education program were asked to incorporate academic English instruction into their lesson planning and implementation in fieldwork placement classrooms. Teacher candidates attended a training session in which one method for identifying academic English features was taught. Artifacts, classroom observations, and interviews from four teacher candidates were analyzed to determine what features of academic English were identified and how these were taught to high school students. While all four teacher candidates accurately identified features of academic English in their lessons, only two participants taught features of academic English to students. The experiences of the participants illustrated that teacher candidates need, in addition to the ability to identify features of academic English, knowledge about how to teach language, a commitment to teaching language in their lessons, and the support of university supervisors and supervising practitioners who possess the same knowledge and commitment

Genetic Similarities Among Geographic Isolates of Lysiphlebus testaceipes (Hymenoptera: Aphidiidae) Differing in Cold Temperature Tolerances

Lysiphlebus testaceipes (Cresson) is a solitary endoparasitoid of aphids and is the primary parasitoid attacking cereal aphids in the Great Plains, especially Schizaphis graminum (Rondani). In a previous study, it was found that a Lincoln, NE, isolate of L. testaceipes had a much higher survivorship at cold temperatures than isolates from Stillwater, OK, and Corpus Christi, TX. This suggested that the Nebraska isolate was locally adapted to the northern environment and perhaps genetically divergent from southern populations. We tested for genetic differentiation of the above isolates by sequencing portions of the COI and 16S mtDNA genes. We also examined a Florida isolate reared from Toxoptera citricida (Kirkaldy) and L. fabarum Marshall as an outgroup. The Great Plains isolates (Nebraska, Oklahoma, and Texas) were homogeneous with 0% and 0Ð0.2% sequence divergence in the COI and 16S gene fragments, respectively. The Florida isolate differed from the Great Plains isolates in nucleotide sequence by 1.4% (COI) and 0.5Ð0.7% (16S). Phylogenetic analysis placed the Florida isolate of L. testaceipes basal to the Great Plains isolates with L. fabarum, suggesting a possible species complex within L. testaceipes

The Development of Language Knowledge in a Teacher Education Program: Preparing Secondary Teacher Candidates to Identify and Teach Academic English in their Content Area Lessons

Thesis advisor: Maria Estela BriskThis mixed methods research study examined the impact of an intervention designed to prepare mainstream secondary teacher candidates to identify and teach features of Academic English. The intervention was intended to develop Disciplinary Linguistic Knowledge (Turkan, deOliveira, Phelps, and Lee, 2014) through engagement in several tasks for preparing linguistically responsive teachers (Lucas and Villegas, 2013). Pre-tests, post-tests, and artifacts created by teacher candidates in their fieldwork placements, as well as observations of a small group of teacher candidates teaching in their placement classrooms and interviews with these participants, were collected in order to analyze the effect that the intervention had on the teacher candidates’ identification of features of AE and their planning and implementation of instruction in these features. While the teacher candidates accurately identified features of AE on the post-tests and in the artifacts, only a small number of participants planned or implemented instruction in features of AE in their lessons. The experiences of the participants in the small group illustrated that teacher candidates need, in addition to the ability to identify features of Academic English, knowledge about how to teach these features, a commitment to teaching language in their lessons, and the support of supervisors and cooperating teachers who possess the same knowledge and commitment. The findings suggest that teacher education programs should engage both teacher candidates and the individuals who guide the planning and teaching of lessons in their pre-practicum experiences in developing the essential knowledge of and commitment to teaching Academic English in mainstream content area classrooms.Thesis (PhD) — Boston College, 2015.Submitted to: Boston College. Lynch School of Education.Discipline: Teacher Education, Special Education, Curriculum and Instruction