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Many parasitic insects, including lice, form close relationships with endosymbiotic bacteria that are crucial for their survival. In this study, we used genomic sequencing to investigate the distribution and evolutionary history of the bacterial genusSodalisacross a broad range of feather louse species spanning 140 genera. Phylogenomic analysis revealed significant diversity amongSodalislineages in feather lice and robust evidence for their independent and repeated acquisition by different louse clades throughout their radiation. Among the 1020 louse genomes analysed, at least 22% containedSodalis, distributed across 57 louse genera. Cophylogenetic analyses between theSodalisand feather louse phylogenies indicated considerable mismatch. This phylogenetic incongruence between lice andSodalis, along with the presence of distantly relatedSodalislineages in otherwise closely related louse species, strongly indicates repeated independent acquisition of this endosymbiont. Additionally, evidence of cospeciation among a few closely related louse species, coupled with frequent acquisition of these endosymbionts from free-living bacteria, further highlights the diverse evolutionary processes shapingSodalisendosymbiosis in feather lice. 

Two new species of the genusMelinirmusMey, 2017, are described from Australian honeyeaters (Meliphagidae). These are:Melinirmus coromandelican. sp. exPtilotula penicillatus penicillatus(Gould, 1837) andMelinirmus palmain. sp. exAnthochaera carunculata(Shaw, 1790). A checklist of all known species ofBrueelia-complex chewing lice known from the Meliphagidae is provided. 

Abstract Evolution results from the interaction of stochastic and deterministic processes that create a web of historical contingency, shaping gene content and organismal function. To understand the scope of this interaction, we examine the relative contributions of stochasticity, determinism, and contingency in shaping gene inactivation in 34 lineages of endosymbiotic bacteria,Sodalis, found in parasitic lice,Columbicola, that are independently undergoing genome degeneration. Here we show that the process of genome degeneration in this system is largely deterministic: genes involved in amino acid biosynthesis are lost while those involved in providing B-vitamins to the host are retained. In contrast, many genes encoding redundant functions, including components of the respiratory chain and DNA repair pathways, are subject to stochastic loss, yielding historical contingencies that constrain subsequent losses. Thus, while selection results in functional convergence between symbiont lineages, stochastic mutations initiate distinct evolutionary trajectories, generating diverse gene inventories that lack the functional redundancy typically found in free-living relatives. 

Meaningful discourse in the mathematics classroom involves creating a learning community that empowers students to articulate their reasoning and make sense of the contributions of their peers while advancing the learning of mathematics for the entire class. This study assessed the degree to which secondary mathematics (Grades 7–12) teacher candidates incorporated discourse into their lessons and the factors influencing their decisions. An explanatory mixed methods design was used, in which data were collected sequentially. Lesson videos were analyzed, followed by interviews of teacher candidates with high-discourse lessons. This study found that participants showed significant growth in their use of effective teaching practices from the beginning of the semester to the end of the semester, including mathematics discourse. The interviews revealed four contributing factors: intentional effort, learning experiences, professional relationships, and pedagogical knowledge. Understanding the experiences of teacher candidates during their own learning of mathematics, their mathematical identities, and beliefs about mathematics could help generate knowledge regarding the implementation of mathematics discourse and other reform-based practices in teacher instruction. 

Abstract Environmental factors such as temperature and humidity influence the distribution of free‐living organisms. As climates change, the distributions of these organisms change along with their associated parasites, mutualists and commensals. Less studied, however, is the possibility that environmental conditions may directly influence the distribution of these symbionts even if the hosts are able to persist in altered environments. Here, we investigate the diversity of parasitic lice (Insecta: Phthiraptera) on birds in arid Utah compared to the humid Bahamas. We quantified the parasite loads of 500 birds. We found that the prevalence, abundance and richness of lice was considerably lower among birds in Utah, compared to the Bahamas, despite sampling greater host taxonomic richness in Utah. Our data suggest that as climates change, birds in arid regions will have less diverse louse communities over time, potentially relieving birds of some of the cost of controlling these ectoparasites. Conversely, birds in more humid regions will see an increase in louse diversity, which may require them to invest more time and energy in anti‐parasite defense. Additional research with other ectoparasites of birds and mammals across different environmental conditions is needed to more fully understand how climate change may reshape parasite communities, and how these changes could influence their hosts. 

This paper clarifies and expands the definition of teacher professional practice, grounded in the commonplaces of professionalism outlined by Lee Shulman. We present the Professional Development: Research, Implementation, and Evaluation (PrimeD) framework as a lens for transforming professional development into a practice that engages teachers as professionals. This discussion explores teachers’ roles in both their classrooms and the profession. The inclusion of PrimeD evaluation and research in the development and practice of mathematics teachers addresses Shulman’s professionalism commonplaces. PrimeD was tested as a lens for professionalism in mathematics teacher education programs at four universities. In the study, teachers collaborated as professionals on developing and testing novel ways to approach mathematics lessons. In general, teachers’ efforts to conduct structured experimentation in their lessons were disconnected from traditional views of the role of a teacher. As a result, teachers who did develop and test lesson trials in this PD program did not frequently continue experimentation. Typically, teachers wanted to collaborate on testing classroom activities but did not have resources to do so (e.g., time, collaborative planning). Systemic changes are needed to promote sustainable change, allowing teachers to collaborate and share the results of classroom research. 

RESUMEN. - We describe a new species of chewing louse, Motmotnirmus danielalfonsoi n. sp., from the Turquoise-Browed Motmot (Eumomota superciliosa). It differs from congeneric species in several characters, including the head shape, the abdominal chaetotaxy of the male, and in the characters of the male genitalia. Females differ from congeneric species primarily in the head shape and the shape and size of abdominal plates. Additionally, we suggest that the true host of Motmotnirmus guatemalensis is the Lesson’s Momot (Momotus lessonii), which is also a new host record. Such suggestion is based on examinations of museum specimens of lice from various motmot species. We also provide a key to the species of Motmotnirmus and an updated checklist of the genus Motmotnirmus. 

Quantitative data for Mathematics Discourse in Secondary Teacher Candidates’ Lessons: A Mixed Methods Analysis. 

Birds have a diverse community of “permanent” arthropods that complete their entire life cycle on the body of the host. Because some of these arthropods are parasites that reduce host fitness, birds control them by grooming, which consists of preening with the beak and scratching with the feet. Although preening is the primary component of grooming, scratching is essential for controlling arthropods on the head and neck, which cannot be preened. Several unrelated groups of birds have evolved comb-like pectinate claws on the middle toenail of each foot. We tested the role of these claws in the control of arthropods by experimentally removing teeth from the claws of captive western cattle egrets (Bubulcus ibis) infested with chewing lice (Insecta: Phthiraptera), feather mites (Acari: Sarcoptiformes), and nasal mites (Acari: Mesostigmata). After a period of 4 mo, we compared the abundance of arthropods on experimental birds to that of control birds with intact teeth. We used video to quantify the grooming rates of the captive birds, which groomed twice as much as wild birds. Experimental and control birds did not differ significantly in grooming time. Both groups virtually eradicated the chewing lice, but not feather mites or nasal mites. We found no support for the hypothesis that pectinate claws increase the efficiency of arthropod control by grooming. Experiments with wild birds are needed to test the hypothesis further under conditions in which birds devote less time to grooming.