Cockroaches as carriers of human medically important parasites.

Cockroaches have been identified as mechanical carriers of pathogens capable of infesting humans. The primary objective of this research was to detect and separate medically significant parasites found within the collected cockroaches. A total of 185 cockroaches were captured. In the laboratory, cockroaches underwent a series of steps. Initially, they were washed in a saturated salt solution and rinsed with 70% alcohol, dried, and subsequently dissected to examine endoparasites. In this study, a transport rate of 29.729% was documented, and four types of helminths were identified, which included Ascaris lumbricoides (47.27%), Enterobius vermicularis (30.91%), Trichuris spp. (7.27%), and Hymenolepis nana (14.55%). The parasites were more frequently found on the external surface of cockroaches (38/69.09%), compared to the internal surface (17/30.91%). Cockroaches captured in toilets were found to carry a higher percentage of parasites (31/16.75%) compared to those from kitchens (11/5.94%) and houses (13/7.02%). These findings suggest that cockroaches can serve as carriers for intestinal parasites and potentially act as mechanical agents in the dissemination of these parasites.

Predicted novel hypertrehalosaemic peptides of cockroaches are verified by mass spectrometry.

Small neuropeptides from the corpora cardiaca are responsible in cockroaches for the mobilisation of trehalose from the fat body into the haemolymph. Such hypertrehalosaemic hormones (HrTHs) belong to the large family of insect adipokinetic hormones (AKHs); a few HrTHs were previously sequenced from cockroaches, and from genomic and/or transcriptomic information one may predict the genes encoding HrTHs from more species. Definite elucidation of the primary structure of the mature peptide with putative modifications needs analytical chemical methods. In the current study, we use high-resolution mass spectrometry coupled with liquid chromatography to identify unequivocally the HrTHs of 13 cockroach species. Either genomic/transcriptomic information was available for most of the species examined, or from related species. We confirm predicted novel sequences and find hydroxyproline modification for the majority of the peptides. The novel decapeptides are structurally close to Bladi-HrTH, which is found in all seven of the investigated blaberid subfamilies. Bladi-HrTH and all the novel peptides elicit a hypertrehalosaemic response in Periplaneta americana, a blattid cockroach.

The neurotoxic mechanism of Jack Bean Urease in insects involves the interplay between octopaminergic and dopaminergic pathways.

In the last decades, the entomotoxicity of JBU and its derived peptides became an object of study, due mainly to the ubiquitous interaction of these compounds with different species of insects and their potential as natural insecticides. In this work, we investigated the neurotoxic effects of JBU in Nauphoeta cinerea cockroaches by dissecting pharmacologically the monoaminergic pathways involved. Selective pharmacological modulators for monoaminergic pathways in in vivo and ex vivo experimental models were employed. Thus, the analysis of N. cinerea neurolocomotory behavior demonstrated that JBU (1.5 and 3 µg/g) induces a significant decrease in the exploratory activity. In these assays, pretreatment of animals with phentolamine, SCH23390 or reserpine, interfered significantly with the response of JBU. Using in vivo abductor metathoracic preparations JBU (1.5 µg/g) induced progressive neuromuscular blockade, in 120 min recordings. In this set of experiments, the previous treatment of the animals with phentolamine, SCH23390 or reserpine, completely inhibited JBU-induced neuromuscular blockade. The recordings of spontaneous compound neural action potentials in N. cinerea legs showed that JBU, only in the smallest dose, significantly decreased the number of potentials in 60 min recordings. When the animals were pretreated with phentolamine, SCH23390, or reserpine, but not with mianserin, there was a significant prevention of the JBU-inhibitory responses on the action potentials firing. Meanwhile, the treatment of the animals with mianserin did not affect JBU's inhibitory activity. The data presented in this work strongly suggest that the neurotoxic response of JBU in N. cinerea involves a cross talking between OCTOPAMIN-ergic and DOPAMIN-ergic nerve systems, but not the SEROTONIN-ergic neurotransmission. Further molecular biology studies with expression of insect receptors associated with voltage clamp techniques will help to discriminate the selectivity of JBU over the monoaminergic transmission.

The NEURON Program: Utilizing Low-Cost Neuroscience for Remote Education Outreach.

The NEURON initiative (Neuroscience Education in Undergraduate Research, Outreach, and Networking) is a free program engaging first year students, including underrepresented minority (URM) students in Neuroscience and Cognitive Science (NSCS) at the University of Arizona (UA). The NEURON program builds on former Grass Foundation-sponsored workshops run by Dr. Ricoy (2010-2019) implementing hands-on and culturally responsive active learning curriculum with low-cost equipment from Backyard Brains to increase student retention of URM students in the sciences at Hispanic Serving Institutions (HSI). We present the implementation of the NEURON program at the onset of the COVID pandemic. Combining best practices of distance learning and peer mentoring, we conducted three-week projects exploring principles of neuroscience and neurophysiology. Enrollment and demographic data from NSCS at the UA demonstrate historical disenfranchisement and program attrition primarily impacting URM students. As an extension on previous URM peer mentorship programs in Neuroscience (Ricoy, presentation at Northern New Mexico College Research Symposium, 2010, 2011; presentation at Society for Advancement of Chicanos/Hispanics and Native Americas in Science, 2012), we leveraged low-cost equipment and remote sessions to advance the community of undergraduate mentors and pair with high school mentees on hands-on curriculum. Throughout the program, undergraduate mentors received guidance while crafting and delivering four laboratory lessons to mentees. By coordinating with a Title I school, we better connected with historically underserved students. Critical to this program was providing hands-on opportunities to students who were undergoing distance-based learning during the pandemic. Distribution of equipment allowed high school students to experiment remotely, guided by undergraduate mentors. The NEURON program met its objectives of fostering both mentors and mentees as burgeoning scientists.

Uncontrolled asthma and household environmental exposures in Puerto Rico.

OBJECTIVE: To describe asthma control and household environmental exposures among adults and children with asthma in Puerto Rico. METHODS: A cross-sectional analysis was conducted using data from the 2014-2016 Behavioral Risk Factor Surveillance System Asthma Call-back Survey on 931 adults and 177 children with current asthma in Puerto Rico. These data were analyzed to assess the prevalence of uncontrolled asthma in Puerto Rico and potential associations with household environmental exposure to cockroaches, smoke, and mold. Asthma control was classified using daytime and nighttime symptoms, activity limitation, and short-acting beta agonist use. Prevalence and prevalence ratios were calculated, adjusting for sample weighting. RESULTS: An estimated 53% of adults with asthma and 29% of children with asthma in Puerto Rico have uncontrolled asthma. Among adults with asthma, in the past 30 days, 29% had seen or smelled mold and 50% had seen cockroaches; in the past week, 12% reported having someone smoke in their home. Adults with uncontrolled asthma were 1.4 times more likely to have observed mold in their homes than were those with controlled asthma when adjusting for age, sex, education, and income (prevalence ratio [95% confidence interval]: 1.4 [1.1, 1.8]). Children with uncontrolled asthma were also more likely to have mold observed in their home than were children with controlled asthma (adjusted PR [95% CI]: 3.0 [1.3, 7.1]). CONCLUSIONS: Uncontrolled asthma is common among adults and children with asthma in Puerto Rico. These results suggest potential differences in household mold exposure by asthma control status.

Evaluation of the effectiveness of three sticky traps to monitor four species of cockroaches (Hexapoda: Blattaria) with simulated use tests.

Background: Cockroaches are the pest of major concern for the disinfestation programs of the sanitary system in Italy. Hygienic-sanitary interest is linked to the role of mechanical vectors of pathogens and to their allergological potential. Sticky traps are the best tool to monitor the presence of these insects and several types of them are available on the market. In most of the cases the traps are not indicated for a given species, but, instead, generically for cockroaches. Domestic cockroaches differ in morphology, size and habits. Consequently, the effectiveness of the trap can change in relation to the target species. Materials and methods: In this study three of the most employed traps in Italy were compared: the INDIA trap with and without its attractant tablet (hereafter mentioned as INDIA-A and INDIA-E, respectively), the ZAPI Simply trap and the CATCHMASTER Spider & Insect Glue trap. We chose the four most common species of cockroach (Blattodea) in Italy, Blatta orientalis (L.), Periplaneta americana (L.) (Blattidae), Blattella germanica (L.) and Supella longipalpa (F.) (Blattellidae). Each species of cockroach was tested separately inside arenas containing one of the traps. Each test (one species with one kind of trap) was replicated five times. Results and discussion: The INDIA-A trap collected more cockroaches of every species, followed by the INDIA-E. The ZAPI trap caught less specimens of each species in respect to the INDIA traps, with the only exception of B. orientalis, for which the ZAPI trap caught more than the INDIA-E. The CATCHMASTER trap performed significantly less for all the species. B. orientalis was the species most abundantly caught by all traps, followed by B. germanica, S. longipalpa and P. americana. No significant difference was observed in the catch according to the developmental stage. In general, there was no particular predisposition of any trap to catch a particular species. Conclusions: It is not possible to indicate a model of trap for each species of cockroach, but it is clear that different traps have different performances in terms of attractiveness and capture. Therefore, the choice of the trap affects the results of the monitoring, and as consequence, the evaluation of the infesting population of the pest.

The First and Last Time I Met Rita Levi-Montalcini: From the Insect Neurotrophic Factor to the Nerve Growth Factor Clinical Application : RLM and the Discovery of Two Neurotrophic Factors.

The neurotrophic factor nerve growth factor (NGF) has been discovered in the 1950s by Rita Levi-Montalcini, first in a neoplastic tissue and, later, in the mouse salivary gland (see 1A). Levi-Montalcini characterized its action in the sensory and sympathetic neurons (1B) and, a few years later, in central nervous, endocrine, and immune systems. Nerve growth factor plays its trophic role both during development and in adulthood, ensuring the maintenance of phenotypic and functional characteristic of several populations of neurons as well as immune cells. The aim of the present overview is to describe my personal scientific and human experiences working with Rita Levi-Montalcini for over 45 years, first at Washington University in St. Louis, Missouri, USA, searching (1) the invertebrate neurotrophic factor in the cockroaches and, later, at the Institute of Neurobiology of the National Research Council (CNR) in Rome studying (2) the role of NGF for various neuronal and non-neuronal functions; (3) the potential involvement of NGF in the pathobiology of human cutaneous, ocular, neurodegenerative, and cardiometabolic diseases; and finally (4) NGF potential clinical application.

A low-cost computational approach to analyze spiking activity in cockroach sensory neurons.

Undergraduates use a spike sorting routine developed in Octave to analyze the spiking activity generated from mechanical stimulation of spines of cockroach legs with the inexpensive SpikerBox amplifier and the free software Audacity. Students learn the procedures involved in handling the cockroaches and recording extracellular action potentials (spikes) with the SpikerBox apparatus as well as the importance of spike sorting for analysis in neuroscience. The spike sorting process requires students to choose the spike threshold and spike selection criteria and interact with the clustering process that forms the groups of similar spikes. Once the spike groups are identified, interspike intervals and neuron firing frequencies can be calculated and analyzed. A classic neurophysiology lab exercise is thus adapted to be interdisciplinary for underrepresented students in a small rural college.

Diatomaceous Earth for Arthropod Pest Control: Back to the Future.

Nowadays, we are tackling various issues related to the overuse of synthetic insecticides. Growing concerns about biodiversity, animal and human welfare, and food security are pushing agriculture toward a more sustainable approach, and research is moving in this direction, looking for environmentally friendly alternatives to be adopted in Integrated Pest Management (IPM) protocols. In this regard, inert dusts, especially diatomaceous earths (DEs), hold a significant promise to prevent and control a wide range of arthropod pests. DEs are a type of naturally occurring soft siliceous sedimentary rock, consisting of the fossilized exoskeleton of unicellular algae, which are called diatoms. Mainly adopted for the control of stored product pests, DEs have found also their use against some household insects living in a dry environment, such as bed bugs, or insects of agricultural interest. In this article, we reported a comprehensive review of the use of DEs against different arthropod pest taxa, such as Acarina, Blattodea, Coleoptera, Diptera, Hemiptera, Hymenoptera, Ixodida, Lepidoptera, when applied either alone or in combination with other techniques. The mechanisms of action of DEs, their real-world applications, and challenges related to their adoption in IPM programs are critically reported.

Cockroaches are scarier than snakes and spiders: Validation of an affective standardized set of animal images (ASSAI).

Research on emotional processes has been closely related to the use of emotional stimuli, promoting the development of different standardized sets of images. However, some kinds of images that would be relevant in clinical psychology research are not available, especially for small animal phobias. The aim of the present study is to validate a set of animal images that includes images of cockroaches, which are not present in the current sets of images. Two hundred and forty images depicting five types of animals (cockroaches, spiders, snakes, cats, and butterflies) were collected from online public domains. Four hundred and twenty-four participants (72.9% women) took part in the study rating the images in two affective dimensions (i.e., valence and arousal). Cockroach pictures were rated as significantly more unpleasant than pictures of spiders, snakes, butterflies, and cats. Moreover, results revealed that women rated cockroach, spider, and snake pictures as more negative than men did. Also, women in comparison with men rated cockroach images as more arousing. The results highlight the importance of using images of cockroaches, due to their high negative valence, which even exceeds that of snakes and spiders, the unpleasant animals typically used in phobic research. This set of images can be useful in research on small-animal phobias.

Diet is not the primary driver of bacterial community structure in the gut of litter-feeding cockroaches.

BACKGROUND: Diet is a major determinant of bacterial community structure in termite guts, but evidence of its importance in the closely related cockroaches is conflicting. Here, we investigated the ecological drivers of the bacterial gut microbiota in cockroaches that feed on lignocellulosic leaf litter. RESULTS: The physicochemical conditions determined with microsensors in the guts of Ergaula capucina, Pycnoscelus surinamensis, and Byrsotria rothi were similar to those reported for both wood-feeding and omnivorous cockroaches. All gut compartments were anoxic at the center and showed a slightly acidic to neutral pH and variable but slightly reducing conditions. Hydrogen accumulated only in the crop of B. rothi. High-throughput amplicon sequencing of bacterial 16S rRNA genes documented that community structure in individual gut compartments correlated strongly with the respective microenvironmental conditions. A comparison of the hindgut microbiota of cockroaches and termites from different feeding groups revealed that the vast majority of the core taxa in cockroaches with a lignocellulosic diet were present also in omnivorous cockroaches but absent in wood-feeding higher termites. CONCLUSION: Our results indicate that diet is not the primary driver of bacterial community structure in the gut of wood- and litter-feeding cockroaches. The high similarity to the gut microbiota of omnivorous cockroaches suggests that the dietary components that are actually digested do not differ fundamentally between feeding groups.

Birth of an order: Comprehensive molecular phylogenetic study excludes Herpomyces (Fungi, Laboulbeniomycetes) from Laboulbeniales.

The class Laboulbeniomycetes comprises biotrophic parasites associated with arthropods and fungi. Two orders are currently recognized, Pyxidiophorales and Laboulbeniales. Herpomyces is an isolated genus of Laboulbeniales, with species that exclusively parasitize cockroaches (Blattodea). Here, we evaluate 39 taxa of Laboulbeniomycetes with a three-locus phylogeny (nrSSU, ITS, nrLSU) and propose a new order in this class. Herpomycetales accommodates a single genus, Herpomyces, with currently 26 species, one of which is described here based on morphological and molecular data. Herpomyces shelfordellae is found on Shelfordella lateralis cockroaches from Hungary, Poland, and the USA. We also build on the six-locus dataset from the Ascomycota Tree of Life paper (Schoch and colleagues, 2009) to confirm that Laboulbeniomycetes and Sordariomycetes are sister classes, and we apply laboulbeniomyceta as a rankless taxon for the now well-resolved node that describes the most recent common ancestor of both classes.

Reconstructed evolution of insulin receptors in insects reveals duplications in early insects and cockroaches.

Social insects show an extreme degree of phenotypic plasticity. In highly eusocial species, this manifests in the generation of distinct castes with extreme differences in both morphology and life span. The molecular basis of these differences is highly entangled and not fully understood, but several recent studies demonstrated that insulin/insulin-like growth factor signaling (IIS) is one of the key pathways. Here, we investigate the molecular evolution of insect insulin receptors (InRs), which are membrane-bound dimers that enable IIS by relaying extracellular signals to intracellular signaling cascades. Classic models of invertebrate IIS include only one InR gene, but some recent studies on less commonly studied insects have found two InRs, which act in an antagonistic manner to facilitate polyphenism in at least one documented case. We search 22 arthropod genomes and identify several InR copies and their evolutionary origin that were lacking from previous annotations. Phylogenetic analysis shows that the two insect InR genes date back at least 400 million years to a common ancestor of winged insects. Most notably, we also identified the evolutionary origin of a third InR copy that is unique to the clade of Blattodea, just before therein the eusocial termites evolved. One of the InR paralogs consistently shows caste-biased expression in all three termites, which strongly suggests a role in caste differentiation. These results have important ramifications for past and future InR inhibition/InR knockdown experiments in insects and they provide a set of key genes regulating life span and morphology in termite castes.

pH Alkalinization by Chloroquine Suppresses Pathogenic Burkholderia Type 6 Secretion System 1 and Multinucleated Giant Cells.

Burkholderia mallei and B. pseudomallei cause glanders and melioidosis, respectively, in humans and animals. A hallmark of pathogenesis is the formation of granulomas containing multinucleated giant cells (MNGCs) and cell death. These processes depend on type 6 secretion system 1 (T6SS-1), which is required for virulence in animals. We examined the cell biology of MNGC formation and cell death. We found that chloroquine diphosphate (CLQ), an antimalarial drug, inhibits Burkholderia growth, phagosomal escape, and subsequent MNGC formation. This depends on CLQ's ability to neutralize the acid pH because other alkalinizing compounds similarly inhibit escape and MNGC formation. CLQ inhibits bacterial virulence protein expression because T6SS-1 and some effectors of type 3 secretion system 3 (T3SS-3), which is also required for virulence, are expressed at acid pH. We show that acid pH upregulates the expression of Hcp1 of T6SS-1 and TssM, a protein coregulated with T6SS-1. Finally, we demonstrate that CLQ treatment of Burkholderia-infected Madagascar hissing cockroaches (HCs) increases their survival. This study highlights the multiple mechanisms by which CLQ inhibits growth and virulence and suggests that CLQ be further tested and considered, in conjunction with antibiotic use, for the treatment of diseases caused by Burkholderia.

Symbiogenesis: Beyond the endosymbiosis theory?

Symbiogenesis, literally 'becoming by living together', refers to the crucial role of symbiosis in major evolutionary innovations. The term usually is reserved for the major transition to eukaryotes and to photosynthesising eukaryotic algae and plants by endosymbiosis. However, in some eukaryote lineages endosymbionts have been lost secondarily, showing that symbiosis can trigger a major evolutionary innovation, even if symbionts were lost secondarily. This leads to the intriguing possibility that symbiosis has played a role in other major evolutionary innovations as well, even if not all extant representatives of such groups still have the symbiotic association. We evaluate this hypothesis for two innovations in termites (Termitoidae, also known informally as "Isoptera"): i) the role of flagellate gut protist symbionts in the transition to eusociality from cockroach-like ancestors, and ii) the role of non-gut associated symbionts in the transition to 'higher' termites, characterized by the absence of flagellate gut protists. In both cases we identify a crucial role for symbionts, even though in both cases, subsequently, symbionts were lost again in some lineages. We also briefly discuss additional possible examples of symbiogenesis. We conclude that symbiogenesis is more broadly applicable than just for the endosymbiotic origin of eukaryotes and photosynthetic eukaryotes, and may be a useful concept to acknowledge the important role of symbiosis for evolutionary innovation. However, we do not accept Lynn Margulis's view that symbiogenesis will lead to a paradigm shift from neoDarwinism, as the role of symbiosis in evolutionary change can be integrated with existing theory perfectly.

SwarmSight: Measuring the temporal progression of animal group activity levels from natural-scene and laboratory videos.

We describe SwarmSight (available at https://github.com/justasb/SwarmSight ), a novel, open-source, Microsoft Windows software tool for quantitative assessment of the temporal progression of animal group activity levels from recorded videos. The tool utilizes a background subtraction machine vision algorithm and provides an activity metric that can be used to quantitatively assess and compare animal group behavior. Here we demonstrate the tool's utility by analyzing defensive bee behavior as modulated by alarm pheromones, wild-bird feeding onset and interruption, and cockroach nest-finding activity. Although more sophisticated, commercial software packages are available, SwarmSight provides a low-cost, open-source, and easy-to-use alternative that is suitable for a wide range of users, including minimally trained research technicians and behavioral science undergraduate students in classroom laboratory settings.

Diversity of Trypanosomatids in Cockroaches and the Description of Herpetomonas tarakana sp. n.

In this study, we surveyed six species of cockroaches, two synanthropic (i.e. ecologically associated with humans) and four wild, for intestinal trypanosomatid infections. Only the wild cockroach species were found to be infected, with flagellates of the genus Herpetomonas. Two distinct genotypes were documented, one of which was described as a new species, Herpetomonas tarakana sp. n. We also propose a revision of the genus Herpetomonas and creation of a new subfamily, Phytomonadinae, to include Herpetomonas, Phytomonas, and a newly described genus Lafontella n. gen. (type species Lafontella mariadeanei comb. n.), which can be distinguished from others by morphological and molecular traits.

Sensitisation to mites and other animal-derived home aeroallergens in children and its concordance as a measure of covariation of sensitisation.

BACKGROUND: Sensitisation to home aeroallergens (mites, furry animals and cockroaches) is predominant in patients in our and other areas. Covariation of sensitisation (CS) to these allergens could be due to cross-reactivity or parallel sensitisation. METHODS: Skin prick tests were performed to common and second-line home aeroallergens, shrimp and tropomyosin in 253 paediatric patients seen in our Unit due to chronic respiratory symptoms. CS among the main allergens was analysed by means of Cohen's kappa coefficient of concordance (κ). RESULTS: House dust mites (HDM) were the main allergens involved in sensitisation, followed by furry animals, pollens, storage mites (SM), moulds and cockroaches. CS was very good between D. pteronyssinus and D. farinae (κ=0.81), and good between Dermatophagoides and Euroglyphus (κ=0.71), and decreased markedly to poor (κ<0.20) between HDM and SM or cockroaches. CS among SM and cockroaches was moderate to fair (κ=0.21-0.44). CS was good between shrimp and tropomyosin (κ=0.62), but null between shrimp-tropomyosin and HDM (κ=0.01-0.02), and poor to fair between shrimp-tropomyosin and SM or cockroaches (κ=0.06-0.34). CS between cat and dog was moderate (κ=0.50). CONCLUSIONS: We have shown the usefulness of κ in exploring CS in a population. In our area, with high sensitisation to HDM and other home allergens, CS is limited for most pairs of allergens, pointing to a lower incidence of cross-reactivity than could be expected, especially between HDM and SM or other invertebrates.

Parent and halogenated polycyclic aromatic hydrocarbons in farmed cockroaches and implications for human exposure.

Medicinal insects have been widely used to cure human diseases for ages. Nevertheless, knowledge about the toxic chemicals accumulated in medicinal insects and their effects on human health was insufficient. In the present study, sixteen priority polycyclic aromatic hydrocarbons (PAHs) and nine halogenated PAHs (HPAHs) were determined in farmed medicinal cockroaches to address this issue. Total concentrations of PAHs in young nymphs, old nymphs, and adults ranged from 162 to 1025, 252 to 967, and 267 to 1168 ng/g, respectively. Levels of the sum of HPAHs varied from 0.84 to 9.17, 1.86 to 5.21, and 1.01 to 8.60 ng/g for young nymphs, old nymphs, and adults, respectively. The daily intake and excess cancer risk of PAHs and HPAHs were calculated for people who take cockroach-related drugs. Our results indicated that females and children have slightly higher exposure levels from the perspectives of gender and age, respectively. The estimated excess cancer risk of PAHs and HPAHs were both lower than the priority risk level (10(-4)), indicating a low potential carcinogenic risk with the medicinal cockroach consumption.

Transmission of antimicrobial resistance in the gut microbiome of gregarious cockroaches: the importance of interaction between antibiotic exposed and non-exposed populations.

Antimicrobial resistance (AMR) is a major global health concern, further complicated by its spread via the microbiome bacterial members. While mathematical models discuss AMR transmission through the symbiotic microbiome, experimental studies are scarce. Herein, we used a gregarious cockroach, Pycnoscelus surinamensis, as an in vivo animal model for AMR transmission investigations. We explored whether the effect of antimicrobial treatment is detectable with metagenomic sequencing, and whether AMR genes can be spread and established in unchallenged (not treated with antibiotics) individuals following contact with treated donors, and under various frequencies of interaction. Gut and soil substrate microbiomes were investigated by metagenomic sequencing for bacterial community composition and resistome profiling. We found that tetracycline treatment altered the treated gut microbiome by decreasing bacterial diversity and increasing the abundance of tetracycline resistance genes. Untreated cockroaches that interacted with treated donors also had elevated tetracycline resistance. The levels of resistance differed depending on the magnitude and frequency of donor transfer. Additionally, treated donors showed signs of microbiome recovery due to their interaction with the untreated ones. Similar patterns were also recorded in the soil substrate microbiomes. Our results shed light on how interacting microbiomes facilitate AMR gene transmission to previously unchallenged hosts, a dynamic influenced by the interaction frequencies, using an in vivo model to validate theoretical AMR transmission models.IMPORTANCEAntimicrobial resistance is a rising threat to human and animal health. The spread of resistance through the transmission of the symbiotic gut microbiome is of concern and has been explored in theoretical modeling studies. In this study, we employ gregarious insect populations to examine the emergence and transmission of antimicrobial resistance in vivo and validate modeling hypotheses. We find that antimicrobial treatment increases the levels of resistance in treated populations. Most importantly, we show that resistance increased in untreated populations after interacting with the treated ones. The level of resistance transmission was affected by the magnitude and frequency of population mixing. Our results highlight the importance of microbial transmission in the spread of antimicrobial resistance.