Data from: The cotton stainer’s gut microbiota suppresses infection of a co-transmitted trypanosomatid parasite

The evolutionary and ecological success of many insects is attributed to mutualistic partnerships with bacteria that confer hosts with novel traits including food digestion, nutrient supplementation, detoxification of harmful compounds and defense against natural enemies. Dysdercus fasciatus firebugs (Hemiptera: Pyrrhocoridae), commonly known as cotton stainers, possess a simple but distinctive gut bacterial community including B-vitamin supplementing Coriobacteriaceae symbionts. In addition, their guts are often infested with the intestinal trypanosomatid parasite Leptomonas pyrrhocoris (Kinetoplastida: Trypanosomatidae). In this study, using experimental bioassays and fluorescence in situ hybridization (FISH), we report on the protective role of the D. fasciatus gut bacteria against L. pyrrhocoris. We artificially infected 2nd instars of dysbiotic and symbiotic insects with a parasite culture and measured parasite titers, developmental time and survival rates. Our results show that L. pyrrhocoris infection increases developmental time and slightly modifies the quantitative composition of the gut microbiota. More importantly, we found significantly higher parasite titers and a tendency towards lower survival rates in parasite infected dysbiotic insects compared to symbiotic controls, indicating that the gut bacteria successfully interferes with the establishment or proliferation of L. pyrrhocoris. The colonization of symbiotic bacteria on the peritrophic matrix along the gut wall, as revealed by FISH, likely acts as a barrier blocking parasite attachment or entry into the peritrophic matrix. Our findings show that in addition to being nutritionally important, D. fasciatus’ gut bacteria complement the host’s immune system in preventing parasite invasions and that a stable gut microbial community is integral for the host’s health

Symbiont transmission entails the risk of parasite infection

Like many animals, firebugs (Hemiptera, Pyrrhocoridae) rely on behavioural adaptations to successfully endow their offspring with microbial mutualists. To transmit the nutritionally beneficial Coriobacteriaceae symbionts, female firebugs smear egg surfaces with symbiont-containing faecal droplets that are subsequently ingested by newly hatched nymphs through active probing to initiate infection. Alternatively, the symbionts can be acquired horizontally through contact with faeces of infected conspecifics. Here, we report that these adaptations ensuring successful transmission of bacterial symbionts among firebugs are exploited by the specialized trypanosomatid parasite Leptomonas pyrrhocoris. Using comparative transcriptomics, fluorescence in situ hybridization (FISH) and controlled bioassays, we demonstrate that the transmission cycle of L. pyrrhocoris mirrors that of the bacterial mutualists, with high efficiency for both vertical and horizontal transmission. This indicates that the parasite capitalizes on pre-existing behavioural adaptations (egg smearing and probing) to facilitate its own transfer within host populations, adaptations that likely evolved to initiate and maintain an association with beneficial gut symbionts. Thus, the transmission of mutualistic microbes across host generations can entail a significant risk of co-transmitting pathogens or parasites, thereby exerting selective pressures on the host to evolve more specific mechanisms of transfer

Dysdercus developmental success and microbiota composition upon parasite infection

Developmental times, survivorship, parasite and symbiont titers (qPCR), and microbiota composition (Illumina 16S microbiota profiling) of symbiotic (S+) and dysbiotic (S-) Dysdercus fasciatus with (P+) and without (P-) infection by the trypanosomatid parasite Leptomonas pyrrhocoris, respectively

Dysdercus microbiota profiling data (with and without parasite infection)

Raw Illumina sequencing reads, QIIME2 analysis pipeline, and output files (OTU table, representative sequence set) for bacterial community profiling of symbiotic Dysdercus fasciatus, infected or not with Leptomonas pyrrhocoris trypanosomes

Vertical transmission of naturally occurring Bunyamwera and insect-specific flavivirus infections in mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in Kenya.

BackgroundMany arboviruses transmitted by mosquitoes have been implicated as causative agents of both human and animal illnesses in East Africa. Although epidemics of arboviral emerging infectious diseases have risen in frequency in recent years, the extent to which mosquitoes maintain pathogens in circulation during inter-epidemic periods is still poorly understood. This study aimed to investigate whether arboviruses may be maintained by vertical transmission via immature life stages of different mosquito vector species.MethodologyWe collected immature mosquitoes (egg, larva, pupa) on the shores and islands of Lake Baringo and Lake Victoria in western Kenya and reared them to adults. Mosquito pools (≤25 specimens/pool) of each species were screened for mosquito-borne viruses by high-resolution melting analysis and sequencing of multiplex PCR products of genus-specific primers (alphaviruses, flaviviruses, phleboviruses and Bunyamwera-group orthobunyaviruses). We further confirmed positive samples by culturing in baby hamster kidney and Aedes mosquito cell lines and re-sequencing.Principal findingsCulex univittatus (2/31pools) and Anopheles gambiae (1/77 pools) from the Lake Victoria region were positive for Bunyamwera virus, a pathogenic virus that is of public health concern. In addition, Aedes aegypti (3/50), Aedes luteocephalus (3/13), Aedes spp. (2/15), and Culex pipiens (1/140) pools were positive for Aedes flaviviruses at Lake Victoria, whereas at Lake Baringo, three pools of An. gambiae mosquitoes were positive for Anopheles flavivirus. These insect-specific flaviviruses (ISFVs), which are presumably non-pathogenic to vertebrates, were found in known medically important arbovirus and malaria vectors.ConclusionsOur results suggest that not only ISFVs, but also a pathogenic arbovirus, are naturally maintained within mosquito populations by vertical transmission, even in the absence of vertebrate hosts. Therefore, virus and vector surveillance, even during inter-epidemics, and the study of vector-arbovirus-ISFV interactions, may aid in identifying arbovirus transmission risks, with the potential to inform control strategies that lead to disease prevention

Localisation and tissue tropism of the symbiont Microsporidia MB in the germ line and somatic tissues of Anopheles arabiensis

The dataset contains Microsporidia MB infection rates and intensities under different experimental investigations i.e., age, diet, developmental stage, and sex of the mosquito.The data was collected by conducting experimental investigations using lab-raised Microsporidia MB infected offspring of field-collected Anopheles arabiensis mosquitoes. Each experiment included biological replicates. Microsporidia MB infections and intensities were determined using PCR and qPCR.</p