Bedbugs evolved before their bat hosts and did not co-speciate with ancient humans

All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]

The discovery of novel coronaviruses in bat guano, Sarawak, Malaysian Borneo

Purpose Virological surveillance was conducted in to determine the presence of bat CoVs in the bat population in Wind Cave Nature Reserve, Sarawak, Malaysian Borneo. Methods & Materials Partial RNA dependent RNA polymerase (RdRp) gene sequences of 11 bat-CoV positive guano collected in Wind Cave Nature Reserve was analysed. Five pellets of fresh guano from insectivorous bats were collected on plastic tarp and pooled in 500uL of ice-cold viral transport medium. The 440-bp gene was amplified using family-wide hemi-nested RT-PCR for phylogenetic analysis. Amplicon sequences were analysed using Basic Local Alignment Search Tool software (BLAST) to determine their corresponding species. Sequence alignment was carried out without primer sequence and phylogenetic tree with Maximum Likelihood bootstrap-Bayesian inference value (MLb/PPv) support. Results The positive rate was 47.6% (10/21) with the distribution of 60% (n=6/10) and 40% (n=4/10) Alpha and Beta-coronaviruses respectively. BatCoVs identified in this study formed four novel monophyletic clades referred to as Borneo Alpha-1 and -2, and Borneo Beta-1 and -2. Borneo Alpha-1 and -2 viruses diverged to form a monophyletic clade with Decacovirus-1 and Decacovirus-2 respectively (83.0-85.1% and 80.7-81.0% nucleotide identity) with batCoV found in Sabah (NCBI Accession# KX284940). Borneo Beta-1 viruses are also closely related to BatCoV found in Sabah (KX284939) (86.5-87.5% nt identity), forming a monophyletic group with Sarbecovirus. Meanwhile, Borneo Beta-2 are closer to BatCoVs in Loas (MN312609) (89.7-90.4% nt identity), forming a monophyletic clade with Hibecovirus. It is worthy to note that viruses found in the Sarbecovirus subgenus such as SARS-CoV-1 and SARS-CoV-2 attributed to two zooneses with Public Health Emergency of International Concern (PHEIC) over the past two decades. However, Borneo Beta-1 viruses are distant to the RaTG13 (MN996532) (69.1-697% nt identity), the proposed progenitor of the pandemic SARS-CoV-2. Conclusion The study has discovered both novel alpha and beta bat-coronaviruses in 40% of the guano sampled in Wind Cave Nature Reserve, Sarawak, East Malaysia based on the phylogeny of the partial RdRp gene sequence. The batCoVs are phylogenetically grouped into four clades via phylogeny confirms the presence of Borneo Beta-1 clade being monophyletic to the epidemic Sarbecoviruses