Sexually transmitted diseases (STDs) of insects are known from the mites, nematodes, fungi, protists and viruses. In total 73 species of parasite and pathogen from approximately 182 species of host have been reported. Whereas nearly all vertebrate STDs are viruses or bacteria, the majority of insect STDs are multicellular ectoparasites, protistans or fungi. Insect STDs display a range of transmission modes, with‘ pure’sexual transmission only described from ectoparasites, all of which are mites, fungi or nematodes, whereas the microparasitic endo‐parasites tend to show vertical as well as sexual transmission. The distribution of STDs within taxa of insect hosts appears to be related to the life histories of the hosts. In particular, STDs will not be able to persist if host adult generations do not overlap unless they are also transmitted by some alternative route. This explains the observation that the Coleoptera seem to suffer from more STDs than other insect orders, since they tend to diapause as adults and are therefore more likely to have overlapping generations of adults in temperate regions.STDs of insects are often highly pathogenic, and are frequently responsible for sterilizing their hosts, a feature which is also found in mammalian STDs. This, combined with high prevalences indicates that STDs can be important in the evolution and ecology of their hosts. Although attempts to demonstrate mate choice for unin‐fected partners have so far failed it is likely that STDs have other effects on host mating behaviour, and there is evidence from a few systems that they might manipulate their hosts to cause them to mate more frequently. STDs may also play a part in sexual conflict, with males in some systems possibly gaining a selective advantage from transmitting certain STDs to females.STDs may well be important factors in host population dynamics, and some have the potential to be useful biological control agents, but empirical studies on these subjects are lacking.

The diversity of endosymbiotic bacteria that kill male host offspring during embryogenesis and their frequencies in certain groups of host taxa suggest that the evolution of male killing and the subsequent spread of male-killing symbionts are primarily determined by host life history characteristics. We studied the 10-spot ladybird beetle,Adalia decempunctataL. (Coleoptera: Coccinellidae), in which male killing has not been recorded previously, to test this hypothesis, and we also assessed the evolution of the male killer identified by DNA sequence analysis. Our results show thatA. decempunctataharbors male-killingRickettsia(α-proteobacteria). Male-killing bacteria belonging to the genusRickettsiahave previously been reported only for the congeneric two-spot ladybird beetle,Adalia bipunctataL. Phylogenetic analysis ofRickettsiaDNA sequences isolated from different populations of the two host species revealed a single origin of male killing in the genusRickettsia. The data also indicated possible horizontal transfer of symbionts between host species. In addition,A. bipunctatais known to bear at least four different male-killing symbionts in its geographic range two of which coexist in the two locations from whichA. decempunctataspecimens were obtained for the present study. Since only a single male-killing taxon was found inA. decempunctata, we assume that the two closely related ladybird beetle species must differ in the number and/or geographic distribution of male killers. We discuss the importance of these findings to our understanding of the evolution and dynamics of symbiotic associations between male-killing bacteria and their insect hosts.

With the invention of the electronic stethoscope and other similar recording and data logging devices, acoustic signal processing concepts and methods can now be applied to bowel sounds. In this paper, the literature pertaining to acoustic signal processing for bowel sound analysis is reviewed and discussed. The article outlines some of the fundamental approaches and machine learning principles that may be used in bowel sound analysis. The advances in signal processing techniques that have allowed useful information to be obtained from bowel sounds from an historical perspective is provided. The document specifically address the progress in bowel sound analysis, such as improved noise reduction, segmentation, signal enhancement, feature extraction, localisation of sounds, and machine learning techniques. We have found that advanced acoustic signal processing incorporating novel machine learning methods and artificial intelligence can lead to better interpretation of acoustic information emanating from the bowel.

1 We know that sexually transmitted parasites and pathogens have extremely deleterious effects in human and domesticated animal populations, but know little of sexually transmitted diseases (STDs) in natural populations. 2 One previously reported natural system is the sexually transmitted mite, Coccipolipus hippodamiae, on the eastern European coccinellid, Adalia bipunctata. Our aims were to determine how widespread this parasite is in terms of incidence and prevalence across host species, to identify the causes of the prevalence pattern and whether the parasite reduces fertility in all host species. 3 Coccipolipus hippodamiae was present on four of 19 European species examined. The wide distribution and high prevalence of C. hippodamiae on A. bipunctata indicates that this is the major host. The mite was also present at substantial prevalence on Adalia decempunctata and at lower prevalence on Synharmonia (=Oenopia) conglobata and Calvia quatuordecimguttata. 4 Laboratory studies on mite development time and transmission efficiency revealed that although physiological factors may affect incidence, they do not explain prevalence variation between hosts, but characteristics of host life history and reproductive behaviour are important in this context. Adalia bipunctata is more promiscuous than the less commonly infected A. decempunctata and S. conglobata. Diapause is needed before breeding will occur in C. quatuordecimguttata, leading to a lack of the consistent sexual activity between generations, which is needed for STD maintenance. Calvia quatuordecimguttata is probably periodically reinfected through hybrid matings with other host species. 5 Coccipolipus hippodamiae infection has similar strong deleterious effects on female reproduction in A. decempunctata and S. conglobata as have previously been demonstrated in A. bipunctata. 6 The results indicate that STDs may play a profound role in the ecology of promiscuous insect populations with overlapping generations. Here they may reach significant prevalence whilst exhibiting extreme virulence.

Gastrointestinal (GI) conditions are highly prevalent, and their standard diagnostic tests are costly and carry risks. There is a need for new, cost-effective, non-invasive tests. Our main objective was to assess the potential for use of bowel sounds computerised analysis in the diagnosis of GI conditions. The systematic review followed the PRISMA requirements. Searches were made of four databases (PubMed, MEDLINE, Embase, and IEEE Xplore) and the references of included papers. Studies of all types were included. The titles and abstracts were screened by one author. Full articles were reviewed and data collected by two authors independently. A third reviewer decided on inclusion in the event of disagreement. Bias and applicability were assessed via a QUADAS tool adapted to accommodate studies of multiple types. Two thousand eight hundred eighty-four studies were retrieved; however, only 14 studies were included. Most of these simply assessed associations between a bowel sound feature and a condition. Four studies also included assessments of diagnostic accuracy. We found many significant associations between a bowel sound feature and a GI condition. Receiver operating characteristic curve analyses revealed high sensitivity and specificity for an irritable bowel syndrome test, and a high negative predictive value for a test for post-operative ileus. Assessment of methodological quality identified weaknesses in all studies. We particularly noted a high risk of bias in patient selection. Because of the limited number of trials included and the variety in conditions, technology, and statistics, we were unable to conduct pooled analyses. Due to concerns over quality and small sample sizes, we cannot yet recommend an existing BSCA diagnostic test without additional studies. However, the preliminary results found in the included studies and the technological advances described in excluded studies indicate excellent future potential. Research combining sophistical clinical and engineering skills is likely to be fruitful. The review protocol (review ID number 42016054028) was developed by three authors (AI, KMW, and JM) and was published in the PROSPERO International prospective register of systematic reviews. It can be accessed from https://www.crd.york.ac.uk/PROSPERO/ .