Descriptions of three congeneric species of chewing lice of the Oxylipeurus-complex (Insecta: Phthiraptera: Philopteridae) from the turkey, Meleagris gallopavo, including a new genus and a new species

The lice of the Oxylipeurus-complex parasitising the turkey, Meleagris gallopavo, belong to a previously undescribed genus. In this paper, we describe this genus as Valimia new genus, redescribe two of its species: Lipeurus polytrapezius Burmeister, 1838 and Oxylipeurus corpulentus Clay, 1938, and describe the new species Valimia necopinata, discovered during our examination of samples of the two known species. This occurrence represents the first record of three congeneric species of chewing lice parasitising the same host individual.

Six new and one little known species of chigger mites (Acariformes: Trombiculidae) from South Africa

Six new chigger mite species were described from rodents of South Africa: Ascoschoengastia ueckermanni sp. nov., Schoutedenichia horaki sp. nov., Herpetacarus octosetosus sp. nov., Herpetacarus decasetosus sp. nov., Microtrombicula graphiuri sp. nov. and Trombicula walkerae sp. nov. The genus Trombicula Berlese, 1905 sensu stricto, which is known from South Asia and Australia, is recorded on the African continent for the first time. Two new species of Herpetacarus Vercammen-Grandjean, 1960 present an example of closely related sympatric chigger species that occur on the same host individual.

The Gills of Reef Fish Support a Distinct Microbiome Influenced by Host-Specific Factors

ABSTRACT Teleost fish represent the most diverse of the vertebrate groups and play important roles in food webs, as ecosystem engineers, and as vectors for microorganisms. However, the microbial ecology of fishes remains underexplored for most host taxa and for certain niches on the fish body. This is particularly true for the gills, the key sites of respiration and waste exchange in fishes. Here we provide a comprehensive analysis of the gill microbiome. We focus on ecologically diverse taxa from coral reefs around Moorea, sampling the gills and intestines of adults and juveniles representing 15 families. The gill microbiome composition differed significantly from that of the gut for both adults and juveniles, with fish-associated niches having lower alpha diversity values and higher beta diversity values than those for seawater, sediment, and alga-associated microbiomes. Of ∼45,000 operational taxonomic units (OTUs) detected across all samples, 11% and 13% were detected only in the gill and the intestine, respectively. OTUs most enriched in the gill included members of the gammaproteobacterial genus Shewanella and the family Endozoicimonaceae . In adult fish, both gill and intestinal microbiomes varied significantly among host species grouped by diet category. Gill and intestinal microbiomes from the same individual were more similar to one another than to gill and intestinal microbiomes from different individuals. These results demonstrate that distinct body sites are jointly influenced by host-specific organizing factors operating at the level of the host individual. The results also identify taxonomic signatures unique to the gill and the intestine, confirming fish-associated niches as distinct reservoirs of marine microbial diversity. IMPORTANCE Fish breathe and excrete waste through their gills. The gills are also potential sites of pathogen invasion and colonization by other microbes. However, we know little about the microbial communities that live on the gill and the factors shaping their diversity. Focusing on ecologically distinct types of coral reef fish, we provide a comprehensive analysis of the fish gill microbiome. By comparison to microbiomes of the gut and the surrounding environment, we identify microbes unique to the gill niche. These microbes may be targets for further studies to determine the contribution of the microbiome to waste exchange or host immunity. We also show that despite exhibiting a unique taxonomic signature, the gill microbiome is influenced by factors that also influence the gut microbiome. These factors include the specific identity of the host individual. These results suggest basic principles describing how association with fishes structures the composition of microbial communities.

The distribution of digenean metacercariae within bream (Abramis brama) gill apparatus: preferences, co-occurrence and interactions of parasites

Species-specific microenvironmental preferences and interactions between parasite species have been the focus of many ecological studies. Here, we studied the distribution of ectoparasite species within the gill apparatus of bream (Abramis brama) from Lake Lubāns (Latvia) to establish whether digenean metacercariae: (1) prefer specific patches within the gill apparatus; (2) co-occur in the same patches with monogeneans and copepods within a host individual; and (3) interact with monogeneans and copepods. We recorded all parasites on gill arches of the same host species and used null models to analyse co-occurrences of digenean metacercariae, monogeneans and copepods. Zero-inflated mixture models were used to define the preferred patches of parasites. We found that digenean metacercariae (Bucephalus polymorphus) prefer specific patches of the gill apparatus to encyst, and shared these preferences with monogeneans and copepods, but did not interact with them. We concluded that digenean metacercariae have a species-specific microenvironmental preference to encyst in the gill apparatus and their occurrence (even in high numbers) does not reduce the success of attachment of monogeneans and copepods in the same gill patches.

Linking parasite populations in hosts to parasite populations in space through Taylor's law and the negative binomial distribution

The spatial distribution of individuals of any species is a basic concern of ecology. The spatial distribution of parasites matters to control and conservation of parasites that affect human and nonhuman populations. This paper develops a quantitative theory to predict the spatial distribution of parasites based on the distribution of parasites in hosts and the spatial distribution of hosts. Four models are tested against observations of metazoan hosts and their parasites in littoral zones of four lakes in Otago, New Zealand. These models differ in two dichotomous assumptions, constituting a 2 × 2 theoretical design. One assumption specifies whether the variance function of the number of parasites per host individual is described by Taylor's law (TL) or the negative binomial distribution (NBD). The other assumption specifies whether the numbers of parasite individuals within each host in a square meter of habitat are independent or perfectly correlated among host individuals. We find empirically that the variance–mean relationship of the numbers of parasites per square meter is very well described by TL but is not well described by NBD. Two models that posit perfect correlation of the parasite loads of hosts in a square meter of habitat approximate observations much better than two models that posit independence of parasite loads of hosts in a square meter, regardless of whether the variance–mean relationship of parasites per host individual obeys TL or NBD. We infer that high local interhost correlations in parasite load strongly influence the spatial distribution of parasites. Local hotspots could influence control and conservation of parasites.

Infracommunity dynamics of chiggers (Trombiculidae) parasitic on a rodent

SUMMARYWe studied the structure of chigger mite (Trombiculidae) communities parasitic on a South African rodent, Rhabdomys pumilio. We aimed to determine whether: (a) different chigger species differ in preferences for certain body areas of a host and (b) chigger assemblages among body areas of the same host individual, are structured and if so, whether the structure of these assemblages is aggregative or segregative. Rhabdomys pumilio is parasitized by seven chigger species belonging to six genera. The three most abundant species (Leptotrombidium sp. nr. muridium, Schoutedenichia sp. and Neoschoengastia sp. A) displayed a non-random distribution across the host body, with the two most abundant species (L. sp. nr. muridium and Schoutedenichia sp.) significantly associated with the tail area. In addition, whenever non-randomness of chigger co-occurrence in the same body area was recorded, it indicated positive but not negative co-occurrences of different species. This might be due to similarity of chigger species in resource needs and strategies to avoid host defence efforts.

Host preferences of bat flies: following the bloody path of stable isotopes in a host–parasite food chain

Almost all mammals are infested with ectoparasites, but even though parasites may have a strong impact on their host, their host specificity is often unknown. We studied the host preferences of two bat fly species, Strebla wiedemanni Kolenati, 1856 and Trichobius parasiticus Gervais, 1844, identified on the common vampire bat, Desmodus rotundus (E. Geoffroy, 1810), using stable carbon isotopes. Since D. rotundus was part of the C4 food web and other bats sharing the roost with D. rotundus were part of the C3 food web, bat flies were exposed to two isotopically distinct potential hosts. The δ13C values of the two bat fly species collected from D. rotundus were similar (–11.5‰ ± 1.1‰ (mean ± SD) for S. wiedemanni and –12.4‰ ± 1.9‰ for T. parasiticus) and identified them as members of the C4 food web, although their δ13C value was significantly lower by –1.7‰ ± 2.6‰ than that of the corresponding host individual. The δ13C value of bat flies collected from Carollia perspicillata (L., 1758) sharing roosts with D. rotundus averaged –24.2‰ ± 0.3‰, which was also significantly lower by –1.3‰ ± 1.1‰ than the host's δ13C value. We concluded that the negative shift in δ13C of D. rotundus bat flies relative to the host individual was caused by isotopic fractionation rather than by a mixed diet. The enrichment in nitrogen-15 from S. wiedemanni and T. parasiticus to D. rotundus equaled 2.3‰, which indicates one trophic step between the host and the parasite. In summary, both bat fly species preferred D. rotundus over other bat species and are therefore truly monoxenous parasites.