Microbiota and the volatile profile of avian nests are associated with each other and with the intensity of parasitism.

Bacteria have been suggested as being partially responsible for avian nest odours and, thus, volatiles from their metabolism could influence the intensity of selection pressures due to parasites detecting olfactory cues of their hosts. Here, we tested this hypothesis by exploring intraspecific and interspecific variability in microbial environments, volatile profiles and intensity of ectoparasitism by Carnus hemapterus in the nests of 10 avian species. As expected, we found that (i) alpha and beta diversity of microbial and volatile profiles were associated with each other. Moreover, (ii) alpha diversity of bacteria and volatiles of the nest environment, as well as some particular bacteria and volatiles, was associated with the intensity of parasitism at early and late stages of the nestling period. Finally, (iii) alpha diversity of the nest microbiota, as well as some particular bacteria and volatiles, was correlated with fledging success. When considering them together, the results support the expected links between the microbial environment and nest odours in different bird species, and between the microbial environment and both ectoparasitism intensity and fledging success. Relative abundances of particular volatiles and bacteria predicted ectoparasitism and/or fledging success. Future research should prioritise experimental approaches directed to determine the role of bacteria and volatiles in the outcomes of host-ectoparasite interactions.

First report of parasitism by Eutrichophilus cercolabes (Phthiraptera: Trichodectidae) on Coendou spinosus (Erethizontidae) in Rio Grande do Sul, Brazil - case report.

Coendou spinosus is a species of rodent popularly known as porcupine, it has a great ability to adapt to different habitats and is found in tropical forests in countries such as Bolivia, Brazil, Venezuela and Guianas. This mammal has already been identified as a reservoir of several pathogenic agents for humans and other animals and has a variety of ectoparasites, endoparasites and hemoparasites little studied and described. Due to this, the objective was to report the parasitism by Eutrichophilus cercolabes in C. spinosus in the central region of Rio Grande do Sul, southern Brazil. In total, 16 lice were found, one male and 15 females of the species. This is the first report of the parasitism of this Phthiraptera on C. spinosus in Rio Grande do Sul. The scarcity of reports on the taxonomy and biotic characteristics, as well as the vector capacity of pathogens of most species of ectoparasites of wild animals, highlights the need for further studies on the distribution of these arthropods in different regions and host species.

Coendou spinosus é uma espécie de roedor conhecida popularmente por porco-espinho, possui uma grande capacidade de adaptação a diferentes habitats sendo encontrada em florestas tropicais de países como Bolívia, Brasil, Venezuela e Guianas. Esse mamífero já foi identificado como reservatório de vários agentes patogênicos para o homem e outros animais e possui uma variedade de ectoparasitos, endoparasitos e hemoparasitos pouco estudados e descritos. Devido a isso, objetivou-se relatar o parasitismo por Eutrichophilus cercolabes em C. spinosus na região central do Rio Grande do Sul, Sul do Brasil. Ao total, foram encontrados 16 piolhos, sendo um macho e 15 fêmeas da espécie. Esse é o primeiro relato do parasitismo deste Phthiraptera em C. spinosus no Rio Grande do Sul. A escassez de relatos sobre a taxonomia e características bióticas, bem como a capacidade vetorial de patógenos da maioria das espécies de ectoparasitos de animais silvestres evidencia a necessidade da realização de mais estudos sobre a distribuição desses artrópodes em diferentes regiões e espécies hospedeiras.

Tropical bat ectoparasitism in continuous versus fragmented forests: A gap analysis and preliminary meta-analysis.

Tropical regions are experiencing rapid rates of forest fragmentation, which can have several effects on wildlife, including altered parasite dynamics. Bats are a useful host group to consider the effects of fragmentation, because they are abundant in the tropics, serve important ecological roles, and harbor many parasites. Nevertheless, research on the effects of fragmentation on bat ectoparasites is still limited. To help guide ongoing and future research efforts, this study had two objectives: (1) conduct a gap analysis to characterize the state of currently available research on fragmentation effects on bat ectoparasites and (2) conduct a preliminary meta-analysis to identify current trends. We systematically highlighted several research gaps: Studies comparing the effects of fragmented versus continuous forests on ectoparasites are limited and have primarily been conducted in the Neotropics, with a focus on bats in the superfamily Noctilionidea (especially frugivorous phyllostomids). Our preliminary meta-analysis suggested that ectoparasite prevalence (but not the mean or variance in intensity) was higher in fragments than in continuous forests. Moreover, prevalence increased with increasing roost duration, and mean intensity was higher for bats with higher wing aspect ratios. Intensity variance was affected by an interaction between forest type and wing aspect ratio, such that variance increased for bats with high-wing aspect ratios in continuous forests but decreased in fragments. These results suggest that fragmentation can shape aspects of bat ectoparasitism and could have implications for the ecology, health, and conservation of bats in fragmented landscapes. However, existing research gaps could bias our current understanding of habitat change and bat health, and future research should thus investigate these effects in the Paleotropics and with other bat families.

A unique case of commensalism: The beaver beetle Platypsyllus castoris (Leiodidae, Coleoptera) and its morphological adaptations.

Platypsyllus castoris is closely associated with beavers and displays a unique set of structural specializations. We document the morphology of adults with modern techniques, and interpret evolutionary changes linked with the specific life style. The small subfamily Platypsyllinae has evolved an entire suite of features correlated with a more or less close association with mammals, for instance a flattened body, a dorsal cephalic shield, flightlessness, eye reduction, and depigmentation. Within this small group, Platypsyllus displays numerous autapomorphic features, correlated with a close association with the beaver. Essential is a combination of mechanical stabilization and firm anchorage on the host, and efficient forward movement in the fur. Exo- and endoskeletal structures of the head and thorax are reinforced by vertical cuticular columns and by an array of internal ridges. The antennae are shortened and strongly modified, the mandibles distinctly reduced and flattened, unsuitable for cutting, scraping or grinding. The musculature of the mouthparts is simplified, whereas an enhanced set of prepharyngeal and pharyngeal dilators forms an efficient sucking pump. The prothoracic musculature is strongly developed. In contrast, the pterothoracic muscle system is distinctly simplified, even though leg muscles are strongly developed. Using the legs, the flattened beetles move sideways through the dense fur of the beaver, using posteriorly directed groups of setae and ctenidia to prevent being pushed backwards by the densely arranged hairs. In contrast to the anterior body, the cuticle of the abdomen is thin, and the entire tagma flexible, with thin layers of segmental muscles. The hind gut is not connected with the mid gut. The beetles probably consume liquid, possibly with emulgated minute skin debris. As the morphology of the mouthparts excludes damage to the skin of the host, the association should not be addressed as ectoparasitic but as commensalism.

CAUSE OF DEATH, PATHOLOGY, AND CHRONIC WASTING DISEASE STATUS OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) MORTALITIES IN WISCONSIN, USA.

White-tailed deer (WTD; Odocoileus virginianus) are a critical species for ecosystem function and wildlife management. As such, studies of cause-specific mortality among WTD have long been used to understand population dynamics. However, detailed pathological information is rarely documented for free-ranging WTD, especially in regions with a high prevalence of chronic wasting disease (CWD). This leaves a significant gap in understanding how CWD is associated with disease processes or comorbidities that may subsequently alter broader population dynamics. We investigated unknown mortalities among collared WTD in southwestern Wisconsin, USA, an area of high CWD prevalence. We tested for associations between CWD and other disease processes and used a network approach to test for co-occurring disease processes. Predation and infectious disease were leading suspected causes of death, with high prevalence of CWD (42.4%; of 245 evaluated) and pneumonia (51.2%; of 168 evaluated) in our sample. CWD prevalence increased with age, before decreasing among older individuals, with more older females than males in our sample. Females were more likely to be CWD positive, and although this was not statistically significant when accounting for age, females were significantly more likely to die with end-stage CWD than males and may consequently be an underrecognized source of CWD transmission. Presence of CWD was associated with emaciation, atrophy of marrow fat and hematopoietic cells, and ectoparasitism (lice and ticks). Occurrences of severe infectious disease processes clustered together (e.g., pneumonia, CWD), as compared to noninfectious or low-severity processes (e.g., sarcocystosis), although pneumonia cases were not fully explained by CWD status. With the prevalence of CWD increasing across North America, our results highlight the critical importance of understanding the potential role of CWD in favoring or maintaining disease processes of importance for deer population health and dynamics.

Parasitoid impairment on the galling Lopesia sp. activity reflects on the cytological and histochemical profiles of the globoid bivalve-shaped gall on Mimosa gemmulata.

Gall cytological and histochemical features established by the constant feeding activity of the associated gall inducer may be changed due to the attack of parasitoids. We accessed two tri-trophic systems involving the globoid bivalve-shaped gall on Mimosa gemmulata Barneby (Fabaceae) and its galling undescribed species of Lopesia (Diptera: Cecidomyiidae), which may be ectoparasitized by Torymus sp. (Hymenoptera: Torymidae) or endoparasitized by a polyembryonic Platygastridae (Hymenoptera), as models of study. The ectoparasitoid species paralyzes and kills Lopesia sp. larva, which stops the feeding stimuli, while the endoparasitoid larvae feed in Lopesia sp. larva body and keep it alive for a certain time. Our hypothesis is that the time lapse of Lopesia sp. feeding impairment by the two parasitoids will cause distinct cytological and histochemical responses in the ecto- and endoparasitized galls compared to the non-parasitized condition. In both parasitoidism cases, the impairment of the feeding activity of the galling Lopesia sp. directs the common storage and nutritive cells toward a similar process of induced cell death, involving cell collapse and loss of membrane integrity. The cell metabolism is maintained mainly by mitochondria, and by the translocation of lipids from the common storage tissue, via plasmodesmata, through the living sclereids of the mechanical zone toward the nutritive tissue. Accordingly, the parasitoid impairment on the feeding activity of Lopesia sp. larvae causes precocious senescence, but similar cytological alterations, and no impact over the histochemical profiles, regarding lipids, reactive oxygen species, and secondary metabolites, which support gall metabolism along the parasitoid cycles.

Botfly Parasitism on Two Primates of the Cebidae Family in Peru.

Botflies (Diptera:Oestridae) are a diverse group of insect parasites that affect various vertebrate species. There are previous reports of myiasis affecting wild primates in Central and South America; however, information about botfly parasitism in Peruvian primates is scarce. We present data from two Cebidae primate specimens: a rescued large-headed capuchin monkey (Sapajus macrocephalus) housed at Taricaya Rescue Center, in Tambopata, Peru, and a free-ranging white-fronted capuchin monkey (Cebus albifrons aequatorialis) inhabiting Cerros de Amotape National Park. The first specimen had a larva identified as Dermatobia hominis, whereas Cuterebra baeri larvae infested the second. In both cases we initially identified the parasite species through their morphologic features before confirming the identification with genetic analysis through the cytochrome C oxidase subunit 1 mitochondrial gene sequencing of the larvae. Further field studies on the primate-parasite dynamics are needed to understand the impact of botfly myiasis on primate populations.

Migratory Gaddi sheep and goats as potential carriers of Theileria infection: a molecular survey.

Theileriosis caused by parasites of the genus Theileria, is a vector-borne haemoprotozoan parasitic disease of critical concern in small ruminants. This study aimed to explore the infection status of migratory Gaddi sheep and goats with parasites from the Theileria genus in concurrence with ectoparasite infestations using molecular methods. Seventy three apparently healthy animals were randomly sampled from different flocks of migratory Gaddi sheep and goats and were systematically screened for ectoparasitic infestations. Molecular investigation for theileriosis was conducted using the genus wide polymerase chain reaction (PCR) technique. Out of 56 (76.71%) animals positive for the genus Theileria, 2 randomly selected amplicons were sequenced and subjected to BLAST analysis and were showing 99.71% identity with Theileria luwenshuni, a pathogenic Theileria species of small ruminants. To confirm the presence of T. luwenshuni, species-specific PCR was attempted to identify that 38 (52.05%) animals were infected by T. luwenshuni. On analysing the molecular prevalence data of Theileria to the ectoparasitism, it was evident that the infection existed in the animals irrespective of the type of ectoparasitic infestation and even T. luwenshuni was found in non-infested animals also. This is the first report of subclinical infections of T. luwenshuni in sheep and goats of Northern India and its potential carrier status. The asymptomatic carrier status of these nomadic animals is a matter possessing serious implications on the disease transmission rates and the production economics of small ruminant production in this region.

The assembled and annotated genome of the pigeon louse Columbicola columbae, a model ectoparasite.

The pigeon louse Columbicola columbae is a longstanding and important model for studies of ectoparasitism and host-parasite coevolution. However, a deeper understanding of its evolution and capacity for rapid adaptation is limited by a lack of genomic resources. Here, we present a high-quality draft assembly of the C. columbae genome, produced using a combination of Oxford Nanopore, Illumina, and Hi-C technologies. The final assembly is 208 Mb in length, with 12 chromosome-size scaffolds representing 98.1% of the assembly. For gene model prediction, we used a novel clustering method (wavy_choose) for Oxford Nanopore RNA-seq reads to feed into the MAKER annotation pipeline. High recovery of conserved single-copy orthologs (BUSCOs) suggests that our assembly and annotation are both highly complete and highly accurate. Consistent with the results of the only other assembled louse genome, Pediculus humanus, we find that C. columbae has a relatively low density of repetitive elements, the majority of which are DNA transposons. Also similar to P. humanus, we find a reduced number of genes encoding opsins, G protein-coupled receptors, odorant receptors, insulin signaling pathway components, and detoxification proteins in the C. columbae genome, relative to other insects. We propose that such losses might characterize the genomes of obligate, permanent ectoparasites with predictable habitats, limited foraging complexity, and simple dietary regimes. The sequencing and analysis for this genome were relatively low cost, and took advantage of a new clustering technique for Oxford Nanopore RNAseq reads that will be useful to future genome projects.

Autoclaving Nest-Material Remains Influences the Probability of Ectoparasitism of Nestling Hoopoes (Upupa epops).

Nest bacterial environment influences avian reproduction directly because it might include pathogenic- or antibiotic-producing bacteria or indirectly because predators or ectoparasites can use volatile compounds from nest bacterial metabolism to detect nests of their avian hosts. Hoopoes (Upupa epops) do not build nests. They rather reuse holes or nest-boxes that contain remains of nest-materials from previous breeding seasons. Interestingly, it has been recently described that the nest's bacterial environment partly affects the uropygial gland microbiota of hoopoe females and eggshells. Blood-sucking ectoparasites use chemical cues to find host nests, so we experimentally tested the hypothetical effects of microorganisms inhabiting nest-material remains before reproduction regarding the intensity of ectoparasitism suffered by 8-day-old nestling hoopoes. In accordance with the hypothesis, nestlings hatched in nest-boxes with autoclaved nest-material remains from the previous reproductive seasons suffered less from ectoparasites than those hatched in the control nest-boxes with nonautoclaved nest-material. Moreover, we found a positive association between the bacterial density of nest-material during the nestling phase and ectoparasitism intensity that was only apparent in nest-boxes with autoclaved nest-material. However, contrary to our expectations, nest bacterial load was positively associated with fledgling success. These results suggest a link between the community of microorganisms of nest-material remains and the intensity of ectoparasitism, and, on the other hand, that the nest bacterial environment during reproduction is related to fledging success. Here, we discuss possible mechanisms explaining the experimental and correlative results, including the possibility that the experimental autoclaving of nest material affected the microbiota of females and nestlings' secretion and/or nest volatiles that attracted ectoparasites, therefore indirectly affecting both the nest bacterial environment at the nestling stage and fledging success.

Influence of weather patterns and air quality on ecological population dynamics of ectoparasites in goats.

Ectoparasitism has a damaging impact on the economy of goat production in India, but the factors influencing its distribution and dynamics are less explored. The present study was designed to investigate the influence of environmental factors like weather and air quality parameters on the occurrence of different types of ectoparasites in goats of two agro-climatic regions of India, viz. the Upper Gangetic Plain (UGP) and the Western Himalayas (WH). The prevalence survey for ectoparasitism among goats was conducted during the four distinct climatic seasons (winter, summer, monsoon, autumn) in both regions. The season-wise data of weather parameters (maximum and minimum temperature, relative humidity in morning and evening, sunrise and sunset time, mean daily temperature and relative humidity, daily variation in temperature and relative humidity, and day length) and air quality parameters (air quality index (AQI), particulate matter 2.5 µm (PM2.5), particulate matter 10 µm (PM10)) of both regions were analyzed in relation with the ectoparasitic prevalence pattern of corresponding regions. The results depict a noticeable correlation between the studied parameters and seasonal variation in the occurrence of each type of ectoparasites. This outcome on the interaction of studied parameters and ectoparasitism is intriguing and it opens a huge scope for future studies on the biometeorological aspects of host-parasite ecological interplay and evolutionary biology. The better understanding of climatological aspects of ectoparasite occurrences helps goat farmers in formulating appropriate timely intervention strategies for the economic control of ectoparasites, which in turn tackles ectoparasiticidal drug resistance and reduces threat of vector-borne diseases.

The mature larva of Poemenia albipes Cresson (Hymenoptera: Ichneumonidae, Poemeniinae) and a review of the biology of Nearctic Poemenia.

The mature larva of Poemenia albipes is figured and described, providing the first knowledge of the larval morphology of this genus. Poemenia is considered to be an ectoparasitoid on the basis of this information. The implications for the larval morphology of the Poemeniinae are discussed. The biology of Nearctic Poemenia is reviewed, with the conclusion that the genus is parasitic upon small xylophilous Apoidea that either make their tunnels or utilize those made by other insects.

Systematics, Phylogeny, and Evolution of Braconid Wasps: 30 Years of Progress.

The parasitoid wasp family Braconidae is likely the second-most species-rich family in the animal kingdom. Braconid wasps are widely distributed and often encountered. They constitute one of the principal groups of natural enemies of phytophagous insects, of which many are serious pest species. The enormous biological diversification of braconid wasps has led to many homoplasies, which contributed widely to instabilities in historical classifications. Recent studies using combinations of genetic markers or total mitochondrial genomes allow for better founded groupings and will ultimately lead to a stable classification. We present the current status of the phylogenetics of the Braconidae in a historical perspective and our understanding of the effects on higher classification.

Cranial morphology in Mollisquama sp. (Squaliformes; Dalatiidae) and patterns of cranial evolution in dalatiid sharks.

Dalatiid sharks are members of a family of predominantly small, midwater meso- and bathypelagic chondrichthyans. The family is notable for both its number of monotypic genera and high morphological disparity. Three of the seven dalatiid genera are known only from holotype specimens (Mollisquama parini) or from only a handful of specimens (Euprotomicroides zantedeschia, Heteroscymnoides marleyi), with the only detailed anatomical work consistent across all taxa being studies of dentition. Here, we present detailed anatomical description of the second-ever specimen of Mollisquama (Mollisquama sp.) covering chondrocranial, jaw, dental, and muscular anatomy, derived from a phase-contrast synchrotron microtomographic scan. Mollisquama sp. is unique among dalatiids in possessing a deep carinal process, extending ventrally from the bar between the subethmoid region and basal angle in squaloid sharks, containing a large fenestra infiltrated by the suborbitalis muscle. Mollisquama sp. also exhibits additional possibly diagnostic features, including a planar configuration of the labial cartilages and the absence of labial folds; a pad-like orbital process on the palatoquadrate; and the origination of the suborbitalis muscle solely on the carina, rather than the intraorbital wall. Character optimization of anatomical data onto a phylogeny of dalatiid sharks suggests Mollisquama sp. to be among the most specialized in the family, expanding the existing dalatiid morphospace. However, the functional significance of such transformations remains unclear. Synchrotron-derived data, which do not require chemical pretreatment of specimens, may elucidate soft-tissue functional correlates in future studies of undersampled taxa, such as dalatiids.

Why come back home? Breeding-site fidelity varies with group size and parasite load in a colonial bird.

Fidelity to a past breeding site is widespread among animals and may confer both costs and benefits. Colonial species occur at specific sites that can accommodate multiple breeders, and the choice of whether to return to last year's site or disperse elsewhere can affect colony site use, the colony size distribution and individual fitness. For the colonial cliff swallow, Petrochelidon pyrrhonota, which occupies colonies of widely different sizes, we used a 30-year field study in western Nebraska to investigate how the extent of infestation by ectoparasites and colony size affected breeders' colony site fidelity between years. We compared philopatry at colonies where parasitic swallow bugs, Oeciacus vicarius, had been removed by fumigation with that at nonfumigated sites exposed to natural levels of ectoparasites. About 25% of birds at nonfumigated colonies returned to their previous year's site, whereas about 69% of birds at fumigated colonies did so. Site fidelity was greatest at nonfumigated sites that changed the least in size between years. Birds were less likely to return to a nonfumigated site as the colony there became increasingly larger. Individuals philopatric to both nonfumigated and fumigated sites resided in colonies more similar in size between years than did dispersing birds. Most cliff swallows settled within 6 km of their previous year's site, indicating that many nonphilopatric birds still may have had some familiarity with the local landscape surrounding the site to which they moved. Removal of ectoparasites at a site allows large colonies to persist there perennially, probably contributing to higher philopatry because such large colonies are rare and would have been difficult to find had the residents dispersed. Cliff swallows are likely to be sensitive to both colony size and general familiarity with a given site or landscape region, and probably integrate these with other cues to select breeding colonies.

Summer time predation on the obligatory off-host stage of an invasive ectoparasite.

Predation can regulate populations and strongly affect invasion success of novel prey. The deer ked (Lipoptena cervi; Linnaeus 1758) is an invasive ectoparasite of cervids that spends a long period of its life cycle outside the host. Prior to this study, virtually nothing was known about natural summer time predation on the deer ked. We aimed to evaluate the magnitude of summer time predation on L. cervi pupae in different habitats and to identify potential predators. We conducted a set of field experiments, where we exposed L. cervi pupae to various ground-dwelling vertebrate and invertebrate predators. The loss of pupae was monitored for different predator guilds. Three habitats of the moose, the main host species, were studied: (1) moist heath forest; (2) dry, logged heath forest; and (3) moist meadow. The results indicate notable summer time predation on L. cervi pupae, and the pupal predation varied within and between habitats, being lowest in the meadow habitat. We found a positive correlation between pupal loss and abundance of the common lizard (Zootoca vivipara), harvestmen (Opiliones), ground spiders (Gnaphosidae) and Formicinae-ants. We conclude that summer time predation during the pupal phase can have a notable local importance for the L. cervi abundance.

Sylvatic Infestation of Oklahoma Reptiles with Immature Ixodes scapularis (Acari: Ixodidae).

Reptiles were collected in nine counties in Oklahoma from September 2002 to May 2004 and examined for Ixodes scapularis (Say) larvae and nymphs to determine seasonal incidence and prevalence of these ticks. In total, 209 reptile specimens consisting of nine species of lizards and seven species of snakes were collected. Plestiodon fasciatus (L.) was the most numerous species collected (55%) followed by Sceloporus undulatus (Latreille) (17%) and Scincella lateralis (Say) (11%). Less than 10 individuals were collected for all remaining reptile species. The infestation prevalence of I. scapularis on all reptile specimens collected was 14% for larvae and 25% for nymphs. Larvae were found on lizards from April until September and peaked in May, while nymphs were found from March until September and peaked in April. I. scapularis larvae (84%) and nymphs (73%) preferentially attached to the axillae/front leg of P. fasciatus. Two chigger species, Eutrombicula splendens (Ewing) and Eutrombicula cinnabaris (Ewing), were found on 2% of the reptiles collected. No ectoparasites, including ticks, were obtained from the seven species of snakes collected.

Physiological condition of bank voles (Myodes glareolus) during the increase and decline phases of the population cycle.

The dynamics of animal populations are greatly influenced by interactions with their natural enemies and food resources. However, quantifying the relative effects of these factors on demographic rates remains a perpetual challenge for animal population ecology. Food scarcity is assumed to limit the growth and to initiate the decline of cyclic herbivore populations, but this has not been verified with physiological health indices. We hypothesized that individuals in declining populations would exhibit signs of malnutrition-induced deterioration of physiological condition. We evaluated the association of body condition with population cycle phase in bank voles (Myodes glareolus) during the increase and decline phases of a population cycle. The bank voles had lower body masses, condition indices and absolute masses of particular organs during the decline. Simultaneously, they had lower femoral masses, mineral contents and densities. Hemoglobin and hematocrit values and several parameters known to respond to food deprivation were unaffected by the population phase. There were no signs of lymphopenia, eosinophilia, granulocytosis or monocytosis. Erythrocyte counts were higher and plasma total protein levels and tissue proportions of essential polyunsaturated fatty acids lower in the population decline. Ectoparasite load was lower and adrenal gland masses or catecholamine concentrations did not suggest higher stress levels. Food availability seems to limit the size of voles during the decline but they can adapt to the prevailing conditions without clear deleterious health effects. This highlights the importance of quantifying individual health state when evaluating the effects of complex trophic interactions on the dynamics of wild animal populations.

Variation in age composition among colony sizes in Cliff Swallows.

Variation in group size is characteristic of most social species. The extent to which individuals sort among group sizes based on age may yield insight into why groups vary in size and the age-specific costs and benefits of different social environments. We investigated the age composition of Cliff Swallow (Petrochelidon pyrrhonota) colonies of different sizes over 18 years at a long-term study site in western Nebraska, USA. Using years elapsed since banding as a relative measure of age for over 194,000 birds, we found that the proportion of age-class-1 swallows (birds banded as nestlings or juveniles or adults in the year of banding) of both sexes increased in larger colonies and at colony sites becoming active later in the summer. Age composition was unrelated to how often a particular colony site was used. The effect of colony size most likely reflected the fact that older birds return to the same colony site in successive years even when the colony size there decreases, and that yearlings and immigrants benefit more from larger colonies than do older, more experienced individuals. The date effect probably resulted in part from later spring arrival by younger and/or immigrant swallows. At fumigated sites where ectoparasitic swallow bugs (Oeciacus vicarius) had been removed, age composition did not vary with either colony size or colony initiation date. The patterns reported here appear to be driven partially by the presence of ectoparasites and suggest that the hematophagous bugs influence variation in Cliff Swallow group composition. Our results are consistent with the hypothesis that variation in colony size reflects, in part, age-based sorting of individuals among groups.

Philornis sp. bot fly larvae in free living scarlet macaw nestlings and a new technique for their extraction.

Bot fly larvae (Philornis genus) are obligate subcutaneous blood-feeding parasites of Neotropical birds including psittacines. We analyze twelve years of data on scarlet macaw (Ara macao) nestlings in natural and artificial nests in the lowland forests of southeastern Peru and report prevalence and intensity of Philornis parasitism. Bot fly prevalence was 28.9% while mean intensity was 5.0 larvae per infected chick. Prevalence in natural nests (11%, N=90 nestlings) was lower than in wooden nest-boxes (39%, N=57) and PVC boxes (39%, N=109). We describe a new technique of removing Philornis larvae using a reverse syringe design snake bite extractor. We compare this new technique to two other methods for removing bots from macaw chicks and find the new method the most suitable.