Optimal settings and advantages of drones as a tool for canopy arthropod collection.

The growing field of aeroecology is limited by difficulties associated with sampling in the air column. Aerial insects are particularly hard to sample, despite being the main prey in the air column, with some recent studies attempting to use drones as a collection method. We conducted a study to determine the optimal drone settings for collecting insects above the canopy, where drones are seldom used. By attaching a net to the body of a small, commercial drone, we tested yield from different height, speed, and net settings in wetlands, as well as compared insect diversity across different habitat canopies. Height was the most important setting; grazing the canopy yielded significantly more insects than flying one meter above it. Speed, drone type, and net size did not influence the number of insects caught per trial. Wetland canopies had higher abundance, diversity, and species richness in its arthropod populations compared to forest canopies or lakes. Compared to the yield of Lindgren funnels-a traditional sampling method in entomology-drones captured higher diversity and abundance of insects in a fraction of the time. This study confirms that drones are an efficient and accurate way to collect canopy arthropods.

Fewer bat passes are detected during small, commercial drone flights.

Advances in technological capabilities, operational simplicity and cost efficiency have promoted the rapid integration of unmanned aerial vehicles (UAVs) into ecological research, providing access to study taxa that are otherwise difficult to survey, such as bats. Many bat species are currently at risk, but accurately surveying populations is challenging for species that do not roost in large aggregations. Acoustic recorders attached to UAVs provide an opportunity to survey bats in challenging habitats. However, UAVs may alter bat behaviour, leading to avoidance of the UAV, reduced detection rates and inaccurate surveys. We evaluated the number of bat passes detected with and without the presence of a small, commercial UAV in open habitats. Only 22% of bat passes were recorded in the presence of the UAV (0.23 ± 0.09 passes/min) compared to control periods without the UAV (1.03 ± 0.17 passes/min), but the effect was smaller on the big brown bat/silver-haired bat (Eptesicus fuscus/Lasionycteris noctivagans) acoustic complex. Noise interference from the UAV also reduced on-board bat detection rates. We conclude that acoustic records attached to UAVs may inaccurately survey bat populations due to low and variable detection rates by such recorders.

Identification of Cytauxzoon felis antigens via protein microarray and assessment of expression library immunization against cytauxzoonosis.

BACKGROUND: Cytauxzoonosis is a disease of felids in North America caused by the tick-transmitted apicomplexan parasite Cytauxzoon felis. Cytauxzoonosis is particularly virulent for domestic cats, but no vaccine currently exists. The parasite cannot be cultivated in vitro, presenting a significant limitation for vaccine development. METHODS: Recent sequencing of the C. felis genome has identified over 4300 putative protein-encoding genes. From this pool we constructed a protein microarray containing 673 putative C. felis proteins. This microarray was probed with sera from C. felis-infected and naïve cats to identify differentially reactive antigens which were incorporated into two expression library vaccines, one polyvalent and one monovalent. We assessed the efficacy of these vaccines to prevent of infection and/or disease in a tick-challenge model. RESULTS: Probing of the protein microarray resulted in identification of 30 differentially reactive C. felis antigens that were incorporated into the two expression library vaccines. However, expression library immunization failed to prevent infection or disease in cats challenged with C. felis. CONCLUSIONS: Protein microarray facilitated high-throughput identification of novel antigens, substantially increasing the pool of characterized C. felis antigens. These antigens should be considered for development of C. felis vaccines, diagnostics, and therapeutics.

Disparate gain and loss of parasitic abilities among nematode lineages.

Plant parasitism has arisen time and again in multiple phyla, including bacteria, fungi, insects and nematodes. In most of these organismal groups, the overwhelming diversity hampers a robust reconstruction of the origins and diversification patterns of this trophic lifestyle. Being a moderately diversified phylum with ≈ 4,100 plant parasites (15% of total biodiversity) subdivided over four independent lineages, nematodes constitute a major organismal group for which the genesis of plant parasitism could be mapped. Since substantial crop losses worldwide have been attributed to less than 1% of these plant parasites, research efforts are severely biased towards this minority. With the first molecular characterisation of numerous basal and supposedly harmless plant parasites as well as their non-parasitic relatives, we were able to generate a comprehensive molecular framework that allows for the reconstruction of trophic diversification for a complete phylum. In each lineage plant parasites reside in a single taxonomic grouping (family or order), and by taking the coverage of the next lower taxonomic level as a measure for representation, 50, 67, 100 and 85% of the known diversity was included. We revealed distinct gain and loss patterns with regard to plant parasitism per se as well as host exploitation strategies between these lineages. Our map of parasitic nematode biodiversity also revealed an unanticipated time reversal in which the two most ancient lineages showed the lowest level of ecological diversification and vice versa.

Evaluation of High Dosages of Oral Meloxicam in American Kestrels ( Falco sparverius ).

To evaluate the toxicity of short-term high doses of meloxicam in American kestrels ( Falco sparverius ), 32 male captive-born, 1- to 4-year-old American kestrels were randomly assigned to 4 groups: 3 groups treated with meloxicam (n = 9 per group) and a control group (n = 5). Meloxicam was administered orally via feeding tube in the proventriculus at 2, 10, and 20 mg/kg every 12 hours for 7 days for the treatment groups, while the control group received saline solution. The birds were evaluated for the presence of clinical signs, abnormalities in the complete blood cell count and in the plasma biochemical panel for the 20-mg/kg group, and gross and histopathologic lesions. No clinical signs or mortality were observed in any group. No significant differences of clinical relevance were found in results of the packed cell volume, total solids, and biochemical panel, and no evidence of renal toxicity was found in the treatment or control groups. A significant correlation was found between hepatic lipidosis and meloxicam dose (P = .02). Two of 9 birds in the 20-mg/kg group developed gastric ulcers, although this result was not significant. None of the birds in the 2- and 10-mg/kg groups had similar lesions. Finally, meloxicam dosages up to 20 mg/kg did not result in nephrotoxicity in American kestrels. Further toxicologic studies to evaluate hepatotoxicity and gastrotoxicity of meloxicam in avian species are needed.

Spatiotemporal patterns and relationships among the diet, biochemistry, and exposure to flame retardants in an apex avian predator, the peregrine falcon.

Flame retardants (FR) are industrial chemicals and some are proven environmental contaminants that accumulate in predatory birds. Few studies have examined the influence of diet on FR profiles in nestling raptors and the possible physiological implications of such FR exposure. The objectives of this research were (1) to determine spatial patterns of ≤ 48 polybrominated diphenyl ether (PBDE) congeners and ≤ 26 non-PBDE FRs, including organophosphate esters (OPEs), in nestling peregrine falcons (Falco peregrinus) across the Canadian Great Lakes-St. Lawrence River Basin (GL-SLR; 2010) and in the eastern Canadian Arctic (2007); (2) to identify temporal changes in FR concentrations from the mid-2000s to 2010 in GL-SLR peregrine nestlings; (3) to investigate the role of diet using stable isotopes on exposure patterns of quantifiable FRs; and (4) to assess possible associations between circulating FRs and total (T) thyroxine (TT4) and triiodothyronine (TT3), tocopherol, retinol and oxidative status (isoprostanes). The summed concentrations of the top 5 PBDEs (Σ5) (BDE-47, -99, -100, -154, -153) were significantly higher in rural nestlings than urban nestlings in the GL-SLR, followed by the eastern Arctic nestlings. The PBDE congener profile of rural nestlings was dominated by BDE-99 (34‰), whereas BDE-209 (31‰) became dominant in the 2010 urban PBDE profile marking a shift since the mid-2000s. Low (ppb) concentrations of 25 novel non-PBDE FRs (e.g., 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE)) were measured in the nestlings in at least one region, with the first report in peregrines of 15 novel non-PBDE FRs (e.g., 2-ethyl-1-hyxyl 2,3,4,5-tetrabromobenzoate (EHTBB), pentabromo allyl ether (PBPAE), tetrabromoethylcyclohexane (α-, ß-DBE-DBCH)) as well as of tris (2-butoxyethyl) phosphate (TBOEP) (0-7.5ng/g ww) > tris(2-chloroisopropyl) phosphate (TCIPP) (0.1-5.5ng/g ww) > tris(2-chloroethyl) phosphate (TCEP) (0.02-2.0ng/g ww) > tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) (0-1.0ng/g ww). Within the GL-SLR, the urban nestlings' diet had significantly more terrestrial sources (greater δ13C values) than the broader, more aquatic-based diet of rural peregrines. Dietary source (δ13C) was significantly associated with concentrations of Σ5PBDE, BDE-209, EHTBB, and 2,2-4,4',5,5'-hexabromobiphenyl (BB-153), with trophic level (δ15N) also positively associated with BDE-209 levels. Compared to urban nestlings, the rural nestlings had significantly lower circulating concentrations of thyroxine (TT4), triiodothyronine (TT3), a greater proportion of TT3 relative to TT4 (TT3:TT4), tocopherol and oxidative status (isoprostanes), but higher retinol levels; the most recalcitrant PBDE congener, BDE-153, in combination with low concentrations of some novel FRs, particularly octabromotrimethylphenyllindane (OBIND), may influence circulating thyroid hormones, especially TT4, and retinol levels of peregrine falcon nestlings. These associations of FR-endocrine-biochemical measures suggest possible exposure-related changes in these birds and further study is warranted.

Mitochondrial Genome Sequences and Structures Aid in the Resolution of Piroplasmida phylogeny.

The taxonomy of the order Piroplasmida, which includes a number of clinically and economically relevant organisms, is a hotly debated topic amongst parasitologists. Three genera (Babesia, Theileria, and Cytauxzoon) are recognized based on parasite life cycle characteristics, but molecular phylogenetic analyses of 18S sequences have suggested the presence of five or more distinct Piroplasmida lineages. Despite these important advancements, a few studies have been unable to define the taxonomic relationships of some organisms (e.g. C. felis and T. equi) with respect to other Piroplasmida. Additional evidence from mitochondrial genome sequences and synteny should aid in the inference of Piroplasmida phylogeny and resolution of taxonomic uncertainties. In this study, we have amplified, sequenced, and annotated seven previously uncharacterized mitochondrial genomes (Babesia canis, Babesia vogeli, Babesia rossi, Babesia sp. Coco, Babesia conradae, Babesia microti-like sp., and Cytauxzoon felis) and identified additional ribosomal fragments in ten previously characterized mitochondrial genomes. Phylogenetic analysis of concatenated mitochondrial and 18S sequences as well as cox1 amino acid sequence identified five distinct Piroplasmida groups, each of which possesses a unique mitochondrial genome structure. Specifically, our results confirm the existence of four previously identified clades (B. microti group, Babesia sensu stricto, Theileria equi, and a Babesia sensu latu group that includes B. conradae) while supporting the integration of Theileria and Cytauxzoon species into a single fifth taxon. Although known biological characteristics of Piroplasmida corroborate the proposed phylogeny, more investigation into parasite life cycles is warranted to further understand the evolution of the Piroplasmida. Our results provide an evolutionary framework for comparative biology of these important animal and human pathogens and help focus renewed efforts toward understanding the phylogenetic relationships within the group.

Genetic Drift, Not Life History or RNAi, Determine Long-Term Evolution of Transposable Elements.

Transposable elements (TEs) are a major source of genome variation across the branches of life. Although TEs may play an adaptive role in their host's genome, they are more often deleterious, and purifying selection is an important factor controlling their genomic loads. In contrast, life history, mating system, GC content, and RNAi pathways have been suggested to account for the disparity of TE loads in different species. Previous studies of fungal, plant, and animal genomes have reported conflicting results regarding the direction in which these genomic features drive TE evolution. Many of these studies have had limited power, however, because they studied taxonomically narrow systems, comparing only a limited number of phylogenetically independent contrasts, and did not address long-term effects on TE evolution. Here, we test the long-term determinants of TE evolution by comparing 42 nematode genomes spanning over 500 million years of diversification. This analysis includes numerous transitions between life history states, and RNAi pathways, and evaluates if these forces are sufficiently persistent to affect the long-term evolution of TE loads in eukaryotic genomes. Although we demonstrate statistical power to detect selection, we find no evidence that variation in these factors influence genomic TE loads across extended periods of time. In contrast, the effects of genetic drift appear to persist and control TE variation among species. We suggest that variation in the tested factors are largely inconsequential to the large differences in TE content observed between genomes, and only by these large-scale comparisons can we distinguish long-term and persistent effects from transient or random changes.

PCR amplification of a multi-copy mitochondrial gene (cox3) improves detection of Cytauxzoon felis infection as compared to a ribosomal gene (18S).

Cytauxzoon felis is a tick-transmitted protozoan parasite that infects felids. Clinical disease caused by acute C. felis infection rapidly progresses in domestic cats, leading to high morbidity and mortality. Accurately diagnosing cytauxzoonosis as soon as possible during acute infection would allow for earlier initiation of antiprotozoal therapy which could lead to higher survival rates. Molecular detection of parasite rRNA genes (18S) by PCR has previously been shown to be a sensitive method of diagnosing C. felis infections. Based on evidence from related apicomplexan species, we hypothesized that C. felis mitochondrial genes would exist at higher copy numbers than 18S and would be a more sensitive diagnostic target. In this study we have designed a PCR assay targeting the C. felis mitochondrial gene cytochrome c oxidase subunit III (cox3). Herein we demonstrate that (1) the cox3 PCR can detect as low as 1 copy of DNA target and can detect C. felis in samples with known mitochondrial sequence heterogeneity, (2) cox3 copy number is increased relative to 18S in blood and tissue samples from acutely infected cats, and (3) the cox3 PCR is more sensitive than 18S PCR for detection of C. felis during early infections.

Population census of a large common tern colony with a small unmanned aircraft.

Small unmanned aircraft systems (UAS) may be useful for conducting high-precision, low-disturbance waterbird surveys, but limited data exist on their effectiveness. We evaluated the capacity of a small UAS to census a large (>6,000 nests) coastal Common tern (Sterna hirundo) colony of which ground surveys are particularly disruptive and time-consuming. We compared aerial photographic tern counts to ground nest counts in 45 plots (5-m radius) throughout the colony at three intervals over a nine-day period in order to identify sources of variation and establish a coefficient to estimate nest numbers from UAS surveys. We also compared a full colony ground count to full counts from two UAS surveys conducted the following day. Finally, we compared colony disturbance levels over the course of UAS flights to matched control periods. Linear regressions between aerial and ground counts in plots had very strong correlations in all three comparison periods (R2 = 0.972-0.989, P < 0.001) and regression coefficients ranged from 0.928-0.977 terns/nest. Full colony aerial counts were 93.6% and 94.0%, respectively, of the ground count. Varying visibility of terns with ground cover, weather conditions and image quality, and changing nest attendance rates throughout incubation were likely sources of variation in aerial detection rates. Optimally timed UAS surveys of Common tern colonies following our method should yield population estimates in the 93-96% range of ground counts. Although the terns were initially disturbed by the UAS flying overhead, they rapidly habituated to it. Overall, we found no evidence of sustained disturbance to the colony by the UAS. We encourage colonial waterbird researchers and managers to consider taking advantage of this burgeoning technology.

Changes in the incubation by American kestrels (Falco sparverius) during exposure to the polybrominated diphenyl ether (PBDE) mixture DE-71.

Polybrominated diphenyl ethers (PBDE) are persistent environmental pollutants that have been detected in wildlife globally. American kestrels exposed to the commercial PBDE mixture DE-71 have previously demonstrated reduced reproductive success and behaviors during courtship and brood rearing; however, it remains unknown whether DE-71 affects incubation. During breeding, captive kestrels were exposed to the DE-71 mixture dissolved in safflower oil at two environmentally relevant concentrations (low: 283.5 ± 48.2, high: 1104.8 ± 124.5 ng/g wet weight [ww]) via diet for an average of 75 d. Unexpected low in ovo concentrations of hexabromocyclododecane (HBCD) were also detected (low: 3 ± 1 ng/g ww, high: 16 ± 3 ng/g ww). All comparisons are made to control pairs. Kestrel pairs in the low- and high-exposure groups experienced longer incubation periods with increasing exposure to ΣPBDE and some individual congeners. As incubation progressed, pairs exposed to DE-71 had significantly lower nest temperatures, which were on average 19% lower in low-exposure nests and 35% lower in high-exposure nests during late incubation. The DE-71 exposed pairs (low and high) also demonstrated significantly reduced incubation constancy (defined as percent of temperature readings above the maximum daily ambient temperature) during early incubation compared to controls. Nest temperatures (all pairs) and incubation constancy (high pairs) during early incubation (d 1-3) were significantly and positively associated with the proportion of eggs that hatched per pair. Higher incubation constancy and incubating nest temperatures in the low-exposure group were associated with markedly less egg weight loss by mid-incubation. These findings demonstrate that exposure to PBDE significantly affected kestrels during incubation, a critical period for embryonic development.

The flame retardant ß-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane: fate, fertility, and reproductive success in American kestrels (Falco sparverius).

Captive American kestrels (Falco sparverius) were exposed via diet during reproduction to an environmentally relevant concentration of ß-1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (ß-TBECH). The ß-TBECH isomer was injected into the food source at a daily dosing concentration of 0.239 ng/g kestrel/day (22 pairs); control birds were exposed via diet to the safflower oil vehicle only (24 pairs). Eight pairs in each group were exposed for four weeks and sacrificed for tissue analysis; the remaining pairs completed their breeding cycle, with exposure ceasing at the end of incubation (82 days). α- and ß-TBECH appeared to be rapidly metabolized and/or eliminated from fat, liver, and plasma; both isomers and potential hydroxylated metabolites of ß-TBECH (plasma) were undetected. Notwithstanding, compared to controls, pairs exposed to ß-TBECH laid fewer eggs (p = 0.019) and laid lighter eggs (successful eggs: p = 0.009). Exposed pairs also demonstrated poorer egg fertility (p = 0.035) although testis mass and histology were similar among males. Reductions in egg production and fertility resulted in decreased hatchling success (p = 0.023). The ß-TBECH-exposed pairs also produced fewer males overall (p = 0.009), which occurred concurrently with increased estradiols maternally deposited in eggs (p = 0.039). These findings demonstrate that ß-TBECH may be detrimental for breeding in wild birds receiving similar exposure levels.

Dietary exposure to technical hexabromocyclododecane (HBCD) alters courtship, incubation and parental behaviors in American kestrels (Falco sparverius).

Hexabromocyclododecane (HBCD) is a high production volume brominated flame retardant that has been detected in the environment and wildlife at increasing concentrations. This study was designed to determine potential effects of dietary exposure to environmentally relevant levels of HBCD on behavior during reproduction in captive American kestrels. Twenty kestrel pairs were exposed to 0.51 µg technical HBCD g(-1) kestrel d(-1) from 4 weeks prior to pairing until chicks hatched (~75 d). Ten pairs of controls received the safflower oil vehicle only and were used for comparison. During the courtship period the chitter-calls were reduced in both sexes (p=0.038) and females performed fewer bonding displays (p=0.053). Both sexes showed a propensity to be less active than controls during courtship. The reduction in male courtship behavior was correlated with reduced courtship behaviors of females (p=0.008) as well as reduced egg mass (p=0.019). During incubation, nest temperatures of treatment pairs were lower at mid-incubation (p=0.038). HBCD-exposed males performed fewer key parental behaviors when rearing nestlings, including entering the nest-box, pair-bonding displays and food-retrievals. HBCD-exposed females appeared to compensate for the reduced parental behavior of their mates by performing these same behaviors more frequently than controls (p=0.004, p=0.027, p=0.025, respectively). This study demonstrates that HBCD affects breeding behavior in American kestrels throughout the reproductive season and behavioral alterations were linked to reproductive changes (egg size). This is the first study to report HBCD effects on reproductive behavior in any animal model.

Diet exposure to technical hexabromocyclododecane (HBCD) affects testes and circulating testosterone and thyroxine levels in American kestrels (Falco sparverius).

Hexabromocyclododecane (HBCD) is a high-production-volume, brominated flame-retardant that is used in items such as polystyrene foams. HBCD has been detected in the environment, wildlife tissues and in humans globally with some of the highest recorded levels in predatory birds. This study examined the effects of exposure to environmentally relevant levels of HBCD on the reproductive physiology of captive male American kestrels (Falco sparverius), a predatory bird. Two sets of males were used: one group not housed with females (unpaired: nc=12, nHBCD=10) and the second group housed with females (breeding: nc=10, nHBCD=20). All treatment birds were exposed to 0.51 µg HBCD/g kestrel/day technical HBCD, and controls to safflower oil only, injected into their food during seasonal testicular development. Unpaired males were exposed for 3 weeks and euthanized for testicular analysis. Breeding males were exposed for 3 weeks prior to pairing and throughout the courtship period. The HBCD-exposed unpaired males had heavier testes (p≤0.017) and a trend towards more seminiferous tubules containing elongated spermatids (p=0.052). There was also a moderate increase in plasma testosterone concentrations (p=0.056) compared to controls. In breeding males, testosterone levels increased during courtship to culminate in higher levels than controls by the time the first egg was laid (p=0.010) and circulating free and total T4 was reduced throughout. The number of sperm cells reaching the perivitelline layer of the first egg for breeding males did not differ between the two groups. This study is the first report that HBCD exposure at environmentally relevant levels alters reproductive physiology in male birds and suggests that birds may be more sensitive to HBCD than mammals.

Reproductive changes in American kestrels (Falco sparverius) in relation to exposure to technical hexabromocyclododecane flame retardant.

Recently, the ban of hexabromocyclododecane (HBCD), a high-production-volume flame retardant, was announced in Europe and North America. However, the effects of HCBD remain understudied in birds. The objectives of the present comparative effects study were to determine whether exposure to an HBCD technical mixture (HBCD-TM) altered avian reproductive measures at an environmentally relevant concentration. American kestrels were exposed daily by food to HBCD-TM, i.e., 0.51 µg HBCD/g kestrel/d; exposed kestrels laid eggs that had α-HBCD concentrations (163.5 ± 75.1 ng/g wet wt) tenfold greater than ß- and γ-HBCD isomers, an isomer profile and concentrations similar to those of eggs of wild peregrine falcons (Falco peregrinus). Concentrations of HBCD were not detected in the control kestrel eggs. In comparison with controls, the kestrels exposed to HBCD began to lay their eggs 6 d earlier and laid larger clutches of smaller eggs. The size of the eggs was inversely correlated with the in ovo α-HBCD concentrations. The smaller eggs of the HBCD exposed kestrels also lost more weight by midincubation, suggesting increased eggshell porosity since eggshell thickness was comparable. Generally birds that lay more eggs and lay earlier in the breeding season gain the advantage of better hatching and fledging success, yet the kestrels exposed to HBCD failed to have better reproductive success than the control birds. These reproductive changes were a function of HBCD exposure, likely through changes in food consumption, with possible impacts on, for example, reproductive behavior and/or alterations in thyroid hormones.

Guidance in Kagome-like photonic crystal fibres I: analysis of an ideal fibre structure.

Propagation of light in a square-lattice hollow-core photonic crystal fibre is analysed as a model of guidance in a class of photonic crystal fibres that exhibit broad-band guidance without photonic bandgaps. A scalar governing equation is used and analytic solutions based on transfer matrices are developed for the full set of modes. It is found that an exponentially localised fundamental mode exists for a wide range of frequencies. These analytic solutions of an idealised structure will form the basis for analysis of guidance in a realistic structure in a following paper.

Guidance in Kagome-like photonic crystal fibres II: perturbation theory for a realistic fibre structure.

A perturbation theory is developed that treats a localised mode embedded within a continuum of states. The method is applied to a model rectangular hollow-core photonic crystal fibre structure, where the basic modes are derived from an ideal, scalar model and the perturbation terms include vector effects and structural difference between the ideal and realistic structures. An expression for the attenuation of the fundamental mode due to interactions with cladding modes is derived, and results are presented for a rectangular photonic crystal fibre structure. Attenuations calculated in this way are in good agreement with numerical simulations. The origin of the guidance in our model structure is explained through this quantitative analysis. Further perspectives are obtained through investigating the influence of fibre parameters on the attenuation.

Embryonic exposure to the polybrominated diphenyl ether mixture, DE-71, affects testes and circulating testosterone concentrations in adult American kestrels (Falco sparverius).

Polybrominated diphenyl ethers (PBDEs) are additive flame retardants that are environmentally persistent and bioaccumulative. The developmental effects of in ovo exposure to environmentally relevant levels of the PBDE technical mixture, DE-71, on male reproductive physiology in captive American kestrels (Falco sparverius) was determined. Males were exposed in ovo by direct maternal transfer to DE-71 at three mean concentrations of 289 ng/g ww (low exposure), 1131 ng/g ww (high-exposure), or background levels of 3 ng/g ww (control). As adults, males were paired with unexposed females for breeding and, 1 year later, sacrificed for testes evaluation. While breeding, high-exposure males demonstrated a trend of reduced circulating testosterone levels when their female mate commenced egg laying when compared with controls (p = 0.056). No differences in circulating free T4 or T3 were detected. Sperm numbers were elevated on the perivitelline layer of the first egg of both high- and low-exposure males when compared with controls (p = 0.021). High-exposure males had a higher gonadosomatic index (p = 0.046) and heavier right testis than controls (p = 0.034) with a similar trend for their left testis (p = 0.055). High-exposure males had more seminiferous tubules containing lumen than controls (p = 0.030), and in proportion to the total number of tubules, low-exposure males had more tubules containing lumen than did controls (p = 0.016). Only high-exposure males had fewer than half of tubules containing final spermatids (43%). The results of the present study demonstrate that embryonic exposure to technical DE-71 affects the reproductive tract of adult male kestrels.

Changes in plasma retinol of American kestrels (Falco sparverius) in response to dietary or in ovo exposure to environmentally relevant concentrations of a penta-brominated diphenyl ether mixture, DE-71.

Polybrominated diphenyl ethers (PBDE) are ubiquitous, lipophilic, and bioaccumulative brominated flame retardants. Plasma retinol concentrations of captive adult American kestrels were assessed at the beginning of the breeding season following 3 wk of daily dietary exposure to vehicle (control), low (0.3 ng/g wet weight [ww]), or high (1.6 ng/g ww) concentrations of DE-71 and in their 25-d-old nestlings following embryonic exposure by maternal deposition to environmentally relevant low (291 ± 48 ng/g ww) or high (1111 ± 160 ng/g ww) sum (Σ) PBDE concentrations. Unexpectedly, low in ovo concentrations of total-α-hexabromocyclododecane (HBCD) were detected. Plasma retinol concentrations of adult males exposed to higher DE-71 concentrations were negatively correlated with in ovo ΣPBDE, BDE-100, and HBCD levels. Maternal (13%) and nestling (11%) retinol levels were lower in the low-exposure group compared to respective controls, and biologically significant since their retinol levels were correlated with hatching success and growth, respectively. Maternal retinol levels were also correlated with BDE-153. The underlying mechanisms may involve (1) PBDE exposure, hydroxylated (OH-) metabolites, and subsequent changes in retinol mobilization; (2) decreased maternal food consumption; and (3) reduced maternal retinol yolk deposits. The apparent lack of retinol changes in the high-exposure kestrel may reflect compensation occurring, either by increased mobilization and transportation of retinol, and/or higher food consumption in these birds. When highly mobile as evidenced during reproduction or development, retinol concentrations of adult and nestling kestrels are sensitive to environmentally relevant PBDE and HBCD levels.