Cues used by the black fly,Simulium annulus,for attraction to the common loon (Gavia immer)

The parasitic relationship between a black fly, Simulium annulus, and the common loon (Gavia immer) has been considered one of the most exclusive relationships between any host species and a black fly species. To test the host specificity of this blood‐feeding insect, we made a series of bird decoy presentations to black flies on loon‐inhabited lakes in northern Wisconsin, U.S.A. To examine the importance of chemical and visual cues for black fly detection of and attraction to hosts, we made decoy presentations with and without chemical cues. Flies attracted to the decoys were collected, identified to species, and quantified. Results showed that S. annulus had a strong preference for common loon visual and chemical cues, although visual cues from Canada geese (Branta canadensis) and mallards (Anas platyrynchos) did attract some flies in significantly smaller numbers.     

A hierarchical nest survival model integrating incomplete temporally varying covariates

Nest success is a critical determinant of the dynamics of avian populations, and nest survival modeling has played a key role in advancing avian ecology and management. Beginning with the development of daily nest survival models, and proceeding through subsequent extensions, the capacity for modeling the effects of hypothesized factors on nest survival has expanded greatly. We extend nest survival models further by introducing an approach to deal with incompletely observed, temporally varying covariates using a hierarchical model. Hierarchical modeling offers a way to separate process and observational components of demographic models to obtain estimates of the parameters of primary interest, and to evaluate structural effects of ecological and management interest. We built a hierarchical model for daily nest survival to analyze nest data from reintroduced whooping cranes (Grus americana) in the Eastern Migratory Population. This reintroduction effort has been beset by poor reproduction, apparently due primarily to nest abandonment by breeding birds. We used the model to assess support for the hypothesis that nest abandonment is caused by harassment from biting insects. We obtained indices of blood‐feeding insect populations based on the spatially interpolated counts of insects captured in carbon dioxide traps. However, insect trapping was not conducted daily, and so we had incomplete information on a temporally variable covariate of interest. We therefore supplemented our nest survival model with a parallel model for estimating the values of the missing insect covariates. We used Bayesian model selection to identify the best predictors of daily nest survival. Our results suggest that the black fly Simulium annulus may be negatively affecting nest survival of reintroduced whooping cranes, with decreasing nest survival as abundance of S. annulus increases. The modeling framework we have developed will be applied in the future to a larger data set to evaluate the biting‐insect hypothesis and other hypotheses for nesting failure in this reintroduced population; resulting inferences will support ongoing efforts to manage this population via an adaptive management approach. Wider application of our approach offers promise for modeling the effects of other temporally varying, but imperfectly observed covariates on nest survival, including the possibility of modeling temporally varying covariates collected from incubating adults.     

Evaluation of the enteric microflora of captive whooping cranes (Grus americana) and sandhill cranes (Grus canadensis)

The enteric flora of captive whooping cranes (Grus americana) and sandhill cranes (Grus canadensis) has not been well described, despite its potential importance in the understanding of both the normal condition of the intestinal physiology of these animals and the altered colonization within disease states in these birds. Nineteen whooping cranes and 23 sandhill cranes housed currently at the Calgary Zoo or its affiliated Devonian Wildlife Conservation Centre (DWCC) in Calgary, Alberta were sampled from October 2004–February 2005 by collecting aerobic and anaerobic cloacal swabs from each bird. There were seven major groupings of bacteria isolated from both species of crane. Gram‐positive cocci, coliforms, and gram‐negative bacilli were the most prevalent types of bacteria isolated for both crane species, with Escherichia coli, Enterococcus faecalis, and Streptococcus Group D, not Enterococcus the bacterial species isolated most commonly. There was a significant difference in the average number of isolates per individual between the two crane species but no differences between age or gender categories within crane species. Campylobacter sp. were isolated from five whooping cranes. The potential zoonotic pathogen Campylobacter jejuni was isolated from one whooping crane and C. upsaliensis was isolated from a second. Three other isolates were unspeciated members of the Campylobacter genus and likely belong to a species undescribed previously. The evaluation of the enteric cloacal flora of whooping cranes and sandhill cranes illustrates that differences exist between these two closely related crane species, and highlights the potential implications these differences may have for current practices involving captive wildlife. Zoo Biol 0:1–13, 2007. © 2007 Wiley‐Liss, Inc.     

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host–parasite associations.     

Contribution to the knowledge on black flies (Diptera: Simuliidae) as vectors of Leucocytozoon (Haemosporida) parasites in Lithuania

Black flies (Diptera: Simuliidae) are among the most bothersome blood-sucking dipterans causing severe irritation and distress to poultry, wild birds, animals, and humans globally. These insects are vectors of viruses, bacteria, parasitic protozoans, and nematodes of humans and animals. Parasitic protozoa belonging to Haemosporida (Apicomplexa) are distributed worldwide and black flies are the principal vectors of avian haemosporidian parasites of the genus Leucocytozoon, a common parasite of birds. Based on the detection of parasite DNA in insects, 13 black fly species were reported to be potential vectors of Leucocytozoon in Europe. Information about which species of Simulium can play a role in the transmission of Leucocytozoon parasites is insufficient and needs to be developed. The aim of our study was to determine which black fly species are involved in the transmission of Leucocytozoon parasites in the Eastern Europe. The black fly females were collected in Lithuania using entomological net. They were morphologically identified, dissected to prepare salivary glands preparations, and then screened for the presence of Leucocytozoon parasites using microscopy and PCR-based methods. In all, we collected 437 black fly females belonging to eight species. The DNA of Leucocytozoon (genetic lineage lCOCO18) was detected in one of analysed females identified as Simulium maculatum. All salivary gland preparations were negative for the presence of Leucocytozoon sporozoites. Our results included S. maculatum as a potential vector of Leucocytozoon parasites. Increasing the knowledge on vector ecology, behaviour and improving collection methods may be the key to understand the evolution and diversity of these parasites.     

Spatial stratification of host-seeking Diptera in boreal forests of northern Europe

The stratification of haematophagous Diptera was assessed in two boreal forests in northern Sweden by placing traps baited with carbon dioxide at 1.5 m, 5.0 m and 10.0 m above the ground. More than 40 000 specimens were captured, including 617 biting midges (Ceratopogonidae), 4029 mosquitoes (Culicidae) and 36 092 black flies (Simuliidae). Catches at the various trap heights reflected the general vertical distribution of the preferred hosts, with mammalophilic flies predominating (68.6%) in catches at 1.5 m and ornithophilic flies (42.4%) in catches at 10.0 m; however, most flies that use host birds at ground level were caught in the lowest traps (e.g. 85.1% of Simulium annulus were collected at 1.5 m). Within-species variation in vertical patterns between forests suggests plasticity in responses to environmental factors such as vegetative structure.     

Long-term emergence patterns of black flies (Diptera: Simuliidae) in northwestern Pennsylvania

Spatial and temporal patterns of black fly emergence at three sites over a 7-year to 11-year period are presented. This study is the longest, continuous collection of emerging black flies ever undertaken. Because ovipositing females were able to enter emergence traps, analysis of emergence patterns for the Simulium vittatum Zetterstedt and S. tuberosum Lundström complexes, was restricted to males. Year, season and stream temperature had significant effects on mean emergence for these complexes. Sampling stations on the same system and within close proximity exhibited synchronous emergence patterns, whereas streams in close proximity but in separate basins showed asynchronous patterns. Dissimilarities might reflect divergent temperature regimes. We suggest that emergence-trap data might provide a less variable picture of community structure than larval data.     

Effects of environmental stressors on nest success of introduced birds

Understanding the influence of environmental stressors on daily nest survival of introduced birds is important because it can affect introduction success as well as the ability to evaluate introduction programs. For long-lived birds with low annual production, adjustment to local breeding conditions can take many years. We examined nest success rates of 2 introduced bird species, whooping crane (Grus americana) and trumpeter swan (Cygnus buccinator), in Wisconsin. Both species are long-lived with low annual reproductive rates. Trumpeter swans were established in our study area approximately 10 years before whooping cranes. We predicted that trumpeter swans would show less sensitivity to environmental stressors. We used daily nest survival rates (DNSRs) as our response variable to model several environmental parameters including weather, phenology, and ornithophilic black flies (Diptera: Simuliidae). Additionally, we examined the influence of captive history, age, release method, energetics, and nesting experience on whooping crane DNSRs. Daily nest survival of whooping cranes was the most sensitive to stressors. Trumpeter swan daily nest survival showed less sensitivity to the same stressors. Daily nest survival for both species peaked later in the nesting season, after 30 April and before 30 May. We also found that the daily nest survival rate (DNSR) for whooping cranes was potentially affected by captive exposure (measured by generations removed from the wild). Our results highlight the difficulties associated with conservation of long-lived birds with low annual productivity as they adjust to local breeding conditions and that nest phenology at the source location can determine how these conditions are interfaced. We recommend that the juxtaposition of source and introduction location nest phenology be considered prior to introduction site selection. Additionally, strategically selecting offspring from captive pairs with nest phenology similar to that of sympatric species at the introduction location should be considered. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Factors affecting the efficacy of a vinegar trap for Drosophila suzikii (Diptera; Drosophilidae)

Drosophila suzukii, Matsumura, is a relatively new pest in the United States attacking a variety of fruit crops. Studies were conducted to develop a standardized, economical trap for monitoring. Laboratory bioassays found that flies were attracted to dark colours ranging from red to black. Similarly, fly catches in 237‐ml plastic ‘spice’ jars with ten 0.48‐cm holes and baited with apple cider vinegar were significantly higher in jars with red or black than white caps. The use of an alternating set of three, horizontal red, black and red bands (‘Zorro’ trap) significantly increased fly catches compared with the use of all‐red or all‐black strips. This increase was associated with a significantly higher proportion of flies first landing on the side near the openings of the trap instead of on the cap with the ‘Zorro’ trap compared with the other traps. Laboratory data were used to develop a predictive model to define total fly capture as a function of trap colour/colour pattern, cumulative area of entry holes and the length of the trapping portion of the trap. Total fly catches by the ‘Zorro’ trap were compared with other red and clear plastic traps in five field trials conducted in several cultivated and uncultivated sites. Comparisons included a commercial red‐capped 200‐ml trap with two 0.63‐cm holes, an all‐red spice jar with ten 0.48‐cm holes and clear and red 473‐ml and clear 946‐ml plastic cups with six or ten 0.48‐ or 0.63‐cm holes. The model was successfully validated, suggesting that performance of cup traps can be predicted based on a few characteristics. The current ‘Zorro’ trap did not catch most of the flies among trap designs, but showed some advantages, including the durability and potential to recycle the plastic, small size, commercial availability and its greater selectivity for D. suzukii than the other traps tested.     

Evaluation of ammonia,human sweat,and bovine blood as attractants for the female canyon fly,Fannia conspicua (Diptera: Muscidae), in southern California

Human sweat, liquid ammonia, and bovine blood are known to be attractive to some hematophagous flies. These materials were evaluated with and without carbon dioxide (CO₂) for their ability to increase capture of female “canyon flies” (Fannia conspicua Malloch) using CDC‐type suction traps (without light). Ammonia acted synergistically with CO₂ to increase trap catch 89.9% over CO₂ alone. There was no synergistic effect of human sweat or bovine blood with CO₂. In the absence of CO₂, none of the three materials increased trap catch of female canyon flies relative to non‐baited traps. Implications for canyon fly control and further trap improvement are discussed.     

Evaluation of a Community-Based Trapping Program to Collect Simulium ochraceum sensu lato for Verification of Onchocerciasis Elimination

Background

Collection of the black fly vectors of onchocerciasis worldwide relies upon human landing collections. Recent studies have suggested that the Esperanza Window Trap baited with a human scent lure and CO₂ had the potential to replace human hosts for the collection of Simulium ochraceum sensu lato in Southern Chiapas focus, Mexico. The feasibility of utilizing these traps in a community-based approach for the collection of S. ochraceum s.l. was evaluated.

Methodology/Principal findings

Local residents of a formerly endemic extra-sentinel community for onchocerciasis were trained to carry out collections using the traps. The residents operated the traps over a 60-day period and conducted parallel landing collections, resulting in a total of 28,397 vector black flies collected. None of the flies collected were found to contain parasite DNA when tested by a polymerase chain reaction assay targeting a parasite specific sequence, resulting in a point estimate of infection in the vectors of zero, with an upper bound of the 95% confidence interval 0.13 per 2,000. This meets the accepted criterion for demonstrating an interruption of parasite transmission.

Conclusions/Significance

These data demonstrate that Esperanza Window Traps may be effectively operated by minimally trained residents of formerly endemic communities, resulting in the collection of sufficient numbers of flies to verify transmission interruption of onchocerciasis. The traps represent a viable alternative to using humans as hosts for the collection of vector flies as part of the verification of onchocerciasis elimination.     

DNA barcoding of tropical black flies (Diptera: Simuliidae) of Thailand

The ecological and medical importance of black flies drives the need for rapid and reliable identification of these minute, structurally uniform insects. We assessed the efficiency of DNA barcoding for species identification of tropical black flies. A total of 351 cytochrome c oxidase subunit 1 sequences were obtained from 41 species in six subgenera of the genus Simulium in Thailand. Despite high intraspecific genetic divergence (mean = 2.00%, maximum = 9.27%), DNA barcodes provided 96% correct identification. Barcodes also differentiated cytoforms of selected species complexes, albeit with varying levels of success. Perfect differentiation was achieved for two cytoforms of Simulium feuerborni, and 91% correct identification was obtained for the Simulium angulistylum complex. Low success (33%), however, was obtained for the Simulium siamense complex. The differential efficiency of DNA barcodes to discriminate cytoforms was attributed to different levels of genetic structure and demographic histories of the taxa. DNA barcode trees were largely congruent with phylogenies based on previous molecular, chromosomal and morphological analyses, but revealed inconsistencies that will require further evaluation.     

Comparison of fecal glucocorticoid metabolite concentrations in hand- versus parent-reared whooping cranes (Grus americana)

Endangered whooping cranes (Grus americana) have been produced in captivity for reintroduction programs since the 1980s, using techniques such as artificial insemination, multiple clutching, and captive-rearing to speed recovery efforts. Chicks are often hand-reared (HR) by caretakers in crane costumes, socialized into groups and released together, unlike parent-reared (PR) cranes that are raised individually by a male/female crane pair and released singly. HR cranes historically exhibit greater morbidity rates during development than PR cranes, involving musculoskeletal and respiratory system disease, among others. We hypothesized that HR crane chicks exhibit a higher baseline fecal glucocorticoid metabolite (FGM) concentrations during the development compared with PR chicks. Fecal samples were collected between 15 and 70 days of age from HR (n = 15) and PR (n = 8) chicks to test for differences in FGM concentrations using a radioimmunoassay technique following ethanol extraction for steroids. Linear mixed model analysis suggests increasing age of the chick was associated with an increase in FGM (p < .001). Analysis also supported the interaction between rearing strategy and sex of the crane chick (p < .01). Female PR chicks had greater FGM concentrations than all other groups (PR male, p < .01; HR female, p < .001; and HR male, p < .001). This result suggests that there may be an effect of rearing strategy on stress physiology of whooping crane chicks, especially among females. Further research is needed to investigate whether the FGM concentrations are reflective of true differences in stress physiology of young cranes and whether this may impact health and conservation success.     

Evaluation of commercial and field‐expedient baited traps for house flies,Musca domestica L. (Diptera: Muscidae)

A comparison of nine commercial baited fly traps on Florida dairy farms demonstrated that Terminator traps collected significantly more (13,323/trap) house flies (Musca domestica L.) than the others tested. Final Flight, Fly Magnet, and FliesBeGone traps collected intermediate numbers of flies (834‐2,166), and relatively few were caught with ISCA, Advantage, Fermone Big Boy, Squeeze & Snap, or OakStump traps (<300). Terminator traps collected about twice as many flies (799.8/trap) as FliesBeGone traps (343.8) when each trap was baited with its respective attractant, but when the attractants were switched between the two trap types, collections were significantly lower (77‐108) than was observed with traps baited with their respective attractant. Solutions of molasses were significantly more attractive to house flies than honey, maple syrup, or jaggery (date palm sugar). Field‐expedient traps constructed from discarded PET water bottles were much less effective than commercial traps, but painting the tops of such traps with black spray paint resulted in a six‐fold increase in trap capture.     

Fruit‐ and seed‐feeding habit of the crane fly Libnotes puella (Diptera: Limoniidae) in Ryukyu Islands,Japan

Although most crane fly larvae consume decaying plant materials and their associated microorganisms, all Libnotes species investigated so far are known to be xylophilous insects. Here we report the novel herbivorous feeding ecology of Libnotes puella. We found that L. puella larvae consumed the fruits or seeds of three unrelated plants, Mitrastemon yamamotoi (Mitrastemonaceae), Balanophora tobiracola (Balanophoraceae) and Barringtonia racemosa (Lecythidaceae). The larvae live within dense tubes formed by their feces fastened by their mucous excretions at the final stage, and they pupate within such tubes. This is the first detailed documentation of the fruit‐ and seed‐feeding habit of crane flies.     

Effects of land use on black fly assemblages (Diptera: Simuliidae) in submontane rivers (West Carpathians, Slovakia)

The effects of land use on black fly assemblages were investigated in submontane rivers (the Ľubochnianka River, the Revúca River, upper Váh River catchment) in the Carpathians. We recorded 11 black fly species in the Ľubochnianka River and 10 species in the Revúca River. Land use differs between the catchments; the Ľubochnianka is a primarily forested catchment, and the Revúca is markedly deforested catchment. Fifteen environmental variables were analysed. Based on the results provided by CANOCO, phosphorus level and stream slope are the most important variables and have significant influences on the variability of black fly assemblages. In spring, Prosimulium rufipes occurred along the entire lengths of the streams. The black fly assemblage of the Revúca River differs from the assemblage of the Ľubochnianka River mainly by its higher abundances of Simulium variegatum and Simulium ornatum, by the presence of Simulium carthusiense, and by the absence of Prosimulium hirtipes.     

Evaluation of traps of six different designs to capture pine sawyer beetles (Coleoptera: Cerambycidae)

1 Sawyer beetles (Coleoptera: Cerambycidae) and metallic wood‐boring beetles (Coleoptera: Buprestidae) attack recently killed or felled trees. They are attracted to potential hosts by volatiles and possibly by visual cues. We examined traps of six different designs to determine the role of silhouette and shape in the capture of pine sawyer beetles, Monochamus L. 2 Traps with a round black cylinder, a single vane (clear or black), or cross vanes (clear or black) all mounted above a pan were compared to an open pan. Each pan contained soapy water to retain insects. 3 Traps with a black silhouette were significantly more effective in capturing male and female Monochamus scutellatus (Say) than traps with or without clear vanes. For both sexes of M. mutator LeConte, pan traps were as effective as traps with a black silhouette. Silhouette was not important for the capture of male and female M. notatus (Drury). Trap catches for the six trap types were not significantly different for male Buprestis maculativentris Say. 4 A pan trap with a black silhouette is recommended for general use in capturing wood‐boring cerambycids and buprestids.     

Are whooping cranes destined for extinction? Climate change imperils recruitment and population growth

Identifying climatic drivers of an animal population's vital rates and locating where they operate steers conservation efforts to optimize species recovery. The population growth of endangered whooping cranes (Grus americana) hinges on juvenile recruitment. Therefore, we identify climatic drivers (solar activity [sunspots] and weather) of whooping crane recruitment throughout the species’ life cycle (breeding, migration, wintering). Our method uses a repeated cross‐validated absolute shrinkage and selection operator approach to identify drivers of recruitment. We model effects of climate change on those drivers to predict whooping crane population growth given alternative scenarios of climate change and solar activity. Years with fewer sunspots indicated greater recruitment. Increased precipitation during autumn migration signified less recruitment. On the breeding grounds, fewer days below freezing during winter and more precipitation during breeding suggested less recruitment. We predicted whooping crane recruitment and population growth may fall below long‐term averages during all solar cycles when atmospheric CO₂ concentration increases, as expected, to 500 ppm by 2050. Species recovery during a typical solar cycle with 500 ppm may require eight times longer than conditions without climate change and the chance of population decline increases to 31%. Although this whooping crane population is growing and may appear secure, long‐term threats imposed by climate change and increased solar activity may jeopardize its persistence. Weather on the breeding grounds likely affects recruitment through hydrological processes and predation risk, whereas precipitation during autumn migration may influence juvenile mortality. Mitigating threats or abating climate change should occur within ≈30 years or this wild population of whooping cranes may begin declining.     

Food consumption and retention time in captive whooping cranes (Grus americana)

Food consumption, digesta retention time, and food preference were measured for captive whooping cranes fed pelleted diets. The basal commercial diet was compared to four mixtures containing 70% basal and 30% of one of four important winter foods for the whooping crane: blue crab (Callinectes sapidus), wolfberry fruit (Lycium carolinianum), live oak acorn (Quercus virginiana), or common Rangia clam (Rangia cuneata). Because captive birds would not eat whole foods, we were prevented from direct food preference tests. Food passed through the gut rapidly, with almost complete elimination within 7 hr. There was some indication that retention time was shorter for the low fiber and high ash and calcium clam diet. Cranes ate less wolfberry feed (g/day) than the other feeds, and all birds ate less wolfberry feed on the day it was first fed, compared to basal diet the previous day. Birds ate more low energy feed than high energy feed. Due to combined effects of low energy content, lower metabolizable energy coefficients, and reduced feed consumption, less energy was assimilated for study diets than basal diet. Apparent shorter retention times for some diets containing whooping crane foods may partly explain lower digestibilities and metabolizable energy of winter whooping crane foods compared to commercial crane diet. Zoo Biol 16:519–531, 1997. © 1997 Wiley-Liss, Inc.