Identification Of Predators Research Articles

Snakes are the principal nest predators of the threatened reed parrotbill in a coastal wetland of eastern China

Nest predation is a major limiting factor of bird reproductive success, and predation by snakes may have particularly adverse effects on passerines. The reed parrotbill (Paradoxornis heudei) is a threatened passerine that inhabits reedbeds in East China, where it faces the risk of population decline due to habitat loss and degradation. Studies on the nest predation of this species are lacking. In this study, we monitored reed parrotbill nests in the core area of the Yancheng Nature Reserve, Jiangsu Province, China. We tracked the final fate of each nest and determined the identity of the predators using infrared cameras. We monitored a total of 13 and 15 active nests in 2017 and 2019, respectively, but only 5 nests were successful. Nest predation was responsible for 22 of 23 nest failures (95.7%). Snakes were the principal predators of the nests, responsible for 19 predation events (86.4%). We used abandoned reed parrotbill nests and quail eggs to create artificial nests. However, the survival rate of the artificial nests (63.3%) was significantly higher than that of the natural nests (11.3%), and rats replaced snakes as the principal predators. The best model indicated that the daily survival rate of reed parrotbill nests decreased with nest age. Our findings suggest that severe snake predation may be an important factor threatening populations of the reed parrotbill, even though the wetland habitat is well protected. The identification of specific nest predators may facilitate the conservation of this near-threatened bird through the development of effective management strategies in reserves. More studies on population estimates of the reed parrotbill and the interactions between this endangered bird and snakes using natural (rather than artificial) nests in different areas are needed.

Identification of land predators of African Penguins Spheniscus demersus through post-mortem examination

The African Penguin Spheniscus demersus is an endangered seabird endemic to southern Africa, and killing sprees by terrestrial predators have been one of the main threats for its mainland colonies. The methods employed to manage predators may differ depending on the species involved, therefore the implementation of strategies to limit the impacts of predation relies on the correct identification of the culprit predator. We report and quantify the lesions seen in African Penguins killed by four species of terrestrial predators: Caracal Caracal caracal (52 kills), Leopard Panthera pardus (27 kills), Domestic Dog Canis lupus familiaris (10 kills), and Cape Grey Mongoose Galerella pulverulenta (4 kills). We discuss patterns of necropsy findings that can be used to identify the predator species involved. Traditional forensic methods are useful tools to direct species-specific management actions for the conservation of the African Penguin and other seabirds so that effective mitigating measures can be deployed quickly to prevent further losses. It should be borne in mind, however, that the age, size and previous hunting experience of the predator are likely to influence the pattern of lesions that will be observed, and not all carcasses will have hallmark lesions or recognisable bite marks.

The use of canid tooth marks on bone for the identification of livestock predation

Historically wolves and humans have had a conflictive relationship which has driven the wolf to extinction in some areas across Northern America and Europe. The last decades have seen a rise of multiple government programs to protect wolf populations. Nevertheless, these programs have been controversial in rural areas, product of the predation of livestock by carnivores. As a response to such issues, governments have presented large scale economic plans to compensate the respected owners. The current issue lies in the lack of reliable techniques that can be used to detect the predator responsible for livestock predation. This has led to complications when obtaining subsidies, creating conflict between landowners and government officials. The objectives of this study therefore are to provide a new alternative approach to differentiating between tooth marks of different predators responsible for livestock predation. Here we present the use of geometric morphometrics and Machine Learning algorithms to discern between different carnivores through in depth analysis of the tooth marks they leave on bone. These results present high classification rates with up to 100% accuracy in some cases, successfully differentiating between wolves, dogs and fox tooth marks.

Regurgitalites – a window into the trophic ecology of fossil cephalopods

Fossil oral ejecta that exclusively contain bivalved calcitic lower jaws of ammonites (=aptychi) from Late Jurassic Solnhofen-type deposits of southern Germany are described. Based on the symphysis length of aptychi the ammonite shell diameters were reconstructed, ranging from 5 to 170 mm. To identify the potential ammonite predator published reports on stomach contents, coprolites and ammonite-palaeopathology were critically assessed. Implementation of the actualistic approach, together with some functional considerations, includes the identification of modern cephalopod predators with a focus on the modern Nautilus , and the distribution of vomiting behaviour among them. Stomach fluid pH is also important because species with an alkaline stomach pH are unable to dissolve calcareous hardparts and have to orally eject such material. Herein, we regard coleoids with an opportunistic diet as the most likely producers of the aptychi-bearing regurgitalites. This is based on finds of aptychi in the stomachs of the two coleoids Plesioteuthis and Trachyteuthis. They were likely fast, highly manoeuvrable swimmers. Both share a strong, triangular-shaped jaw apparatus that could possibly crush ammonite shells as well as arms equipped with suckers to hold their prey. Circumstantial evidence for coleoids as the producers comes from the alkaline pH of the stomach fluids of modern coleoids. Supplementary material: Data for lamellaptychi are available at https://doi.org/10.6084/m9.figshare.c.4695002

Genetic Identification of Species Responsible for Depredation in Commercial and Recreational Fisheries

AbstractDepredation, the partial or complete removal of hooked fish (prey) by a nontarget predator species, is a cryptic interaction that negatively affects predators, prey, and fishing industries. However, these interactions are rarely observed, rendering positive identification of the predator nearly impossible. We therefore tested a genetic method for predator identification. Depredated remains from sharks and bony fish were sampled with buccal swabs. Genetic material was isolated from the swabs, which we hypothesized contained oral cells from the predator. A portion of the cytochrome‐c oxidase subunit I locus was amplified using prey‐specific blocking primers and sequenced in high depth using a metagenetics approach. We sequenced haplotypes from the remains of four sharks, where the predator was visually confirmed, and four bony fish, where the predator was unknown. For all interactions with known predators, our technique suggested the correct predator species. For all interactions where the predators were unknown, our technique suggested species previously confirmed as perpetrators in depredation events. Our findings provide a basis for the development of a genetic technique for predator identification, while highlighting challenges to be overcome before predator identification can be applied to large‐scale fisheries.

A text classification framework for simple and effective early depression detection over social media streams

With the rise of the Internet, there is a growing need to build intelligent systems that are capable of efficiently dealing with early risk detection (ERD) problems on social media, such as early depression detection, early rumor detection or identification of sexual predators. These systems, nowadays mostly based on machine learning techniques, must be able to deal with data streams since users provide their data over time. In addition, these systems must be able to decide when the processed data is sufficient to actually classify users. Moreover, since ERD tasks involve risky decisions by which people’s lives could be affected, such systems must also be able to justify their decisions. However, most standard and state-of-the-art supervised machine learning models (such as SVM, MNB, Neural Networks, etc.) are not well suited to deal with this scenario. This is due to the fact that they either act as black boxes or do not support incremental classification/learning. In this paper we introduce SS3, a novel supervised learning model for text classification that naturally supports these aspects. SS3 was designed to be used as a general framework to deal with ERD problems. We evaluated our model on the CLEF’s eRisk2017 pilot task on early depression detection. Most of the 30 contributions submitted to this competition used state-of-the-art methods. Experimental results show that our classifier was able to outperform these models and standard classifiers, despite being less computationally expensive and having the ability to explain its rationale.

Communicate and Fuse: How Filamentous Fungi Establish and Maintain an Interconnected Mycelial Network.

Cell-to-cell communication and cell fusion are fundamental biological processes across the tree of life. Survival is often dependent upon being able to identify nearby individuals and respond appropriately. Communication between genetically different individuals allows for the identification of potential mating partners, symbionts, prey, or predators. In contrast, communication between genetically similar (or identical) individuals is important for mediating the development of multicellular organisms or for coordinating density-dependent behaviors (i.e., quorum sensing). This review describes the molecular and genetic mechanisms that mediate cell-to-cell communication and cell fusion between cells of Ascomycete filamentous fungi, with a focus on Neurospora crassa. Filamentous fungi exist as a multicellular, multinuclear network of hyphae, and communication-mediated cell fusion is an important aspect of colony development at each stage of the life cycle. Asexual spore germination occurs in a density-dependent manner. Germinated spores (germlings) avoid cells that are genetically different at specific loci, while chemotropically engaging with cells that share identity at these recognition loci. Germlings with genetic identity at recognition loci undergo cell fusion when in close proximity, a fitness attribute that contributes to more rapid colony establishment. Communication and cell fusion also occur between hyphae in a colony, which are important for reinforcing colony architecture and supporting the development of complex structures such as aerial hyphae and sexual reproductive structures. Over 70 genes have been identified in filamentous fungi (primarily N. crassa) that are involved in kind recognition, chemotropic interactions, and cell fusion. While the hypothetical signal(s) and receptor(s) remain to be described, a dynamic molecular signaling network that regulates cell-cell interactions has been revealed, including two conserved MAP-Kinase cascades, a conserved STRIPAK complex, transcription factors, a NOX complex involved in the generation of reactive oxygen species, cell-integrity sensors, actin, components of the secretory pathway, and several other proteins. Together these pathways facilitate the integration of extracellular signals, direct polarized growth, and initiate a transcriptional program that reinforces signaling and prepares cells for downstream processes, such as membrane merger, cell fusion and adaptation to heterokaryon formation.

Predation on Eggs of Aedes aegypti (Diptera: Culicidae): Temporal Dynamics and Identification of Potential Predators During the Winter Season in a Temperate Region.

In temperate regions, the populations of Aedes aegypti (L.) remain in the egg stage during the cold season. The ability of these eggs to survive until the next favorable season is affected by several mortality factors, including the action of predators. In the present study, we analyzed the temporal dynamics of the loss of eggs and identified predators of Ae. aegypti eggs along the unfavorable season in a temperate region of Argentina. To this end, eggs were exposed in field conditions in pitfall traps, where walking arthropod taxa were captured during 1-wk periods from early June to early September (Austral winter). The association of arthropod taxa with the loss of eggs was analyzed to identify potential predators. Based on the results obtained, two taxa were chosen to confirm their capacity to consume eggs in a laboratory study. The proportion of lost eggs and the abundance of predators were significantly higher in the winter-spring transition, although results were heterogeneous among traps in all exposure periods. Ants of the genus Strumigenys, isopods of the species Armadillidium vulgare (Isopoda: Armadilloidea), and dermapterans of the species Euborellia annulipes (Dermaptera: Anisolabidae) were positively associated with a high proportion of lost eggs. In laboratory conditions, A. vulgare and E. annulipes consumed the offered eggs, thus confirming their predator capacity. This study represents the first record of predation of Ae. aegypti eggs in temperate South America and the first evidence of dermapterans consuming mosquito eggs.

Using reliable predator identification to investigate feeding habits of Neotropical carnivores (Mammalia, Carnivora) in a deforestation frontier of the Brazilian Amazon

Abstract Accurate identification of predator species is a critical requirement to investigate their diet using faecal samples. We used non-invasive sampling and two methods of predator identification to investigate the diets of sympatric carnivores in a highly deforested region of the Brazilian Amazon. Of 108 scats, 81 could be identified at the species level using DNA sequencing and/or trichology. The former performed better than the latter (81.5% vs. 54.3% of the identified samples), and results were quite congruent (89.7% concordance in the 29 samples that could be assessed with both approaches). Nine species were identified, out of which four (crab-eating fox, ocelot, puma and jaguar) presented a sufficient number of samples to allow dietary analyses. The crab-eating fox was the most generalist (BA=0.92); ocelots focused on small- to medium-sized prey; pumas fed mostly on medium-sized items; and jaguars mostly targeted large-sized prey. A considerable overlap was observed between ocelots and pumas in all estimations (O=0.47–0.83). The presence of jaguars in the same region could be driving pumas to select medium- and small-sized prey. The results of this study highlight the importance of reliable predator identification and the need for in-depth ecological studies in areas where carnivore species are sympatric.

Parent-absent begging and the risk of nest predation

Despite the fact that parent-absent begging (PAB) has been studied as a communication tool during competition between nestlings for food or as a signal of need, its role in nest predation has been poorly investigated. In this study we examined whether the natural level of Common Cuckoo (hereafter “Cuckoo”) PAB increases the risk of artificial nest predation (n = 48) by using three types of experimental playback of parent-present begging (PPB) which differ in the presence or absence of additional PPB, PAB or periods of silence. Contrary to our predictions, we did not find a significant difference in daily survival rates between PPB + PAB vs. PPB + PPB nests or between PPB + PAB vs. PPB + silence nests, indicating that the natural level of Cuckoo PAB did not influence nest vulnerability to predation. Moreover, we did not find a significant difference between nests with any of the types of playback and completely silent control nests, suggesting that not only PAB, but also begging behaviour itself, does not present an important predation cost for nestlings, at least not in cases when nestlings beg at the natural level used in our experiment. As we filmed all experimental nests during their exposure to predators, we were able to show that eight of 20 filmed nest-predation events were caused by predators that never or rarely predate upon passerine nests. Excluding predation events by these unlikely predators, however, did not change our original results. Nonetheless, we advocate direct identification of nest predators to strengthen the interpretation of future studies on the predation cost of begging.

QUANTIFYING THE DIGESTIVE FINGERPRINTS OF PREDATORS ON THE BONES OF THEIR PREY USING SCANNING ELECTRON MICROSCOPY

Paleoecological reconstruction relies on accurately determining the taphonomic origin of fossil deposits. Predation is a common mechanism by which skeletal remains become concentrated over time, leading to the formation of modern and fossil prey death assemblages. Skeletal element representation and breakage patterns within such death assemblages can be used to infer the identity of the responsible predator. However, assemblage-level metrics cannot be used to infer if a single fossil specimen is predator-derived. Microscopic digestive etching on individual bones can also indicate past predation events because acidic gastric fluids create distinctive micrometer-scale fissures in cortical bone. Here we establish a quantitative approach to predator identification from small mammal prey remains using microscopic digestive damage patterns. To do this, we collected mandibles from rodents digested by 13 predator species from local wildlife rehabilitation centers, and imaged them using an FEI Quanta 200 SEM. Results indicate that bones exposed to gastric fluids show clear digestive fissures, and that owl-digested specimens can be readily distinguished from specimens that were digested by diurnal raptors and mammalian carnivores. Specifically, owl-digested specimens are characterized by a high density of small and short digestive fissures. Within the owls, digestive fissure patterns appear to scale with owl body size. Finally, we used linear discriminant analysis to build a classification scheme from our modern data and applied it to Holocene mouse fossils from Two Ledges Chamber, Nevada. We found that the fossil specimens display the digestive fingerprints of owls. Quantification of microscopic digestive fissures thus offers a promising new approach for elucidating the taphonomic history of individual fossil specimens.

Variation in age-dependent nest predation between island and continental Rufous Fantail (Rhipidura rufifrons) subspecies

ABSTRACT Comparative studies of nest predation and identification of nest predators promote understanding of the selective environment that shapes avian life histories. Due to the low diversity of native mammalian and reptilian predators on oceanic islands, insular forest birds are assumed to incur lower nest predation rates than related continental species. We studied correlates of nest predation in insular and continental subspecies of Rufous Fantail (Rhipidura rufifrons) found on the island of Rota and in eastern Australia. Overall, daily survival rate (DSR) was similar between study sites, but egg stage DSR (laying and incubation) was higher in Australia than on Rota while nestling stage DSR was higher on Rota than in Australia. DSR was negatively related to nest age in Australia and the magnitude of this relationship varied by year. On Rota, DSR was higher in the nestling stage than during the egg stage and also higher on our study plot where Mariana Crows (Corvus kubaryi)—the principal nest predator...

Accuracy of nest fate classification and predator identification from evidence at nests of Least Terns and Piping Plovers

For federally listed species such as Least Tern Sternula antillarum and Piping Plover Charadrius melodus, correct determination of nest fates and causes of nest failure is crucial for understanding population dynamics and improving monitoring programmes. We used video cameras to evaluate nest fate misclassification rate and to identify factors that may cause researchers monitoring nests at different intervals to classify Least Tern and Piping Plover nest fates incorrectly. During the 2013–2015 breeding seasons, we installed miniature surveillance cameras at 65 of 294 Least Tern and 89 of 551 Piping Plover nests under observation on the Missouri River in North Dakota. Nest fates were assigned in the field from remains found at the nest‐site and then again by an independent researcher who reviewed camera footage. We used ordinal logistic regressions to examine whether monitoring interval, clutch age or temporal factors influenced a correct, partially misclassified (probable successful in the field vs. successful by camera) or misclassified nest fate classification. During a 7‐day monitoring interval between visits, 45% of nests were partially and 27.5% were fully misclassified. The percentage of partially (20%) and fully (8.0%) misclassified nests decreased with a more intensive (3‐day) monitoring schedule. Researchers were also less likely to correctly classify nest fates for Least Terns than for Piping Plovers, and as clutch age and monitoring interval increased for both species. Furthermore, causes of failure (e.g. predators, weather) as determined from field evidence vs. video disagreed for 53.5% of nests. The ability to identify accurately nest fate and cause of nest failure will facilitate a better understanding of factors that limit productivity and will lead to better informed management decisions for improving nest survival.

Human-Wildlife Conflict Pattern and Suggested Mitigation Strategy in the Pamirs of Northwestern China

Predation of livestock by wildlife and the retribution responses it elicits can have strong negative impacts on both people and carnivores. A questionnaire survey designed to investigate human-carnivore conflicts was completed by 66 herders from local communities within Taxkorgan Nature Reserve, located in the Pamir and Karkorum mountains of Northwestern China. A total of 127 livestock predation events with associated predator identification were reported and 583 livestock were killed. Wolves (315 livestock) and dholes (129 livestock) were responsible for the largest number of livestock losses. Livestock depredation significantly differed between guarded and unguarded management strategies. Positive relationships between loss and the total amount of the major livestock species, as well as the total loss and total amount of livestock, were detected. Use of guard dogs did not affect the likelihood of carnivore attacks, whereas keeping livestock in pens at night or all day did reduce the number of depredation events. Depredation showed significant seasonal variation (month of occurrence) for large carnivores. Numbers of goat, sheep, and cattle predated also varied by month, but did not for yak because of different husbandry practices. No compensation policy has yet been established in this area, but if it were to be developed in the future, 83% of interviewed herders would require compensation in cash, whereas 14% of herders would prefer replacement livestock. Our study offers suggestions to mitigate livestock depredation in this region of China. To prevent livestock depredations, local herders should mainly prevent wolves and dholes because they cause most livestock killings, and employ guarded grazing practice. Managers could make herders keep a reasonable number of livestock to raise grazing efficiency, introduce suitable sheepdog breeds, and provide essential dog training as useful aids to herders to increase livestock-guarding effectiveness.

The Braveheart amphipod: a review of responses of invasiveDikerogammarus villosusto predation signals

Predator pressure is a fundamental force driving changes at all levels of the community structure. It may protect native ecosystems from alien species. Therefore, resistance to diverse predators resulting from a universal anti-predator strategy seems crucial for invasion success. We present a comprehensive review of the responses of an invasive amphipod Dikerogammarus villosus to sympatric and allopatric predator signals. We summarize diverse aspects of the gammarid anti-predator strategy, including predator identification, morphological and behavioural adaptations, effectiveness of shelter use and resistance to indirect predator effects. The response of D. villosus is independent of predator species (including totally allopatric taxa), which assures the high flexibility of its predator recognition system. It has a harder exoskeleton and better capability of utilizing shelters compared to other gammarids, resulting in relatively high resistance to predators. Therefore, it can use predator kairomones as indirect food signals (sharing the diet with the predator) and follow the predator scent. This resistance may allow D. villosus to reduce the costs of its physiological responses to predators and sustain growth in their presence. This might facilitate invasion success by increasing its competitive advantage.

The National Collection of Arachnida, South Africa: Making the Collection more Accessible

The National Collection of Arachnida (NCA) was established in 1976 at the Agricultural Research Council – Plant Health & Protection (ARC-PHP) in Pretoria, South Africa. This collection forms part of South Africa’s National Assets, which the ARC manages and maintains on behalf of the Department of Agriculture, Forestry and Fisheries (DAFF) and the Department of Science and Technology (DST). The specimen holdings of the NCA contain a wealth of associated taxonomic, biological and geographical information. Currently the collection is managed by a dedicated collection manager responsible for the day-to-day running of the collection assisted by one research assistant. It is utilized for various research activities and knowledge generation in the fields of agriculture and natural resource management. The specimens are preserved using 75% alcohol and held in a double vial method in order to maximize protection of the specimens against evaporation and breakage. Hand-written catalogue books are still used to record and allocate a unique NCA – AcAT number for each specimen. This number links to all primary data recorded for the specimen. Furthermore, the data associated with the specimens are digitized according to Darwin-Core guidelines in an Structured Query Language (SQL) relational database. The database was developed by the ARC-Information Technology services. The entire NCA presently houses approximately 77,780 catalogue entries representing more than 233,300 specimens from six Arachnida orders. The NCA is made up mainly of reference specimens, but also has a type specimen collection of newly described species. The type collection currently contains 1,018 type specimens representing 321 species in 136 genera and 42 families. Of these, 207 specimens are holotypes. The type collection is housed separately from the reference collection and was recently moved to a newly acquired fireproof cabinet. Further planned activities include taking photos of all type specimens using a Zeiss V.16 Zoom microscope so that all type holdings are fully digitized. This will allow the implementation of an electronic loans system. Updating of the types list in the collection will facilitate availability for the wider community. The NCA provides support for key services such as the identification of arachnid predators that have an impact on agricultural production and bio-security as well as a specimen identification and advisory service to government, farmers, industry, researchers, students and the public. These services are essential for research projects on biosystematics and relevant related fields such as conservation, decision-making, agriculture and natural resource management.

Towards more efficient large-scale DNA-based detection of terrestrial mammal predators from scats

The DNA detection of wildlife from environmental samples has the potential to contribute significantly to wildlife management and ecological research. In terrestrial ecosystems, much work has focused on the identification of mammal predators from faecal (scat) samples. However, the relatively high time and financial costs of collecting and analysing scat DNA remain barriers to more widespread implementation of such DNA detection methods, especially for high-throughput surveys. Here, we evaluate methods used for DNA extraction from scats, as applied to detection of the Australian red fox, an introduced predator. We compare the relative costs of two approaches: the method previously used to screen thousands of scat samples in surveys over several years, and a modified version which involves swabbing scats at the time of collection and using a mechanised liquid handling platform to extract DNA from the swabs. We demonstrate that mechanised DNA extraction from swabs is more efficient than manual DNA extraction from whole scats, in terms of both time and resources. This provides a means for rapid, high-throughput screening of scats for the presence of mammal predators, enabling time-effective management responses to non-invasive surveys.

Quantifying Conservation Biological Control for Management of Bemisia tabaci (Hemiptera: Aleyrodidae) in Cotton.

Conservation biological control can be an effective tactic for minimizing insect-induced damage to agricultural production. In the Arizona cotton system, a suite of generalist arthropod predators provides critical regulation of Bemisia tabaci Gennadius (MEAM1) (Hemiptera: Aleyrodidae) and other pests. Arthropod predator and B. tabaci populations were manipulated with a range of broad-spectrum and selective insecticide exclusions to vary predator to prey interactions in a 2-yr field study. Predator to prey ratios associated with B. tabaci densities near the existing action threshold were estimated for six predator species found to be negatively associated with either adult and/or large nymphs of B. tabaci [Misumenops celer (Hentz) (Araneae: Thomisidae), Drapetis nr divergens (Diptera: Empididae), Geocoris pallens Stäl (Hemiptera: Geocoridae), Orius tristicolor (White) (Hemiptera: Anthocoridae), Chrysoperla carnea s.l. (Neuroptera: Chrysopidae), and Collops spp. (Coleoptera: Melyridae)] with the first three most consistently associated with declining B. tabaci densities. Ratios ranged from 1 M. celer per 100 sweeps to 1 B. tabaci adult per leaf to 44 D. nr. divergens per 100 sweeps to 1 large nymph per leaf disk. These ratios represent biological control informed thresholds that might serve as simple-to-use decision tool for reducing risk in the current B. tabaci integrated pest management strategy. The identification of key predators within the large, flexible food web of the cotton agro-ecosystem and estimation of predator to B. tabaci ratios clarifies the role of key predators in B. tabaci suppression, yielding potential decision-making advantages that could contribute to further improving economic and environmental sustainability of insect management in the cotton system.

Cryptophyta as major bacterivores in freshwater summer plankton

Small bacterivorous eukaryotes play a cardinal role in aquatic food webs and their taxonomic classification is currently a hot topic in aquatic microbial ecology. Despite increasing interest in their diversity, core questions regarding predator–prey specificity remain largely unanswered, e.g., which heterotrophic nanoflagellates (HNFs) are the main bacterivores in freshwaters and which prokaryotes support the growth of small HNFs. To answer these questions, we fed natural communities of HNFs from Římov reservoir (Czech Republic) with five different bacterial strains of the ubiquitous betaproteobacterial genera Polynucleobacter and Limnohabitans. We combined amplicon sequencing and catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) targeting eukaryotic 18 S rRNA genes to track specific responses of the natural HNF community to prey amendments. While amplicon sequencing provided valuable qualitative data and a basis for designing specific probes, the number of reads was insufficient to accurately quantify certain eukaryotic groups. We also applied a double-hybridization technique that allows simultaneous phylogenetic identification of both predator and prey. Our results show that community composition of HNFs is strongly dependent upon prey type. Surprisingly, Cryptophyta were the most abundant bacterivores, although this phylum has been so far assumed to be mainly autotrophic. Moreover, the growth of a small lineage of Cryptophyta (CRY1 clade) was strongly stimulated by one Limnohabitans strain in our experiment. Thus, our study is the first report that colorless Cryptophyta are major bacterivores in summer plankton samples and can play a key role in the carbon transfer from prokaryotes to higher trophic levels.

Identification and impact of hyperparasitoids and predators affecting Cyzenis albicans (Tachinidae), a recently introduced biological control agent of winter moth (Operophtera brumata L.) in the northeastern U.S.A.

The success or failure of an introduced biological control agent may depend on its rate of mortality from disease, predation, and hyperparasitism. Cyzenis albicans Fallén (Diptera: Tachinidae) was introduced to the northeastern U.S. as a biocontrol agent of the invasive species winter moth, Operophtera brumata L. (Lepidoptera: Geometridae). This study aimed to determine the rates of mortality from predation by generalist ground predators and hyperparasitism of C. albicans puparia, identify any hyperparasitoids, and assess the impact of predation and hyperparasitism on the potential success of C. albicans in controlling the winter moth. Mortality of C. albicans puparia was primarily due to predation, but there was also hyperparasitism. Predation and parasitism of C. albicans puparia were consistently high across the six study sites and two years of study, but somewhat lower than was reported from British Columbia, where successful establishment of C. albicans in the 1970s was followed by a decrease in winter moth densities. In this study, three genera of ichneumonid hyperparasitoids were detected and identified using a combination of morphological and molecular approaches: Phygadeuon (1 species), Pimpla (2 species), and Gelis (2 species), all of which contain species with broad host ranges and were likely acting as facultative hyperparsitoids. We conclude that while total mortality of C. albicans puparia is high, it is unlikely to have a significant effect on biological control of winter moth in this system, although it may explain why C. albicans has been slow to establish in this region. Our study emphasizes the importance of assessing the mortality of introduced biological control agents caused by native predators and hyperparasitoids.