Microbial Gut Diversity of Africanized and European Honey Bee Larval Instars

The first step in understanding gut microbial ecology is determining the presence and potential niche breadth of associated microbes. While the core gut bacteria of adult honey bees is becoming increasingly apparent, there is very little and inconsistent information concerning symbiotic bacterial communities in honey bee larvae. The larval gut is the target of highly pathogenic bacteria and fungi, highlighting the need to understand interactions between typical larval gut flora, nutrition and disease progression. Here we show that the larval gut is colonized by a handful of bacterial groups previously described from guts of adult honey bees or other pollinators. First and second larval instars contained almost exclusively Alpha 2.2, a core Acetobacteraceae, while later instars were dominated by one of two very different Lactobacillus spp., depending on the sampled site. Royal jelly inhibition assays revealed that of seven bacteria occurring in larvae, only one Neisseriaceae and one Lactobacillus sp. were inhibited. We found both core and environmentally vectored bacteria with putatively beneficial functions. Our results suggest that early inoculation by Acetobacteraceae may be important for microbial succession in larvae. This assay is a starting point for more sophisticated in vitro models of nutrition and disease resistance in honey bee larvae

Virulence of mixed fungal infections in honey bee brood

<p>Abstract</p> <p>Introduction</p> <p>Honey bees, <it>Apis mellifera</it>, have a diverse community of pathogens. Previous research has mostly focused on bacterial brood diseases of high virulence, but milder diseases caused by fungal pathogens have recently attracted more attention. This interest has been triggered by partial evidence that co-infection with multiple pathogens has the potential to accelerate honey bee mortality. In the present study we tested whether co-infection with closely related fungal brood-pathogen species that are either specialists or non-specialist results in higher host mortality than infections with a single specialist. We used a specially designed laboratory assay to expose honey bee larvae to controlled infections with spores of three <it>Ascosphaera </it>species: <it>A. apis</it>, the specialist pathogen that causes chalkbrood disease in honey bees, <it>A. proliperda</it>, a specialist pathogen that causes chalkbrood disease in solitary bees, and <it>A. atra</it>, a saprophytic fungus growing typically on pollen brood-provision masses of solitary bees.</p> <p>Results</p> <p>We show for the first time that single infection with a pollen fungus <it>A. atra </it>may induce some mortality and that co-infection with <it>A. atra </it>and <it>A. apis </it>resulted in higher mortality of honey bees compared to single infections with <it>A. apis</it>. However, similar single and mixed infections with <it>A. proliperda </it>did not increase brood mortality.</p> <p>Conclusion</p> <p>Our results show that co-infection with a closely related fungal species can either increase or have no effect on host mortality, depending on the identity of the second species. Together with other studies suggesting that multiple interacting pathogens may be contributing to worldwide honey bee health declines, our results highlight the importance of studying effects of multiple infections, even when all interacting species are not known to be specialist pathogens.</p

Ant colonies prefer nest sites containing infectious corpses

The process of connected text reading has received very little attention in contemporary cognitive psychology. This lack of attention is in parts due to a research tradition that emphasizes the role of basic lexical constituents, which can be studied in isolated words or sentences. However, this lack of attention is in parts also due to the lack of statistical analysis techniques, which accommodate interdependent time series. In this study, we investigate text reading performance with traditional and nonlinear analysis techniques and show how outcomes from multiple analyses can used to create a more detailed picture of the process of text reading. Specifically, we investigate reading performance of groups of literate adult readers that differ in reading fluency during a self-paced text reading task. Our results indicate that classical metrics of reading (such as word frequency) do not capture text reading very well, and that classical measures of reading fluency (such as average reading time) distinguish relatively poorly between participant groups. Nonlinear analyses of distribution tails and reading time fluctuations provide more fine-grained information about the reading process and reading fluency

Ant colonies prefer infected over uninfected nest sites

During colony relocation, the selection of a new nest involves exploration and assessment of potential sites followed by colony movement on the basis of a collective decision making process. Hygiene and pathogen load of the potential nest sites are factors worker scouts might evaluate, given the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice of an infected and an uninfected nest. The ants had an intermediate preference for empty nests. Pharaoh ants display an overall preference for infected nests during colony relocation. While we cannot rule out that the ants are actually manipulated by the pathogen, we propose that this preference might be an adaptive strategy by the host to "immunize" the colony against future exposure to the same pathogenic fungus

Standard methods for fungal brood disease research

Chalkbrood and stonebrood are two fungal diseases associated with honey bee brood. Chalkbrood, caused by Ascosphaera apis, is a common and widespread disease that can result in severe reduction of emerging worker bees and thus overall colony productivity. Stonebrood is caused by Aspergillus spp. that are rarely observed, so the impact on colony health is not very well understood. A major concern with the presence of Aspergillus in honey bees is the production of airborne conidia, which can lead to allergic bronchopulmonary aspergillosis, pulmonary aspergilloma, or even invasive aspergillosis in lung tissues upon inhalation by humans. In the current chapter we describe the honey bee disease symptoms of these fungal pathogens. In addition, we provide research methodologies and protocols for isolating and culturing, in vivo and in vitro assays that are commonly used to study these host pathogen interactions. We give guidelines on the preferred methods used in current research and the application of molecular techniques. We have added photographs, drawings and illustrations to assist bee-extension personnel and bee scientists in the control of these two diseases.La ascosferiosis (o cría yesificada) y cría de piedra son dos enfermedades fúngicas asociadas con la cría de la abeja melífera. La ascosferiosis, causada por el hongo Ascosphaera apis, es una enfermedad comú;n de amplia distribución que puede resultar en una severa disminución en el número de obreras emergentes y por lo tanto afecta la productividad de la colonia. La cría de piedra es causada por Aspergillus spp. los cuales son raramente observados y su impacto en la salud de la colonia no está esclarecido. El mayor problema con la presencia de Aspergillus en abejas es la producción de conidios aéreos, que pueden llevar a aspergillosis broncopulmonares alérgicas, aspergilomas pulmonares o aun aspergilosis invasivas en tejidos pulmonares en humanos luego de inhalarlos. En este capítulo describimos los síntomas de las enfermedades producidas por estos patógenos fú;ngicos. Además proveemos metodologías de investigación y protocolos para su aislamiento y cultivo, ensayos in vivo e in vitro que son comú;nmente usados para estudiar las interacciones de estos patógenos con su hospedero. Damos una guía sobre los métodos preferidos utilizados en la investigación actual y la aplicación de técnicas de moleculares. Hemos añadido fotografías, dibujos e ilustraciones para ayudar al personal.EEA BalcarceFil: Jensen, Annette Bruun. University of Copenhagen. Department of Plant and Environmental Sciences; DinamarcaFil: Aronstein, Kathrine. USDA-ARS. Honey Bee Research Unit; Estados UnidosFil: Flores, José Manuel. University of Córdoba. Department of Zoology; EspañaFil: Vojvodic, Svjetlana. University of Arizona. Center for Insect Science; Estados UnidosFil: Palacio, Marí­a Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Spivak, Marla. University of Minnesota. Department of Entomology; Estados Unido

Ant Colonies Prefer Infected over Uninfected Nest Sites

During colony relocation, the selection of a new nest involves exploration and assessment of potential sites followed by colony movement on the basis of a collective decision making process. Hygiene and pathogen load of the potential nest sites are factors worker scouts might evaluate, given the high risk of epidemics in group-living animals. Choosing nest sites free of pathogens is hypothesized to be highly efficient in invasive ants as each of their introduced populations is often an open network of nests exchanging individuals (unicolonial) with frequent relocation into new nest sites and low genetic diversity, likely making these species particularly vulnerable to parasites and diseases. We investigated the nest site preference of the invasive pharaoh ant, Monomorium pharaonis, through binary choice tests between three nest types: nests containing dead nestmates overgrown with sporulating mycelium of the entomopathogenic fungus Metarhizium brunneum (infected nests), nests containing nestmates killed by freezing (uninfected nests), and empty nests. In contrast to the expectation pharaoh ant colonies preferentially (84%) moved into the infected nest when presented with the choice of an infected and an uninfected nest. The ants had an intermediate preference for empty nests. Pharaoh ants display an overall preference for infected nests during colony relocation. While we cannot rule out that the ants are actually manipulated by the pathogen, we propose that this preference might be an adaptive strategy by the host to “immunize” the colony against future exposure to the same pathogenic fungus