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"Hughes, William"
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Parasites in bloom: flowers aid dispersal and transmission of pollinator parasites within and between bee species
The dispersal of parasites is critical for epidemiology, and the interspecific vectoring of parasites when species share resources may play an underappreciated role in parasite dispersal. One of the best examples of such a situation is the shared use of flowers by pollinators, but the importance of flowers and interspecific vectoring in the dispersal of pollinator parasites is poorly understood and frequently overlooked. Here, we use an experimental approach to show that during even short foraging periods of 3 h, three bumblebee parasites and two honeybee parasites were dispersed effectively onto flowers by their hosts, and then vectored readily between flowers by non-host pollinator species. The results suggest that flowers are likely to be hotspots for the transmission of pollinator parasites and that considering potential vector, as well as host, species will be of general importance for understanding the distribution and transmission of parasites in the environment and between pollinators.
Journal Article
The Trojan hives: pollinator pathogens, imported and distributed in bumblebee colonies
1. Over a million commercially produced bumblebee colonies are imported annually on a global scale for the pollination of greenhouse crops. After importation, they interact with other pollinators, with an associated risk of any parasites they carry infecting and harming native bees. National and supranational regulations are designed to prevent this, and commercially produced bumblebee colonies are accordingly now often sold and imported as being parasite-free. 2. Here, we used molecular methods to examine the occurrence of parasites in bumblebee colonies that were commercially produced in 2011 and 2012 by three producers. We then used controlled experiments to determine whether any parasites present were infectious. 3. We found that 77% of the commercially produced bumblebee colonies from the three producers, which were imported on the basis of being free of parasites, in fact carried microbial parasites, with five different parasites being detected across the total sample of bumblebees and a further three in the pollen supplied with the colonies as food. 4. Our controlled experiments demonstrated that at least three of these parasites were infectious to bumblebees with significant negative effects on their health. Furthermore, we also found that at least four of the parasites carried by commercially produced bumblebees were infectious to honeybees, indicating that they pose a risk to other pollinators as well. 5. Synthesis and applications. The results demonstrate that commercially produced bumblebee colonies carry multiple, infectious parasites that pose a significant risk to other native and managed pollinators. More effective disease detection and management strategies are urgently needed to reduce the pathogen spillover threat from commercially produced bumblebees.
Journal Article
Seasonality, long-term trends and co-occurrence of sharks in a top predator assemblage
Shark predator assemblages play an important role in the top-down processes that are vital to marine ecosystem functioning. Spatiotemporal partitioning of sharks due to seasonal movements or population changes may have significant consequences for the top-down effects, depending on the level of functional redundancy in the assemblage. However, long-term, co-occurrence data for sharks is hard to obtain and often lacking. Here we use citizen science data collected by professional scuba guides over seven years to model the seasonal and across-year temporal dynamics, and intraguild and trophic co-occurrence interactions, for an assemblage of six shark top predators ( Carcharhinus leucas , Carcharhinus obscurus , Carcharhinus limbatus , Carcharias taurus , Sphyrna lewini , and Galeocerdo cuvier ). The presence of all six study species were clearly seasonal and, in most cases, exhibited positive long-term trends across years. The seasonalities observed, combined with temporal co-occurrence analysis, suggests that dietary redundancy but temporal complementarity exists amongst the top predator assemblage. The study shows citizen science data collected by professional non-scientists is a cost-effective method for monitoring top predators and may be able to highlight potential predator-prey interactions worthy of further investigation.
Journal Article
Ancestral Monogamy Shows Kin Selection Is Key to the Evolution of Eusociality
Close relatedness has long been considered crucial to the evolution of eusociality. However, it has recently been suggested that close relatedness may be a consequence, rather than a cause, of eusociality. We tested this idea with a comparative analysis of female mating frequencies in 267 species of eusocial bees, wasps, and ants. We found that mating with a single male, which maximizes relatedness, is ancestral for all eight independent eusocial lineages that we investigated. Mating with multiple males is always derived. Furthermore, we found that high polyandry (∼2 effective mates) occurs only in lineages whose workers have lost reproductive totipotency. These results provide the first evidence that monogamy was critical in the evolution of eusociality, strongly supporting the prediction of inclusive fitness theory.
Journal Article
The encyclopedia of the Gothic
Comprehensive and wide-ranging, this book brings together over 200 newly-commissioned essays by leading scholars writing on all aspects of the Gothic as it is currently taught and researched, along with challenging insights into the development of the genre and its impact on contemporary culture. The A-Z entries provide comprehensive coverage of relevant authors, national traditions, critical developments, and notable texts that continue to define, shape, and inform the genre. The volume's approach is truly interdisciplinary, with essays by specialist international contributors whose expertise extends beyond Gothic literature to film, music, drama, art, and architecture.
Book
Pervasiveness of Parasites in Pollinators
Many pollinator populations are declining, with large economic and ecological implications. Parasites are known to be an important factor in the some of the population declines of honey bees and bumblebees, but little is known about the parasites afflicting most other pollinators, or the extent of interspecific transmission or vectoring of parasites. Here we carry out a preliminary screening of pollinators (honey bees, five species of bumblebee, three species of wasp, four species of hoverfly and three genera of other bees) in the UK for parasites. We used molecular methods to screen for six honey bee viruses, Ascosphaera fungi, Microsporidia, and Wolbachia intracellular bacteria. We aimed simply to detect the presence of the parasites, encompassing vectoring as well as actual infections. Many pollinators of all types were positive for Ascosphaera fungi, while Microsporidia were rarer, being most frequently found in bumblebees. We also detected that most pollinators were positive for Wolbachia, most probably indicating infection with this intracellular symbiont, and raising the possibility that it may be an important factor in influencing host sex ratios or fitness in a diversity of pollinators. Importantly, we found that about a third of bumblebees (Bombus pascuorum and Bombus terrestris) and a third of wasps (Vespula vulgaris), as well as all honey bees, were positive for deformed wing virus, but that this virus was not present in other pollinators. Deformed wing virus therefore does not appear to be a general parasite of pollinators, but does interact significantly with at least three species of bumblebee and wasp. Further work is needed to establish the identity of some of the parasites, their spatiotemporal variation, and whether they are infecting the various pollinator species or being vectored. However, these results provide a first insight into the diversity, and potential exchange, of parasites in pollinator communities.
Journal Article