Norman Carreck

Honey bee colony losses

Apis mellifera, colony losses. honey bee, Varroa destructor Journal of Apicultural Research 49(1): 1-6 (2010)

Clarity on Honey Bee Collapse

The worldwide losses of honey bee colonies continue to puzzle researchers and the beekeeping industry. Over the past few years, the media have frequently reported deaths of honey bee (Apis mellifera L.) colonies in the United States, Europe, and Japan. Most reports express opinions but little hard science. A recent historical survey (1) pointed out that extensive colony losses are not unusual and have occurred repeatedly over many centuries and locations. Concern for honey bees in the United States has been magnified by their vital role in agriculture. The California almond industry alone is worth

Flight metabolic rate and Pgi genotype influence butterfly dispersal rate in the field.

2 billion annually and relies on over 1 million honey bee hives for cross-pollination. So what is killing honey bee colonies worldwide, and what are the implications for agriculture?

Landscape context not patch size determines bumble-bee density on flower mixtures sown for agri-environment schemes

Dispersal is a key life-history trait, especially in species inhabiting fragmented landscapes. The process of dispersal is affected by a suite of morphological, physiological, and behavioral traits, all of which have a more or less complex genetic basis and are affected by the prevailing environmental conditions. To be able to identify genetic and phenotypic effects on dispersal, movements have to be recorded over relevant spatial and temporal scales. We used harmonic radar to track free-flying Glanville fritillary butterflies (Melitaea cinxia) released in the field and reconstructed their flight tracks for several hours. Flight track lengths for individual butterflies ranged from tens of meters to several kilometers. Butterflies were most mobile at midday and in intermediate temperatures. Flight metabolic rate (MR), measured prior to the tracking, explained variation in mobility at all scales studied. One-third of the variation in the distance moved in one hour could be attributed to variation in flight MR. Heterozygous individuals at a single nucleotide polymorphism in the phosphoglucose isomerase (Pgi) gene moved longer distances in the morning and at lower ambient temperatures than homozygous individuals. A similar genotype x temperature interaction was found to affect the metabolic rate. Our results establish connections from molecular variation in a single gene to flight physiology and movement behavior at the landscape level. These results indicate a fitness advantage to the heterozygous genotype in low temperatures and suggest a mechanism by which varying environmental conditions maintain genetic polymorphism in populations.

Tracking butterfly movements with harmonic radar reveals an effect of population age on movement distance

Bumble-bee declines across Europe have been linked to loss of habitat and forage availability due to agricultural intensification. These declines may have severe ecological and commercial consequences since bumble-bees pollinate a range of wildflowers and crops. In England, attempts are being made to reintroduce forage resources through agri-environment schemes, yet there are few data on how the area of forage, or the landscape context in which it is provided, affects their success. We investigated the effects of sown forage patches on bumble-bees across sites varying in landscape characteristics. Bumble-bee densities were higher on sown patches compared with control habitats but did not vary with patch size, i.e. total forager numbers were proportional to patch area. Importantly, the relative response to sown forage patches varied widely across a landscape gradient such that their impact in terms of attracting foraging bumble-bees was greatest where the proportion of arable land was highest.

The dose makes the poison: have “field realistic” rates of exposure of bees to neonicotinoid insecticides been overestimated in laboratory studies?

We used harmonic radar to track freely flying Glanville fritillary butterfly (Melitaea cinxia) females within an area of 30 ha. Butterflies originated from large and continuous populations in China and Estonia, and from newly established or old (> 5 years) small local populations in a highly fragmented landscape in Finland. Caterpillars were raised under common garden conditions and unmated females were tested soon after eclosion. The reconstructed flight paths for 66 individuals comprised a total distance of 51 km with high spatial resolution. Butterflies originating from large continuous populations and from old local populations in Finland exhibited similar movement behaviors, whereas butterflies originating from newly established local populations in the fragmented landscape in Finland moved significantly more than the others. There was no difference in the lengths of individual flight bouts, but the new-population females flew more frequently, resulting in longer daily movement tracks. The flight activity of all individuals was affected by environmental conditions, peaking at 19–23°C (depending on population type), in the early afternoon, and during calm weather. Butterflies from all population types showed a strong tendency to follow habitat edges between the open study area and the neighboring woodlands.

The economic value of bees in the UK

Summary Recent laboratory based studies have demonstrated adverse sub-lethal effects of neonicotinoid insecticides on honey bees and bumble bees, and these studies have been influential in leading to a European Union moratorium on the use of three neonicotinoids, clothianidin, imidacloprid, and thiamethoxam on “bee attractive” crops. Yet so far, these same effects have not been observed in field studies. Here we review the three key dosage factors (concentration, duration and choice) relevant to field conditions, and conclude that these have probably been over estimated in many laboratory based studies.

Honey-bee-mediated infection of pollen beetle (Meligethes aeneus Fab.) by the insect-pathogenic fungus, Metarhizium anisopliae.

In the UK, as elsewhere in Europe, bees are valued not only for the honey and wax that they produce, but also for the pollination service that they provide to the majority of our crops and wild flowers. However, no estimate of their value in economic terms has been made in recent years.

Honey bee colony collapse and changes in viral prevalence associated with Varroa destructor

Pollen beetles (Meligethes aeneus) are pests that feed and oviposit in the buds and flowers of oilseed rape. Honey-bees foraging from a hive fitted with an inoculum dispenser at the entrance effectively delivered dry conidia of the entomogenous fungus, Metarhizium anisopliae , to the flowers of oilseed rape in caged field plots. In both winter- and spring-sown rape experiments, a greater mortality of pollen beetles occurred in treated plots than in control plots. The mortality (61% on winter rape, 100% on spring rape) was greatest during peak flowering, when the feeding activity of both bees and beetles from the flowers was maximal, providing optimal conditions for inoculum dissemination and infection. Conidial sporulation occurred on a significant proportion of the dead pollen beetles. There was no evidence of any adverse effect on the honey-bee colonies.

A review of methods for discrimination of honey bee populations as applied to European beekeeping

Present address: Department of Biological and Environmental Science, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK. Received 16 March 2009, accepted subject to revision 15 July 2009, accepted for publication 30 November 2009. *Corresponding author: Email: norman.carreck@btinternet.com