This project addresses a decline in honey production and loss of European honeybee colonies (Apis mellifera) in the Solomon Islands since the arrival of the Asian honeybee (Apis cerana). Research is aimed at reversing these declines by developing methods that, when implemented, will suppress the Asian honeybee populations. This, in turn, will increase the foraging competitiveness of the European honeybees and restore hive numbers. Other project research will develop and implement surveillance systems for Asian honeybees on islands currently free of the bee and determine the pest and disease status of both Asian and European honeybees throughout the Solomon Islands.
Since their initial detection in the Solomon Islands in 2003, Asian honeybees have spread to approximately half of the large Islands. Sea shipping and commercial logging operations have facilitated this spread. In some cases swarms of bees have been able to fly between islands that are close together. The arrival of the bees on Guadalcanal has resulted in a decline of hived European honeybee colonies from approximately 2000 hives in 2000 to five in 2008. This decline appears to have been a result of the newly arrived bees out-competing the European honeybees for floral resources, as well as robbing. Extension activities carried out in this project over the past year have led to the introduction of surveillance for Asian honeybees on Malaita Island, one of the last large beekeeping islands still free of the bees.
Trials aimed at suppressing Asian honeybees are now being conducted on Savo Island, as it contains no European honeybees. Approval to conduct the trials was obtained from leaders of the local community. Initially, different lures are being tested for their ability to attract forager Asian honeybees to bait stations containing a sugar reward. Once a suitable lure is identified and optimised, an insecticide will be added to it that the foraging bees will carry back to their parent colonies. The effectiveness of the insecticide in suppressing the island population of Asian honeybees will then be gauged. During the past year, 4 different lures were tested for their ability to attract forager Asian honeybees. The most effective and cheapest lure tested was a flat open dish, that initially contained fresh honey and honeycomb collected from a feral Asian honeybee colony, but which was subsequently replaced with 60% sugar syrup. When offered during early morning (before 9.00am) this lure attracted no non-target insects. The addition of an Asian honeybee swarming pheromone to the lure did not improve its attractiveness. However, early results indicate that low concentrations of eicosanol (0.1mg or less) may improve the attractiveness of the lure, as may the addition of an A. cerana footprint pheromone and odors extracted from coconut flower.
As part of activities aimed at determining the health status of honeybees in the Solomon Islands, two viruses were isolated from samples of dead adult Asian honeybees. Isolates of varroa mites, collected from both A. cerana and A. mellifera brood throughout the Solomons, were also identified by DNA finger-printing as the Java strain of Varroa jacobsoni. Reproduction by these mites was only observed on drone brood of A. cerana.

Asian honeybees (Apis cerana) continue to spread in the Solomon Islands and continue to impact on European honeybees (A. mellifera). Since Asian honeybees were first detected on Kolombangara Island (in Western Province) a little more than a year ago, the number of hived European honeybees has declined by 76.4% and feral European honeybees have virtually disappeared. These losses follow the complete demise of European honeybees on Guadalcanal Island following the arrival of Asian honeybees shortly before 2003. Surveillance systems are now in place to monitor the continued spread of Asian honeybees in the Solomon Islands.
The decline of European honeybees on Guadalcanal and Kolombangara Islands was thought to have resulted from the combined effects of (a) the newly arrived Asian honeybees out-competing the resident European honeybees for floral resources, (b) intense robbing of European honeybee colonies by the newly arrived Asian honeybees and (c) poor management of the hived European honeybees. However, during the past year of this project the serious microsporidian pathogen Nosema ceranae, which has recently been implicated in severe mortality of European honeybees in Europe and the United States, was detected in the Solomon Islands for the first time. High levels of the pathogen were found in Asian honeybees on Savo Island, which is free of European honeybees, indicating that the Asian honeybees may have introduced the pathogen and that the pathogen may be playing an important role in the decline of European honeybees in the Solomon Islands. This will be investigated further during the coming year.
The main activity of this project is to develop a means of suppressing Asian honeybee densities in the Solomon Islands, with the assumption that fewer Asian honeybees will improve the competitiveness of European honeybees. During the past year a trial was conducted on Savo Island to determine whether the broad-spectrum insecticide Fipronil would suppress Asian honeybees. For a two-week period, foraging Asian worker bees were attracted to a feeding station with a sugar-syrup lure. The lure was then replaced for a one-hour period with fresh sugar syrup containing 0.05% Fipronil. Within an hour, eight (8) Asian honeybee colonies under observation showed clear signs of poisoning and within 14 days these colonies were dead, with most dead after 7 days. No detrimental side effects were observed from using Fipronil and Asian honeybees have only slowly recolonised the site. Observations are continuing, but it is evident that Fipronil is highly effective at suppressing Asian honeybees. During the coming year another trial will be conducted to determine how long it takes before European honeybees can be safely introduced to a site at which Asian honeybees have been suppressed with Fipronil. With this information, an effective method will have been developed for suppressing Asian honeybees in the Solomon Islands.
Another activity of this project is to determine the health status of honeybees in the Solomon Islands. As well as confirming the presence of Nosema ceranae during the past year, the reproductive behaviour of the varroa mite hosted by the newly arrived Asian honeybees (the Java strain of Varroa jacobsoni) was monitored. This task assumed greater urgency following the discovery in May 2008 that the same mite had developed a newfound ability to reproduce on European honeybees in Papua New Guinea. Monitoring confirmed that the mite in the Solomon Islands still lacks the ability to reproduce on European honeybees.

Significant progress was made over the past year in developing methodologies that, when fully implemented, will assist Solomon Island beekeepers maintain beekeeping activities with European honeybees (Apis mellifera) in the presence of invasive Asian honeybees (A. cerana).
The main method under development is aimed at giving European honeybees a competitive advantage when accessing local floral resources (nectar and pollen). It passed through final testing during the past year and is now ready for uptake by beekeepers. The method relies on beekeepers using the broad-spectrum insecticide Fipronil to suppress Asian honeybee populations. Final monitoring on Savo Island showed that one treatment of 1 litre of 0.05% Fipronil in sugar-syrup, applied over a 60-minute period at a single 'feeding station', effectively suppressed Asian honeybees in a half square-kilometre area for approximately 8 months. Further final testing on the more populated and accessible Guadalcanal Island showed that wider suppression of Asian honeybees in a particular area may be achieved by simultaneously applying Fipronil at several feeding stations placed 500 metres apart, without causing harm to humans, domestic animals or wildlife. This testing also showed that hived European honeybees may be safely introduced to an area in which Fipronil has been used to suppress Asian honeybees approximately 2 weeks after Fipronil has been applied to the feeding stations.
Hence, for beekeepers to now use Fipronil to reduce the impact of Asian honeybees on their hived European honeybees, they will need to: (a) remove their hived European honeybees to a safe distance (at least 5 km from intended feeding stations), (b) lure foraging Asian honeybees to feeding stations placed 500 apart over a 4-day period, using 60% sugar-syrup as an attractant, (c), replace the sugar syrup on the 4th or 5th day at each feeding station with 1 litre of 0.05% Fipronil in sugar-syrup for a 60-minute period and, (d) re-introduce their hived honeybees 2-weeks later. Clearly, it would be more practical and useful for beekeepers to use this method only when Asian honeybees become troublesome and then preferably about 3 weeks prior to a major 'honey-flow'.
The uptake of improved European honeybee hive-management practices, such as reducing the size of hive-openings and increasing hive-ventilation, which were developed in previous years of this project, will also help Solomon Island beekeepers reduce the impact of Asian honeybees. During the past year, beekeepers in Western and Makira Provinces were trained in the use of these practices. Beekeepers on all the larger islands where Asian honeybees are present have now been trained to use the practices. Full adoption of these and other improved hive-management practices, together with the ability to use Fipronil-poisoning, means that Solomon Island beekeepers can now confidently maintain their beekeeping activities in the presence of Asian honeybees and that beekeeping with European honeybees can be further developed throughout the Solomon Islands.
Surveillance for Asian honeybees in the Solomon Islands was also further improved during the past year, being introduced to Ranongga, Vella Lavella and Choiseul Islands. Asian honeybee surveillance is now being carried out on all the larger islands free of the bees. Evidence suggests the spread of the Asian honeybee in the Solomon Islands has been assisted by commercial forestry activities.
The health status of honeybees in the Solomon Islands was also finally confirmed during the past year. Asian honeybees carry the serious microsporidian pathogen Nosema ceranae, viruses and the Java strain of the parasitic mite Varroa jacobsoni. They do not host any other species of parasitic mite, including V. underwoodi or Acarapis woodi (the tracheal mite). European honeybees on the other hand carry both N. ceranae and N. apis, and evidence suggests they acquired the former from Asian honeybees. They also carry sacbrood and chronic bee paralysis viruses but are free of (a) chalkbrood disease (caused by Ascosphaera apis) (b) European and American foulbrood diseases (caused by Melissococcus plutonius and Paenibacillus larvae respectively) and (c) the parasitic mites, V. destructor, A. woodi and Tropilaelaps spp. Even though European honeybee colonies may be regularly invaded by low numbers of female V. jacobsoni (that spread from nearby Asian honeybee colonies), they are harmless as they lack the ability to produce offspring on the European honeybee brood.