June 16, 2007 Four swarms of Asian bees found in Cairns, Australiahave been cleared of carrying the dreaded Varroa destructor mite but the intruders themselves could pose the beginning of a serious threat to Australian honey bee populations.
Asian bees are known to have found their way into Australian ports at least half a dozen times in the last decade.
This time it’s a Javanese strain of the bee and because the latest incursion had lain undiscovered for at least three months, it is unknown how many more swarms might exist and how far afield they may have flown.
Within a one kilometre radius from the first colony, disturbed in the mast of a yacht undergoing repairs after two years docked at a wharf in Cairns, three more swarms were found and the search widened.
Already operating under marginal circumstances, many of Australia’s beekeepers can only afford a momentary sigh of relief.
Asian bees (Apis cerana) are capable of carrying two types of Varroa mite – destructor and jacobsoni; the latter would not threaten the health of local bee populations but destructor has wiped out commercial hives and feral populations the world over and Australia is the last remaining major beekeeping country free of it.
Asian bees remain feral, cannot be hived commercially and will attack Australian bees and rob their hives. Compared to the home breed, Apis mellifera, the intruders are nowhere near the same league in the volume of honey they produce.
In the recent experience of Papua New Guinea and the Solomon Islands, they could become a serious pest, not just for beekeepers, but of concern to agriculture generally.
Bees play a big role in the food supply chain.
“In the big scheme of things, honey's a bit of a minor product, really,” NSW Department of Primary Industries apiarist Dr Doug Somerville said.
“Roughly one-third of the food we eat relates back to bee pollinated crops, so most of the benefits of honeybees actually come from pollinations.
“About 90 fruit and vegetable crops, including melons, pumpkins, and even cotton are more productive with their help.
“And almond crops rely entirely on honeybees for pollination and Australia’s young almond industry is booming right now in the tri-State region.”
Since varroa mite and other bee diseases hit America and wiped out huge numbers, US beekeepers have also relied on NSWgrown stock to help pollinate their almond trees.
In 2006, Australian beekeepers cashed in, shipping export package bees worth $3-4 million to America.
However, this is in contrast with the rest of the local industry, beset by poor yields and low prices, brought on by the drought.
“The bee industry had a reasonable summer honey crop, but domestic prospects for the next two years look very bleak,” Dr Somerville said.
“There will be very few eucalypt flowerings in the next 12 months, which will lead to a yield well below average in the Australian honey crop over the next 12 months to two years.”
All sections of the local industry accept that the arrival of destructor in Australia is a matter of when, not if, and its effects would be far more dramatic than a wide incursion of Apis cerana.
Bees drop like flies but mobile phone toll unlikely
Speculation but no defined cause surrounds a massive die-off of bee hives in the US.
Between 25 and 80 per cent of colonies in apiaries have just disappeared, says NSW DPI apiarist Dr Doug Somerville, describing a phenomenon that North American beekeepers have called Colony Collapse Disorder.
“This is causing major concern in the US almond industry, because well over one million bee hives are required to pollinate this crop every February,” Dr Somerville (pictured) said.
He told ABC-TV’s 7.30 Report the collapse has caused US beekeepers to escalate their prices for pollination fees for a range of crops, including almonds and blueberries.
“At this stage, the same collapses have not been reported by Australian beekeepers.”
Mobile phone waves are amongst factors reported as possible causes of collapse in the US but Dr Somerville is dubious this is the cause.
“You would probably expect a lot more colony deaths in urban areas than rural, and this has not been the case,” Dr Somerville said.
“Their problems are likely to be a combination of factors,” Dr Somerville said.
Pesticides residues in the environment from a class of insecticides called neonicotinoids, used variously as seed treatments, on cut flowers, stone fruits, cotton aphids and locusts have not caused any problems in Australia but are now under the spotlight in the US, according to CSIRO entomologist Denis Anderson.
Varroa mites, poor nutrition and generally stressed bees compromising the immune system of the others in hives are also postulated as causes.
Dr Somerville says 30 per cent of beekeepers have exited the US and New Zealand industries since varroa mites arrived because they found managing the pest too hard.
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