2 The female mite is brown to reddishbrown in color, measuring 1.1 to 1.2 mm in length and 1.5 to 1.6 mm in width (about the size of a pinhead). When on adult bees, female varroa are found mainly on the top of the bee's thorax at the point where the wings attach, between the head and the thorax, between the thorax and the abdomen, or between overlapping segments of the abdomen. These are places where the mites can easily use their piercing mouthparts to penetrate the exoskeleton of their host and gain access to the bee's emolymph (blood).
When female mites are ready to lay eggs, they move into brood cells containing young larvae just before the cells are capped. They go to the bottom of the brood cells and immerse themselves in the remaining brood food. After the cells are capped and the larvae have finished spinning cocoons, the mites start feeding on the larvae. They begin laying eggs approximately three days after the cell has been capped. Mating occurs in the brood cells before the new adult females emerge. The adult males die after copulation since their mouth parts (chelicerae) are modified for sperm transfer rather than feeding. The old female and the newly-fertilized female offspring remain in the brood cell until the young bee emerges.
3 Australia remains the only country in the world yet to be incurred by Varroa mite {Varroa destructor). This a serious disease of the honey bee colony that will spread rapidly across Australia with significant impacts, such as:
• destruction of feral bee colonies leading to potential environment ecosystem impacts;
• no natural pollination service currently supplied to the horticulturai industry by feral bees leading to the requirement for paid pollination services, which are likely to be in high demand due to the impact of Varroa on managed honey bees;
• widespread managed honey bee colony deaths, with all untreated hives dying;
• decreased honey production;
* increased and on-going chemical control usage within the industry, including chemical misuse;
• increased production costs due to Varroa control measures and more intense husbandry;
* increased pollination costs to the horticultural industry, including the threat of an unavailable pollination service impacting on food supply and quality;
• loss of business viability for many beekeeping enterprises, resulting in a decreased number of beekeepers and enterprises.
The National Sentinel Hive Program (NSHP) was established as a means of monitoring appropriate locations, such as ports, for the presence of exotic pests, in particular Varroa mite. This program of surveillance is considered essential.
The CSIRO have estimated the cost of Varroa to the Australian economy would be $36.7 million pa, this figure identifies a benchmark that Australia could spend on programs ensuring it remains Varroa free.
Ref 1 : Department of Entomology Blacksburg, VA 24061
Ref 2: MAAREC Publication 4.7
Ref 3: Submission 055 - aph.gov.au/house/committee/primind/honeybee/subs
