Volume 42, Issue 3 (May 1997)
The Entomological Evidence
The primary task was to investigate and explain the source of blockage in an elbow (B2) and in other parts of the fuel supply unit recovered from the wreckage of a private airplane. A small clump of pollen associated with a disc-shaped gummy mass of plant fibers suggested that bees belonging to the family Megachilidae might have been responsible for accumulating these plant materials. Examination of other parts of the fuel control unit revealed three dead adult bees identified as Osmia gaudiosa Cockerell (Megachilidae) and a single dead individual of the genus Ashmeadiella (Megachilidae). A survey of the tubing of a heater that had been stored showed that 69% of its tubings and fittings contained nest material and other arthropod debris including those of Ashmeadiella meliloti (Cockerell) and Anthidium sp. (Megachilidae). Through SEM examination, a single branched hair partly embedded in the clump of pollen was matched with the postgenal hairs of an adult Ashmeadiella. These facts left no doubt that the B2 elbow mass was part of a nest of Ashmeadiella. This conclusion was consistent with the facts that the wreckage had been available to the bees for nesting during the entire time of the spring and summer nesting season, and that the plant materials (leaves of Sphaeralcea and pollen sources) were readily available near the storage yard during that time. Contamination of the wreckage by nesting bees was obviously a post-crash phenomenon. Plant materials as well as dead bees would have been consumed by the intense fire that accompanied the crash if they had been present before.