Tropilaelaps - Symptoms
Tropilaelaps mites are reddish brown, about 1mm long and 0.6mm wide, with a life cycle similar to that of varroa. The mites move freely and rapidly on combs, and rely on brood for feeding; (they cannot feed on adult bees because their mouthparts are not capable of piercing the membranes).
Tropilaelaps causes damage similar to varroa, resulting in irregular brood patterns and stunted adults with deformed wings and shrunken abdomens.
The mites are thought to be unable to survive in broodless colonies. Parasitisation by these mites can cause abnormal brood development, death of both brood and bees, leading to colony decline and collapse, and can cause the bees to abscond from the hive.
Colonies heavily infested with either Tropilaelaps or varroa show similar damage. The infestation and feeding activities of the mites causes brood mortality and a reduction in the lifespan of any adult bees that survive the parasitized brood stage. Individual bees infested during their development that survive to emergence may show signs of physical or physiological damage as adults. These include a shorter lifespan, lower body weight, with shrunken and deformed wings and legs. These bees may be seen crawling at the entrance to the hive.
Other signs include: irregular and poor brood patterns with patches of neglected brood and perforated cappings (due to worker bees attempting to clean out sick or dead larvae); in severe infestations up to 50% of the developing brood may be killed (in some infested colonies there may be so much dead brood that you will notice the smell of decaying pupal and larval remains). At this stage colonies may abscond and so aid the spread of the mite.