In a 1986 survey taken in northeastern Mexico, 44% of the 6,200 honey bees, Apis mellifera L., examined were infested with tracheal mites, Acarapis woodi (Rennie). Mites were found in 80% of the 310 colony samples of 20 bees each. These samples were taken monthly from 10 colonies in each of three apiaries located from 130 to 230 km apart in the state of Tamaulipas.
Infestation levels varied greatly among apiaries, months, and between samples. Monthly infestations in individual bees ranged from a low of 2% in the Hidalgo apiary in August to a high of 97% in February in the Aldama apiary. The average infestation was 11% of the bees in the Hidalgo apiary, 35% in the Ciudad Mante apiary, and 71% in the Aldama apiary. Mite populations tended to decline in late spring and summer.
There was a significant correlation (r = 0.91, p < 0.01) between the percentage of bees infested in the apiary and the number of mites in each infested bee. The number of mites per infested bee ranged from an average of 14 for infested bees from the four monthly apiary samples with the lowest percentage of infested bees to 44 mites/infested bee in the four samples with the highest percent of infested bees. The average number of mites per infested bee was 34.2.
The proportion of mites in each life stage varied markedly. Overall, 19% of the 92,392 mites were in the egg stage, 37% were larvae, and 44% were adults. The ratio of males to females was 1:2.43 or 29% males to 71% females.
Both right and left tracheae were equally susceptable to becoming infested, as mites were found in 2,144 right and 2,138 left trachea. Both tracheae were infested in 58% of the bees parasitized with mites. There was also a highly significant correlation (r = 0.98, P < 0.01) between percentage of bees infested in each sample and percentage of infested bees with mites present in both tracheae.
Influence of worker age on the infestation of resistant and susceptible honey bees (Apis mellifera) with tracheal mites (Acarapis woodi)
