TY - JOUR

T1 - Differential resistance and the importance of antibiotic production in Acromyrmex echinatior leaf-cutting ant castes towards the entomopathogenic fungus Aspergillus nomius

AU - Poulsen, Michael

AU - Hughes, William Owen Hamar

AU - Boomsma, Jacobus Jan

N1 - Keywords. Acromyrmex - Aspergillus - caste - entomopathogenic fungi - metapleural glands

PY - 2006

Y1 - 2006

N2 - Paired exocrine metapleural glands are present in almost all ants and produce compounds with antibiotic properties towards a variety of pathogenic fungi and bacteria. In Acromyrmex leaf-cutting ants, small workers have relatively large metapleural glands compared to large workers, and thus harbour approximately half the number of gland cells of large workers, despite being only one-fifteenth their body mass. Here we present results showing that when the two worker castes of A. echinatior are treated with spores of the pathogenic fungus Aspergillus nomius in doses that correspond to the difference in metapleural gland cell numbers they do not differ in survival. However, we also show, for the first time, that small workers survive significantly longer than large workers when both are challenged with a dose of spores that corresponds to their difference in body mass. Furthermore, the time until Aspergillus nomius hyphae and spores appear on the cadavers of workers dead from infection, is significantly increased in the small worker caste. In addition to supporting previous findings that the metapleural glands have an important defence function, the results of this study indicate that the relatively large glands in small workers makes this caste particularly well adapted to preventing pathogenic microorganisms from entering the colony.

AB - Paired exocrine metapleural glands are present in almost all ants and produce compounds with antibiotic properties towards a variety of pathogenic fungi and bacteria. In Acromyrmex leaf-cutting ants, small workers have relatively large metapleural glands compared to large workers, and thus harbour approximately half the number of gland cells of large workers, despite being only one-fifteenth their body mass. Here we present results showing that when the two worker castes of A. echinatior are treated with spores of the pathogenic fungus Aspergillus nomius in doses that correspond to the difference in metapleural gland cell numbers they do not differ in survival. However, we also show, for the first time, that small workers survive significantly longer than large workers when both are challenged with a dose of spores that corresponds to their difference in body mass. Furthermore, the time until Aspergillus nomius hyphae and spores appear on the cadavers of workers dead from infection, is significantly increased in the small worker caste. In addition to supporting previous findings that the metapleural glands have an important defence function, the results of this study indicate that the relatively large glands in small workers makes this caste particularly well adapted to preventing pathogenic microorganisms from entering the colony.

U2 - 10.1007/s00040-006-0880-y

DO - 10.1007/s00040-006-0880-y

M3 - Journal article

VL - 53

SP - 349

EP - 355

JO - Insectes Sociaux

JF - Insectes Sociaux

SN - 0020-1812

IS - 3

ER -