Are workers of Atta leafcutter ants capable of reproduction?
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Are workers of Atta leafcutter ants capable of reproduction? / Dijkstra, Michiel Bendert; Boomsma, Jacobus Jan.
In: Insectes Sociaux, Vol. 53, No. 2, 2006, p. 136-140.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Are workers of Atta leafcutter ants capable of reproduction?
AU - Dijkstra, Michiel Bendert
AU - Boomsma, Jacobus Jan
N1 - Keywords. Dwarf males - worker sons - orphaned colonies - worker sterility - worker infertility
PY - 2006
Y1 - 2006
N2 - Workers of most eusocial Hymenoptera can produce sons after queen loss, which (posthumously) benefits the queen and increases worker inclusive fitness. However, the evolutionary loss of worker ovaries has occurred in several lineages, while workers in other taxa may be infertile despite having ovaries. Workers of Atta leafcutter ants only lay trophic eggs in queenright colonies. Although Atta colonies are commonly kept at universities, museums, and zoos, no reports of worker sons in orphaned colonies exist, suggesting that Atta workers are infertile. To explicitly test this, we created eleven orphaned laboratory nests of Atta cephalotes, A. sexdens, and A. colombica, and maintained them for 3-6 months after queen loss. Eight colonies did not produce any brood, but three nests produced 1-4 worker-derived male larvae and pupae. Microsatellite genotyping indicated that these were worker sons. However, all males were tiny (3.5-9 mm long) compared to normal queen sons (16 mm long), and would almost certainly be unable to mate. We also found reproductive eggs, but most of these had no yolk and were thus inviable. We conclude that Atta workers are not completely infertile, but that worker fertility is low compared to the sister genus Acromyrmex, where workers routinely produce normally-size males after queen loss in the laboratory. We hypothesize that worker reproduction in orphaned Atta field colonies is almost never successful because the last workers die before their sons can be raised to adulthood, but that the importance of worker-laid trophic eggs for queen feeding has precluded the evolutionary loss of worker ovaries.
AB - Workers of most eusocial Hymenoptera can produce sons after queen loss, which (posthumously) benefits the queen and increases worker inclusive fitness. However, the evolutionary loss of worker ovaries has occurred in several lineages, while workers in other taxa may be infertile despite having ovaries. Workers of Atta leafcutter ants only lay trophic eggs in queenright colonies. Although Atta colonies are commonly kept at universities, museums, and zoos, no reports of worker sons in orphaned colonies exist, suggesting that Atta workers are infertile. To explicitly test this, we created eleven orphaned laboratory nests of Atta cephalotes, A. sexdens, and A. colombica, and maintained them for 3-6 months after queen loss. Eight colonies did not produce any brood, but three nests produced 1-4 worker-derived male larvae and pupae. Microsatellite genotyping indicated that these were worker sons. However, all males were tiny (3.5-9 mm long) compared to normal queen sons (16 mm long), and would almost certainly be unable to mate. We also found reproductive eggs, but most of these had no yolk and were thus inviable. We conclude that Atta workers are not completely infertile, but that worker fertility is low compared to the sister genus Acromyrmex, where workers routinely produce normally-size males after queen loss in the laboratory. We hypothesize that worker reproduction in orphaned Atta field colonies is almost never successful because the last workers die before their sons can be raised to adulthood, but that the importance of worker-laid trophic eggs for queen feeding has precluded the evolutionary loss of worker ovaries.
U2 - 10.1007/s00040-005-0848-3
DO - 10.1007/s00040-005-0848-3
M3 - Journal article
VL - 53
SP - 136
EP - 140
JO - Insectes Sociaux
JF - Insectes Sociaux
SN - 0020-1812
IS - 2
ER -
ID: 80725