INVESTIGADORES
PIRK Gabriela Ines
artículos
Título:
Evaluation of three techniques for the study of harvester ant (Pogonomyrmex spp) diet
Autor/es:
PIRK, G. I.; LOPEZ DE CASENAVE, J.; MARONE, L.
Revista:
ENVIRONMENTAL ENTOMOLOGY
Editorial:
Entomological Society of America
Referencias:
Año: 2007 vol. 36 p. 1092 - 1099
ISSN:
0046-225X
Resumen:
The estimation of an antÕs diet is crucial in many ecological studies. Different techniques,
which involve different assumptions and Þeld procedures, have been used to estimate the composition of
harvester ant diet. In this study, three techniques are compared for the estimation of the diet of Pogonomyrmex
rastratus (Mayr), Pogonomyrmex pronotalis (Santschi), and Pogonomyrmex inermis (Forel) in the
central Monte desert, Argentina: (1) hand collection of items brought back to the nest by foragers, (2)
collection of items with a semiautomated device with pitfall traps, and (3) collection of the discarded
material accumulated in middens. The hand collection technique and the collection of middens provided
the lowest and the highest number of items, respectively. Midden samples and pitfall traps contained a
higher proportion of nonseed items, probably coming from sources other than ants, than hand-collected
items. The three techniques provided similar estimations of species richness but a bias against small seeds
was detected for P. pronotalis and P. inermis with the hand collection technique, possibly because of the
difÞculty of collecting small items by hand. The percentage of seed species in the diet obtained with
different techniques was positively correlated in the great majority of colonies. Overall, despite their
intrinsic differences, the three techniques proved consistent, which constitutes a robustness test for the
estimations obtained. In comparative ecological studies, the awareness that results depend on the techniques
and their assumptions is particularly important.Pogonomyrmex
rastratus (Mayr), Pogonomyrmex pronotalis (Santschi), and Pogonomyrmex inermis (Forel) in the
central Monte desert, Argentina: (1) hand collection of items brought back to the nest by foragers, (2)
collection of items with a semiautomated device with pitfall traps, and (3) collection of the discarded
material accumulated in middens. The hand collection technique and the collection of middens provided
the lowest and the highest number of items, respectively. Midden samples and pitfall traps contained a
higher proportion of nonseed items, probably coming from sources other than ants, than hand-collected
items. The three techniques provided similar estimations of species richness but a bias against small seeds
was detected for P. pronotalis and P. inermis with the hand collection technique, possibly because of the
difÞculty of collecting small items by hand. The percentage of seed species in the diet obtained with
different techniques was positively correlated in the great majority of colonies. Overall, despite their
intrinsic differences, the three techniques proved consistent, which constitutes a robustness test for the
estimations obtained. In comparative ecological studies, the awareness that results depend on the techniques
and their assumptions is particularly important.(Mayr), Pogonomyrmex pronotalis (Santschi), and Pogonomyrmex inermis (Forel) in the
central Monte desert, Argentina: (1) hand collection of items brought back to the nest by foragers, (2)
collection of items with a semiautomated device with pitfall traps, and (3) collection of the discarded
material accumulated in middens. The hand collection technique and the collection of middens provided
the lowest and the highest number of items, respectively. Midden samples and pitfall traps contained a
higher proportion of nonseed items, probably coming from sources other than ants, than hand-collected
items. The three techniques provided similar estimations of species richness but a bias against small seeds
was detected for P. pronotalis and P. inermis with the hand collection technique, possibly because of the
difÞculty of collecting small items by hand. The percentage of seed species in the diet obtained with
different techniques was positively correlated in the great majority of colonies. Overall, despite their
intrinsic differences, the three techniques proved consistent, which constitutes a robustness test for the
estimations obtained. In comparative ecological studies, the awareness that results depend on the techniques
and their assumptions is particularly important.P. pronotalis and P. inermis with the hand collection technique, possibly because of the
difÞculty of collecting small items by hand. The percentage of seed species in the diet obtained with
different techniques was positively correlated in the great majority of colonies. Overall, despite their
intrinsic differences, the three techniques proved consistent, which constitutes a robustness test for the
estimations obtained. In comparative ecological studies, the awareness that results depend on the techniques
and their assumptions is particularly important.