INVESTIGADORES
LOPEZ DE CASENAVE Javier Nestor
artículos
Título:
Activity patterns of harvester ants Pogonomyrmex pronotalis and Pogonomyrmex rastratus in the central Monte desert, Argentina
Autor/es:
R. G. POL; J. LOPEZ DE CASENAVE
Revista:
JOURNAL OF INSECT BEHAVIOUR
Editorial:
Springer Science
Referencias:
Año: 2004 vol. 17 p. 647 - 661
ISSN:
0892-7553
Resumen:
Seed-eating ants could have a significant effect on plant communities in
deserts and semiarid zones. This effect is mediated through spatial and temporal
foraging patterns, and seed selection within patches. Foraging patterns
of harvester ants in South American deserts are almost unknown. The purpose
of this work is to determine the temporal variations in the activity levels
of Pogonomyrmex pronotalis and P. rastratus in the central Monte desert,
and how these patterns may be related to abiotic factors, particularly to soil
temperature. Activity levels and soil surface temperature were recorded at
hourly intervals in five colonies for each species during the activity season
(October,December, February, and April) in both 19992000 and 20002001
periods (except for October 1999). Surface ant activity starts in October, increases
between December and February, and then ceases by April. Surface
ant activity is diurnal throughout the season and usually has a unique peak
during midday in October and April, and two peaks in the morning and the
afternoon from December to February. The proportion of the activity budget
devoted to nests maintenance activity was similar for both species. Activity
levels of foraging workers tended to be higher in P. pronotalis than in P.
rastratus. P. pronotalis is active between 20 and 59◦C, with higher levels of
activity between 35 and 45◦C, whereas P. rastratus shows activity between
18 and 58◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.Pogonomyrmex pronotalis and P. rastratus in the central Monte desert,
and how these patterns may be related to abiotic factors, particularly to soil
temperature. Activity levels and soil surface temperature were recorded at
hourly intervals in five colonies for each species during the activity season
(October,December, February, and April) in both 19992000 and 20002001
periods (except for October 1999). Surface ant activity starts in October, increases
between December and February, and then ceases by April. Surface
ant activity is diurnal throughout the season and usually has a unique peak
during midday in October and April, and two peaks in the morning and the
afternoon from December to February. The proportion of the activity budget
devoted to nests maintenance activity was similar for both species. Activity
levels of foraging workers tended to be higher in P. pronotalis than in P.
rastratus. P. pronotalis is active between 20 and 59◦C, with higher levels of
activity between 35 and 45◦C, whereas P. rastratus shows activity between
18 and 58◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.P. pronotalis than in P.
rastratus. P. pronotalis is active between 20 and 59◦C, with higher levels of
activity between 35 and 45◦C, whereas P. rastratus shows activity between
18 and 58◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.is active between 20 and 59◦C, with higher levels of
activity between 35 and 45◦C, whereas P. rastratus shows activity between
18 and 58◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.◦C, whereas P. rastratus shows activity between
18 and 58◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.◦C, with higher levels of activity between 30 and 40◦C.
Our results suggest that temporal changes in surface activity respond mainly to soil temperature
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.
fluctuations. However, at intermediate temperatures (those probably
encompassing the thermal tolerance range of these ant species), temperature
appears not to be a good predictor of daily and seasonal activity fluctuations.