scholarly journals Forager Polymorphism and Foraging Ecology in the Leaf-Cutting Ant,Atta colombica

1995 ◽  
Vol 102 (3-4) ◽  
pp. 131-145 ◽  
Author(s):  
James K. Wetterer

I compare forager size and foraging selectivity of the leaf-cutting antAtta colombicaand that of its close relativeAtta cephalotes. In both species, larger foragers cut fragments of greater mass and area, and at vegetation sources of greater specific density (mass/area). However, the size-range ofA. colombicaforagers (1.5–56.8 mg) was wider than the range typical forA. cephalotes(1.4–32.1 mg). InA. colombica, the maxima workers (24–60 mg) commonly participate in foraging, making up 13% of all foragers in this study and in a previous study. In contrast,A. cephalotesmaxima workers (24–100 mg) rarely forage (less than 1% of all foragers in two previous studies), but instead serve primarily as soldiers defending the nest. Thus,A. colombicamaxima workers are smaller and do not appear to be so specialized as soldiers as areA. cephalotesmaxima workers. The broader size-range of workers participating in foraging appears to allowA. colombicato exploit a wider range of resources thanA. cephalotes, including tougher, denser vegetation and fallen fruits.

1998 ◽  
Vol 14 (5) ◽  
pp. 705-710 ◽  
Author(s):  
J. W. Dalling ◽  
Rainer Wirth

While leaf-cutter ants are thought to collect mainly vegetative plant material, they have also been observed collecting seeds or fruit parts on the forest floor (Alvarez-Buylla & Martínez-Ramos 1990, Kaspari 1996). For example, leaf-cutter ants have been observed carrying considerable numbers of Brosimum alicastrum Sw. and Cecropia spp. seeds into their nests (Wirth 1996) and Leal & Oliveira (1998; pers. comm.) found them foraging on the fruits and seeds of 19 different species of Brazilian cerrado vegetation, including six Miconia species. Under some circumstances, seed removal and relocation by leaf cutter ants might even be sufficient to affect local recruitment patterns of trees. For example, in Costa Rica, Atta cephalotes can remove all fallen fig fruit from beneath a Ficus hondurensis crown in a single night (Roberts & Heithaus 1986), while in Venezuela, seedling recruitment of the savanna tree Tapirira velutinifolia was positively associated with the seed harvesting and seed cleaning activities of the ant Atta laevigata (Farji Brenner & Silva 1996).


2002 ◽  
Vol 159 (3) ◽  
pp. 283
Author(s):  
Burd ◽  
Archer ◽  
Aranwela ◽  
Stradling

1979 ◽  
Vol 69 (1) ◽  
pp. 141-148 ◽  
Author(s):  
A. Mudd ◽  
G. L. Bateman

AbstractGrowth of the food fungus of the leaf-cutting ant Atta cephalotes (L.) on extracts of plants selected by the ants was shown to be affected by the plant species, the pH of the extract, the concentration of the sap or plant extract and pretreatment of the substrate by the ants. It was not possible to establish an unambiguous relationship between the rate of growth of the fungus on leaf extracts and the foraging preferences of the ants for the leaves. There were indications, however, that the fungus grows most rapidly on extracts of plant material preferred by A. cephalotes. Relative growth rates of the fungus on different substrates may be related to the presence of growth inhibitors rather than to nutrient availability.


1991 ◽  
Vol 69 (6) ◽  
pp. 1530-1533 ◽  
Author(s):  
Dave Shutler ◽  
Adele Mullie

In a Costa Rican forest adjacent to cattle pasture, larger individuals of the leaf-cutting ant Atta colombica carried heavier loads and foraged farther from the colony, as predicted by foraging theory. Counter to foraging theory, individual ants did not increase their load mass if they foraged farther from the colony. However, the colony avoided this apparent inefficiency by sending larger ants to more distant trees. The colony harvested simultaneously from several individuals of the same tree species, even though distant trees were twice as far from the colony as nearby trees. The reasons for this behaviour require further investigation. In a wide foraging trail, larger ants travelled faster than their smaller counterparts. In addition, ant velocity was reduced when loads were experimentally supplemented, and increased when loads were experimentally reduced. Ants using narrow trails in the leaf litter may all be constrained to travel at the same speed, irrespective of load or body size, simply because they get in each other's way.


2010 ◽  
Vol 7 (1) ◽  
pp. 30-32 ◽  
Author(s):  
L. S. Bittleston ◽  
F. Brockmann ◽  
W. Wcislo ◽  
S. A. Van Bael

Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high ( E high ) or low ( E low ) densities of endophytes. The E high seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the E low treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from E low relative to E high seedlings and had a tendency to recruit more ants to E low plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities.


2010 ◽  
Vol 36 (1) ◽  
pp. 14-24 ◽  
Author(s):  
SEBASTIAN T. MEYER ◽  
INARA R. LEAL ◽  
MARCELO TABARELLI ◽  
RAINER WIRTH

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