Variability in the selection of substrate by the leaf-cutting ants atta cephalotes (L.) and acromyrmex octospinosus (Reich) (Formicidae, Attini)

Abstract

In laboratory colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich) pick-up responses to paper discs impregnated with arrestant and inhibitory solutions and feeding responses to measured amounts of these solutions were progressively increased by increasing the concentration of arrestants and decreasing the concentration of inhibitor; the inhibitor had a much greater effect on feeding than on pick-up. Both species picked up paper discs impregnated with arrestants and Acromyrmex readily incorporated these into the fungus garden, while Atta did this less readily. Foraging of arrestive paper discs presented regularly for several days was maintained by Acromyrmex but declined in Atta. Both species were less selective during periods of high foraging activity and during a shortage of suitable substrate. Incoming foragers did not seem to influence the preferences of the outgoing ants, but different colonies showed different preferences. Initially little preference was shown for new materials but on subsequent encounters widely fluctuating preferences emerged, which stabilised within two weeks. Over longer time periods further changes in preferences occurred. The ants' pick-up, cutting or feeding response to a particular material is determined by its chemical and physical nature, the amount of chemical information which the ants obtain, and the threshold of their response. This threshold is modified by such factors as the genetic composition of the colony, the previous quantitative and qualitative availability of the substrate, and the general level of foraging activity. Practical implications of these findings for toxic bait production are discussed.

Field evaluation of methyl 4-methylpyrrole-2-carboxylate, an ant trail pheromone, as a component of baits for leaf-cutting ant (Hymenoptera Formicidae) control

“…With relatively unacceptable baits such as the sugar-impregnated discs, inducing a larger number of ants to find them only results in a smaller proportion picking them up. Littledyke & Cherrett (1975) listed a series of factors which influenced the selection of materials; the present studies suggest (Tables I & II) that in the field Acromyrmex octospinosus may be more selective about what it picks up than it is in the laboratory, thus in the field, filter-paper discs seemed less and citrus-pulp particles more acceptable.…”

Fallen Branches as Part of Leaf‐Cutting Ant Trails: Their Role in Resource Discovery and Leaf Transport Rates inAtta cephalotes

“…However, the evidence that leafcutters prefer new materials is contradictory (Littledyke & Cherrett 1975, Howard et al 1996. First, ants may be attracted to novel materials placed near the trails.…”

Flexible seed selection by individual harvester ants, Pogonomyrmex occidentalis

“…Flexible food choices have been reported in many ants (Rissing and Wheeler 1976;Rissing and Pollock 1984;Schmid-Hempel 1984;Traniello et al 1984;Breed et al 1987;Traniello 1987Traniello , 1988. In contrast to specialization, novel food types are preferred in leaf-cutter ants (Cherrett 1972;Littledyke and Cherrett 1975), suggesting that dietary diversity may be an important goal for foragers of these species. We determine whether dietary history affects seed choice in this population by examining the behavior of individual foragers encountering familiar and novel seeds.…”