Foraging Pattern, Colony Distribution, and Foraging Range of the Florida Harvester Ant, Pogonomyrmex Badius

Abstract

This report describes the foraging pattern of the Florida harvester ant Pogonomyrmex badius in a high-density population of colonies. The foraging pattern has both promoted and been influenced by the colony distribution. Pogonomyrmex badius forages from short trails which extend into a surrounding foraging range. Direction of foraging trails is influenced by the location of a colony's near neighbors. Seasonal nest relocations always occur along a foraging trail, usually the main trail. Foraging ranges are not actively defended, but are used almost exclusively by foragers from a single colony. Foraging ranges will be extended into an area abandoned by neighboring foragers, indicating that forager presence may define each colony's range. Colony distribution has remained essentially the same for several years, despite seasonal nest relocations and addition of new colonies. Establishment of trails and exclusive foraging ranges by each colony minimizes encounters with neighboring foragers and guarantees access to available resources; this pattern also promotes maintenance of the existing colony distribution and partitioning of resources.

Population-wide lineage frequencies predict genetic load in the seed-harvester antPogonomyrmex

“…Sexuals mate at leks, after which the queen produces her first worker cohort using energetic reserves provisioned by her natal colony (25,26). The colony-founding environment is highly desiccating, and mature colonies are overdispersed because of intraspecific competition (27)(28)(29). Founding colonies suffer severe selection at this stage of the life cycle, and the probability that a new colony will survive is Ͻ1% (25).…”

Reclaiming Lost Territory: the Response of Owyhee Harvester Ants to Forager Intrusions by Neighboring Colonies

“…Prior to experimental manipulation of colony foraging ranges we did not observe any overt aggression between neighbors along their foraging boundaries, similar to the observations of Jorgensen and Porter (1982 -P. salinus) and Gordon (1991 -P. barbatus). Instead, occasional encounters between neighbors along foraging boundaries resulted in one or both individuals becoming agitated and scurrying away in opposite directions, much like Harrison and Gentry (1981) describe for P. badius. Such uneventful encounters between neighbors may serve to reinforce the boundaries of foraging ranges between longstanding neighbors without costly escalation to either colony (Harrison and Gentry 1981;Jorgensen and Porter 1982;Gordon 1991).…”

“…To the contrary, a case is growing for the importance of regular interactions among neighbors to establish and maintain the integrity of territorial boundaries in harvester ants (Harrison and Gentry 1981;Kugler 1984;Gordon 1992;Brown and Gordon 2000) and other territorial ants species (Adams 1990;2003), although Whitford (1976) argues this is not the case in P. rugosus (but see Hölldobler 1976). In the absence of regular encounters with their neighbors, P. salinus usually occupied their neighbor's foraging range in short order; in 7 of 10 cases foragers from the beta colony entered the alpha colony's foraging range within one day of the alpha colony being excluded.…”

“…Aggressive, and sometimes lethal contests have been reported in P. californicus (De Vita 1979), P. rugosus, P. maricopa (Hölldobler 1976), P. mayri (Kugler 1984), and P. barbatus (Hölldobler 1976;Gordon 1992Gordon , 1995Gordon and Kulig 1996). By contrast, Harrison and Gentry (1981) observed overlapping foraging ranges and no aggressive interactions among neighboring P. badius colonies; chance encounters between neighbors were brief and resulted in little more than mutual agitation (Harrison and Gentry 1981). Similarly, Porter and Jorgensen (1981) and Jorgensen and Porter (1982) observed no aggressive encounters between neighboring P. owyheei (a species now accepted as P. salinus Olsen, as interpreted by Shattuck 1987) colonies.…”

Species-specific patterns in the social activities of harvester ant colonies (Pogonomyrmex)

“…Other work shows that aggressive encounters and the spacing of trunk trails play a role in intra-and interspecific competition (H6LLDOBLER, 1976a;HARRISON and GENTRY, 1981). However, some species use trunk trails only part of the time (e. g., on P. rugosus : CHEW, 1976 ;BERNSTEIN, 1975 ;DAVIDSON, 1977 a ;Ht~LLDOBLER, 1976 a ;RISSING, 1981).…”