Vertical organization of the division of labor within nests of the Florida harvester ant, Pogonomyrmex badius.

In the Florida harvester ant, Pogonomyrmex badius, foragers occur only in the top 15 cm of the nest, whereas brood and brood-care workers reside mostly in the deepest regions, yet the food and seeds foragers collect must be transported downward 30 to 80 cm to seed chambers and up to 2 m to brood chambers. Using mark-recapture techniques with fluorescent printer's ink, we identified a class of workers that ranges widely within the vertical structure of the nest, rapidly moving materials dropped by foragers in the upper regions downward, and excavated soil from deeper upward. Within the nest, only 5% of foragers were recovered below 20 cm depth, but about 30% of transfer workers and 82% of unmarked workers were found there.

An illustrated guide to seeds found in nests of the Florida harvester ant, Pogonomyrmex badius.

The Florida harvester ant, Pogonomyrmex badius collects the seeds of many plant species and stores them in underground nest chambers for later consumption. Seeds taken from multiple nests in 1989, 2014 and 2015 were separated by size and species and identified through published keys, comparison with herbarium specimens and with identified seed collections. Harvester ants stored at least 58 species of seeds from 20 plant families in their chambers.

The Florida Harvester Ant, Pogonomyrmex badius, Relies on Germination to Consume Large Seeds.

The Florida harvester ant, Pogonomyrmex badius, is one of many ant species and genera that stores large numbers of seeds in damp, underground chambers for later consumption. A comparison of the sizes of seeds recovered from storage chambers with those of seed husks discarded following consumption revealed that the used seeds are far smaller than stored seeds. This difference in use-rate was confirmed in field and laboratory colonies by offering marked seeds of various sizes and monitoring the appearance of size-specific chaff.

Bioturbation by the Fungus-Gardening Ant, Trachymyrmex septentrionalis.

Soil invertebrates such as ants are thought to be important manipulators of soils in temperate and tropical ecosystems. The fungus gardening ant, Trachymyrmex septentrionalis, is an important agent of biomantling, that is, of depositing soil excavated from below onto the surface, and has been suggested as an agent of bioturbation (moving soil below ground) as well. The amount of bioturbation by this ant was quantified by planting queenright colonies in sand columns consisting of 5 layers of different colored sand.

Experimental evidence that dispersal drives ant community assembly in human-altered ecosystems.

A key shortcoming in our understanding of exotic species' success is that it is not known how post-introduction dispersal contributes to the success of exotic species and the reassembly of invaded communities. Exotic and native species face poorly understood competition-colonization trade-offs in heterogeneous landscapes of natural and anthropogenic habitats. We conducted three experiments that tested how ant queen behavior during dispersal affects community composition.

Experiments Testing the Causes of Namibian Fairy Circles.

The grasslands on the sandy soils of the eastern edge of the Namib Desert of Namibia are strikingly punctuated by millions of mostly regularly-spaced circular bare spots 2 to 10 m or more in diameter, generally with a margin of taller grasses. The causes of these so called fairy circles are unknown, but several hypotheses have been advanced. In October 2009, we set up experiments that specifically tested four hypothesized causes, and monitored these 5 times between 2009 and 2015.

Sequential Subterranean Transport of Excavated Sand and Foraged Seeds in Nests of the Harvester Ant, Pogonomyrmex badius.

During their approximately annual nest relocations, Florida harvester ants (Pogonomyrmex badius) excavate large and architecturally-distinct subterranean nests. Aspects of this process were studied by planting a harvester ant colony in the field in a soil column composed of layers of 12 different colors of sand. Quantifying the colors of excavated sand dumped on the surface by the ants revealed the progress of nest deepening to 2 m and enlargement to 8 L in volume.

Biomantling and bioturbation by colonies of the Florida harvester ant, Pogonomyrmex badius.

In much of the world, soil-nesting ants are among the leading agents of biomantling and bioturbation, depositing excavated soil on the surface or in underground chambers. Colonies of the Florida harvester ant, Pogonomyrmex badius excavate a new nest once a year on average, depositing 0.1 to 12 L (3 L average) of soil on the surface.

Nest relocation and excavation in the Florida harvester ant, Pogonomyrmex badius.

The Florida harvester ant (Pogonomyrmex badius) excavates deep nests in the sandy soils of the Gulf and Atlantic coastal plains. Nest relocations of over 400 colonies in a north Florida coastal plains pine forest were tracked and mapped from 2010 to 2013. Individual colonies varied from one move in two years to four times a year, averaging about one per year.

The morphometry of solenopsis fire ants.

Size-related changes of body shape were explored in 15 polymorphic species of Solenopsis fire ants by analyzing body weight along with linear measurements of 24 body parts. Log regression slopes were used to detect changes of shape with increasing size. Within species, the largest workers weighed from about 5 to 30-fold as much as the smallest.

The role of habitat in the persistence of fire ant populations.

The association of the exotic fire ant, Solenopsis invicta with man-modified habitats has been amply demonstrated, but the fate of such populations if ecological succession proceeds has rarely been investigated. Resurvey of a fire ant population in a longleaf pine plantation after 25 years showed that the recovery of the site from habitat disturbance was associated with a large fire ant population decline. Most of the persisting colonies were associated with the disturbance caused by vehicle tracks.

Florida harvester ant nest architecture, nest relocation and soil carbon dioxide gradients.

Colonies of the Florida harvester ant, Pogonomyrmex badius, excavate species-typical subterranean nests up the 3 m deep with characteristic vertical distribution of chamber area/shape, spacing between levels and vertical arrangement of the ants by age and brood stage. Colonies excavate and occupy a new nest about once a year, and doing so requires that they have information about the depth below ground. Careful excavation and mapping of vacated and new nests revealed that there was no significant difference between the old and new nests in any measure of nest size, shape or arrangement.

Ant distribution in relation to ground water in north Florida pine flatwoods.

Longleaf pine savannas are one of the most threatened ecosystems in the world, yet are understudied. Ants are a functionally important and diverse group of insects in these ecosystems. It is largely unknown how local patterns of species diversity and composition are determined through the interaction of this dominant animal group with abiotic features of longleaf pine ecosystems.

The life cycle and life span of Namibian fairy circles.

In Namibia of southwestern Africa, the sparse grasslands that develop on deep sandy soils under rainfall between 50 and 100 mm per annum are punctuated by thousands of quasi-circular bare spots, usually surrounded by a ring of taller grass. The causes of these so-called "fairy circles" are unknown, although a number of hypotheses have been proposed. This paper provides a more complete description of the variation in size, density and attributes of fairy circles in a range of soil types and situations.

The nest architecture of three species of north Florida Aphaenogaster ants.

The architecture of the subterranean nests of Aphaenogaster floridana Smith (Hymenoptera: Formicidae), A. treatae Forel and A. ashmeadi (Emery), was studied from plaster, wax, or metal casts.

The organization of foraging in the fire ant, Solenopsis invicta.

Although natural selection in ants acts most strongly at the colony, or superorganismal level, foraging patterns have rarely been studied at that level, focusing instead on the behavior of individual foragers or groups of foragers. The experiments and observations in this paper reveal in broad strokes how colonies of the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), allocate their available labor to foraging, how they disperse that force within their territory, and how this force changes with colony size, season and worker age. Territory area is positively related to colony size and the number of foragers, more so during the spring than fall.

Early climate change consensus at the National Academy: the origins and making of "Changing Climate".

The 1983 National Academy of Sciences report entitled "Changing Climate," authored by a committee of physical and social scientists chaired by William Nierenberg, was an early comprehensive review of the effects of human-caused increases in the levels of atmospheric CO2. Study of the events surrounding the committee's creation, deliberations, and subsequent report demonstrates that the conclusions of the report were the consensus of the entire committee and in line with the scientific consensus of the time. This result contraverts a 2008 paper in which Naomi Oreskes, Erik M.

Worker allometry in relation to colony size and social form in the fire ant Solenopsis invicta.

Workers of the polymorphic fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) show modest changes of shape with increases in body size. These shape changes (allometries) have been described only for workers taken from mature colonies of the monogyne social form. For the study reported here, workers were collected from small and large monogyne and large polygyne colonies for tests of the effects of colony size and social form on allometry.

Methods for casting subterranean ant nests.

The study of subterranean ant nests has been impeded by the difficulty of rendering their structures in visible form. Here, several different casting materials are shown to make perfect casts of the underground nests of ants. Each material (dental plaster, paraffin wax, aluminum, zinc) has advantages and limitations, which are discussed.

The foraging tunnel system of the Namibian desert termite, Baucaliotermes hainesi.

The harvester termite, Baucaliotermes hainesi (Fuller) (Termitidae: Nasutitermitinae), is an endemic in southern Namibia, where it collects and eats dry grass. At the eastern, landward edge of the Namib Desert, the nests of these termites are sometimes visible above ground surface, and extend at least 60 cm below ground. The termites gain access to foraging areas through underground foraging tunnels that emanate from the nest.

The nest architecture of the ant Odontomachus brunneus.

The architecture of the subterranean nests of the ant Odontomachus brunneus (Patton) (Hymenoptera: Formicidae) was studied by means of casts with dental plaster or molten metal. The entombed ants were later recovered by dissolution of plaster casts in hot running water. O.

Ant fat extraction with a Soxhlet extractor.

Stored fat can be informative about the relative age of an ant, its nutritional status, and the nutritional status of the colony. Several methods are available for the quantification of stored fat. Before starting a project involving fat extraction, investigators should weigh the advantages and disadvantages of different methods in order to choose the one that is best suited to the question being addressed.

Collecting live ant specimens (colony sampling).

Because of the great diversity of ants, it is difficult to give a single protocol for the collection of live specimens. Ant body size can be very small or extremely large; the ants can be hard or soft, sting or spray toxic chemicals, live in the open or in hard-to-reach places; and colony size can range from tens of individuals to millions. Thus, collection techniques must be tailored to each particular species.