Temnothorax allardycei

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This species nests in and around marshy areas and swamps in southern Florida and the Caribbean. They are often found living in the culms of sawgrass plants but colonies have also been found in hollow twigs and vines. This ant was once the focus of intensive behavioral caste studies by Blaine Cole.

Identification
Usually pale yellow, occasionally brownish yellow. Workers with short robust scapes that do not reach the occiputal margin; funiculus with a three segmented club that can be half of the length of the entire funiculus. Eyes large and convex; situated at middle of sides of head. Spines on propodeum widely separated at base, longer than peduncle, sickle-shaped, curved downward and moderately divergent.

Distribution
CARIBBEAN, United States. US - Tropical Florida.

This taxon was described from Bahamas.

Habitat
This species is typically found in swamps and areas that are periodically inundated, e.g., nesting in sawgrass culms and at the edge of swamps and in floodplain forests.

Abundance
Colonies occur in relatively low densities even in this ant's preferred habitats.

Colony Attributes
Cole (1994) states colonies average 60 workers. Kaspari and Vargo (1995) report a mean of 53 ants per colony (n=30) and cite Cole (1984) as the source of this data. The cited paper does not explicitly provide this information but does include a graph of per colony worker number X per colony brood number for 28 colonies.

(Cole 1984) Twenty percent of colonies contain no queen. Colonies exhibit a linear relationship between colony size, i.e., number of workers, and brood number. There is, on average, 1.32 brood per worker.

Nesting Biology
The type specimens were collected from the hollow stem of a sawgrass (Cladium jamaicensis) plant. Cole conducted much of his research with Temnothorax allardycei colonies collected from sawgrass culms in the Florida Keys.

Deyrup and Cover (2004) report "Nests are usually in hollow twigs or vines on living trees, occasionally in sawgrass culms at edges of marshes; in Bahamas sometimes in fallen twigs. Often in poisonwood (Metopium toxiferum)."

Behavior
The behavior of this species has been the focus of intensive study by Blaine Cole. The following presents some highlights of the findings from these behavioral studies but does not begin to approach presenting an exhaustive summary of this work.

Cole's insightful research led to discovery that dominance hierarchies can occur within ant colonies (Cole 1982). Of equal significance was showing that the highest ranking individuals were able to solicit more food from other workers than their subordinates. The flow of food through the colony was up the chain of dominance, with no food being given from dominant to subordinate adult workers. Dominate workers also found to exhibit greater ovarian development than their coworkers. Cole was able to show that the dominant workers were producing 22% of the eggs in a colony and that these eggs did developed into normal males.

These studies also examined how workers spend their time and showed (as reported from the abstract of Cole 1986): "Analysis of time budgets indicate that a typical ant spends a large fraction (0.55) of its time quiescent and another large fraction of time (0.32) involved in undifferentiated activity. Dominance activity and brood care together make up about 11% of the total time. The amount of time spent on dominance activity is negatively related to the amount of time spent on brood care, but positively related to the amount of time that an ant is active. The amount of time that an ant has available for brood care which is actually spent on brood care declines with the amount of time spent on dominance activity. The amount of time that a worker spends feeding liquid food to larvae is a function of hierarchy rank; alpha spends the most time, beta less and gamma still less."

Castes
Mann (1920): The most curious thing about the species is the presence of some degree of polymorphism, one worker, the largest in the series, having the head proportionately broader than the others and the epinotal spines bent slightly upward.

Worker
Head longer than broad, as broad in front as behind with feebly convex sides and occipital border. Mandibles with five teeth. Clypeus convex, tricarinate; anterior border straight. Antenna short, scapes extending about two-thirds the distance to occipital corners in the smallest workers and three-fourths in the largest; first funicular joint more than twice as long as the two following joints together; joints three to eight twice as broad as long; club well-defined, as long as the rest of funiculus, with the first and second joints only slightly longer than broad and the terminal joint distinctly longer than the other two together. Eyes large and convex; situated at middle of sides of head. Thorax robust, without sutures, slightly tapering from greatest width (at anterior part of pronotum) to the epinotal declivity. Epinotal spines widely separated at base, longer than peduncle, sickle-shaped, curved downward and moderately divergent. Petiole with a thick peduncle, shorter than the node, armed anteroventrally with a strong, elongate tooth; node longer than high, dorsal surface broad (in profile but slightly convex), anterior and posterior surfaces sloping; from above evenly tapering into the peduncle, with two minute lateral tubercles a little in front of middle. Postpetiole a little broader than the petiole and broader than long, slightly narrowed in front, with moderately rounded sides. Gaster short and broad. Sting very feeble. Femora and tibiae somewhat swollen.

Shining throughout. Mandibles striate. Head, thorax, epinotum, and petiole reticulately carinulate, with the intermediate spaces foveolately punctate and rugulose. Postpetiole rugulose. Gaster and legs minutely punctate and more shining than the rest.

Erect, stiff, acuminate, yellowish hairs moderately abundant on head, body and appendages.

Color uniformly testaceous.

Queen
Head about as long as broad, broadest behind. Epinotal spines stout, triangular, shorter than their distance apart at base. Petiolar node shorter and deeper than in the worker, and more declivous in front. Postpetiole twice as broad as long.

Head, epinotum, petiole and postpetiole sculptured as in the worker. Mesonotum and scutellum with very fine longitudinal strife and sparse, foveolate punctures.

Color darker than the worker, with the mesonotum and gaster and a spot at the ocelli, ferruginous, and the margins of the mesonotum and scutellum fuscous.

Male
Males have been collected but this caste has not been formally described.

Type Material
Presumably in the USNM

Type Locality Information
Bahamas: New Providence. "on the borders of a swamp on the road between Grants Town and the Blue Hills."

Etymology
Patronym. "dedicated to Sir William Allardyce, Governor of the Bahamas, a naturalist himself and a friend of naturalists"

Additional References
Cole, B. 1988. Individual differences in social insect behavior: Movement and space use in Leptothorax allardycei. Pages 113-145 in R. L. Jeanne, editor. Interindividual behavioral variability in social insects. Westview Press, Boulder, CO. 456 p.

Cole, B. J. 1981. Dominance hierarchies in Leptothorax ants. Science (Washington D. C.). 212:83-84.

Cole, B. J. 1982. The guild of sawgrass-inhabiting ants in the Florida Keys. Psyche (Cambridge). 89:351-356.

Cole, B. J. 1984. Colony efficiency and the reproductivity effect in Leptothorax allardycei (Mann). Insectes Sociaux. 31:403-407.

Cole, B. J. 1986. The social behavior of Leptothorax allardycei (Hymenoptera, Formicidae): time budgets and the evolution of worker reproduction. Behavioral Ecology and Sociobiology. 18:165-173.

Cole, B. J. 1988b. Escalation of aggression in Leptothorax ants. Insectes Sociaux. 35:198-205.

Cole, B. J. 1991a. Is animal behaviour chaotic? Evidence from the activity of ants. Proceedings of the Royal Society of London B Biological Sciences. 244:253-259.

Cole, B. J. 1991c. Short-term activity cycles in ants: generation of periodicity by worker interaction. American Naturalist. 137:244-259.

Cole, B. J. 1992. Short-term activity cycles in ants: age-related changes in tempo and colony synchrony. Behavioral Ecology and Sociobiology. 31:181-187.

Cole, B. J., J. McDowell, and D. Cheshire. 1994. Demography of the worker caste of Leptothorax allardycei (Hymenoptera: Formicidae). Annals of the Entomological Society of America. 87:562-565.

Cole, B. J. and D. Cheshire. 1996a. Mobile cellular automata models of ant behavior: Movement activity of Leptothorax allardycei. American Naturalist. 148:1-15.

Cole, B. J. and L. Hoeg. 1996b. The influence of brood type on activity cycles in Leptothorax allardycei (Hymenoptera: Formicidae). Journal of Insect Behavior. 9:539-547.

Cole, B. J., J. McDowell, and D. Cheshire. 1994. Demography of the worker caste of Leptothorax allardycei (Hymenoptera: Formicidae). Annals of the Entomological Society of America. 87:562-565.

Deyrup, M. and S. Cover. 2004. A new species of the ant genus Leptothorax from Florida, with a key to the Leptothorax of the southeast (Hymenoptera: Formicidae). Florida Entomologist. 87:51-59.

Kaspari, M. and E. L. Vargo. 1995. Colony size as a buffer against seasonality: Bergmann's rule in social insects. American Naturalist. 145:610-632.

Mann, W. M. 1920. Additions to the ant fauna of the West Indies and Central America. Bulletin of the American Museum of Natural History. 42:403-439.