Pogonomyrmex salinus
Images of Pogonomyrmex salinus - at various locations in Nevada, Oregon, and Washington states, USA.
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Pogonomyrmex salinus
● NW of Mattawa [Grant Co], WA USA [el. 152 m/500 ft] view location in Google Maps » ● 9/27/09 8:47AM sunny, air temp: 18°C / 64°F
This unusual scene was captured on the last day of our 2009 season. Looking like an out-of-focus mirror image, a 'normal' P. salinus worker (background) gazes back at a newly eclosed nestmate (the yellowish-gold ant in the foreground). 'Eclosion' refers to the emergence of the adult ant from the pupal phase (the final stage of its pre-adult metamorphosis [1]). These 'new' ants, referred to as callow, are light in color, and their exoskeleton (integument) is rather soft. At least for some Pogo species, the exoskeleton of the callows will darken and take on the rigidity of a 'normal' worker in several days, to a few weeks after eclosion [2]. Callow workers are not usually seen outside the interior of the nest [3], and in 2 years of observing and imaging P.salinus, we have seen them on only three occasions. Finally, the uniqueness of the scene is enhanced by the proximity of the callow ant to a quartz pebble of strikingly similar color! [scroll down for additional notes/references]
ADDITIONAL NOTES/REFERENCES:
[1]
Pogos, like all other ants, undergo a complete metamorphosis: egg → larva → pupa → adult.
[2]
In one study, Pogonomyrmex rugosus callow workers took 5 days or less to take on the appearance of an adult, and P. monatnus workers took about 3 weeks. It is also noted, the callow worker population for three species, Pogonomyrmex monatnus, P. rugosus, and P.subnitidus, reached its maximum in September.
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
[3]
In a great number of ant species (possibly the majority), workers tend to progress from interior tasks like brood care, to exterior tasks such as external defending of the nest and foraging, as they grow older. Groups of workers performing different duties depending on their age are known as temporal castes. Callow workers are usually confined relatively deep within the nest, caring for the eggs, larvae, and pupae (known collectively as brood).
·Hölldobler, B. & E.O. Wilson. 1990. The Ants. Cambridge, MA, Belknap/Harvard Press
·MacKay, W.P. 1981. A Comparison of Nest Phenologies of Three Species of Pogonomyrmex Harvester Ants (Hymenoptera: Formicidae). Psyche, Vol. 88, No. 1-2, 1981
·Porter, S.D., and C.D. Jorgensen. 1981. Foragers of the Harvester Ant, Pogonomyrmex owyheei: a Disposable Caste? Behavioral Ecology and Socialbiology (1981) 9:247-256
·Tschinkel WR. 2004. The Nest Architecture of the Florida Harvester Ant, Pogonomyrmex badius. Journal of
Insect Science, 4:21
pogopogonomyrmexpogonomyrmex salinusantsmacroharvester antspogos
