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Throughout the Neotropics, from southern Texas to Argentina and on numerous Caribbean islands.
Crematogaster crinosa is an extremely widespread and generalized species that prefers highly insolated habitats. It is common in seasonally dry areas, less common in wet forests. In wet forest habitats it is typically found in the high canopy or in disturbed areas. It may form monodominant populations in mangrove forests.
Colonies are large and polydomous and it is usually difficult to locate colony boundaries. Nests are found in almost any kind of cavity (figs. 1, 2, 4), and columns of workers move from nest to nest. Nests can be in live or dead branches, in small rotten knots, under bark flaps, in cavities in fence posts, opportunistically in ant plants, and thinly dispersed in multiple small bark cavities. Workers, brood, and alate sexuals are dispersed across nests. Small amounts of carton construction are used to form baffles inside of nest cavities and to restrict nest entrances, but large external carton nests are never constructed.
Although new alate queens are relatively common in nests, I have rarely encountered physogastric colony queens. In my collecting experience, I have never found a colony that was obviously polygynous, with many dealate queens dispersed in many nests. However, I am treating Forel's minutior as a synonym of crinosa, and minutior from St. Vincent Island in the West Indies forms large polygynous, polydomous colonies in coastal areas (Forel 1893).
In Colombia I observed the beginning of a nuptial flight just after dusk. I found a dense aggregation of males and workers under a bark flap, and the males were just beginning to fly.
Workers are omnivorous. They are attracted to protein and carbohydrate baits, they scavenge dead or injured insects, they visit extrafloral nectaries, and they tend Homoptera. When nests are disturbed they can be aggressive and will bite. Workers are continuously polymorphic, with a broad range of worker sizes.
I often find cockroach egg cases scattered in the nest chambers of C. crinosa (fig. 1), at a much higher density than in the environment generally. The nature of the relationship between cockroaches and the crinosa group would be worth investigation.
Ecological equivalents are torosa and rochai. I can detect very few behavioral or ecological differences among these species. Crematogaster crinosa is the only member of the group that regularly dominates mangrove habitats. Mangrove forests in Costa Rica are sometimes dominated by Azteca, sometimes by C. crinosa. I found a similar situation in the Santa Marta area of Colombia. I have only one record of rochai from mangroves (a voucher collection from Adams' studies of mangrove communities, Adams 1994), and I have no record of torosa from mangroves. Other than in mangroves, crinosa is less abundant relative to torosa or rochai. For example, a collecting trip to a wildlife refuge in southern Texas yielded 13 separate collections of torosa but only one of crinosa. In northwestern Costa Rica, torosa and rochai are far more abundant than crinosa. Based on museum collections, crinosa seems to be the most common member of the crinosa group on various Caribbean and Pacific islands.
Members of the crinosa complex are among the most frequently encountered Neotropical ants, particularly in open or seasonally dry habitats. They are geographically variable and taxonomically difficult, and species boundaries are poorly defined. Crematogaster crinosa, rochai, and torosa are three very similar species that occur together in Costa Rica. They are difficult to distinguish and workers may not always be clearly identified. All three have the face with sparse erect setae over short appressed pubescence, the mesosomal dorsum and fourth abdominal tergite with short, stiff erect setae (or erect setae absent), the dorsal face of the petiole short with convex sides, and the propodeal spines short and upturned. Crematogaster crinosa can be differentiated from rochai throughout the range, because crinosa has a dense, even covering of erect setae on the fourth abdominal tergite, while rochai completely lacks these setae or has only a small cluster on each anterolateral humerus. Distinguishing crinosa from torosa is more difficult. In Costa Rica, torosa also has abundant erect setae on the fourth abdominal tergite, but these are usually clustered laterally and anterolaterally, leaving a median strip free of setae. Also, crinosa always has a long, sharp anteroventral petiolar process, while torosa more often has a short, blunt or squared-off process. Crematogaster crinosa can also be confused with erecta and moelleri, but these have flexuous erect setae on the pronotal humeri.
crinosa, torosa, and rochai are extremely close in external morphology. Occasional intermediates occur which can be difficult to assign to one form or the other. Further research is needed to clarify the meaning of these morphological patterns. Are they discrete genotypic clusters with occasionally overlapping phenotypes? Are they not genotypic clusters, but instead caused by selection on relatively few genes that generates complex clinal patterns? If they are genotypic clusters, are they maintained by reproductive barriers or by selection? Do the different morphological forms, species or not, have different ecological characteristics that might explain the geographic and habitat patterns?
|Crematogaster crinosa||Wild, A. L., 2007, A catalogue of the ants of Paraguay (Hymenoptera: Formicidae)., Zootaxa 1622, pp. 1-55: 32, (download)||32||21367|
|Crematogaster crinosa||Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 126-128, (download)||126-128||20256|
|Crematogaster atra||Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 129, (download)||129||20256|
|Crematogaster sericea||Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 130, (download)||130||20256|
|Crematogaster uruguayensis||Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 130, (download)||130||20256|
|Crematogaster crinosa||Longino, J. T., 2003, The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa Rica., Zootaxa 151, pp. 1-150: 49-53, (download)||49-53||20256|
Found most commonly in these habitats: 13 times found in coastal scrub, 10 times found in Mangrove estuary, 12 times found in Pisonia-Tabebuia, 6 times found in mangroves, 1 times found in rainforest, 3 times found in wet forest, 3 times found in mature secondary forest along dry creek, 4 times found in dry forest, 1 times found in lime orchard, 1 times found in beach edge, sand dune with Cocoloba uvifera, ...
Found most commonly in these microhabitats: 8 times on oil palm, 11 times on low vegetation, 8 times ground forager, 1 times canopy fogging, 4 times dead twig above ground, 2 times Workers in Avicennia knot, 1 times nest in dead stem, 4 times under stone, 3 times on low veg, 1 times ex Cecropia, 4 times Malaise trap, ...
Collected most commonly using these methods: 35 times hand collection, 15 times search, 1 times canopy fogging, 5 times Beating, 5 times Malaise, 3 times direct collection, 2 times Fogging, 1 times pan trap, 1 times pyrethrum/insecticide fogging, 1 times Baiting, 1 times beating vegetation (3 hour period), ...
Elevations: collected from 5 - 1800 meters, 261 meters average
Type specimens: holotype brevispinosa: jtl055912; Lectotype of Crematogaster brevispinosa chathamensis: castype03689; syntype ampla: jtl027868, jtl027869; syntype crinosa: jtl055907, jtl055908; syntype crinosa?: jtl055909, jtl055910; syntype minutior: jtl027871, jtl027872; syntype of Crematogaster brevispinosa: casent0916976, casent0919695; syntype of Crematogaster brevispinosa minutior: casent0908392; syntype of Crematogaster brevispinosa recurvispina: casent0908401; syntype of Crematogaster brevispinosa sampaioi: casent0908403; syntype of Crematogaster brevispinosa schuppi: casent0908393; syntype of Crematogaster brevispinosa striatinota: casent0901466, casent0902170, casent0908394; syntype of Crematogaster brevispinosa townsendi: casent0912762; syntype of Crematogaster crinosa: casent0919698; syntype of Crematogaster minutior: casent0902173; syntype striatinota: jtl027882; syntypes sampaioi: jtl056062; syntypes semisericea: jtl055911; syntypes thalia: jtl027883; type of Crematogaster (Orthocrema) brevispinosa var. schuppi: focol0072; type of Crematogaster brevispinosa var. striatinota: focol0694-1, focol0694-2; Type of unavailable quadrinomial: Crematogaster brevispinosa minutior themis: casent0912759; unpublished name: Crematogaster brevispinosa buchi: casent0912754; unpublished name: Crematogaster pygmaea divergens: casent0904523