Ants of Hispaniola

The ants of this Caribbean island, an important component of the Greater Antilles, are primarily known from Mann's Haitian study (Wheeler and Mann 1914) and contemporary Dominican Republic (DR) studies. The DR still contains areas with naturally occurring habitat and likely retains much its native ant fauna. Unfortunately many protected areas with natural vegetation are fragmented and continue to be degraded and destroyed. Modern Haiti is ecologically devastated. It is no longer possible to study or understand the naturally occurring distribution and abundance of its native ant species.

Pogonomyrmex
Key to Pogonomyrmex of Hispaniola

Johnson and Cover (2015) recently revised the Hispaniola species of this genus. Their comments in regards to the genus and the species that occur here:

Recent collections provided material to re-evaluate species boundaries and to update information on taxonomic status, distribution, biogeography, and biology for the Pogonomyrmex of Hispaniola so as to make this interesting group more accessible for future studies. Unresolved problems include determining microhabitat preferences, dietary preferences, and foraging strategies of all three species. Males are presently unknown in Pogonomyrmex schmitti and Pogonomyrmex aterrimus, and additional collections are needed to verify the taxonomic status of “P. darlingtoni”.

Colony founding behavior promises to be a rewarding subject to investigate given the very small size of queens for P. schmitti and Pogonomyrmex saucius. Based on our morphological data, P. schmitti probably has the lowest queen to worker mass dimorphism (for species with alate queens) within the genus. Previously, the lowest queen to worker mass ratio occurred in Pogonomyrmex pima (queen dry mass/worker dry mass = 2.05), in which alate queens are significantly larger than workers (Johnson et al. 2007; R.A. Johnson, unpub. data). Queens of P. saucius were also small as their HW and HL fell within the range of measured workers, but their pronotal width was greater than that of all measured workers. The small size of these queens suggests that colony founding occurs via queen foraging, pleometrosis, or budding.

At this time, all three Hispaniola species of Pogonomymex are known to have only alate queens, which is interesting given that closely related Ephebomyrmex clade species in North America (P. pima, Pogonomyrmex imberbiculus) (Heinze et al. 1992; Johnson et al. 2007) and South America (Pogonomyrmex naegelii, Pogonomyrmex cunicularius, Pogonomyrmex pencosensis, Pogonomyrmex serpens, and two undescribed species in the P. brevibarbis-group) (Johnson 2015; R.A. Johnson, unpub. data) have ergatoid (wingless) or dimorphic queens (ergatoid and winged). However, we note that few Pogonomyrmex queens have been collected on Hispaniola (1 for aterrimus, 1 for saucius, 4 for schmitti), leaving open the possibility that additional queen phenotypes remain to be collected.

Lastly, we note that all three species of Pogonomyrmex are endemic to and contribute to the high level of endemism for the ants of Hispaniola. Approximately 52% (64 of 124 species) of the native ant species are endemic to Hispaniola (Perez-Gelabert 2008), which is higher than the 36.9% rate for all insects (Perez-Gelabert 2008). Interestingly, species of Pogonomyrmex are absent from other parts of the Greater Antilles (i.e., Cuba, Puerto Rico, Jamaica, and the Cayman Islands) (Fontenla 1997; Reyes 2002) and all islands in the Lesser Antilles.