Morphology and number of Ommatidia in the compound eyes of Solenopsis invicta, Solenopsis richteri, and their hybrid (Hymenoptera: Formicidae)

The morphology and number of ommatidia of the compound eyes of Solenopsis invicta, Solenopsis richteri and their hybrid are investigated. Comparisons are made of the morphology and number of ommatidia in S. invicta, S. richteri and their hybrid. Major workers have significantly more facets than minor workers, male reproductive more than female reproductive, and the reproductives more than workers. Workers and reproductives have significantly more ommatidia in S. invicta than in S. richteri and significantly fewer in the hybrid than in either species. The major workers of each species have significantly wider facets than the minor workers, and workers have significantly wider facets than reproductives, which showed no difference in their facet diameter. There are no significant differences when the facet diameter is compared between the members of the castes of different species. These morphological and numerical dissimilarities are discussed in connection with known behavioral differences in the castes.