Hierarchical analysis of population genetic structure in the monogynous ant Cataglyphis cursor using microsatellite and mitochondrial DNA markers

Despite having winged queens, female dispersal in the monogynous ant Cataglyphis cursor is likely to be restricted because colonies reproduce by fission. We investigated the pattern of population genetic structure of this species using eight microsatellite markers and a mitochondrial DNA (mtDNA) sequence, in order to examine the extent of female and nuclear gene flow in two types of habitat. Sampling was carried out at a large spatial scale (16 sites from 2.5 to 120 km apart) as well as at a fine spatial scale (two 4.5-km transects, one in each habitat type). The strong spatial clustering of mtDNA observed at the fine spatial scale strongly supported a restricted effective female dispersal. In agreement, patterns of the mtDNA haplotypes observed at large and fine spatial scales suggested that new sites are colonized by nearby sites. Isolation by distance and significant nuclear genetic structure have been detected at all the spatial scales investigated. The level of local genetic differentiation for mitochondrial marker was 15 times higher than for the nuclear markers, suggesting differences in dispersal pattern between the two sexes. However, male gene flow was not sufficient to prevent significant nuclear genetic differentiation even at short distances (500 m). Isolation-by-distance patterns differed between the two habitat types, with a linear decrease of genetic similarities with distance observed only in the more continuous of the two habitats. Finally, despite these low dispersal capacities and the potential use of parthenogenesis to produce new queens, no signs of reduction of nuclear genetic diversity was detected in C. cursor populations.     

Territorial Marking in the Desert Ant Cataglyphis niger: Does It Pay to Play Bourgeois?

Here we report on territorial behavior in the desert ant Cataglyphis niger. We show that, similar to the bourgeois strategy, contests are settled quickly through nonescalating fights, with the owner of the territory usually being placed in the winning role. The chemical cue that advertises ownership is shown to come from pheromones secreted by the cloacal gland. Differences in size did not influence the outcome of the experimental contests, but resource value did. The observed results fit in well with the biology of Cataglyphis, where, due to the harsh semidesert environment, fighting costs (C) are expected to be high relative to the value of the contested resources (V). A situation where V < C is exactly that in which bourgeois behavior is expected to be seen.     

Structural and chemical ontogeny of the postpharyngeal gland in the desert ant Cataglyphis niger

Abstract. The postpharyngeal gland of Cataglyphis niger (André, 1881) workers is characterized, at the ultrastructural level, by a well-developed smooth endoplasmic reticulum, Golgi apparatus, and numerous mitochondria and lamellar inclusions suggesting an involvement in lipid metabolism. In addition, the microvillar differentiation of the apical membrane and basal invaginations of the cell imply a transportation process.
The gland shows a clear structural as well as chemical age-dependent development. Epithelial thickness increases with age, reaching its maximum within the first week after emergence. Concurrently there is a progressive development of microvilli and appearance of the lamellar inclusions. The gland's secretion consists mainly of hydrocarbons, with a predominance of monomethyl and dimethyl alkanes. Congruency was found between the hydrocarbon composition of glandular exudates and those of the epicuticular washes. An age-dependent increase in the total amount of hydrocarbons was found to correlate with the ultrastructural development and gross morphology (thickness of epicuticular lining) of the gland.     

Characterization and phylogenetic implication of complete mitochondrial genome of the Cataglyphis aenescens (Hymenoptera: Formicidae): Genomic comparisons in Formicinae

Ants are the most widely distributed social insects in terrestrial ecosystems with the largest number of species and quantities; their ecological function is very significant and they have certain medicinal value. Because mitochondria have their own DNA (mtDNA) and genetic system, so the complete mitochondrial genome has been used more and more in molecular phylogeny, population genetics, molecular diagnosis, and evolution of insects. In this study, the mitochondrial genome of Cataglyphis aenescens (Nylander, 1849) (Hymenoptera: Formicidae) was sequenced and annotated. The results showed that the total length of the mitochondrial genome of C. aenescens (Nylander, 1849) was 17,197 bp; it contained 37 genes, including 13 protein coding genes (PCGs), 22 tRNA genes (tRNAs), 2 rRNA genes (rRNAs) and a non-coding region. All PCGs of C. aenescens were initiated with ATN codons and terminated with the TAA codon. The overall nucleotide composition of C. aenescens was AT-biased (81.74%). Cataglyphis and Formica clustered together. C. aenescens is closely related to Formica sinae, Formica. fusca and Formica selysi. This work enhances the genetic data of Formicidae and contributes to our understanding of their phylogenic relationship, evolution, and utilization.     

Characterization of nuclear DNA microsatellite markers in the ant Cataglyphis cursor

The ant Cataglyphis cursor is exceptional in that unmated workers are potentially able to lay both male and female eggs. We characterized eight pairs of primers for microsatellite loci, developed from genomic DNA for this species. Variability was tested with DNA from 19 workers and all eight loci were highly polymorphic, displaying 5–10 alleles and a high level of heterozygosity. Cross‐species amplifications indicate that these microsatellites might be useful in genetic studies of other species belonging to the genus Cataglyphis.     

Adult transport in the ant Cataglyphis iberica: a means to maintain a uniform colonial odour in a species with multiple nests

Abstract. . Societies of the ant Cataglyphis iberica (Hymenoptera, Formicidae) comprise several satellite queenless nests around a queenright nest. During spring, at the end of hibernation, the incidence of adult transport between these nests is high, but it decreases during summer. Quantitative analyses of the contents of postpharyngeal glands of transporter and transportee ants reveal the amounts of hydrocarbons to be lower in the latter, indicating that these ants are generally younger. Moreover, the more diverse composition of the transportees' secretion may reflect their individual makeup. Transporters, in contrast, maintained a uniform colony odour uirough trophallactic exchanges before entering hibernation. The odour disparity between the transportees and the general colony odour may stimulate the transporters to bear them to the nest containing the queen where they can obtain the colony odour via trophallaxis. The intense traffic between satellite nests in the spring may thus be the means by which a uniform colonial odour is regained after hibernation. Adult transport seems also to be necessary since the young transportee ants are not able to orient themselves and find the other nests.