PCR primers for polymorphic microsatellite loci in the plant‐ant Azteca ulei cordiae (Formicidae: Dolichoderinae)

Twelve microsatellite loci were isolated from the Peruvian tropical plant‐ant, Azteca ulei cordiae (Hymenoptera: Dolichoderinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from four to 18, and heterozygosity from 0.118 to 1 per population sample. Cross‐species amplification of these loci was also successfully tested in several other species of the same ant genus Azteca.     

Polymerase chain reaction primers for polymorphic microsatellite loci in the ant Pseudomyrmex gracilis (Formicidae: Pseudomyrmecinae)

The elongate twig ant Pseudomyrmex gracilis is widely distributed in the New World ranging from southern USA to Brazil and northern Argentina. To investigate its within-colony relatedness, we developed primers for nine polymorphic microsatellite loci. High levels of within-population variation were observed, with number of alleles ranging from two to 13, and heterozygosity from 0.28 to 0.90. The loci showed no deviations from Hardy-Weinberg equilibrium and no linkage disequilibrium.     

Army ant behaviour in the poneromorph hunting ant Onychomyrmex hedleyi Emery (Hymenoptera: Formicidae; Amblyoponinae)

Onychomyrmex belongs to the phylogenetically basal ant tribe Amblyoponini but shows prototypical army ant behaviours, i.e. group predation and nomadism. In order to investigate these behaviours, Onychomyrmex hedleyi was observed in the field and in laboratory experiments. Workers of O. hedleyi would frequently hunt centipedes but rarely social insects. Workers did not dismember the victims but recruited the colony mates to conduct group retrieval. If the prey were too large or too heavy to retrieve, the entire colony moved from the bivouac site to the prey site. Although foraging on the forest floor, a colony repeated the extension and withdrawal of a raiding column, which was up to 80 cm long (mean ± SD, 41.6 ± 18.5 cm). Colonies were nomadic and the relocation distance was up to 150 cm (mean ± SD, 74.4 ± 45.0 cm). Retinues guarded a queen who moved to a new bivouac site in the early phase of relocation. Colonies were found to stay at a site statistically longer if they had come from a more distant site, and were also observed to move to a more distant site if they had spent a longer time at a particular bivouac site. The consecutive migrations did not show significant directionality.     

Nest architecture and colony size of the fungus-growing ant <Emphasis Type="Italic">Mycetophylax simplex</Emphasis> Emery, 1888 (Formicidae,Attini)

Detailed measurements on nest architecture and colony size of the fungus-growing ant Mycetophylax simplex Emery, 1888 (Formicidae, Attini) are reported for the first time, based on excavations of 55 nests from two sites in southern Brazil. All nests were subterranean, with a single entrance hole. Most nests consisted of two chambers, an upper and a lower chamber, but one and three-chamber nests were also found. The chambers were more cone-shaped than rounded, and located at a depth ranging from 4.0 cm to 32.5 cm below the nest entrance. The chamber dimensions generally increased as the depth of the chambers increased, and the lower chamber was mostly wider than the upper one. The fungus garden was always found resting on the chamber floor. The average colony size was 264.1 workers, ranging from 67 to 610 workers. Colonies produced most sexuals during the summer (from December to March) and a few during the winter (July). Direct observations showed that colonies were mostly monogynous, but more than one queen was recorded in two nests, suggesting that polygyny may also occur in this species. Received 30 November 2006; revised 20 April 2007; accepted 23 April 2007.     

Population genetics and history of the introduced fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in Australia

Abstract  The red imported fire ant, Solenopsis invicta , a damaging invasive pest, was discovered in February 2001 in Brisbane, Australia at two sites, Fisherman Islands and suburban Richlands-Wacol. Using four microsatellite loci and the protein marker Gp-9 , we compared the two infestations with each other, and with potential source populations in North and South America to better understand the history of their introduction to Brisbane. Based on an analysis of molecular variance, as well as a maximum likelihood tree of colonies from the two Australian sites, we found that the two sites were genetically distinct and were almost certainly introduced separately. All of the colonies at Fisherman Islands were monogynous, headed by a single queen, while the Richlands-Wacol site had a mixture of single-queen monogynous and multiple-queen polygynous colonies. However, the monogynous and polygynous colonies at the Richlands-Wacol site were not genetically distinct from each other, and probably constitute a single, mixed introduction. Based on allele frequencies at the microsatellite loci, and Gp-9 , both Australian infestations were more similar to North American populations than to South American, though the Fisherman Islands infestation was intermediate, making it difficult to assign. Thus, there has been one introduction from either a North or South American monogynous population at Fisherman Islands, and one introduction from a mixed monogynous/polygynous North American population at Richlands-Wacol. These findings have implications for the control of the current infestations, as well as for the quarantine regulations necessary to prevent additional introductions to Australia.     

A procedure for the transient expression of genes by agroinfiltration above the permissive threshold to study temperature‐sensitive processes in plant–pathogen interactions

Localized expression of genes in plants from T‐DNAs delivered into plant cells by Agrobacterium tumefaciens is an important tool in plant research. The technique, known as agroinfiltration, provides fast, efficient ways to transiently express or silence a desired gene without resorting to the time‐consuming, challenging stable transformation of the host, the use of less efficient means of delivery, such as bombardment, or the use of viral vectors, which multiply and spread within the host causing physiological alterations themselves. A drawback of the agroinfiltration technique is its temperature dependence: early studies have shown that temperatures above 29 °C are nonpermissive to tumour induction by the bacterium as a result of failure in pilus formation. However, research in plant sciences is interested in studying processes at these temperatures, above the 25 °C experimental standard, common to many host–environment and host–pathogen interactions in nature, and agroinfiltration is an excellent tool for this purpose. Here, we measured the efficiency of agroinfiltration for the expression of reporter genes in plants from T‐DNAs at the nonpermissive temperature of 30 °C, either transiently or as part of viral amplicons, and envisaged procedures that allow and optimize its use for gene expression at this temperature. We applied this technical advance to assess the performance at 30 °C of two viral suppressors of silencing in agropatch assays [Potato virus Y helper component proteinase (HCPro) and Cucumber mosaic virus 2b protein] and, within the context of infection by a Potato virus X (PVX) vector, also assessed indirectly their effect on the overall response of the host Nicotiana benthamiana to the virus.     

Characterization of six polymorphic microsatellites for the polychaete tubeworm Hydroides elegans and cross‐species amplification in the congener Hydroides hexagonus

We isolated and characterized six polymorphic microsatellite loci for the polychaete tubeworm, Hydroides elegans. Two additional loci were not reliably scorable and estimates of heterozygosity were obtained for the other six. In addition, cross‐species amplification was successful for two loci using the congener H. hexagonus. Given that few microsatellite loci are available for polychaetes, these markers will be useful in assessing dispersal and gene flow in H. elegans and probably also other polychaetes.     

Isolation and characterization of polymorphic microsatellites in a sex‐reversal fish,rice field eel (Monopterus albus)

The rice field eel (Monopterus albus) is a fish of economic importance in China and some Asian countries. From a (GT)_n‐enriched genomic library, 30 microsatellites were developed by employing the fast isolation by AFLP of sequences containing repeats (FIASCO) protocol. Thirteen loci exhibited polymorphism with two to 13 alleles (mean 7.9 alleles/locus) in a test population and observed heterozygosity ranged from 0.3125 to 0.9688 (mean 0.7140). These loci should provide sufficient level of genetic variation to study the fine‐scale population structure and reproductive ecology of the species.     

Population- and sociogenetic structure of the leaf-cutter ant <Emphasis Type="Italic">Atta colombica</Emphasis> (Formicidae,Myrmicinae)

Relatedness and genetic variability in colonies of social insects are strongly influenced by the number of queens present and the number of matings per queen, but also by the genetic variability in the population. Thus, multiple paternity will enhance within-colony genetic variability more strongly when the males a queen mates with are unrelated. To study the kin-structure within colonies of the leaf-cutter ant Atta colombica and the population structure of this species around Barro Colorado Island, Panama, we developed five polymorphic microsatellite loci with a range of three to 17 alleles in At. colombica, all of which cross-amplify in other higher attines as well. The average effective mating frequency calculated from four-locus microsatellite genotypes was 1.89 ± 0.12 (harmonic mean ± SE) and thus slightly lower than the average observed mating frequency of 2.50 ± 0.11 (arithmetic mean ± SE) over the 55 colonies studied, confirming former studies that utilized fewer loci. The discrepancy between observed mating frequency and effective mating frequency is most probably due to paternity skew within colonies. The study population proved to be genetically diverse and in Hardy-Weinberg equilibrium, suggesting random mating within the study area. No population substructure was observed, neither considering nuclear (global F _ST = 0.011 ± 0.003 SE) nor mitochondrial markers (mean Φ_ST = 0.008). Consequently, gene flow is obviously promoted by both sexes across the range investigated here. Thus, multiple mating and long-distance dispersal appear to be two interconnected behavioural mechanisms to create and maintain genetic diversity in At. colombica. The advantages of this system are partly offset by paternity skew and the non-zero relatedness among colony fathers found in the study population. Received 18 March 2008; revised 14 July 2008; accepted 18 July 2008.     

Characterization of 11 polymorphic tetranucleotide microsatellites for forensic applications in California elk (Cervus elaphus canadensis)

Eleven polymorphic tetranucleotide microsatellite loci have been developed for forensic use in the protection of California elk. Based on a reference sample of elk taken from three races throughout California, the loci consist of 4–9 alleles (average 6.125). Probabilities of identity ( Paetkau et al. 1995 ) range from 0.079 to 0.288, with an overall probability of identity of 1.3 × 10^?9 (one in 7.8 × 10⁸).     

Polygynous supercolonies of the acacia‐ant Pseudomyrmex peperi,an inferior colony founder

In ant–plant protection mutualisms, plants provide nesting space and nutrition to defending ants. Several plant–ants are polygynous. Possessing more than one queen per colony can reduce nestmate relatedness and consequently the inclusive fitness of workers. Here, we investigated the colony structure of the obligate acacia‐ant Pseudomyrmex peperi, which competes for nesting space with several congeneric and sympatric species. Pseudomyrmex peperi had a lower colony founding success than its congeners and thus, appears to be competitively inferior during the early stages of colony development. Aggression assays showed that P. peperi establishes distinct, but highly polygynous supercolonies, which can inhabit large clusters of host trees. Analysing queens, workers, males and virgin queens from two supercolonies with eight polymorphic microsatellite markers revealed a maximum of three alleles per locus within a colony and, thus, high relatedness among nestmates. Colonies had probably been founded by one singly mated queen and supercolonies resulted from intranidal mating among colony‐derived males and daughter queens. This strategy allows colonies to grow by budding and to occupy individual plant clusters for time spans that are longer than an individual queen’s life. Ancestral states reconstruction indicated that polygyny represents the derived state within obligate acacia‐ants. We suggest that the extreme polygyny of Pseudomyrmex peperi, which is achieved by intranidal mating and thereby maintains high nestmate relatedness, might play an important role for species coexistence in a dynamic and competitive habitat.     

Disruption of parasitism of the California red scale (Homoptera: Diaspididae) by three ant species (Hymenoptera: Formicidae)

The relative influence of the southern fire ant, Solenopsis xyloni McCook, Argentine ant, Linepithema humile (Mayr), and native gray ant, Formica aerata (Francoeur), on parasitism of California red scale, Aonidiella aurantii Maskell, was studied in the laboratory for two parasitoids, Comperiella bifasciata Howard and Aphytis melinus DeBach. All three ant species reduced percentage parasitism by C. bifasciata and both percentage parasitism and host mutilation by A. melinus. Southern fire ant was the least disruptive and native gray ant the most disruptive. Southern fire ant removed 12% of scale from the lemons, presumably to feed on them, while the other ant species did not exhibit significant removal of scale compared to the controls. Percentage parasitism of California red scale exhibited by C. bifasciata was more than 2-fold the level exhibited by A. melinus. Percentage mutilation of California red scale, including probing and host feeding, was nearly 5-fold higher for A. melinus than C. bifasciata. Because A. melinus required a longer total host examination + oviposition period in the absence of ants than C. bifasciata and because oviposition occurs as the last act in a sequence of behaviors, disruption by the ants had a more significant negative effect on oviposition by A. melinus.     

Carbon dioxide concentrations in the nests of the mud-dwelling mangrove ant Polyrhachis sokolova Forel (Hymenoptera: Formicidae)

Abstract The nests of the mangrove ant Polyrhachis sokolova are found in soil in intertidal mangrove communities, and are thus inundated at high tides for several hours. Some of the nest galleries are flooded, but others retain air pockets, to which the ants retreat. During and following inundation, we measured carbon dioxide concentrations in air samples collected from different levels in the nests and from artificial 'control' holes in the mud. To account for the relative contribution of different sources of carbon dioxide, we also measured the carbon dioxide production by individual ants (including larvae and pupae) and small samples of mud collected near the ant nests. Nest carbon dioxide concentrations were high (2.5−11%) during and immediately following inundation, but the concentrations in the upper regions of the nest fell as soil water levels receded. However, at depths>10 cm below the level soil surface, the carbon dioxide concentrations remained relatively high and stable (at approximately 2%) over the 11 days between one high tide and the next. The contribution of the mud (and associated microorganisms) to the carbon dioxide concentration in the nests was substantial, and the contribution of the respiration of the ants was approximately 10−15% of the total. The carbon dioxide concentrations in the nests of this species during high tides are among the highest recorded for insect nests, suggesting that these ants may have unusual physiological attributes to match the behavioural and ecological challenges associated with living in the intertidal zone.     

Isolation and characterization of polymorphic microsatellites in the Potato Tuber Moth Tecia solanivora (Povolny, 1973) (Lepidoptera: Gelechiidae)

Nine polymorphic microsatellite markers were isolated from Tecia solanivora, one of the most serious pests of potato tubers in Central and South America. As found in other studies of Lepidoptera, development of microsatellites is a difficult task: in our case, despite the large number of clones sequenced (796), of which 70 were unique, only nine loci were found to be both variable, and in Hardy-Weinberg equilibrium, No null alleles were detected. The loci were tested in three other co-occurring Gelechiidae species, one of which was variable. These loci will be used to provide a greater understanding of the genetic changes occurring during the invasive process in this species.     

Notes on the biology of the Oriental amblyoponine ant Myopopone castanea: Queen‐worker dimorphism,worker polymorphism and larval hemolymph feeding by workers (Hymenoptera: Formicidae)

Queen‐worker dimorphism, worker polymorphism and worker behavior in the Oriental amblyoponine ant Myopopone castanea were studied. Queen body size was large (head width, 3.0 mm) with 24 to 32 ovarioles while workers showed a remarkable size variation in both body size (head width 1.48 to 2.18 mm) and ovariole number (6 to 22). Both head width and abdomen width showed allometric growth against thorax width. Workers performed larval hemolymph feeding as was described for Amblyopone silvestrii queens.