Dietrich Gotzek

Smithsonian Institution

Although savanna woody encroachment has become a global phenomenon, relatively little is known about its effects on multiple dimensions and levels of savanna biodiversity. Using a combination of field surveys, a species‐level phylogeny, and functional metrics drawn from a morphological dataset, we evaluated how the progressive increase in tree cove...

Elucidating invasion pathways of invasive species is often challenging because invasive populations frequently have low genetic diversity caused by genetic bottlenecks during introduction events. Genome-wide sequencing such as Restriction Site-Associated DNA Sequencing (RADseq) can overcome these challenges by generating thousands of genome-wide si...

Although savanna woody encroachment has become a global phenomenon, few studies have simultaneously evaluated its effects on multiple dimensions and levels of savanna biodiversity. We evaluated how the progressive increase in tree cover in a fire-suppressed savanna landscape affects the taxonomic, functional, and phylogenetic diversity of neotropic...

Background: Parasitoidism, a specialized life strategy in which a parasite eventually kills its host, is frequently found within the insect order Hymenoptera (wasps, ants and bees). A parasitoid lifestyle is one of two dominant life strategies within the hymenopteran superfamily Cynipoidea, with the other being an unusual plant-feeding behavior kno...

Species delimitation offered by DNA-based approaches can provide important insights into the natural history and diversity of species, but the cogency of such processes is limited without multigene phylogenies. Recent attempts to barcode various Solenopsidini ant taxa (Hymenoptera: Formicidae: Myrmicinae), including the thief ant Solenopsis saudien...

The myrmicine ant genus Solenopsis is species-rich, globally distributed, and is often a common and ecologically important faunal element of the leaf litter. The genus is also well-known for containing several widely distributed tramp species and some of the worst invasive species in the World (the Red Imported Fire Ant, S. invicta, and the Tropica...

Supergenes are clusters of linked genetic loci that jointly affect the expression of complex phenotypes, such as social organization. Little is known about the origin and evolution of these intriguing genomic elements. Here we analyse whole-genome sequences of males from native populations of six fire ant species and show that variation in social o...

The fire ants of the Solenopsis geminata species-group of Trager (1991) are revised based on the morphology of worker larvae and of adult forms of workers, males, and gynes (winged or dealated members of the queen caste). The amount of intraspecific variation occurring in the adult males and gynes was equivalent to that of workers, making the taxon...

The native North American fire ants (Solenopsis Westwood) comprise a difficult group taxonomically that has undergone multiple revisions in the past century yet remains in a state of taxonomic uncertainty. In the present study, we utilised a set of 59 microsatellite markers analysed in 238 specimens to conduct the first robust genetic analysis of t...

The fire ant Solenopsis invicta and its close relatives display an important social polymorphism involving differences in colony queen number. Colonies are headed by either a single reproductive queen (monogyne form) or multiple queens (polygyne form). This variation in social organization is associated with variation at the gene Gp-9, with monogyn...

A central goal of biology is to uncover the genetic basis for the origin of new phenotypes. A particularly effective approach is to examine the genomic architecture of species that have secondarily lost a phenotype with respect to their close relatives. In the eusocial Hymenoptera, queens and workers have divergent phenotypes that may be produced v...

Biological invasions are largely thought to be contemporary, having recently increased sharply in the wake of globalization. However, human commerce had already become global by the mid-16th century when the Spanish connected the New World with Europe and Asia via their Manila galleon and West Indies trade routes. We use genetic data to trace the g...

In the past decade, Houston, Texas has been virtually overrun by an unidentified ant species, the sudden appearance and enormous population sizes and densities of which have received national media attention. The Rasberry Crazy Ant, as it has become known due to its uncertain species status, has since spread to neighboring states and is still a maj...

Molecular data and GenBank accession numbers. (XLSX)

Morphometric data. For specimens where GPS coordinates were not provided on the label (indicated by an asterisk), when possible we estimated the GPS data based on the collection information. Specimens highlighted in red were excluded from DAPC due to missing data points. (XLS)

Ants have evolved very complex societies and are key ecosystem members. Some ants, such as the fire ant Solenopsis invicta, are also major pests. Here, we present a draft genome of S. invicta, assembled from Roche 454 and Illumina sequencing reads obtained from a focal haploid male and his brothers. We used comparative genomic methods to obtain ins...

We describe the odorant binding proteins (OBPs) of the red imported fire ant, Solenopsis invicta, obtained from analyses of an EST library and separate 454 sequencing runs of two normalized cDNA libraries. We identified a total of 18 putative functional OBPs in this ant. A third of the fire ant OBPs are orthologs to honey bee OBPs. Another third of...

Primers used for PCR amplification and sequencing of fire ant genomes. Primers names and sequences used in this study. J and N within primer names refer to heavy and light strands, respectively, and indicate the orientation of the primers. Primer names beginning with "Gem" were designed specifically to amplify the mitogenome of S. geminata.

Complete mitochondrial genome sequences have become important tools for the study of genome architecture, phylogeny, and molecular evolution. Despite the rapid increase in available mitogenomes, the taxonomic sampling often poorly reflects phylogenetic diversity and is often also biased to represent deeper (family-level) evolutionary relationships....

Species delimitation has been invigorated as a discipline in systematics by an influx of new character sets, analytical methods, and conceptual advances. We use genetic data from 68 markers, combined with distributional, bioclimatic, and coloration information, to hypothesize boundaries of evolutionarily independent lineages (species) within the wi...

The Gp-9 gene in fire ants represents an important model system for studying the evolution of social organization in insects as well as a rich source of information relevant to other major evolutionary topics. An important feature of this system is that polymorphism in social organization is completely associated with allelic variation at Gp-9, suc...

Colony social organization in the fire ant Solenopsis invicta appears to be under strong genetic control. In the invasive USA range, polygyny (multiple queens per colony) is marked by the presence of the Gp-9 b allele in most of a colony’s workers, whereas monogyny (single queen per colony) is associated with the exclusive occurrence of the Gp-9 B...

GenBank Accession Numbers for Gp-9 Sequences Used in this Study. (0.06 MB DOC)

Expression of colony social organization in fire ants appears to be under the control of a single Mendelian factor of large effect. Variation in colony queen number in Solenopsis invicta and its relatives is associated with allelic variation at the gene Gp-9, but not with variation at other unlinked genes; workers regulate queen identity and number...

The fire ant Solenopsis invicta and its close relatives display an important social polymorphism involving differences in colony queen number. Colonies are headed by either a single reproductive queen (monogyne form) or multiple queens (polygyne form). This variation in social organization is associated with variation at the gene Gp-9, with monogyn...

We studied the age, origins, and possible routes of colonization of the Australian Chenopodiaceae. Using a previously published rbcL phylogeny of the Amaranthaceae–Chenopodiaceae alliance (Kadereit et al. 2003) and new ITS phylogenies of the Camphorosmeae and Salicornieae, we conclude that Australia has been reached in at least nine independent col...

Caterpillars of Arsenura armida (Cramer) (Saturniidae: Arsenurinae) are diurnal nomadic foragers in early instars, maintaining aggregations within the host tree crown through the use of a trail pheromone. In the fourth instar, larvae switch foraging strategies to become nocturnal central place foragers. In central place foraging mode, the caterpill...

This research presented here represents a modest contribution to the regulation of social organization in the red imported fire ant, Solenopsis invicta Buren, and close relatives. Colony queen number is associated with a certain allele at the nuclear protein-coding locus general protein-9 (Gp-9). Multiple queen colonies (polygyny) always contain th...

Includes bibliographical references (leaves 91-116). Thesis (M.S.)--Western Carolina University, 2000.