Invasive fire ants are aggressive predators of ground nesting birds and reptiles and are spreading rapidly throughout tropical and temperate climates. Fire ants have been known to prey on a variety of reptile species, including threatened loggerhead sea turtles. The granular fire ant bait AMDRO® is being used on sea turtle nesting beaches to protect nests and hatchlings from these predators, however no studies have been conducted to thoroughly assess its effect on any reptile species. In this field study, I examined the impact of AMDRO® on hatching and emergence success, body condition, and orientation behavior in loggerhead sea turtles (Caretta caretta) in Juno Beach, Florida, USA. Pesticide granules were placed in a one-foot diameter circle directly above nest chambers during the final 5-10 days of incubation, which is representative of typical field applications of this pesticide on nesting beaches. Two controls were used in this study: cornmeal granules in soybean oil served as the vehicle control, and a second group of untreated control nests were left to incubate naturally, undisturbed. After a natural emergence, hatchlings were collected to calculate a body condition index (BCI). For a subset of the nests, 20 hatchlings were collected to perform orientation assays to assess the hatchlings’ ability to orient correctly toward the ocean, a visually mediated process that could be altered by visual impairments resulting from ADMRO® exposure. Three days following a mass emergence event, nests were excavated to collect hatching and emergence success data. Sand samples were collected to determine if the toxicant persisted in the environment or penetrated the egg chamber. Analyses indicated that the toxicant had no effect on hatchling morphology, hatching success, or emergence success. It also had no effect on the ability of hatchlings to orient toward the ocean. However, the pesticide granules attracted more predators than were seen at control nests. Thus, while AMDRO® might not directly impact reproductive success or hatchling behavior, it had the unanticipated effect of possibly increasing nest vulnerability to predators. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Ants are highly abundant and ubiquitous in many terrestrial ecosystems. They perform many important ecological functions and have been widely employed as bioindicators for various terrestrial monitoring programmes. In agroecosystems, their role is controversial because ants can act as predators against herbivorous pest but also associate with and protect honeydew-producing hemipteran pests. The ecology, function and interactions of ants with other arthropods in vineyards are poorly known and this thesis therefore examines their distribution and ecology in south-eastern Australian vineyards. / An extensive survey of 50 vineyards distributed in five regions in South Australia and Victoria recorded 147 native ant species and one invasive species, Linepithema humile (Mayr). Species richness, compositional similarities and assemblage structure varied within and across regions. High species turnover and variation in assemblage structure were found across regions and implications of these patterns are discussed. The invasive L. humile was only detected in some vineyards in one region. The potential impact of management practices and off-farm vegetation on augmenting ant diversity and conserving biodiversity are considered. / The impact of non-target agrochemical applications on ants was investigated in 19 vineyards that received varying levels of agrochemical input. Ant assemblage structure and assemblages were not found to be impacted by pesticides. In contrast, ant assemblage structure was influenced by the presence of shelterbelts near the sampling area. Reasons for the resilience of ants to pesticides are given and assessment at the colony level instead of worker abundance is suggested. / An ant-exclusion experiment was designed to test the impact of native ants on both canopy and ground arthropods concurrently. The potential influence of ants on predation and parasitism on eggs of light brown apple moth (LBAM), a grape pest, was also examined. Adult grapevine scale insects and earwigs under bark were also counted after a season of ant-exclusion. While ant exclusion was successful, there was no detectable difference in the abundance of most arthropod orders and feeding groups between ant-excluded and control vines, although ground spiders were more abundant under ant-excluded vines, despite increased ground ant foraging pressure. LBAM egg parasitism and predation were low and probably affected by weather and other arthropods. Ant exclusion did not reduce survival of scale insects, although the distribution and abundance of scale insects were negatively associated with earwigs. Reasons for the lack of negative effects of ants are discussed. / The spatial patterns of ants were investigated with intensive pitfall trappings in two vineyards to examine if non-random patterns occur and whether these might be the result of competitive species interactions as well as non-crop vegetation adjacent to the vineyards. Null model analyses suggested competitive species interactions within ant assemblages that might have been driven by dominant species even though both positive and negative associations between dominants were also found. Consistent spatial aggregations indicated significant spatial overlap in distributions of some species. Such overlap suggests that potential co-existence might be attributed to temporal partitioning or differences in foraging strategies. The presence of vegetation had a marked influence on ant assemblage structure and competitive interactions, and might also facilitate co-existence by increasing resource heterogeneity. The implications of these findings for sampling strategies and ecological processes within vineyards are discussed. / This thesis has provided new information about ants in vineyards. The high ant diversity could be important in maintaining ecosystem services. Among the 33 ant genera recorded, Iridomyrmex, Paratrechina and Rhytidoponera have the greatest potential in contributing to canopy pest suppression although their associations with honeydew-producing hemipterans need to be considered. Stable isotope analysis or/and molecular gut content analysis should reveal their trophic position in vineyards. Evaluation of crop yield that is directly attributed to soil conditioning by ants in agroecosystems should be explored. The importance of landscape composition, complexity and connectivity is highlighted and role of agroecosystems in conserving biodiversity is emphasised. Future research should be directed towards understanding how landscape composition and complexity may enhance ant diversity and alter dynamics and interactions that may be functionally important (biological control, soil conditioning, etc) in a landscape context.

Selon la théorie de la sélection de la parentèle, les individus peuvent transmettre des copies de leurs gènes à la génération suivante sans accéder eux-mêmes à la reproduction, mais en aidant des apparentés à augmenter leur propre succès reproductif. Ce concept reste aujourd'hui l'explication la plus probable pour justifier l'évolution de l’altruisme de reproduction dans le règne animal. Les coefficients de corrélations génétiques entre les membres d’un groupe ont une importance capitale, puisqu'ils influencent directement les bénéfices génétiques indirects associés au comportement altruiste. Trois principaux facteurs sont cependant connus pour influencer profondément l'architecture des sociétés: (i) le nombre de reines présentes dans un nid (polygynie), (ii) le nombre d'accouplements des reines (polyandrie), et (iii) l’accouplement entre apparentés (consanguinité). Nous avons étudié les stratégies de reproduction de cinq espèces de fourmis du genre Plagiolepis. Nous avons d’abord déterminé l’origine endogène des signaux de reconnaissance responsables de la fermeture des sociétés (I). Nous avons également identifié les causes proximales de la forte consanguinité observée chez P. pygmaea : une éviction par les ouvrières des mâles étrangers tentant de s’introduire dans leur société et une préférence des femelles vierges à s’accoupler avec des mâles apparentés (II). A l’aide de marqueurs génétiques, nous avons estimé le degré de polygynie, le taux de polyandrie des reines, et le niveau de consanguinité pour quatre espèces libres : P. pygmaea, P. taurica, P. schmitzii et P. maura (III; IV). Enfin, nous avons testé l’hypothèse d’une réversion du nombre d’accouplements vers la monandrie chez les espèces parasites, au travers de P. xene. (V).

Las hormigas invasoras desplazan a las especies de hormigas nativas y otros artrópodos. Como consecuencia, las interacciones biológicas del sistema invadido y los servicios ecológicos prestados por las especies nativas son modificados. El objetivo de este trabajo fue investigar los efectos de la hormiga invasora Lasius neglectus sobre algunos de los componentes superficiales y subsuperficiales de un encinar urbano y compararlos con los efectos de las hormigas nativas, en particular con Lasius grandis. Lasius neglectus visita principalmente árboles aislados donde permanece más meses atendiendo áfidos. Por el contrario, las hormigas nativas no visitaron los árboles según su ubicación (aislado, borde o centro del bosque). Excepto en el caso de la hormiga nativa Lasius grandis, que permaneció más tiempo en los árboles aislados cuando Lasius neglectus no estaba presente en el fragmento. La riqueza de especies nativas de hormigas y su visita a los árboles fue menor en fragmentos de bosque con Lasius neglectus. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis lograron coexistir con la hormiga invasora. La estructura de la comunidad de hormigas nativas en fragmentos con o sin Lasius neglectus mostró un patrón aleatorio. Entre Mayo y Octubre, en las encinas se encontraron dos especies de áfidos, Hoplocallis picta, ocasionalmente atendido por las hormigas, y Lachnus roborisun un mirmecófilo obligado. En encinas visitadas por la hormiga invasora, se observó que la abundancia de Lachnus roboris tendió a duplicarse, como así también su producción de melaza, porcentaje de colonias atendidas comparado con los resultados obtenidos en encinas visitadas por la hormiga nativa Lasius grandis. Consecuentemente, durante el periodo estudiado la hormiga invasora duplicó su colecta de melaza por encina respecto de la hormiga nativa. Las colonias de Lachnus roboris se ubicaron principalmente sobre las bellotas. Sin embargo, no se detectó ningún efecto en la producción o calidad de bellotas y en la emergencia o calidad de las plántulas. Ambas especies de hormigas capturaron principalmente Pscópteros y Hoplocallis picta como fuente de proteínas. El porcentaje de obreras que llevaba insectos o trozos de artrópodos entre sus mandíbulas fue superior para Lasius grandis. La comunidad de artrópodos y el nivel de herbivoría no fueron modificados por la presencia de una u otra especie de hormiga. Sin embargo, en las encinas visitadas por Lasius neglectus las arañas, los curculiónidos y los áfidos tendieron a incrementar su abundancia mientras que las larvas de coccinélidos (predadores de áfidos) disminuyeron marcadamente. La melaza que no es recogida por las hormigas puede incorporarse al suelo disuelta en el agua de trascolación de la copa como carbono orgánico disuelto (COD). La colecta de melaza de Lasius neglectus disminuyó el COD disuelto en el agua de trascolación de las encinas lo cual indicaría una interrupción del flujo de materia y energía entre la copa de las encinas y el suelo aledaño. En relación a los efectos subsuperficiales se observó que el contenido de nutrientes en el suelo aledaño a las encinas visitas por Lasius neglectus fue mayor respecto del encontrado en encinas visitadas por hormigas nativas. Asimismo, la comunidad de microorganismos se diferenció según la presencia de hormigas nativas o de la invasora; tendiendo la biomasa microbiana del suelo a ser mayor en el caso de la presencia de Lasius neglectus. Según la localidad estudiada, la calidad de la hojarasca producida fue menor en los árboles visitados por Lasius neglectus. Sin embargo, la descomposición de la hojarasca de encina no fue modificada por la presencia de la hormiga invasora. Se concluye que la presencia de Lasius neglectus modifica aquellos componentes, superficiales y subsuperficiales, del sistema de la encina que están directa o indirectamente relacionados con la colecta de melaza. / Invasive ants displace native ant species and other arthropods. As a consequence, at the invaded system biological interactions and ecological services provided by native ant species are modified. The aim of this study was to investigate some of the above-belowground effects of the invasive ant Lasius neglectus in an urban holm oak forest and to compare these effects with those of native ant species, in particular related to Lasius grandis.Lasius neglectus mainly visited isolated trees where workers remained more months tending aphids and other insects. On the contrary, native ant tree visitation was not related to tree position in the fragments (isolated, edges or core trees). The only exception was the native ant Lasius grandis which remained more months at isolated trees in fragments where Lasius neglectus was not present. Native ant species richness and its tree visitation were lower at fragments where Lasius neglectus was present. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis were able to coexist with the invasive ant specie. Community structure of native ants did not differ from a random pattern with or without Lasius neglectus.Some effects of the ant presence were investigated in detail at the holm oak (Quercus ilex) since this tree was the most abundant at the studied forest fragments. Between May and October, two aphid species were found feeding at holm oak canopy: Hoplocallis picta, which was occasionally tended and Lachnus roboris which was the main tended species. At holm oaks visited by the invasive ant, the abundance of Lachnus roboris tended to increase twice, as well as their honeydew production related to results obtained at holm oaks visited by the native ant Lasius grandis. The percentage of tended colonies tended by Lasius neglectus was higher compared to the percentage tended by Lasius grandis. As a consequence, at the studied period, the invasive ant collected two fold of honeydew per tree related to the native ant. At holm oaks visited by Lasius neglectus or Lasius grandis colonies of Lachnus roboris fed mainly on acorn petiole or on their cap. However, there was not any difference of acorn production acorn or quality and sapling emergency or quality between these holm oaks.Both ant species mainly captured Pscoptera and Hoplocallis picta as source of proteins. The percentage of workers carrying insects or pieces of arthropods in its jaws was higher for Lasius grandis. Arthropod community and herbivory level was not modified due the presence of the invasive or the native ant. However, some particular groups showed differences of its abundance. At holm oaks visited by Lasius neglectus, spiders, weevils and aphids tended to increase its abundance while ladybird larvae (aphid predators) decreased markedly.Honeydew production that was not collected by ants may reach the soil dissolved in throughfall as dissolved organic carbon (DOC). Honeydew collection by Lasius neglectus decreased DOC content in throughfall. This result suggests that the invasive ant interrupts the flux of energy and matter between canopy and the soil surrounding holm oaks.In relation with belowground effects of Lasius neglectus soil nutrient content was higher beneath holm oaks visited by the invasive ant in relation to those trees visited by native ants. Soil microbial community was characterized by the presence of Lasius neglectus and microbial biomass tended to increase beneath holm oaks visited by this invasive ant. Depending on the study site, litter quality was lower at holm oaks visited by Lasius neglectus. Litter decomposition was not modified by the presence of the invasive ant.I conclude that Lasius neglectus presence modifies those below-aboveground components of the holm oak system that are directly or indirectly related to honeydew collection.

Urbanization, the creation of cities and their growth, is a process with profound implications for the diversity and community composition of local ecosystems. Urban environments are made up of a diverse patchwork of natural, seminatural and modified habitats that might harbor different plant and animal communities. Frequently, they include invasive or exotic organisms. In arid environments in particular, irrigated spaces constitute a novel habitat that contrasts heavily with natural environments. In the present study, I considered the biodiversity and composition of the ant communities in contrasting environments within the urban area of Tucson, Arizona. First, I assessed the relationship between plant productivity, measured using satellite imagery, ant abundance and ant diversity in irrigated parks, urban desert remnants and natural desert habitat. I found no significant differences in ant diversity among these habitats, despite clear differences in abundance and productivity. Next I considered the differences in ant species composition among the assemblages in the same three habitats. I found that each habitat included a distinct ant community, although those from desert remnants and natural desert were functionally similar to each other. Irrigated parks showed a potential to act as refuges for ant species threatened by the effects of climate change, but they also included a greater abundance of ants considered pests. Finally, I considered some of the characteristics behind the success of the only widespread exotic ant species found in urban habitats in Tucson: the dark rover ant (Brachymyrmex patagonicus).These ants were found in large numbers in every park sampled. As a recently introduced species, little was known of their biology. Colonies of these ants displayed aggression among each other which makes it impossible for them to form large interconnected networks of nests. Although colonies occupied nearby nests in the laboratory, under field conditions, each colony inhabited a small territory.

Ant colonies are often considered to be a superorganism, exhibiting complex collective behaviors, reproducing at the colony level, and dividing functional roles among groups of workers. For this reason, it is often appropriate to study ant behavior at the colony, rather than the individual, level. In this study, I investigated decision-making and foraging behavior in colonies of several species belonging to the ant community of Sonoran Desert scrub habitat. First, I used laboratory experiments to examine how the spatial structure of Crematogaster torosa colonies changes in response to the availability of temporally stable food sources. I found that in this polydomous species the formation of nests is associated with foraging, but that colonies will build broodless structures called “oustations” regardless of food presence. Next, I examined colony spatial structure of a related polydomous species, Crematogaster opuntiae, in the field. I found that colonies used large foraging territories up to three hectares in size, containing up to twenty nest entrances interconnected by a network of trails. Nest location appeared to be related to foraging, with nests located close to extrafloral nectar-secreting cacti (Ferocactus wislizeni) and a negative relationship between cactus density and territory size. Within colonies, forager behavior on neighboring cacti was not independent at short distances, suggesting that separate plants in this system cannot be treated as independent replicates. In the third chapter, I used an individual-based simulation model to investigate the effects of individual worker behavior on the ability of pheromone-recruiting ant colonies to maintain trails to multiple food sources simultaneously. Interestingly, small changes in the behavior rules used by individuals led to large-scale changes in emergent behaviors at the colony level. Lastly, I used field experiments to relate the ability of colonies of three ant species to maintain multiple trails to their ranking in the community competitive dominance hierarchy. I found that the most dominant species tended to forage asymmetrically, whereas the least dominant species exhibited more symmetrical patterns of foraging. The ability of ant colonies to collectively maintain multiple trails may therefore be an adaptive trait linked to the foraging ecology of species.

The biodiversity of Durban (eThekwini municipality) in KwaZulu Natal is primarily threatened by urbanization although other factors such as climate change and the spread of invasive species also pose a significant threat. Knowledge of what species exist within the city is important for biodiversity surveillance, detecting invasive taxa and uncovering cryptic species. Conducting a comprehensive biodiversity inventory is a daunting task, especially for hyperdiverse groups such as terrestrial arthropods, where closely related species can often only be separated by subtle morphological characters. This study investigated whether the barcoding marker, Cytochrome Oxidase C Subunit 1 (COI) can be used to efficiently and accurately delineate species of ants (family Formicidae) in comparison to traditional taxonomic approaches. The feasibility of DNA barcoding for assembling biodiversity inventories for urban areas which could be useful in conservation planning was also evaluated. A total of 619 individuals were sequenced from 23 geographic localities within the eThekwini region and surrounding regions. DNA barcoding revealed 80 provisional species/ “barcode clusters” or monophyletic lineages which could represent distinct species, while morphology revealed 51 different morphospecies. Extrapolation measures of species richness indicated that as many as 153 species of ants could occur in the city. Phylogenetic and phylogeographic analyses were performed on co-distributed species belonging to the genera Lepisiota, Camponotus, Pheidole and Pachycondyla to better understand the spatial distribution of genetic variability in the eThekwini region. Nuclear markers 18S rDNA and 28S rDNA were also sequenced and compared for a subsample of individuals from Camponotus and Pachycondyla. There was genetic variation at COI and the nuclear markers for each of the species examined. In order to fully elucidate the population genetic patterns which could be expected in eThekwini and surrounding regions, further sampling across more localities is essential. The use of more nuclear markers could also assist in uncovering these unique patterns of genetic variation in an urban setting. In this study, the utility of COI as a species diagnostic tool in ants was confirmed. The barcoding library constructed showed promise in highlighting reserves that should be preserved and possible cryptic speciation for further investigation. / M. Sc. University of KwaZulu-Natal, Durban 2014.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1979. / Bibliography: leaves [86]-89. / Microfiche. / xiii, 89 leaves ill. 29 cm

Thesis (M.S.)--University of Nevada, Reno, 2005. / "May 2005." Includes bibliographical references (leaves 26-29). Online version available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 161-172).