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- All Subjects: Entomology
- Creators: Pigg, Kathleen
- Creators: Hoelldobler, Bert
Description
The repression of reproductive competition and the enforcement of altruism are key components to the success of animal societies. Eusocial insects are defined by having a reproductive division of labor, in which reproduction is relegated to one or few individuals while the rest of the group members maintain the colony and help raise offspring. However, workers have retained the ability to reproduce in most insect societies. In the social Hymenoptera, due to haplodiploidy, workers can lay unfertilized male destined eggs without mating. Potential conflict between workers and queens can arise over male production, and policing behaviors performed by nestmate workers and queens are a means of repressing worker reproduction. This work describes the means and results of the regulation of worker reproduction in the ant species Aphaenogaster cockerelli. Through manipulative laboratory studies on mature colonies, the lack of egg policing and the presence of physical policing by both workers and queens of this species are described. Through chemical analysis and artificial chemical treatments, the role of cuticular hydrocarbons as indicators of fertility status and the informational basis of policing in this species is demonstrated. An additional queen-specific chemical signal in the Dufour's gland is discovered to be used to direct nestmate aggression towards reproductive competitors. Finally, the level of actual worker-derived males in field colonies is measured. Together, these studies demonstrate the effectiveness of policing behaviors on the suppression of worker reproduction in a social insect species, and provide an example of how punishment and the threat of punishment is a powerful force in maintaining cooperative societies.
ContributorsSmith, Adrian A. (Author) / Liebig, Juergen (Thesis advisor) / Hoelldobler, Bert (Thesis advisor) / Gadau, Juergen (Committee member) / Johnson, Robert A. (Committee member) / Pratt, Stephen (Committee member) / Arizona State University (Publisher)
Created2011
Description
A notable feature of advanced eusocial insect groups is a division of labor within the sterile worker caste. However, the physiological aspects underlying the differentiation of behavioral phenotypes are poorly understood in one of the most successful social taxa, the ants. By starting to understand the foundations on which social behaviors are built, it also becomes possible to better evaluate hypothetical explanations regarding the mechanisms behind the evolution of insect eusociality, such as the argument that the reproductive regulatory infrastructure of solitary ancestors was co-opted and modified to produce distinct castes. This dissertation provides new information regarding the internal factors that could underlie the division of labor observed in both founding queens and workers of Pogonomyrmex californicus ants, and shows that changes in task performance are correlated with differences in reproductive physiology in both castes. In queens and workers, foraging behavior is linked to elevated levels of the reproductively-associated juvenile hormone (JH), and, in workers, this behavioral change is accompanied by depressed levels of ecdysteroid hormones. In both castes, the transition to foraging is also associated with reduced ovarian activity. Further investigation shows that queens remain behaviorally plastic, even after worker emergence, but the association between JH and behavioral bias remains the same, suggesting that this hormone is an important component of behavioral development in these ants. In addition to these reproductive factors, treatment with an inhibitor of the nutrient-sensing pathway Target of Rapamycin (TOR) also causes queens to become biased towards foraging, suggesting an additional sensory component that could play an important role in division of labor. Overall, this work provides novel identification of the possible regulators behind ant division of labor, and suggests how reproductive physiology could play an important role in the evolution and regulation of non-reproductive social behaviors.
ContributorsDolezal, Adam G (Author) / Amdam, Gro V (Thesis advisor) / Brent, Colin S. (Committee member) / Gadau, Juergen (Committee member) / Hoelldobler, Bert (Committee member) / Liebig, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
The weevil genus Pachnaeus Schoenherr, 1826 (Coleoptera: Curculionidae: Entiminae: Eustylini Lacordaire) is revised to accommodate 21 species, including the following 10 new species from the northern Caribbean region: Pachnaeus andersoni sp. nov. (Little Cayman), Pachnaeus eisenbergi sp. nov. (Jamaica), Pachnaeus godivae sp. nov. (Cayman Brac), Pachnaeus gordoni sp. nov. (Jamaica), Pachnaeus howdenae sp. nov. (Bahamas), Pachnaeus ivieorum sp. nov. (Bahamas with adventive records from Florida), Pachnaeus maestrensis sp. nov. (Cuba), Pachnaeus morelli sp. nov. (Haiti), Pachnaeus obrienorum sp. nov. (Cuba and Bahamas), and Pachnaeus quadrilineatus sp. nov. (Jamaica).Pachnaeus can be distinguished from similar, co-occurring taxa such as Exophthalmus quadrivittatus (Olivier, 1807), Exophthalmus roseipes (Chevrolat, 1876), Exophthalmus vittatus (Linnaeus, 1758), and Diaprepes abbreviatus (Linnaeus, 1758) by (1) the presence of postocular vibrissae, (2) endophallus primarily membranous and sac-like proximally, and long (>3 × width), tubular, and sclerotized distally, (3) additional endophallic sclerites typically absent, (4) a never bicarinate, typically tricarinate, rostrum, and several additional characteristics of the pedon, endophallus, pronotal structure, rostral structure, and scaling. Based on these characters, Pachnaeus sommeri (Munck af Rosenschoeld in Schoenherr, 1840) comb, nov. and Pachnaeus gowdeyi (Marshall, 1926) comb. nov. are transferred into the genus from Exophthalmus Schoenherr and Lachnopus Schoenherr respectively.
This revision provides genus and species redescriptions, diagnoses, illustrations, and the first comprehensive key to all 21 species within the present circumscription of Pachnaeus, in addition to reviewing the known biology and observed intraspecific variation within species. The complex taxonomic history of the genus is reviewed, and the evolutionary relationships of its presumed constituent clades are proposed through the construction of informal species groups and subgroups based on diagnosable shared traits. Lectotypes for Pachnaeus citri Marshall, Pachnaeus costatus Perroud, and Exophthalmus sommeri Munck af Rosenschoeld in Schoenherr and paralectotypes of P. citri (3 specimens) and E. sommeri (4 specimens) are designated. New state and national records are reported for Pachnaeus azurescens Gyllenhal in Schoenherr for Florida, U.S.A. and new national records are reported for Pachnaeus litus (Germar) for the Bahamas. Validity of the names Docorhinus Schoenherr, 1823 and Pachnaeus Schoenherr, 1826 is treated. Generic placement of Pachnaeus roseipes Chevrolat, 1876 is explored.
ContributorsReily, Brian Herndon (Author) / Franz, Nico M (Thesis advisor) / Taylor, Jesse (Committee member) / Pigg, Kathleen (Committee member) / Johnston, Murray A (Committee member) / Arizona State University (Publisher)
Created2022
Description
The diverse weevil genus Rhyssomatus Schoenherr, 1837 (Curculionidae: Molytinae: Cleoginini) is currently composed of 175 species throughout the New World (O’Brien et. al 1982; Wibmer et. al 1986). The majority of species are generalist feeders and the group contains many notorious agricultural pests, such as Rhyssomatus nigerimus Fahraeus 1837 and R. subtillis Fiedler 1937 that cause thousands of dollars’ worth of crop damage in South America, Central America, and West Indies (Cazado, 2016; Lopez-Guillen, et. al). Although most notable as a crop pest in the literature, the species Rhyssomatus maginatus Fahraeus has also proven to be a great success in an Integrated Pest Management (IPM), controlling the invasive leguminous tree Sesbenia punicea (Cav.) Benth., in South Africa. (Hoffman & Moran 1991; 1992; 1998; 1999). The last century has seen revisions of the Neotropical species with Central American species revised in 1904 by Champion and the South American taxa treated by Fiedler in the subsequent years of 1937 and 1942 (O’Brien & Wibmer, 1982; Wibmer & O’Brien, 1986). However, North American fauna have not been treated since Casey in 1895 and revision is needed as climate change and global trade have more than likely expanded the distributional range of previously lower latitude Rhyssomatus species northwards.
ContributorsArguez, Katherine MacKenzie (Author) / Franz, Nico (Thesis advisor) / Pigg, Kathleen (Committee member) / Gile, Gillian (Committee member) / Arizona State University (Publisher)
Created2023
Description
Understanding the diversity, evolutionary relationships, and geographic distribution of species is foundational knowledge in biology. However, this knowledge is lacking for many diverse lineages of the tree of life. This is the case for the desert stink beetles in the tribe Amphidorini LeConte, 1862 (Coleoptera: Tenebrionidae) – a lineage of arid-adapted flightless beetles found throughout western North America. Four interconnected studies that jointly increase our knowledge of this group are presented. First, the darkling beetle fauna of the Algodones sand dunes in southern California is examined as a case study to explore the scientific practice of checklist creation. An updated list of the species known from this region is presented, with a critical focus on material now made available through digitization and global aggregation. This part concludes with recommendations for future biodiversity checklist authors. Second, the psammophilic genus Trogloderus LeConte, 1879 is revised. Six new species are described, and the first, multi-gene phylogeny for the genus is inferred. In addition, historical biogeographic reconstructions along with novel hypotheses of speciation patterns within the Intermountain Region are given. In particular, the Kaibab Plateau and Kaiparowitz Formation are found to have promoted speciation on the Colorado Plateau. The Owens Valley and prehistoric Bouse Embayment are similarly hypothesized to drive species diversification in southern California. Third, a novel phylogenomic analysis for the tribe Amphidorini is presented, based on 29 de novo partial transcriptomes. Three putative ortholog sets were discovered and analyzed to infer the relationships between species groups and genera. The existing classification of the tribe is found to be highly inadequate, though the earliest-diverging relationships within the tribe are still in question. Finally, the new phylogenetic framework is used to provide a genus-level revision for the Amphidorini, which previously contained six valid genera and 253 valid species. This updated classification includes more than 100 taxonomic changes and results in the revised tribe consisting of 16 genera, with three being described as new to science.
ContributorsJohnston, Murray Andrew (Author) / Franz, Nico M (Thesis advisor) / Cartwright, Reed (Committee member) / Taylor, Jesse (Committee member) / Pigg, Kathleen (Committee member) / Arizona State University (Publisher)
Created2018
Description
Weevils are one of the most diverse groups of animals with thousands of species suspected to remain undiscovered. The Conoderinae Schoenherr, 1833 are no exception, being especially diverse and unknown in the Neotropics where they are recognizable for their unique behaviors and color patterns among weevils. Despite these peculiarities, the group has received little attention from researchers in the past century, with almost nothing known about their evolution. This dissertation presents a series of three studies that begin to elucidate the evolutionary history of these bizarre and fascinating weevils, commencing with an overview of their biology and classificatory history (Chapter 1).
Chapter 2 presents the first formal cladistic analysis on the group to redefine the New World tribes Lechriopini Lacordaire, 1865 and Zygopini, Lacordaire, 1865. An analysis of 75 taxa (65 ingroup) with 75 morphological characters yielded six equally parsimonious trees and synapomorphies that are used to reconstitute the tribes, resulting in the transfer of sixteen genera from the Zygopini to the Lechriopini and four generic transfers out of the Lechriopini to elsewhere in the Conoderinae.
Chapter 3 constitutes a taxonomic revision of the genus Trichodocerus Chevrolat, 1879, the sole genus in the tribe Trichodocerini Champion, 1906, which has had an uncertain phylogenetic placement in the Curculionidae but has most recently been treated in the Conoderinae. In addition to redescriptions of the three previously described species placed in the genus, twenty-four species are newly described and an identification key is provided for all recognized species groups and species.
Chapter 4 quantitatively tests the similarity in color pattern among species hypothesized to belong to several different mimicry complexes. The patterns of 160 species of conoderine weevils were evaluated for 15 categorical and continuous characters. Non-metric multidimensional scaling (NMDS) is used to visualize similarity by the proximity of individual species and clusters of species assigned to a mimicry complex in ordination space with clusters being statistically tested using permutational multivariate analysis of variance (PERMANOVA).
Chapter 2 presents the first formal cladistic analysis on the group to redefine the New World tribes Lechriopini Lacordaire, 1865 and Zygopini, Lacordaire, 1865. An analysis of 75 taxa (65 ingroup) with 75 morphological characters yielded six equally parsimonious trees and synapomorphies that are used to reconstitute the tribes, resulting in the transfer of sixteen genera from the Zygopini to the Lechriopini and four generic transfers out of the Lechriopini to elsewhere in the Conoderinae.
Chapter 3 constitutes a taxonomic revision of the genus Trichodocerus Chevrolat, 1879, the sole genus in the tribe Trichodocerini Champion, 1906, which has had an uncertain phylogenetic placement in the Curculionidae but has most recently been treated in the Conoderinae. In addition to redescriptions of the three previously described species placed in the genus, twenty-four species are newly described and an identification key is provided for all recognized species groups and species.
Chapter 4 quantitatively tests the similarity in color pattern among species hypothesized to belong to several different mimicry complexes. The patterns of 160 species of conoderine weevils were evaluated for 15 categorical and continuous characters. Non-metric multidimensional scaling (NMDS) is used to visualize similarity by the proximity of individual species and clusters of species assigned to a mimicry complex in ordination space with clusters being statistically tested using permutational multivariate analysis of variance (PERMANOVA).
ContributorsAnzaldo, Salvatore (Author) / Franz, Nico (Thesis advisor) / Martins, Emilia (Committee member) / Rabeling, Christian (Committee member) / Pigg, Kathleen (Committee member) / Arizona State University (Publisher)
Created2019