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Honey bees mark artificial flowers with scents that advertise about the previous history of the flower to subsequent foragers. Unrewarding flowers are marked with a scent, after a single visit, that makes the flower less attractive to subsequent foragers. Previously rewarding flowers are initially less attractive than unvisited flowers but become more and more attractive with each rewarding visit. Flowers that have rewarded bees four times are more attractive than unvisited flowers. This attractant is applied by the bees in response to the presence of nectar and is not, as has been suggested by other researchers, inadvertently applied to anything on which the bee lands. Similar scent-markings are applied to a real flower, Lotus corniculatus. One visit was enough to make a flower less attractive to subsequent foragers but flowers that consistently offered high amounts of nectar became more attractive than unvisited flowers. Repellents may be used by bees to avoid revisiting recently emptied flowers while attractants may be applied to flowers within a patch that consistently offer high rewards. The possible selective pressures responsible for the evolution of scent-marking was investigated by doing an energetic analysis. The presence of scent-markings in a patch results in a 33% increase, over an unmarked patch, in the amount of sugar obtained per time. The attractive scent-marking was extracted from a glass flower and maintained its biological activity when applied to a clean glass flower. The extract was chemically analyzed using gas chromatography-mass spectrometry. Four chemicals were identified; none of the chemicals has previously been found in honey bees. Mandibular glands were analyzed as a possible source of the attractant. Although none of the components was found in the gland extracts, two previously unidentified chemicals were found. / Graduation date: 1994

Thesis (Ph. D.)--Michigan State University. Dept. of Fisheries and Wildlife, 2008. / Title from PDF t.p. (viewed on Aug. 19, 2009) Includes bibliographical references. Also issued in print.

Thesis--University of Florida. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 196-211).

A commercial sawmill in British Columbia, Canada, was surveyed in 1979 for the presence of the ambrosia beetles Trypodendron lineatum (Olivier) and Gnathotrichus retusus (LeConte) using pheromone-baited traps. The temporal and spatial distribution and relative abundance of these species were determined. This information was used during 1980 and 1981 to develop a mass-trapping program for these species while maintaining the integrity of an existing trapping program for a third ambrosia beetle species, G. sulcatus (LeConte). A fourth ambrosia beetle species, Platypus wilsoni (Swaine) responded in significantly larger numbers to traps baited with the pheromone sulcatol plus ethanol and α-pinene than to those baited with the pheromone lineatin or unbaited. Several experiments were conducted in order to improve or assess the trapping system. It was found that both G. retusus and T. lineatum response to their respective pheromones was increased by the inclusion of ethanol and α-pinene on the traps. T. lineatum response to lineatin was significantly reduced when sulcatol was included in the bait. An experiment conducted to determine optimum trap height showed that largest numbers of T. lineatum were caught on the lowest traps that cleared surrounding understory vegetation. A mark-recapture technique was tested as a potential means of assessing trapping efficiency. Recommendations were made that could result in this technique becoming a useful means of optimizing and evaluating ambrosia beetle mass-trapping programs. This concurrent mass-trapping program for three species of ambrosia beetles demonstrated that large numbers of beetles can be captured using pheromone-baited traps. The relatively low cost of this pest management tactic compared with the high values at risk has already resulted in much of the technology developed in this thesis being incorporated in ambrosia beetle management programs by forest industries in British Columbia. / Forestry, Faculty of / Graduate

In addition to their conventional role as hormones, studies have shown that steroids can act as pheromones in mammals. Emphasis has been placed on evaluating the physiological and behavioural effects of male, urinary 17β- estradiol (E2) exposure in pheromone phenomena including the prevention of embryo implantation and induced precocious puberty in females. Steroids have also been observed to transfer between female mice, leading to changes in the duration of their estrous cycle. Progesterone (P4), a crucial female sex steroid, promotes pro-social sexual reproductive behaviour and the growth of the endometrium in preparation for ovum implantation. Few studies have investigated the effects of P4 in a pheromonal context. Big brown bats (Eptesicus fuscus) are ideal models for pheromone research because they are evolutionarily distinct from rodents, live in highly social and sexually-competitive harems, and are regularly exposed to conspecific secretions in the close confines of their roost. Experimental analysis revealed absorption of tritium-labeled progesterone (3H-P4) (10 μCi) 1 h after cutaneous and intranasal application to adult females. Additionally, radioactivity was observed in mature female bats caged for 48 h with an adult female conspecific that had been intraperitoneally-injected with 3H- P4 (50 μCi). Using the same paradigm, 3H-E2 transfer was not observed between females. Enzyme-linked immunosorbent assays revealed measurable levels of unconjugated P4 and E2 present in the urine of female bats, suggesting urine as one likely vector for P4 transfer. Given corroborative findings in mice, progesterone transfer during cohabitation is likely a mammalian-wide phenomenon that could have evolved to prime conspecifics—and more specifically kin—for sexual reproduction. / Thesis / Master of Science (MSc) / Steroid molecules are conventionally assumed to act solely within the individual that produced them; however, recent experiments have demonstrated that the sex steroid 17β-Estradiol (E2) can be excreted in the urine of adult male mice and taken up into the neural, reproductive, and peripheral tissues of cohabitating females. This exogenous E2 can result in changes to female physiology and behaviour. Our lab has observed E2 to transfer between male and female captive big brown bats during the mating season. The current project aimed to determine whether E2 transfers between captive cohabitating female bats. We also examined whether progesterone (P4), an important female sex steroid involved in the preparation and maintenance of pregnancy, transfers between female bats. We determined that P4 reliably transfers between female bats, but E2 does not. Bioactive E2 and P4 were measured in the urine of non- pregnant female bats and propose urine as one likely vector of P4 transfer between cohabitating individuals.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 124-140). Also available on the World Wide Web.

My dissertation focuses on the evolutionary forces that have shaped the chemical signaling system of plethodontid salamanders. Pheromones mediate two phases of plethodontid reproduction: mate attraction prior to courtship and female persuasion during courtship. Substrate-borne chemical signals are believed to play an important role in mate attraction for these animals. A behavioral assay of sex- and species-specific odor preferences in closely related species of Plethodon indicates that: (1) there is asymmetry on the receiver side of the system, wherein male salamanders invest more energy searching for mating partners than do females; (2) substrate-borne chemical signals are sexually dimorphic and male preference strongly favors the female odor versus the male odor; (3) females of allopatric salamander species have evolved distinctive chemical cues; and (4) female chemical signals of sympatric species are divergent and may play a role in sexual isolation. Sexual persuasion is another phase of plethodontid reproduction that is mediated by chemical signals. Plethodontid Receptivity Factor (PRF) is a proteinaceous pheromone that is produced by the male and delivered to the female during courtship. Female receptivity increases following application of this pheromone. PRF is a recent innovation of the male courtship signal, originating in eastern Plethodon (~27 MYA). Codon-substitution models indicate that several amino acid sites along the PRF protein have experienced positive selection. Structural modeling suggests that many of these selected residues are important for receptor binding. Adaptive change in this pheromone is likely driven via a coevolutionary association with female receptors. The male plethodontid courtship signal, however, is comprised of multiple chemical components. I investigate micro- and macro-evolutionary divergence in plethodontid chemical communication by surveying two additional pheromone component genes, PMF and SPL. Like PRF, regions of the PMF and SPL genes have experienced adaptive change. At least one of these components (SPL) has been retained in the signaling system for ~100 MY. However, significant differences in the composition of the courtship pheromone are evident in some plethodontid lineages. It appears as if at least two lineages (Desmognathus and eastern Plethodon) use different major pheromone components and yet achieve the same behavioral response in the female (increased receptivity). / Graduation date: 2005