1. The taxonomic history and currently accepted classification of the family Asclepiadaceae is presented and discussed. The evolutionary relationship with nearest families, overall geographical distribution and a brief note on economic importance of asclepiads are provided in a general account of the family. 2. A complete taxonomic account of the family for the Flora of Bangladesh is prepared for the first time after a comprehensive survey of the existing taxa. 56 species and 4 varieties from 25 genera are recognized from the area. A dichotomous key to the genera, based on field characters, is provided, and suprageneric, infrageneric and infraspecific classifications are given. A nomenclatural and typification note is provided with a proposal for 16 lectotypes and 3 topotypes according to ICBN. A few nomenclatural changes in some species are made and a full attention is paid to synonymy which results in a number of reductions. Wallich's asclepiad material from Bangladesh held at K-W and other major herbaria have been examined critically, and an index has been prepared with nomenclatural notes and current taxonomic status. There are 7 species and 2 varieties recorded new to the flora of Bangladesh. 2 new varieties, <i>Gymnema acuminatum</i> var. <i>glabrum</i> and <i>Tylophora indica</i> var. <i>intermedia</i>, have been described from Bangladesh. Some investigations on pollinaria, seed morphology and leaf flavonoids have been done. A comparative account of the morphology of the pollinaria of 50 species from 25 genera is prepared with a dichotomous key for the <i>Flora of Bangladesh</i>. Seed morphology under SEM for 14 species from 11 genera provides diagnostic features which may prove useful for supra- and infra-generic classifications. Flavonoid distribution in asclepiads is not taxonomically useful at any level of the taxonomic hierarchy. 3. Two genera, <i>Calotropis</i> and <i>Pentasacme</i>, have been revised for the first time with notes on their taxonomic history, distribution, ecology and synonymy. 3 species of <i>Calotropis</i> and 4 in <i>Pentasacme</i> are recognized. <i>C. procera</i> ssp. <i>hamiltonii</i> (Wight) Ali is reduced to <i>C. procera</i> (Aiton) R. Br. Two sections in the genus <i>Pentasacme</i> are recognized: sect. <i>Pentasacme</i> and sect. <i>Wallichiana</i> (sect. nov.). <i>Pentasacme championii</i> Benth. is considered as a synonym of <i>P. caudatum</i> Wall. ex Wight.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1960. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The association of the Large Milkweed Bug, Oncopeltus fasciatus Dallas, with, a potentially poisonous Asclepiad, Asclepias, has been investigated to determine the fate of sequestered cardiac glycosides in this insect and to investigate the possibility that these compounds and/or odorous and volatile alkyl secretions of this insect may be serving as (an) anti-predator device(s). Nineteen species of Asclepias from diverse parts of North America have been shown to contain cardiac glycosides. Evidence is also given that Oncopeltus plus several other species of brightly coloured Coleopterans and Hemipterans, which are associated with Asclepias as a food-host, contain cardenolides which could function as the chemical basis for a Mullerian mimicry complex. The large quantities of polar cardiac glycosides sequestered by Oncopeltus fasciatus (approximately 111 micrograms) from the seeds of Asclepias syriaca were found to be concentrated in a complex of dorso-lateral abdominal and thoracic secretory glands. Various parameters of the uptake and entry of the natural cardiac glycosides of Asclepias syriaca and unnatural isotopic cardiac glycosides into the dorso-lateral glands were examined. The high levels of polar glycosides in Oncopeltus is also related to other aspects of the insect's physiology and the cardenolide composition of the food-host. The literature cites that lipid cardenolides are more emetic to birds than are the polar glycosides: therefore, the high levels of polar glycosides in this Hemipteran feeding on the above plant could make it non-emetic. Oncopeltus fasciatus was shown to be aposematic to chickens, turtles, lizards and starlings because of the volatile secretions of the ventral metathoracic glands. Frogs and toads did not consider this insect to be aposematic. The cardiac glycosides that had been sequestered from the seeds of this northern Asclepiad by Oncopeltus were not shown to be effective in causing rejection by the above predators in laboratory conditions. The predation studies on Oncopeltus suggest that the responses of various predators to a complex of glycoside containing mimics are not equivalent. This study also shows that along with predator responses being a critical feature in a palatability spectrum, the insect's physiology and its behavioural association with the plant are poignant aspects of the insect's potential to be unpalatable. / Science, Faculty of / Zoology, Department of / Graduate

Human encroachment on ecosystems is one of the key environmental stressors facing natural habitats. Understanding how individual species are affected by these disturbances is therefore fundamental to preserving the stability of vital ecosystem services, such as pollination. Roughly 87.5% of plants are animal pollinated, with pollination contributing over $175 billion to the global economy each year. Despite its ecological and economic importance, studies that have comprehensively evaluated how multiple components of pollination success are impacted by human disturbances are limited. Here we evaluate how different aspects of pollination success, including patterns of pollinator visitation, pollen removal (male fitness), and deposition, fruit and seed production (female fitness) vary across an urbanization gradient in populations of Asclepias syriaca (Common Milkweed). Preliminary data was collected on four naturally occurring Asclepias syriaca sites (Watauga Lake, Warrior’s Path, Lake Ridge, Jacob’s Nature Park) in Northeast Tennessee. Urbanization around each site was quantified using ArcGIS and the National Land Cover Database. Sites were visited every other day (5-12 visits per population) during the flowering season and data was collected on male reproductive success (proportion of pollinaria removed), female reproductive success (proportion of flowers receiving pollinaria), pollinator visitation rate and composition, fruit production, and seed set. Preliminary data on four Asclepias syriaca populations shows large among-site variation in male and female reproductive success, pollinator visitation rate, pollinator community composition, fruit abundance, and seed set. Specifically, the quantity and quality of pollen received varies between all four sites. Pollen quality was highest at Lake Ridge (mean 2.57 fruits per plant and 278 seeds per fruit), and lowest at Warrior’s Path (mean 1.54 fruits and 199 seeds), the most agricultural site. Male success was highest at Warrior’s Path (0.492) and lowest at Watauga Lake (0.308). Female success was approximately equal between three of the sites (between 0.208 and 0.179), but lower at Jacob’s Nature Park (0.072). There was significant among-site variation in pollinator community, not only in terms of composition, but also visitation rate. Visitation rate was highest at Warrior’s Path and Lake Ridge (0.214 and 0.283, respectively), and lowest at Watauga Lake and Jacob’s Nature Park (0.126 and 0.123, respectively). Interestingly, Jacob’s Nature Park and Watauga Lake represent the most and least developed sites, respectively, though the Watauga Lake population was adjacent to a major road. Among-site variation in pollination success is likely due to variation in pollinator community across the sites.

Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 82-92).

Common integrated vegetation management (IVM) practices including herbicide and mowing applications on right-of-ways and forages were evaluated on green antelopehorn populations near Starkville, MS. Live stems in each plot were counted prior to treatment application and approximately one year after treatment (YAT). Analysis of the stem counts 1YAT indicated aminopyralid+metsulfuron, imazapyr, picloram+2,4-D, maximum rates of triclopyr ester or choline, glyphosate, imazapyr+aminocyclopyrachlor+metsulfuron reduced the number of green antelopehorn stems compared to the untreated. Aminocyclopyrachlor, aminocyclopyrachlor+chlorsulfuron, aminopyralid, aminopyralid+2,4-D, dicamba+2,4-D, foramsulfuron+iodosulfuron+thiencarbazone, fluroxypyr, hexazinone, metsulfuron, metsulfuron+chlorsulfuron, nicosulfuron+metsulfuron, sulfometuron, sulfosulfuron or low rates of triclopyr did not reduce the stem count 1YAT when compared to the untreated. Mowing timing and frequencies applications were initiated May through July and evaluated through August. Mowing early in the season increased milkweed stems one month after treatment versus late season mowings. Majority of milkweed plants developed mature seed pods and senesced by early August.

Experiments were conducted to test the relative importance of the two pairs of wing and the flight musculature of Oncopeltus fasciatus. Further, the postembryonic development of this musculature was investigated. It is shown that flight is impossible with only the hind-wings present. The fore-wings are the major propulsive organs, with the hind-wings providing only a part of the lift component. The hind-wings are operated by the mesothoracic musculature acting through a hook mechanism which joins the two pairs of wings together. The development of the mesothoracic muscles is shown to be in two stages; the first involves the degeneration of the original muscle fibres present in the first instar insect, the second involves the aggregation of myoblasts to form fibres which mature by about the third day after the moult into the adult stage. Some evolutionary comments are offered on how the developmental processes described in this thesis, compare with those previously described in other insect orders. / Science, Faculty of / Zoology, Department of / Graduate

archives@tulane.edu / The Eastern migratory monarch butterfly undertakes one of the longest annual migrations known among animal taxa, journeying from as far north as Canada down to central Mexico. A small subpopulation of monarchs has been found dropping out of migration in favor of breeding year-round along the U.S. Gulf Coast. The majority of these dropouts, known as winter-breeders, are feeding and breeding on a non-native milkweed species called tropical milkweed (Asclepias curassavica) that has greater concentrations of toxic cardenolides. The effects of tropical milkweed on monarchs are not yet fully understood, but it is correlated to breakage of reproductive diapause and migratory drop-out. The drop-out phenomenon is concerning due to the increased prevalence of infection by the monarch’s specialized protozoan parasite, Ophryocystis elektroscirrha (OE). OE is often physically damaging and can be lethal to monarchs. Here, we investigate the effects of a colder climate that winter-breeders experience on the Gulf Coast in the winter, exposure to OE, and a diet of exclusively tropical milkweed on larval development and adult wing morphology and pigmentation. Morphology and pigmentation are often functional traits that enhance fitness; thus, we use these measures as proxies for fitness components such as flight performance and immune function. In the first chapter, we found that monarchs reared on tropical milkweed developed faster and had larger wings and higher aspect ratios than monarchs reared on a low-cardenolide native milkweed species, swamp milkweed (Asclepias incarnata). In the second chapter, we found that monarchs reared in a suboptimal temperature developed slower and emerged with smaller, darker (redder and more melanized) wings than monarchs reared in a warmer or ‘normal’ temperature. Additionally, exposure to OE affected wing shape such that exposed monarchs had rounder wings with a slightly lower aspect ratio than unexposed monarchs. Lower temperature did not significantly affect melanism in monarch wings, but monarchs exposed to OE had less melanin deposited onto their wings than unexposed monarchs. Together, the findings from both chapters suggest that the conditions experienced by winter-breeders on the Gulf Coast are detrimental to monarch morphology. Smaller, rounder wings with lower aspect ratios are not conducive to migratory success, and paler color or less melanin are potential negative responses to exposure or infection by OE. While monarchs reared on tropical milkweed were larger and slightly redder which is a seemingly positive result, it may be limited to nonmigratory monarchs or winter breeders who may be adapted to tropical milkweed. Thus, it remains unclear how tropical milkweed is affecting the biology of migratory monarchs versus winter-breeders, but we suggest that the colder winter and increased risk of OE infection are negatively affecting winter-breeding populations and possibly migratory behavior. Migratory monarchs are already of conservation concern, and further monitoring and studying of the winter-breeding population and migrant populations are necessary to ensure the stability of monarch populations if and when they encounter tropical milkweed and whether the milkweed is driving population-level shifts in migratory behavior. / 1 / Caitlin Ducat

No description available.

Orientador: Jose Roberto Trigo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-12T18:54:20Z (GMT). No. of bitstreams: 1 Stanton_MarianaAlves_M.pdf: 682844 bytes, checksum: 36b7ed46fcdc82eacc95256aae48e173 (MD5) Previous issue date: 2008 / Resumo: A produção de defesas contra a herbivoria é essencial para o sucesso reprodutivo das plantas, no entanto pode ser custosa. Esses custos resultam da redução de investimento em outras partes do metabolismo, como o crescimento e a reprodução. Nesse estudo, usamos Asclepias curassavica (Apocynaceae: Asclepiadoideae) como modelo para avaliar como uma planta divide seus recursos entre crescimento, reprodução e defesas. A. curassavica é uma planta anual que possui cardenolidas como defesas. Para verificar como esta responde a herbivoria, simulamos a mesma através de dano artificial (DA) e medimos crescimento (biomassa de folhas e raízes) e reprodução (número de flores, frutos e sementes e biomassa de sementes) em um experimento em longo prazo. Em um experimento em curto prazo, medimos a produção de defesas (concentração de cardenolidas), para avaliar se estas podem estar interferindo no crescimento e reprodução desta espécie. Correlacionamos também, em uma população natural, a concentração de cardenolidas com a percentagem de herbivoria foliar. O hormônio jasmonato de metila (JM) é usado para induzir compostos do metabolismo secundário em plantas, sem o custo adicional da remoção de tecido fotossinteticamente ativo causada por dano artificial ou natural. Usamos esse composto em ambos os desenhos experimentais acima ao invés de remoção da área foliar para avaliar se havia indução de cardenolidas e seu efeito sobre o crescimento e reprodução de A. curassavica. Nossos resultados demonstraram uma redução significativa do número total de frutos, sementes e da massa final de raízes em plantas com tratamento de DA em longo prazo. O crescimento do tratamento DA não diferiu do controle, sugerindo crescimento compensatório das folhas à custa do investimento em raízes e em reprodução. Os custos reprodutivos e de crescimento de raízes detectados no experimento de longo prazo podem resultar da diminuição da capacidade fotossintética em plantas danificadas e investimento simultâneo em crescimento compensatório das folhas. No experimento de curto prazo, não houve alteração da razão de indução de cardenolidas sugerindo que o dano artificial não induz defesas nessa espécie. A ausência de correlação entre cardenolidas e porcentagem de dano natural em plantas coletadas em campo pode sugerir dois cenários excludentes: 1. a indução de cardenolidas não seria importante para a defesa de A. curassavica, ou 2. a ausência de correlação, associada a baixa percentagem de herbivoria implicaria em uma defesa constitutiva eficaz contra herbívoros. O tratamento com JM a longo prazo também mostrou uma tendência à redução do crescimento de raízes e redução significativa da biomassa e porcentagem de germinação de sementes. Nas plantas tratadas com JM a curto prazo, houve um aumento significativo de cardenolidas tardio (384 h após tratamento) sugerindo que estas podem contribuir para a redução de aptidão observada no experimento de longo prazo e que existem custos da produção das mesmas. Dano artificial leva à diminuição da aptidão, através de desvio de investimento em raízes para o crescimento compensatório das folhas. No caso do jasmonato, não houve perda de massa fotossinteticamente ativa (folhas) e a redução do crescimento de raízes pode ser resultado de um efeito direto do tratamento de JM ou indireto causado pela indução de outras partes do metabolismo (p.ex. metabolismo secundário) causada por esse fitohormônio. Experimentos futuros devem comparar os presentes resultados com dano real por um dos herbívoros especialistas para avaliar a eficácia do dano artificial em induzir cardenolidas e o papel dessa indução sobre outras partes do metabolismo da mesma / Abstract: Although the investment in defensive traits against herbivory is essential to the reproductive success of plants, it may be costly. These costs result from reduced investment in other metabolic functions such as growth and reproduction. In the present study, we used the milkweed Asclepias curassavica (Apocynaceae: Asclepiadoideae) as a model to study how a plant divides its resources between growth, reproduction and defense. A. curassavica is an annual weed that uses cardenolides as defenses against herbivory. To evaluate how Asclepias curassavica responds to herbivores, we simulated herbivory by artificial damage (AD) and measured growth (leaf and root biomass) and reproduction (number of flowers, fruit and seeds and seed biomass) in a long term experiment. We also measured defensive traits (cardenolide concentration) in a short term experiment to verify whether there is an investment in defense that may interfere with growth and reproduction. We also correlated cardenolide concentration in a natural population with percent leaf damage. As the plant hormone, methyl jasmonate (MJ) is commonly used to induce secondary metabolism in plants without the additional costs of tissue removal, we used this compound in the same experimental designs instead of AD. Our results from the long term AD treatment showed a significant decrease in final root biomass and in total fruit set and seed number. Plants from the AD treatment did not differ from controls in leaf growth, suggesting that there was a compensatory growth in the former at the expense of root growth. The reproductive and growth costs detected in this experiment may result from reduced photosynthetic capacity in damaged plants and concomitant compensatory leaf growth. In the short term, we found no induction of cardenolides compared to controls, suggesting that artificial damage does not induce defenses. The lack of correlation between cardenolides and percentage leaf damage in plants collected from a natural population suggest two self-excluding scenarios: 1. the induction of cardenolides is not important for the defense of A. curassavica, or 2. the lack of correlation, coupled with low herbivore damage, suggests that this plant has an efficient constitutive defense against herbivores. The long term MJ treatment showed a trend in reduced root biomass and significantly reduced seed biomass and percentage germination. In the short term MJ treatment we found a significant increase in cardenolide concentration (after 384 h) suggesting that the production of these defenses is costly and this may have contributed to observed costs in the long term experiment. Apparently, the artificial damage treatment leads to reduced fitness through reduced root growth which is a consequence of compensatory leaf growth. In the methyl jasmonate treatment, there was no removal of photosythetically active tissue (leaves) and the reduced root growth may be a direct effect of this phytohormone or an indirect effect caused by the induction of other metabolic pathways (such as secondary metabolism) caused by this hormone. Future experiments should compare the present results with natural damage by specialist herbivores to evaluate the efficiency of artificial damage in inducing cardenolides and the role of the induction of these substances on other metabolic functions / Mestrado / Mestre em Ecologia