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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Queen-specific selective pressures and caste dimorphism in the social wasp Vespula maculifrons

Kovacs, Jennifer L. 19 August 2009 (has links)
Within social insect colonies, sterile workers are responsible for brood care, while queens are the primary egg-layers. These reproductive caste differences are often accompanied by pronounced morphological distinctions. Queen and worker phenotypic differences are particularly remarkable considering caste is environmentally, rather than genetically, determined. Environmental caste determination can produce intralocus genetic conflict between castes, particularly when homologous traits are highly dimorphic. Therefore, when studying the evolution of social insect caste dimorphism, one must consider the genetic architecture underlying phenotypic expression as well as the selective pressures that have shaped caste morphology. This dissertation presents the results of four studies that investigated factors affecting caste morphology in the social wasp Vespula maculifrons. The first two studies focused on identifying queen morphological traits that were positively associated with queen fitness and would therefore be subject to selection. Queen length, specifically gaster length, was positively associated with overwintering survival and was consistently associated with mating success. Both of these findings suggest that queen gaster length is under selection during two life-history events, mating and overwintering, in which workers do not participate. These findings provide empirical support for the adaptive evolution of a caste dimorphic trait. The third and fourth studies used classical quantitative genetic and morphological analyses to examine the genetic architecture underlying caste dimorphism in V. maculifrons. I determined which traits were under caste-specific selection by analyzing trait allometries and the levels of genetic control, variation, and dimorphism of traits between castes. Little genetic variation for morphological trait size was detected for most worker and queen traits, suggesting a strong influence of environment on phenotypic variation. Additionally, analyses of trait allometries indicated that several queen traits (mass, thorax width and length) were under queen-specific selection. The relationship between thorax length, gaster length, and overall body size is further evidence of selection on length in queens. Overall, these studies provide evidence for the importance of queen-specific selection in the evolution of caste dimorphism. When placed in the broader context of caste evolution, they point to the importance of life-history in shaping the genetic architecture underlying caste dimorphism.
142

Vespas parasitoides em capítulos de Asteraceae: caracterização da fauna, distribuição e padrões de associação no cerrado do estado de São Paulo

Nascimento, André Rangel 28 April 2014 (has links)
Made available in DSpace on 2016-06-02T19:30:01Z (GMT). No. of bitstreams: 1 6046.pdf: 2350666 bytes, checksum: aed9a60807abef9e46cdb0ad2d5f6de5 (MD5) Previous issue date: 2014-04-28 / Financiadora de Estudos e Projetos / This is the first and most complete study of parasitoid wasps fauna associated with endophagous herbivores reared from flower-heads of Asteracea. A total of 36 remnants of Cerrado were sampled around São Paulo states, Brazil. 15,372 specimens of 192 species of parasitoid wasps were reared from 74 species of family Asteraceae. The subfamilies Eulophidae (Chalcidoidea) and Braconidae (Ichneumonoidea) represented most than a half of parasitoid wasps species. In addition to presenting a rich fauna of parasitoids, this study also addresses ecological issues regarding the main determinants of the parasitoid species richness from Brazilian savannah. The availability of food resources has crucial role in determining the species richness of parasitoids. In the first chapter of this thesis, we verified the role of geographical distribution of plants on the accumulation of natural enemies of their endophagous herbivores. In the second chapter, we verified through a path analysis which was the effect of local richness and phylogenetic diversity of plant species and their herbivores endophagous of flower-heads on local parasitoid species richness. In the third chapter we tested through an analysis of randomization if the patterns of the proportions of species of three trophic levels were consistent or stochastic. We conclude that both plants and their associated herbivores play a key role in determining the species richness of parasitoids in the Cerrado biome and the principals determinants of parasitoid wasps species richness were geographical distribution of plants, plant and herbivore richness, and the phytophysiognomy where species live. Due copyrights, all chapters of this thesis can be found published online in Neotropical Entomology, Insect Conservation and Diversity and Biota Neotropica magazines. / O presente estudo representa o primeiro e mais completo levantamento da fauna de vespas parasitoides associados a herbívoros endófagos de capítulos de Asteraceae. As coletas de dados foram realizadas em 36 remanescentes de Cerrado do Estado de São Paulo, Brasil. Um total de 15.372 espécimes de 192 morfoespécies de Hymenoptera foram criados a partir dos capítulos de 74 espécies da família Asteraceae. As famílias Eulophidae (Chalcidoidea) e Braconidae (Ichneumonoidea) representaram mais da metade das espécies encontradas. Além de apresentar uma rica fauna de parasitoides, este estudo também aborda questões ecológicas a respeito dos principais determinantes da riqueza de parasitoides na savana brasileira. A oferta dos recursos tem papel fundamental na determinação da riqueza das espécies de parasitoides. No primeiro capítulo desta tese verificamos o papel da distribuição geográfica das plantas sobre o acúmulo de espécies de inimigos naturais de seus herbívoros endófagos. No segundo capítulo verificamos através de uma análise de rota qual foi o efeito da riqueza e diversidade filogenética locais das espécies de plantas e de seus herbívoros endófagos de capítulos sobre a riqueza local de parasitoides. No terceiro capítulo testamos através de uma análise de aleatorização, se os padrões das proporções das espécies dos três níveis tróficos entre as fisionomias foram consistentes ou se estocásticos. Concluímos que tanto plantas como seus herbívoros associados exercem um papel fundamental na determinação da riqueza de espécies de parasitoides no domínio do Cerrado. Os temas contidos nesta tese foram organizados em capítulos independentes e estão elaborados em formato de artigos para as revistas Neotropical Entomology, Insect Conservation and Diversity e Biota Neotropica.
143

Finding the Way Back Home : A study of Spatial Orientation, Navigation and Homing Behaviour in the Social Wasp Ropalidia marginata

Mandal, Souvik January 2017 (has links) (PDF)
For most of the animals, if not all, finding their way to a particular place is crucial for survival. To address this challenge of way-finding, different animals have evolved with different homing strategies. Social hymenopterans like honey bees, ants and wasps are of special interest – foragers of these insects show excellent homing capabilities while having simple neural resources. In this study field, honey bees and ants (desert ants, in particular) are among the most studied animals. Compared to these insects, our understanding on the homing mechanisms of social wasp is rather poor. For my thesis, I have studied homing behaviour of the tropical social wasp Ropalidia marginata, a predator in their foraging habit. To begin with, first I had to know their typical foraging range, which I found to be within about 500 m from their nest. Forager wasps possess a surprisingly well-developed familiarity with their foraging landscape, apparently more intricate than honey bees and desert ants. They acquire this spatial familiarity through flying around the landscape before starting foraging for food. Compared to honey bees and desert ants, this learning period in wasps appears to be much longer – this can be attributed to the much higher density of the tropical landscape in which they have evolved. I have also found that, if needed, they can fly to a distance of about 1.5 km for foraging and can return to their nest even if passively displaced to familiar and unfamiliar places. To return from unfamiliar places, they probably use some sort of searching mechanisms – a skill that they improve with their age. Such searching behaviour is prevalent throughout other hymenopteran insects. I conclude that capability and mechanisms of spatial orientation, navigation and homing in animals are much influenced by their evolutionary origin and the environment in which they have evolved.
144

Aspectos morfo-bioecológicos de Epichrysocharis burwelli (Eulophidae, Hymenoptera), vespa-das-galhas das folhas de Corymbia citriodora / Morphological and bioecological aspects of Epichrysocaris burwelli (Hymenoptera, Eulophidae) the gall wasp of Corymbia citriodora (Myrtaceae) leaves

Rosylaine Aparecida Pereira 11 June 2010 (has links)
Este trabalho teve como objetivos estudar aspectos da morfologia, biologia e ecologia de Epichrysocharis burwelli, uma micro-vespa recentemente introduzida no Brasil e que induz galhas em folhas de Corymbia citriodora. Foram verificados neste trabalho, porcentagem média de infestação de galhas em folhas, horário de emergência e longevidade de adultos, razão sexual e caracterização do macho, duração do período de desenvolvimento, sazonalidade de adultos, nível de infestação no campo e influência da pilosidade de folhas sobre a ocorrência de galhas e adultos. Além disso, a influência da formação de galhas sobre o rendimento de óleo essencial de C. citriodora foi verificada. 65% das folhas avaliadas apresentaram algum grau de infestação de galhas de E. burwelli, com uma densidade média de sete galhas/cm2, variando entre 0,04 e 44,10 galhas/cm2. Foram encontradas diferenças significativas entre as árvores avaliadas quanto ao nível de infestação de galhas nas folhas. O período da manhã foi o preferencial para a emergência de adultos, com um pico às 9:00 horas. A longevidade da espécie foi significativamente maior quando o mel foi incorporado à dieta, tanto com água como com folhas jovens de C. citriodora. A razão sexual encontrada foi de 165 fêmeas para cada macho e não foram encontradas diferenças entre os sexos além dos caracteres sexuais da genitália e uma pequena estrutura na antena do macho, visível apenas sob microscópio. A duração total do ciclo, de ovo a adulto é de aproximadamente 75 dias em condições de campo. As galhas passam por cinco estágios de crescimento, que provavelmente são acompanhados por mudanças no estágio de vida do inseto. Os adultos ocorrem durante todo o ano e sua ocorrência está relacionada com a liberação de ramos novos pela planta. A espécie é multivoltina e ocorre sobreposição de gerações. A pilosidade das folhas quando a planta se encontra no estágio juvenil funciona como uma barreira mecânica para a oviposição do adulto e teve influência significativamente negativa sobre a ocorrência desses e a formação de galhas. Altos níveis de galhas nas folhas causam efeito significativamente negativo sobre o rendimento de óleo essencial das folhas de C. citriodora, que ainda é potencializado devido à queda prematura de folhas, quando estas estão sob altas infestações. A pesquisa permitiu ter um maior conhecimento sobre aspectos da biologia e ecologia da espécie que podem auxiliar no manejo desta em condições de campo, além de quantificar a redução de óleo causada pela presença das galhas. / This research deals with aspects of morphology, biology and ecology of Epichrysocaris burwelli a micro-wasp inducing galls on leaves of Corymbia citriodora, and recently introduced in Brazil. The following parameters were studied: percentage of galls on the leaf, time of adult emergence, adult longevity, sex ratio and characterization of the male, duration of the developmental period, seasonal occurrence of adults, level of infestation in the field and the influence of leaf hairs on the occurrence of galls and adults. The influence of galls on the yield of C.citriodora oil was studied as well. From the total of leaves evaluated, 65% presented galls ranging between 0.04 and 44.10 galls/cm2, with a mean density of 7 galls per square centimeter. One also observed significant differences among the evaluated trees as to the number of galls on the leaves. Adult emergence occurred during the morning hours, with a peak at 9 am and adult longevity was longer when honey solution was available. The sex ratio was 165 females: 1 male. The external morphology of the genitalia and a microscopic structure in the male antenna were the only differences between the sexes. The life cycle, from egg to adult, lasted 75 days in field conditions. The galls presented five growing stages which probably are related to the changes in the immature insect periods. The adults are seen all year round and such occurrence is related to the continuous flushing of sprouts by the plant. This insect species is multivoltine and thus present overlapping generations. Young plants present hairy leaves acting as a mechanical barrier to oviposition, preventing the occurrence of adults and galls. The yield of C.corymbia oil leaves is negatively affected not only by the high levels of gall infestation but also by the following premature defoliation.
145

Análise cladística dos grupos de espécies de Zethus (Zethoides) Fox, 1899 (Hymenoptera, Vespidae, Eumeninae) / Cladistic analysis of the species groups of Zethus (Zethoides) Fox, 1899 (Hymenoptera, Vespidae, Eumeninae)

Rogério Botion Lopes 20 March 2014 (has links)
Vespidae possui aproximadamente 5000 espécies, sendo 3500 dessas são eumeníneos. Zethus é o maior gênero de Eumeninae, com mais de 250 espécies no mundo. Atualmente, encontra-se dividido em quatro subgêneros: Z. (Zethus), Z. (Zethusculus), Z. (Zethoides) e Z. (Madecazethus). Z. (Zethoides), com 42 espécies, se destaca por construir ninhos expostos e apresentar comportamento subsocial. Essas espécies encontram-se divididas em oito grupos, cada qual uma unidade filogenética natural que, porém, foram criados sem qualquer análise filogenética. Exemplares de 18 espécies de Z. (Zethoides), correspondentes aos grupos foram examinadas junto com terminais de outras linhagens de Zethus, Zethini e Eumeninae para elaboração de uma análise cladística afim de averiguar as divisões elaboradas. Todos os grupos de espécies foram recuperados como monofiléticos, exceto Z. bilgumis, que é parafilético em relação ao grupo Z. clypearis. Z. (Zethoides), apesar de monofilético, junto com Z. (Madecazethus), situa-se dentro de Zethus s. s. Z. (Zethusculus) também não foi recuperado como monofilético. Zethus é parafilético em relação aCtenochilus. Assim, o grupo Z. clypearisnão foi recuperado e seus integrantes pertencem agora ao grupo Z. biglumis, e as seguinte sinonímias serão propostas: Ctenochilus (=Zethus); Z. (Madecazethus) (=Z. (Zethus)); Z. (Zethoides) (=Z. (Zethus)). / Vespidae has approximately 5000 species, of which 3500 are eumenines. Zethus is the largest genus in Eumeninae, with over 250 species. Currently, it is divided in four subgenera: Z. (Zethus), Z. (Zethusculus), Z. (Zethoides) and Z. (Madecazethus). Z. (Zethoides), with 42 species, stands out for building exposed nests and presenting subsocial behavior. These species are further divided in eight groups, each considered a phylogenetic unit that were created without any phylogenetic analysis. Eighteen species of Z. (Zethoides) corresponding to different groups were examined, altogether with terminals fromdistict lineages of Zethus, Zethini and Eumenine, in order to elaborate a cladistics analysis to verify the proposed divisions. All species groups were monophyletic except for the Z. biglumis group, that is paraphyletic in relation to the Z. clypearis group. Z. (Zethoides), although monophyletic as Z. (Madecazethus), is placed within Zethus s. s. Z. (Zethusculus) was also retrieved paraphyletic. Thus, the Z. clypearis group is dismantled, and its integrates are incorporated in the Z. biglumis group. Also, the following synonymies will be proposed: Ctenochilus (=Zethus); Z. (Madecazethus) (=Z. (Zethus)); Z. (Zethoides) (=Z. (Zethus)).
146

Comportamento de nidificação em Polybia platycephala Richards, 1978: dinâmica de temperatura e luminosidade

Detoni, Mateus Fajardo de Freitas Salviato January 2017 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-17T18:05:35Z No. of bitstreams: 1 mateusfajardodefreitassalviatodetoni.pdf: 1310680 bytes, checksum: 07d34f3c206819ff6b208c6ab33be11a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-18T13:50:54Z (GMT) No. of bitstreams: 1 mateusfajardodefreitassalviatodetoni.pdf: 1310680 bytes, checksum: 07d34f3c206819ff6b208c6ab33be11a (MD5) / Made available in DSpace on 2017-04-18T13:50:54Z (GMT). No. of bitstreams: 1 mateusfajardodefreitassalviatodetoni.pdf: 1310680 bytes, checksum: 07d34f3c206819ff6b208c6ab33be11a (MD5) Previous issue date: 2017 / Os ninhos de insetos sociais funcionam como a interface entre as colônias e o ambiente, e estudar como os fatores ambientais se relacionam com o comportamento de nidificação é essencial para compreender o sucesso desses animais em colonizar e sobreviver na área urbana. Dessa forma, este trabalho teve como objetivo estudar a relação entre a orientação dos ninhos da vespa social Polybia platycephala em áreas urbanas e a incidência de luz ambiental sobre os mesmos, além de descrever sua dinâmica de temperatura em relação ao microambiente em que estão localizados. Para a orientação e a incidência de luz, 11 ninhos foram selecionados em 2016 na cidade de Juiz de Fora, MG, sendo 11 na estação chuvosa e 11 na seca (n= 22). A orientação dos ninhos foi constatada e a incidência de luz de cada ninho foi verificada ao longo do dia (06:00h – 18:00h). Adicionalmente, seis ninhos tiveram sua orientação experimentalmente invertida e a luminosidade foi acompanhada antes e depois da inversão de forma a verificar o efeito da orientação natural sobre a exposição dos ninhos à luz. Para a dinâmica de temperatura utilizaram-se os mesmos 22 ninhos, e a temperatura dos ninhos e do ambiente foram medidas paralelamente à luminosidade. Para verificar o efeito da atividade das vespas sobre a temperatura da colônia, um ninho abandonado e uma colônia ativa foram acompanhados por 24 horas. Os resultados permitiram-nos concluir que P. platycephala apresenta uma orientação de ninhos fortemente enviesada para leste, aumentando a exposição à luz ambiental no período da manhã; são, no entanto, capazes de modificar esse comportamento para adaptar-se ao seu microambiente para otimizar essa exposição. A temperatura dos ninhos é muito relacionada à ambiente, flutuando paralelamente a esta, o que indica uma grande dependência das colônias do mesmo para sua sobrevivência. De forma geral, constatou-se que P. platycephala possui uma íntima relação com o seu microambiente, o que pode ajudar a explicar seu sucesso em colonizar áreas urbanas, mas também a torna sensível a alterações ambientais e climáticas nas mesmas. / Nests of social insects function as the interface between colonies and the environment, and studying how environmental factors relate to the nesting behavior is essential in order to understand these organisms’ success in settling and surviving in the urban area. On this sense, our work aimed to study the relation between the social wasp Polybia platycephala nest orientation and the incidence of environmental light, aside from describing its temperature dynamics regarding the microenvironment where it is set. In order to study nest orientation and light incidence, 22 nests were chosen in 2016 in the city of Juiz de Fora, MG, being 11 in the rainy season and 11 in the dry (n= 22). Nest orientation was verified and light incidence on each nest was assessed through the day (06:00h - 18:00h). Additionally, six nests had their orientation experimentally inverted and luminosity was assessed before and after the inversion in order to verify the effect of nest orientation on exposure to light. In order to study temperature dynamics, the same 22 nests were used, and the nest and ambient temperatures were assessed in parallel with the luminosity. In order to verify the effect of the wasp activity on colony temperatures, an abandoned nest and an active colony were observed for 24 hours. The results allowed us to conclude that P. platycephala shows nest orientation strongly biased towards east, increasing exposure to light during the morning; colonies are, however, able to perform modifications on this behavior in order to adapt themselves to their microenvironment and optimize this exposure. Nest temperatures are intensely related to the ambient, fluctuating in parallel with it, which indicates a great dependence of the colonies on the environment to assure their survival. Overall, we found that P. platycephala has an intimate relation with its microenvironment, which may help explain its success in settling urban areas, but also makes it sensible to environmental and climatic changes in them.
147

Ants, Figs, Fig Wasps : The Chemical Ecology Of A Multitrophic System

Ranganathan, Yuvaraj 07 1900 (has links) (PDF)
Plant–animal interaction systems are complex food webs where the members—plants, pollinators, herbivores, parasites and predators of the pollinators/herbivores—interact with each other in ways which maximize their own fitness. Based on the net outcome, such interactions could be mutually beneficial to the interacting members (mutualism) or beneficial to only one of the interacting members at the cost of the other interacting members (herbivory, predation, parasitism). It is possible that such outcomes are actually a continuum and could swing in either direction from beneficial to detrimental and vice versa. Such transitions happen not only over long time scales, but could also happen within shorter time scales based on conditionalities. Conditional outcomes are those in which the outcome of an interaction between two partners is conditional on the involvement of a third partner. Thus, studying such outcomes necessitates taking into account systems beyond the classical two-partner interactions. In such complex multitrophic plant–animal interaction systems in which there are direct and indirect interactions between species, comprehending the dynamics of these multiple partners is very important for an understanding of how the system is structured. In Chapter 2 we investigate Ficus racemosa and its community of obligatory mutualistic and parasitic fig wasps that develop within the fig inflorescence or syconium, as well as their interaction with opportunistic ants. We focus on temporal resource partitioning among members of the fig wasp community over the development cycle of the fig syconia during which wasp oviposition and development occur and we study the activity rhythm of the ants associated with this community. We found that the members of the wasp community partitioned their oviposition across fig syconium development phenology and showed interspecific variation in activity across the diel cycle. The wasps presented a distinct sequence in their arrival at fig syconia for oviposition. We documented night oviposition in several fig wasp species for the first time. Ant activity on the fig syconia was correlated with wasp activity and was dependent on whether the ants were predatory or trophobiont-tending species; only numbers of predatory ants increased during peak arrivals of the wasps. In Chapter 3, we found that predatory ants (Oecophylla smaragdina) patrolling F. racemosa trees were attracted to the odour from fig syconia at different developmental phases, as well as to the odours of fig wasps, whereas other predatory ants (Technomyrmex albipes) responded only to odours of syconia from which fig wasps were dispersing and to fig wasp odour. However, trophobiont-tending ants (Myrmicaria brunnea) patrolling the same trees and exposed to the same volatiles were unresponsive to fig or fig wasp odours. The predatory ants demonstrated a concentration-dependent response towards volatiles from figs receptive to pollinators and those from which wasps were dispersing while the trophobiont-tending ants were unresponsive to such odours at all concentrations. Naıve predatory ants failed to respond to the volatiles to which the experienced predatory ants responded, indicating that the response to fig-related odours is learned. In Chapter 4 we characterise the dynamics of the volatile bouquet of the fig syconium from the initiation through pre-receptive, receptive, and late inter-floral stages which act as signals/ cues for different fig wasp species. We were also interested in diel patterns of volatile emission as some fig wasp species were strictly diurnal (the pollinator, Ceratosolen fusciceps) whereas other fig wasps such as Apocryptophagus fusca were observed ovipositing even during the nocturnal hours. We identified volatiles that were specific to syconium development phase as well as to the time of day in this bouquet. α-muurolene was identified as the sesquiterpene specific to receptive-phase as well as being present only during the day thus coinciding with the diurnal pollinator arrival pattern. Volatiles such as (E)-β-ocimene were present in increasing levels across the developmental stages of the fig and thus could act as background volatiles providing suitable information to fig wasps about host plants and their phases. Chapter 5 examines the responses of predatory and trophobiont-tending ant species to the cuticular hydrocarbon (CHC) extracts of four galler and two parasitoid fig wasp species associated with F. racemosa. Interestingly, the antennation response of both experienced and na¨ıve ants to these wasp extracts was identical indicating that prior exposure to such compounds is not necessary for eliciting such response. We also characterised these cuticular hydrocarbon extracts to find potential compounds which could as short-range cues for predatory ants. Ants were more responsive to the cuticular extracts of parasitoids rather than to those of galler wasps, implying that the CHC profile of carnivorous prey may contain more elicitors of aggressive behaviour in ants compared to herbivorous prey whose profiles may be more similar to those of their plant resources. We also find congruency between the cuticular profiles of parasitoids and their hosts suggesting that parasitoids could sequester compounds from their diet. Important findings and conclusions of the thesis are presented in Chapter 6. The first two parts of the appendices section discuss work carried out on alternative ways of analysing multivariate data sets such as plant volatiles and insect cuticular hydrocarbons. Appendix A details the use of Random Forests, an algorithm-based method of analysing complex data sets where there are more variables than samples, a situation akin to microarray data sets. This work illustrates the use of such techniques in chemical ecology, highlighting the potential pitfalls of classical multivariate tests and the advantages of newer more robust methods. Appendix B, an invited article following the publication of the earlier work, compares different data transformation procedures currently employed in such multivariate analysis. Appendix C details sex-specific differences in cuticular hydrocarbons of fig wasps, using the pollinator C. fusciceps as a case study.
148

BSF-colony management efficiency at a large scale fly larvae composting company in Kenya – A field study / Utvärdering av flugkolonieffektiviteten på ett storskaligt fluglarvskomposteringsföretag i Kenya – En fältstudie

Anderberg, Hilda January 2023 (has links)
The majority of organic waste globally is either dumped or placed on landfills, which can result in spreading of disease and pests, methane gas emissions, the deterioration of landscapes and odour pollution. One of the solutions to poor organic waste management is to create value from waste. A way to do this is with black soldier fly (Hermetia illucens) larvae (BSFL) composting. The interest for BSFL composting has increased the past 10 years mainly because it is a technology with relatively low investment costs. The part of the process where the seed larvae that are used in the treatment are produced is called BSF-colony. Producing seed larvae in an efficient way is an important part of the technology’s feasibility. However, there is limited research published on BSF-colony management, especially on a larger scale. The aim of the study was to investigate the factors that impact the efficiency of the BSF-colony on a large scale BSFL composting company in Kenya in a semi-open setting. The efficiency of the BSF-colony management was assessed in terms of emergence rate (percentage of pupa that emerge as flies), hatching rate (percentage of eggs that hatch and survive to 5 day old larva) and number of eggs laid per female BSF. The result of the study suggests that parasitic wasps (Dirhinus giffardii) can reduce the emergence rate significantly, and high temperatures and water shortage for the adult BSF can reduce the egg production. Observations made during the study indicate that personnel routines and how the BSF-colony is arranged also could affect the egg production significantly. The overall variation in the results suggests that other factors, beyond the ones investigated in the study, impact the efficiency of the BSF-colony, and further research regarding BSF-colony management is recommended / Merparten av det organiska avfallet i världen dumpas eller läggs på deponier, vilket kan leda till spridning av sjukdomar och skadedjur, utsläpp av metangas, förstörelse av landskap och luktföroreningar. En av lösningarna på bristfällig hantering av organiskt avfall är att skapa värde av avfallet. Ett sätt att göra det är med hjälp av fluglarvskompostering med amerikansk soldatfluga (Hermetia illucens). Intresset för fluglarvskompostering har ökat under de senaste tio åren, främst på grund av att det är en teknik som inte behöver innebära höga investeringskostnader. Flugkolonin är den del av processen där sättlarverna som användes i komposteringen produceras. Att sättlarver produceras på ett effektivt sätt är en viktig del av teknikens genomförbarhet. Det finns dock begränsad forskning publicerad om effektivisering av flugkolonier, speciellt sådan som berör storskaliga kolonier. Syftet med studien var att undersöka vilka faktorer som påverkar flugkolonins effektivitet på ett storskaligt fluglarvskomposteringsföretag i Kenya i en halvöppen miljö. Flugkolonins effektivitet bedömdes i termer av metamorfosfrekvens (den andel av pupporna som blir flugor), antalet lagda ägg per fluga och kläckningsfrekvens (den andel ägg som kläcks och överlever till 5-7 dagar gamla larver). Resultatet av studien tyder på att parasitsteklar kan minska metamorfosfrekvensen avsevärt, och att höga temperaturer samt vattenbrist kan minska äggproduktionen. De observationer som gjordes under studien tyder på att personalens rutiner och hur flugkolonin är anordnad också kan påverka äggproduktionen avsevärt. Den relativt stora variationen i alla resultat tyder på att andra faktorer än de som undersökts i studien påverkar flugkolonins effektivitet, fortsatta studier inom effektivisering av flugkolonier rekommenderas
149

Descriptions, Ecological Associations and Predictive Species Distribution Models of New Species of Psilochalcis Kieffer (Hymenoptera; Chalcididae) Occurring in Utah's Eastern Great Basin

Petersen, Mark J. 18 April 2023 (has links) (PDF)
The genus Psilochalcis, of the Family Chalcididae, was originally described in 1905 by Kieffer. Mainly considered an Old-World taxon, the first North American Psilochalcis were not identified until 1981 by Grissell and Schauff. Little is known about the species distributions, biologies and ecological relationships of these parasitic wasps. This dissertation describes research conducted in central Utah setting arrays of Malaise traps in 4 different habitat types common to the Great Basin at three separate locations. A result of this sampling revealed a high abundance of multiple species of Psilochalcis wasps, particularly from one location and two habitat types. Chapter 1 describes three new species of Psilochalcis wasps namely; P. adenticulata Petersen, P. minuta Petersen, and P. quadratis Petersen. A review of all North American Psilochalcis species explains their distribution in Utah and throughout the surrounding western United States. A taxonomic key for all North American Psilochalcis species is given. Chapter 2 examines the seasonal abundance of P. minuta and P. quadratis and their associations with two common Great Basin habitat types. Both species show their highest abundance from late June through early August. Their peak abundance is shown to change dependent on the environmental conditions of temperature and precipitation. Psilochalcis minuta is significantly associated with pinyon/juniper (Pinus edulis or P. monophylla and Juniperus osteosperma) and P. quadratis is significantly associated with cheatgrass (Bromus tectorum). Chapter 3 describes the building of species distribution models for P. minuta and P. quadratis using a maximum entropy (Maxent) approach. Ten environmental variables were used to predict areas of optimal suitable habitat for each species. Multiple predicted sites were field sampled to test each model's effectiveness. Psilochalcis minuta occurred at nearly 90% of predicted sites, and P. quadratis occurred at 50% of predicted sites. Both species occurred at some non-predicted sites in other habitat types. Model analyses and field-testing results show the P. minuta model to be reliable in predicting areas of probable species occurrence, while the P. quadratis model is much less reliable in doing so. Aspect and fire disturbance show the highest percent contribution to both species' models. Slight differences in variable percent contribution between models suggest these species have sympatric distributions. Soil and slope are more important predictors of optimal suitable habitat for each species. Maintaining integrity between model predictions and field testing gave insights into other factors contributing to probable occurrence of Psilochalcis species.
150

Parents and the Priceless Child in Elite Early Childhood Admissions

Diaz, Estela B. January 2023 (has links)
Education is a crucial site and primary driver of elite status maintenance and reproduction. Decades of research highlight how elite colleges and universities use various forms of gatekeeping to admit and represent the interests of dominant groups. This body of research explains that most elite private schools served White, Anglo-Saxon, and Protestant upper-class children, preparing them to be the country's future leaders. These schools and colleges work together, creating well-trodden pipelines for young elites. However, there is limited research considering how parents think about securing their child's place in elite schools or how organizations external to the educational institutions facilitate this decision-making process. What logics of justification and frameworks do parents and organizations use to secure their child's place in the proven pipeline for elites? This dissertation investigates how parents and organizations decide to socialize children in elite independent schools, beginning at preschool or kindergarten. The empirical context for this work is the early admissions process for independent schools in New York City. I draw on 52 interviews with parents, ten interviews with expert service providers, and 24 months of ethnographic fieldwork at a for-profit educational consulting firm that supports families in the elite independent school admissions process. By centering parents and early childhood admissions, I examine a critical moment when parental decision-making and organizational maneuvering have the potential to impact life-long outcomes. I also highlight how social positions of race, class, and gender complicate parental and organizational logics. The first chapter introduces this dissertation’s motivating research questions and situates it within the broader literature on elites, parental investments during early childhood, rising inequalities and the fear of downward mobility, and the literature on educational admissions. In Chapter 2, I examine the parenting logics of justification during the early childhood admissions process. I argue that parents have "speculative projects" for their children, defined as ideas parents have about their children's imagined futures that underlie parents' day-to-day choices. I examine how parents allocate resources to these speculative projects and how education shapes the projects. Chapter 3 illustrates how organizations facilitate and influence parental decisionmaking. I present research on how brokers of the educational marketplace – in this case, educational consultants – regularly realign the moral boundaries of their work to justify profiting off their chosen commodity – in this case, the potential outcomes of young children. I also demonstrate how educational consultants make tremendous non-economic gains through their line of work, gaining trust and being seen as “experts” in a high-status social field. Chapter 4 examines how parents feel about their decisions one year later. I review their range of outcomes and show how other social positions mediate their ability to access privileged spaces and identities. Finally, I end with Chapter 5, highlighting the broader implications of this work and directions for future research. Together, these chapters illuminate how parents of young children attempt to understand, navigate, and manage elite educational admissions processes under conditions of uncertainty. This work has broader implications for understanding the cultural meaning and the social value of children in the 21st century, a time when parents are placing a premium on education amidst a landscape of unprecedented economic inequality.

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