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Call number: LD2668 .T4 1958 Q85

Typescript. / Thesis (Ph. D.)--University of Hawaii, 1965. / Bibliography: leaves [52]-54. / xi, 54 l mounted illus., tables

D.Sc. (Zoology) / The influence of some natural enemies and pesticides was studied on Tetranychus cinnabarinus (Boisduval), T. lombardinii Baker & Pritchard and T. ludeni Zacher (Acari: Tetranychidae). Two important predators were discovered, viz: Pardosa crassipalpis (Purcell) (Arachnida: Araneida) and Labidura riparia (Insecta: Dermaptera). Both are more susceptible to some acaricides, especially dimethoate, than the mites. It is proved that the injudicious use of these acaricides, also of DDT and carbaryl, can cause an outbreak of these mites. As to the biologies of the species, the appearance was noted of a fourth chrysalis stage during the development of three T. cinnabarinus females.

Note:

The effect of pH upon the aquatic toxicity of cyfluthrin was determined in 48 h static acute toxicity tests using 2nd instar Chironomus tentans larvae. Tests were conducted in both dechlorinated tap water and lake water of pH 8.0, 7.2, and 6.6. After 48 h, immobilized and dead larvae were removed and replaced with 2nd instar larvae to assess the persistence of toxicity. Midges were cultured in water adjusted to the pH values used in testing. Toxicity if cyfluthrin varied inversely with pH. An increase in the pH of tap water by 2 units resulted in a 2-decrease in toxicity. Toxicity of cyfluthrin also varied between tap and lake water of the same pH. EC50 values in lake water were approximately 2-3 times lower than those in tap water. Toxicity in the lake water and tap water at every pH tested was also significantly different when regression line elevations were compared. Natural waters amended with cyfluthrin were consistently more toxi to the chironomids than tap water of the same pH. Persistence of cyfluthrin at low pH also influenced chironomid behavior. Recovery of normal behavior generally began within 24 h at pH 8.0 At pH 6.0, recovery did not begin until one week after dosing. The persistence of cyfluthrin also varied with pH. Averaged across all concentrations, 30% of the initial dose remained in tap water (pH 8.0) after 48 h, compared with 45% (pH 7.2), and 75 % (pH 6.6).

The Quotient Method (QM), a laboratory-based risk assessment methodology used by the Environmental Protection Agency to evaluate pesticides for registration and use, has not been thoroughly field-tested and its performance has not always been reliable. My objective was to determine if variation in vegetation structure or diet of exposed animals could result in adverse ecological effects that were not predicted by the QM. In April and early May 1993, I established populations of herbivorous gray-tailed voles (Microtus canicaudus) and omnivorous deer mice (Peromyscus maniculatus) in 24 0.2-ha enclosures planted with alfalfa (Medicago sativa). Alfalfa in 12 enclosures was mowed on 22 June to reduce vegetation height. Small mammal populations were monitored by live trapping from May through August 1993. On 14 July, an organophosphorus insecticide, azinphos-methyl, was applied at 0, 0.88, and 3.61 kg/ha. Insecticide residues were measured on canopy-level spray cards, soil samples, and alfalfa. I compared the observed residue concentrations with predictions based on the nomogram used to estimate exposure for QM risk assessments. I also compared QM predictions of risk with observed effects on population size and growth, survival, reproductive activity, recruitment, body growth, movements, and diet of the small mammals. Much of the insecticide reached ground level in mowed enclosures, but dense alfalfa intercepted most of the spray in unmowed enclosures. The mean half-life of azinphos-methyl on alfalfa was 3.4 days and was not affected by mowing. Mean residue concentrations on mowed alfalfa and the top 15 cm of unmowed alfalfa were underestimated by the QM exposure nomogram. Therefore, pesticides may pose greater risk to organisms inhabiting sparse vegetation or the tops of plants than predicted by the QM. Treatment with azinphos-methyl at 3.61 kg/ha caused severe effects in both mowed and unmowed enclosures on population size and growth, survival, recruitment, and body growth of voles. Effects of azinphos-methyl on vole recruitment and body growth and on survival of female voles were greater in mowed than in unmowed enclosures. However, I did not find that population-level responses of voles to the chemical differed between mowing treatments. Most effects on voles were of short duration (<27 days) but vole densities in 3.61 kg/ha enclosures remained depressed >6 weeks after spraying. The 3.61 kg/ha application rate resulted in a 42% decrease in deer mouse densities in mowed enclosures during the week of spraying, but the insecticide had no adverse effects on deer mice in unmowed enclosures. In addition, the insecticide may have reduced recruitment of deer mice in mowed enclosures. Analysis of deer mouse feces indicated that consumption of arthropods increased in insecticide-treated enclosures just after spraying occurred. Survival, reproductive activity, body growth, and movements of deer mice were highly variable and not significantly affected by azinphos-methyl. Mowing resulted in greater residue concentrations than predicted and, consequently, the insecticide adversely affected voles and deer mice in mowed enclosures at application rates characterized as low risk by the QM. However, food aversion or selective feeding on alfalfa tops may have resulted in similar exposure of voles to the 3.61 kg/ha treatment in mowed and unmowed enclosures. I did not find that insectivorous feeding behavior of deer mice made them more susceptible than predicted. Although residue concentrations on alfalfa did not follow predictions, the gross pattern of effects on small mammals was consistent with QM risk characterization. However, the QM may underestimate exposure and risk when pesticides are sprayed on sparse vegetation. / Graduation date: 1995

Orientador: Wilma De Grava Kempinas / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-05T10:14:11Z (GMT). No. of bitstreams: 1 Nassr_AzizeCristinaCapelli_M.pdf: 10674778 bytes, checksum: 6e73e575f70e9f4c4cdd81eb7eac3586 (MD5) Previous issue date: 2005 / Resumo: o fenvalerato é um inseticida piretróide sintético usado na agricultura, pecuária e no controle de insetos domésticos, e seus efeitos reprodutivos são pouco conhecidos. Algunsestudos têm proposto que o fenvaleratoseja um desregulador endócrino,atuando como um estrógeno ambiental. Estudos realizados com ratos adultos expostos a determinados piretróides mostraram a redução do número de espermatozóides e das concentrações plasmáticas de testosterona. Sabendo-se que o sistema reprodutor masculino de ratos é mais sensível ao efeito de substâncias tóxicas durante as fases fetal e neonatal, o objetivo deste trabalho foi avaliar os possíveis efeitos tardios sobre o desenvolvimento reprodutivo na pré-puberdade (40 dias de idade), puberdade (60 dias) e maturidadesexual (90 dias), em ratos machos cujas mães foram expostas ao fenvalerato durante a prenhez e lactação. Adicionalmente,investigou-seo comportamentosexual, a fertilidadedos ratos adultos,a transferênciado fenvaleratodas mães para a prole,e a sua persistência no organismo dos descendentes machos. Para este estudo ratas prenhes (n=8) foram tratadas com fenvalerato técnico (96% de pureza), na dose diária de 40 mg/Kg, do 12° dia de prenhez até o final da lactação (período crítico de diferenciação do sistema reprodutor masculino da prole). Ratas controles (n=8) receberam óleo de milho (veículo), nas mesmas condições experimentais. O desenvolvimento reprodutivo foi avaliado através da idade da descida testiculare da separação prepucial,pesos dos órgãos reprodutores, concentração plasmática de testosterona, contagem de células germinativas no testículo e epidídimo, morfologia espermática, estudo do processo espermatogênico, número de células de Sertoli, do diâmetro dos túbulos seminíferos e altura de epitélio germinativo. Tambémfo~m avaliados o comportamentosexual e a fertilidadedos ratos adultos após acasalamentos naturais. A quantificação de resíduos de fenvalerato foi realizada por Cromatografia Líquida de Alta Precisão (CLAP) em amostras de órgãos e tecidos das mães, fetos e filhotes. Os resultados da quantificação de fenvalerato revelaram que o piretróide foi transferido das mães para os fetos, pela placenta, e para os filhotes, pelo leito matemo, respectivamente. O piretróide permaneceu no organismo dos filhotes até, pelo menos, 40 dias de idade, com destaque para o testículo e epidídimo. A exposição in utero e lactacional ao fenvalerato foi tóxica para o testículo, conforme mostrado pela diminuição dos pesos deste órgão nos grupos tratados e pela redução da produção espermática na puberdade, sem que tenha havido depleção androgênica ou diminuição da população de células de Sertoli. Os estudos morfológicos e morfométricos não mostraram danos sobre o aspecto histológico do testículo e o processo espermatogênico, sugerindo a ação do fenvalerato sobre a formação dos cordões seminíferos nos testículos fetais. Na idade adulta houve aumento significativo do peso da vesícula seminal e do número de ejaculações, embora os resultados dos testes de fertilidade tenham sido semelhantes entre os grupos controle e tratado. Esses achados podem ter sido uma conseqüência tardia de um desequilíbrio neuroendócrino durante o período crítico de diferenciação do sistema reprodutor masculino, quando ocorreu a exposição ao fenvalerato. Concluiu-se que o fenvalerato, diluído em óleo de milho, na dose de 40 mg/Kg, administrado para ratas do 12°. dia de prenhez até o final da lactação, foi transferido pela placenta e pelo leite matemo, provocando efeitos tardios no desenvolvimento reprodutivo da prole masculina / Abstract: Fenvalerate is a synthetic pyrethroid insecticide used in agriculture, cattle raising and in the control of domestic insects, and its reproductive effects are little-known.Some studies already have proposed that fenvalerate is an endocrine disruptor, acting as an environmentalestrogen. Studies done with rats exposed to some pyrethroids showed reduction of sperm number and plasmatic testosterone concentration. Knowingthat the male reproductive system of rats is more sensitive to the effects of toxic substances during fetal and neonatal phases, the objective of this work was to evaluate the possible Iate effects on the reproductive development at pre-puberty (aged 40 days), puberty (aged 60 days) and sexual maturity(aged 90 days) in male rats whose mothers were exposed to fenvalerate during gestation and lactation. Additionally,sexual behavior, fertilityof adult rats, transference of fenvalerate from the mothers to the offspringand its persistence in the organism of the male descendents were investigated. For this study pregnant rats (n=8) were treated with technical fenvalerate (96% purity), in the dose of 40 mglKg, from gestational day 12 until the end of lactation (critical period for differentiation of the male reproductive system of the offspring). Control rats (n=8) received com oil (vehicle), irí the same experimental conditions. The reproductive development was evaluated through of the age when testicular descent and preputial separation occurred, weight of reproductive organs, plasmatictestosterone levels, numbers of germ cells in the testis and epididymis and sperm morphology. The spermatogenic process, the number of Sertoli cells, seminiferous tubule diameter and height of the germinative epithelium were also evaluated. The sexual behavior and fertilityof adult rats were also evaluated by natural matings. Fenvalerate -residues were quantified using High Performance Liquid Chromatography (HPLC)in samples of organs and tissues of mothers,fetuses and pups. The results of the fenvalerate quantification revealed that the pyrethroid was transferred from the mothersto the fetuses through the placenta, and to the pups by maternal milk, respectively. The pyrethroid remained in the organism of the pups until at least 40 days of age, especially in the testis and epididymis. In utero and lactational exposure to fenvalerate was toxic for the testis, as shown by the diminished weight of this organ in the treated groups and reduction of the sperm production at puberty, without androgen depletion or decrease of the Sertoli cell population. The morphological and morphometrical studies did not show injuries in the histological aspect of the testis or the spermatogenic process, suggesting the action of fenvalerate on the formation of seminiferous cords in the fetal testicJe. At adult age there was a significant increase of the seminal vesicJe weight and in the number of ejaculations, although the fertilitytest results were similarbetween control and treated groups. These effects can be a Iate consequence of a neuroendocrinedysregulationduringthe critical period of differentiation of the male reproductive system, when the exposure to fenvalerate occurred. It was concluded that fenvalerate, diluted in com oil at the dose of 40 mg/Kg, administered to rats from the gestational day 12 until the end of lactation was transferred through the placenta and milk, provoking Iate effects in the reproductive development of the male offspring / Mestrado / Biologia Celular / Mestre em Biologia Celular e Estrutural