A descoberta dos elementos genéticos móveis na década de 40 representa a formação de um novo paradigma no campo da genética, onde existe a formação de uma abordagem dinâmica à interpretação do genoma de organismos eucarióticos e procarióticos. A presença de elementos de transposição em praticamente todos os seres vivos indica a sua origem ancestral e indica a importância dos processos de transposição como mecanismo evolutivo. Apesar de em muitos casos os elementos de transposição apresentarem-se como agentes de processos deletérios, sua atividade também está ligada a diversos eventos adaptativos incluindo a formação de novos genes, regulação gênica e constituição estrutural do genoma. Com o recente desenvolvimento de novas tecnologias de sequenciamento, que possibilitaram a expansão massiva do número de genomas completos sequenciados, acumulou-se um grande número de dados de sequência que permitem a comparação direta entre diferentes genomas e assim a realização de análises específicas em larga escala sobre a evolução dos elementos de transposição. Este trabalho utilizou 12 genomas completos de espécies de Drosophila para comparações em larga escala entre genes e transposons, analisando diferentes variáveis evolutivas. Através dessas comparações foi possível identificar padrões específicos de sequências de elementos de transposição em relação às sequências gênicas do genoma hospedeiro. Especificamente, um grande número de sequências de elementos de transposição apresentam valores de Ks significantemente inferiores aos valores de Ks encontrados em sequências gênicas, ao mesmo tempo que apresentam alta similaridade da sequência de DNA. Contudo, em média a sequência de proteína destas mesmas sequências tende a possuir similaridade menor que as sequências gênicas da respectiva comparação. É possível distinguir dois tipos de padrão evolutivo nas sequências de elementos de transposição, o primeiro relacionado a sequências com alta similaridade, baixo valor de Ks e Ka. Tais sequências são provavelmente derivadas de eventos de transposição recente. Um segundo padrão é caracterizado por sequências com alta similaridade, baixo valor de Ks e valor de Ka superior ao encontrado no genoma, gerando sequências com grande valor de Ka/Ks, mas fortemente conservadas, indicando uma possível seleção positiva em sequências de elementos de transposição sujeitos a recente transferência horizontal. / The discovery of transposable elements in the 1940s represents the constitution of a new paradigm in the field of genetics, where is consolidated a new and dynamic interpretation of eukaryotic and prokaryotic genomes. The existence of transposable elements as ancestral components of the genome, indicates the importance of transposition processes as evolutionary mechanisms. Although transposable elements could cause a range of deleterious effects in the host, its activity is also connected to a broad number of adaptative events, including the constitution of new genes, gene regulation and the structural integrity of the genome. With the recent development of new sequencing technologies and massive increase in the number of complete sequenced genomes a new opportunity window was created for the large scale evolutionary analysis of transposable elements in different species. This work analysed 12 complete genomes of Drosophila to conduct large scale comparative analysis between transposable elements and nuclear genes, analysing a number of different variables. Trought this comparisons was possible to identify specific evolutionary patterns of transposable elements and Drosophila nuclear genes. A great number of transposition element sequences presented Ks values significantly lower than the Ks value found for nuclear gene sequences, also presenting a high DNA sequence similarity in relation to the genome sequences. However, the average protein sequence similarity of the transposable element sequences is lower than the nuclear genes protein sequence in the same comparison. It is possible to identify two evolutionary patterns in the transposable element sequences. The first one is characterized by sequences with high similarity and low Ks and Ka values. This sequences are probably subject of a recent horizontal transfer event. The second pattern is characterized by sequences with high similarity, low Ks values and Ka values above the average genome nuclear gene sequences Ka values, producing high values of Ka/Ks. Those second pattern sequences are highly conserved, although with a high Ka/Ks value, probably indicating positive selection over transposable element sequences subject to horizontal transfer.

A descoberta dos elementos genéticos móveis na década de 40 representa a formação de um novo paradigma no campo da genética, onde existe a formação de uma abordagem dinâmica à interpretação do genoma de organismos eucarióticos e procarióticos. A presença de elementos de transposição em praticamente todos os seres vivos indica a sua origem ancestral e indica a importância dos processos de transposição como mecanismo evolutivo. Apesar de em muitos casos os elementos de transposição apresentarem-se como agentes de processos deletérios, sua atividade também está ligada a diversos eventos adaptativos incluindo a formação de novos genes, regulação gênica e constituição estrutural do genoma. Com o recente desenvolvimento de novas tecnologias de sequenciamento, que possibilitaram a expansão massiva do número de genomas completos sequenciados, acumulou-se um grande número de dados de sequência que permitem a comparação direta entre diferentes genomas e assim a realização de análises específicas em larga escala sobre a evolução dos elementos de transposição. Este trabalho utilizou 12 genomas completos de espécies de Drosophila para comparações em larga escala entre genes e transposons, analisando diferentes variáveis evolutivas. Através dessas comparações foi possível identificar padrões específicos de sequências de elementos de transposição em relação às sequências gênicas do genoma hospedeiro. Especificamente, um grande número de sequências de elementos de transposição apresentam valores de Ks significantemente inferiores aos valores de Ks encontrados em sequências gênicas, ao mesmo tempo que apresentam alta similaridade da sequência de DNA. Contudo, em média a sequência de proteína destas mesmas sequências tende a possuir similaridade menor que as sequências gênicas da respectiva comparação. É possível distinguir dois tipos de padrão evolutivo nas sequências de elementos de transposição, o primeiro relacionado a sequências com alta similaridade, baixo valor de Ks e Ka. Tais sequências são provavelmente derivadas de eventos de transposição recente. Um segundo padrão é caracterizado por sequências com alta similaridade, baixo valor de Ks e valor de Ka superior ao encontrado no genoma, gerando sequências com grande valor de Ka/Ks, mas fortemente conservadas, indicando uma possível seleção positiva em sequências de elementos de transposição sujeitos a recente transferência horizontal. / The discovery of transposable elements in the 1940s represents the constitution of a new paradigm in the field of genetics, where is consolidated a new and dynamic interpretation of eukaryotic and prokaryotic genomes. The existence of transposable elements as ancestral components of the genome, indicates the importance of transposition processes as evolutionary mechanisms. Although transposable elements could cause a range of deleterious effects in the host, its activity is also connected to a broad number of adaptative events, including the constitution of new genes, gene regulation and the structural integrity of the genome. With the recent development of new sequencing technologies and massive increase in the number of complete sequenced genomes a new opportunity window was created for the large scale evolutionary analysis of transposable elements in different species. This work analysed 12 complete genomes of Drosophila to conduct large scale comparative analysis between transposable elements and nuclear genes, analysing a number of different variables. Trought this comparisons was possible to identify specific evolutionary patterns of transposable elements and Drosophila nuclear genes. A great number of transposition element sequences presented Ks values significantly lower than the Ks value found for nuclear gene sequences, also presenting a high DNA sequence similarity in relation to the genome sequences. However, the average protein sequence similarity of the transposable element sequences is lower than the nuclear genes protein sequence in the same comparison. It is possible to identify two evolutionary patterns in the transposable element sequences. The first one is characterized by sequences with high similarity and low Ks and Ka values. This sequences are probably subject of a recent horizontal transfer event. The second pattern is characterized by sequences with high similarity, low Ks values and Ka values above the average genome nuclear gene sequences Ka values, producing high values of Ka/Ks. Those second pattern sequences are highly conserved, although with a high Ka/Ks value, probably indicating positive selection over transposable element sequences subject to horizontal transfer.

The telomeres of most organisms are characterized by a protein-capping complex that protects chromosome ends, a series of repetitive subtelomeric sequences known as Telomere-Associated Sequences (TAS), and a behavioral phenomenon known as Telomere Position Effect (TPE). TPE is a phenomenon whereby normally active genes become repressed and silenced if relocated near to telomeres, and is thought to be a property of the proteins that constitute telomeric heterochromatin. Genetic dissection was used to exploit this phenomenon in order to identify components of telomeric heterochromatin in Drosophila melanogaster. Using genetic dissection, followed by a chromatin analysis technique known as Chromatin ImmunoPrecipitation (ChIP) I was able to identify three proteins, HDAC1, SU(VAR)3-9, and HP1c, as integral components of telomeric heterochromatin in Drosophila. HDAC1 and SU(VAR)3-9 are both believed to be involved in the gene-silencing process, and thus, their presence at telomeres could explain the phenomenon of TPE. Furthermore, I found that these proteins were specifically associated with the TAS region on the centromere-proximal side of the HeTA transposable elements that maintain telomere length in Drosophila. As a result of this, I proposed a model, which I call the ‘pairing-sliding model of telomere length control in Drosophila,’ which proposes that temporary incorrect pairing of Drosophila telomeres results in the deacetylation and subsequent methylation of the nucleosomes associated with the HeT-A and TART elements by TAS-associated HDAC1 and SU(VAR)3-9, resulting in these elements being transcriptionally silent. Thus, I propose that the TAS region, and the HDAC1 and SU(VAR)3-9 associated with it play a role in the negative regulation of telomere length in Drosophila. / Science, Faculty of / Zoology, Department of / Graduate

A series of experiments were conducted to observe the effect of various environments on the duration of life of wild-type Drosophila melanogaster. Natural duration of life curves were prepared for these insects from 10.5 days of age and it was found that the average life expectancy of the males was greater than that of the females. A 10ˉ⁴ M concentration of the mutagen acridine orange in the medium markedly reduced the average life span of Drosophila males and females. The 10ˉ⁵ M concentration reduced the male life expectancy slightly but had no effect on the females. A method utilizing a separatory funnel type population container was developed to test the effect of a chemical stress on Drosophila populations. Some preliminary experiments were performed in order to evaluate the effect of 10ˉ³ M 2, 4-dinitrophenol, a metabolic inhibitor, combined with various food environments on life duration. The sexes differed in their response to these environments and the relative durations of life of the flies were compatible with a priori considerations. From the results a non-linear relationship is suggested between the time of 50% population death and the rate of death. Starvation death curves were compiled for the Drosophila after they were exposed to various conditions which were thought to be representative of the natural environment. Following exposure to various media conditions, female Drosophila under starvation conditions outlived their male counterparts. The difference between the starvation life expectancies of the females and males tended to become greater after the insects had been kept under optimum conditions, due predominantly to an increase in female life duration. Utilizing a combination of a rapid 'quantitized' heat-shock and starvation conditions it was found that only the male starvation life duration was significantly decreased compared with the unshocked starved controls. The female starvation life duration did not appear to be significantly decreased by the heat-shock. Under starvation conditions wholly female populations had a life duration similar to female populations mixed with an equal number of males. Some explanation is given for the results obtained in this thesis and recommendations for further experiments are made. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate

The sex-linked Notch locus plays an important role in embryogenesis and determination of many adult structures of the fruit fly, Drosophila melanogaster. Mutation at this locus can cause lethality in embryonic or later stages, as well as morphological abnormalities of the adult eyes, wings, bristles and legs. Alleles of the Notch locus can be broadly grouped into three classes: 1) recessive lethal Notch (N) alleles, which may be deficiencies or point mutations, 2) Abruptex (Ax) alleles, which are probably point mutations and may be either lethal or viable, and 3) viable recessive alleles with visible phenotypes, which affect a variety of traits and are point mutations. The present investigation was initiated with a view to understanding the relationships between N and Ax alleles and the nature of their role in development, and has consisted mainly of the following approaches: 1) an examination of the phenotypes of certain unusual N alleles and the phenotypic responses to alteration of the dosage of these alleles in relation to wild-type (N+), 2) an examination of the interaction of Ax alleles with N alleles and with one another, and 3) developmental studies of the conditional (temperature-sensitive) phenotypes associated with certain Notch-locus genotypes. The results of the N-allele dosage study indicate that a single mutation in the Notch locus can affect different functions associated with this locus in fundamentally different ways. Depending on the genotype and phenotype examined, the responses of various N alleles to dosage changes suggest that mutation at the Notch locus may result in reduced, increased or novel activity at the locus. Four ethyl methanesulfonate-induced Ax alleles have been examined, none of which is cytologically abnormal in salivary gland chromosome preparations, and at least three of which map within the Notch locus. Depending on culture conditions and the alleles involved, Ax/N heteroallelic combinations may be viable or lethal. All Ax/N combinations studied exhibited less severe Abruptex phenotypes (bristle loss and wing vein gapping) than the respective Ax/Ax homozygotes. However, the Ax alleles differed from one another in their effects on the wing nicking of the N alleles, in that the viable allele Ax9B2 and the semi- lethal allele AxE1 both suppressed wing nicking, whereas the two viable alleles AxE2 and AX16172 both enhanced wing nicking. Furthermore, heteroallelic combinations of Ax alleles which affected nicking in different direction, were lethal (AxE1/AxE2, AxE1/Ax16172, Ax9B2/Ax16172), whereas combinations of Ax alleles with similar effects on nicking were viable (AxE1/Ax9B2, AxE2/ Ax16172). The temperature-shift experiments have revealed an interesting pattern of temperature-sensitive periods (TSPs) for lethality or adult morphological abnormalities associated with various Notch-locus genotypes. TSPs for lethality may be monophasic occurring in the embryo (N60g11/N6g11;Dp51b7), or the second larval instar (Ax16172/n264-40), or they may be polyphasic, occurring in embryo, larval and pupal stages (N264-103/fano). On the other hand, the TSPs for all the adult morphological abnormalities examined occur during the third larval instar, including rough eyes and wing nicking (N60gll/+,N264-103/spl), leg segment fusion (N264-103/+, N264-103/spl), wing vein gapping (Ax16172/+) and disturbance of bristle numbers (N264-103/spl, Ax16172/+). Several molecular models are discussed in relation to the observations on N-allele dosage and interactions of the Ax and N alleles. The results are consistent with the hypothesis that the Notch locus is a regulator gene influencing many developmental processes, that mutations can affect the activity either of the entire gene or of various parts of the gene individually, and that N and Ax mutations usually affect this regulatory system in opposite ways from one another. / Science, Faculty of / Zoology, Department of / Graduate

Conditional lethal mutants which die under restrictive conditions but are viable in a permissive environment provide useful tools for the genetic and developmental analysis of certain loci. One class of conditional mutants, temperature-sensitive recessive lethals which die at 29°C but survive at 23°C has been reported for an extensive number of loci in Drosophila melanogaster. However, loci may exist which are highly redundant, or concerned with functions requiring the total output of both wild type alleles or with synthesis of a structural component which would pre-exempt their ready detection as recessive mutations. Mutations within such regions could, however, be recovered by selecting temperature-sensitive mutations which behave as dominant lethals at the restrictive temperature. In addition, such mutants would permit the first genetic characterizations of dominant lethals. Ethyl methanesulfonate-induced dominant temperature-sensitive lethal and semi lethal mutations were induced in chromosome 2. Twenty-one lethals of this type were isolated from 6,130 tested chromosomes and sixteen were characterized with respect to their genetic localization and developmental effects. Unexpectedly, eleven of the mutants were found to be closely linked to the dumpy, dp, locus. All eleven were recessive lethals at room temperature and were functionally allelic. The temperature-sensitive period (TSP) was similar for all cluster mutants although the effective lethal phase (LP) at 29°C differed. It was concluded that the cluster lethals are, in fact, genetically allelic. Three other loci were demonstrated by genetic recombination and each had a characteristic TSP and LP. In addition, two mutants caused sterility of females and could not be localized. The recovery of mutations which map genetically within a segment and are dominant lethals, proves that dominant lethality need not reflect gross chromosomal alterations in higher organisms. / Science, Faculty of / Zoology, Department of / Graduate

The antibiotic, Mitomycin-C (MC), increases recombination in Drosophila females, yet has no effect on crossing over in males. This sexual difference in recombinagenic response to MC cannot be attributed to a sex difference in permeability to MC, since MC is mutagenic in both sexes. MC increases the frequency of exchange events involving X and Y chromosomes as well as those involving the two arms of the Y in both sexes. On the basis of brood analysis it was found that those cells which are most sensitive to the recombinagenic and X-Y and Y-Y exchange effects of MC were in a premeiotic stage of gametogenesis at the time of treatment. It is proposed that the apparent inability of MC to induce crossovers in males is related to the normal absence of spontaneous meiotic crossing over in males. MC can act as a monofunctional or as a bifunctional alkylating agent which primarily reacts with guanine residues of DNA. Bifunctional alkylation results in the crosslinking of the two strands in the DNA double helix. It is postulated that prior to meiosis, alkylated guanine residues are excised from the DNA molecule through the action of natural repair mechanisms. Depending on whether mono or bifunctional alkylation has taken place, either single strand nicks or double strand cuts will be induced in the DNA. Double strand cuts may be repaired as a mutation or as a non-reciprocal exchange event whereas single strand nicks might act as the natural pre-condition for genuine meiotic crossovers and could thus form crossovers when the necessary "crossover substances" are present. This model predicts that an alkylating agent such as ethyl methanesulfonate (which alkylates guanine monofunction-ally, and therefore would give rise to single strand nicks following excision), should be recombinagenic in females, but not in males but should not effect the frequency of X-Y and Y-Y exchange events in either sex. This prediction was indeed demonstrated thus supporting the model. / Science, Faculty of / Zoology, Department of / Graduate

Cold-sensitive mutants of E. coli have been valuable in the study of the structure and assembly of bacterial ribosomes. Some cold-sensitive mutations of E. coli have been mapped to loci coding for ribosomal proteins. Other cold-sensitive mutations have been shown to alter the regulatory properties of bacterial enzymes. In contrast, little was known about the genetics and biochemistry of cold-sensitive mutants of Drosophila and other eukaryotes. Also, the genetic loci of ribosomal proteins of D. me1anogaster were unknown although the ribosomal RNA genes have been located on the X and 2nd chromosomes. Therefore the following questions were asked: Can cold-sensitive lethals of the X chromosomes of Drosophila melanogaster be isolated? If so, what are their genetic properties? Do some have altered ribosomal proteins as in cold-sensitive mutants of bacteria? The study was part of a general search for and characterization of cold-sensitive lethals of all the chromosomes of D. melanogaster. Among 3,919 EMS-treated X chromosomes, 25 were retained as cold-sensitive lethals or semi-lethals. That is, more than 20% of the flies carrying a cold-sensitive lethal survived at 22°C and none at 17°C, and for cold-sensitive semi-lethals, > 30% survived at 22°c and <13% at 17°c. The cold-sensitive mutations were not randomly distributed, 7 being located at the X tip and 3 being alleles to the right of car. Over half exhibited female sterility at the permissive temperature and 7 exhibited visible phenotypes characteristic of bobbed and Minute mutations. As the presence of altered ribosomal proteins has been demonstrated in cold-sensitive mutants of bacteria, the ribosomal proteins from Drosophila mutants and controls were studied by 2-dimensional gel electrophoresis. By this method, it was estimated that 69-72 proteins are present in the ribosomes of Drosophila. No qualitative differences were observed in the gel patterns of ribosomal proteins from 5 cold-sensitive, sex-linked mutants and the controls. A summary of the biochemical testing of the ribosomes from other cold-sensitive mutants of Drosophila is also given. No biochemical evidence to support the hypothesis that cold-sensitive mutants of Drosophila have altered ribosomes was obtained. The limitations of the study and recommendations for future research are discussed. / Medicine, Faculty of / Medical Genetics, Department of / Graduate

Orientadora : Maria Luiza Silveira Mello / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-15T07:53:14Z (GMT). No. of bitstreams: 1 Recco-Pimentel_ShirleiMaria_M.pdf: 3650484 bytes, checksum: c7a228c7c7fcf9cd7ecbba91b378c9e5 (MD5) Previous issue date: 1980 / Resumo: Com o objetivo de se efetuar um estudo citoquímico e citofisio1ógico dos dois tipos de heterocromatina descritos por Pavan, em 1946, para Drosophi1a nebulosa (regiões heterocromáticas centroméricasprincipa1mente dos cromosso-mos II e X), os cromossomos mitóticos de gânglios cerebrais e os politênicos de glândulas salivares de larvas de 3º estádio desse díptero, foram submetidos a métodos para a obtenção de bandas C e G e à ação do composto Hoechst 33258 em cultura. Em cromossomos po1itênicos, foram comparados, ainda, os padrões de basofilia e perfis espectrais de Feulgen do cromocentro (hete-rocromatlna centromérica do cromossomo II, especialmente) com relação aos da eucromatina. Os resultados relativos a bandas C, G e após tratamento com o composto Hoechst em cultura não salientaram diferenças de resposta entre a heterocromatina centro-mérica dos cromossomos mitóticos X e II. Da mesma forma se comportou o cromossomo III. As regiões heterocromáticas centroméricas dos autossomos e cromossomo X responderam positivamente a esses métodos, sempre diferindo do comportamento das regiões eucromáticas. Os dados sugerem que o teor de bases AT do DNA não deva ser drasticamente superior ao de CG, nem que ocorram diferentes proteínas, cuja ação pudesse afetar os padrões de bandeado ou alongamento pela atuação do composto Hoechst, na heterocromatina desses cromossomos. O cromossomo Y mitótico salientou diferença em composição dos demais cromossomos, com uma riqueza em AT em ambos os braços, em áreas ligeiramente afastadas do centrô-mero e telômeros, e proteínas supostamente diferentes, quando se comparam os dois braços entre si. As respostas relativamente homogêneas aos mé-todos de bandas C e G e ao tratamento com o composto Hoe-chst em cultura das áreas heterocromáticas de D. nebulosacomparadas às de outras Drosophila parecem estar de acordo com a posição das mesmas na árvore filogenética respectiva, se se considerar padrões mais complexos, encontrados Drosophila filogenêticamente superiores, como caráter nas mais evoluído. Os dados dedesnaturação-renaturaçãoindicaram semelhanças entre a heterocromatina do cromocentro com rel_ ção à eucromatina, em cromossomos politênicos, possivelmen-te devido a alterações qualitativas e quantitativas em ti-pos de DNA e/ou proteínas cromossômicas, quando se passa da condição de cromossomos mitóticos (diplóides) para a de cro mossomos politênicos. Semelhanças entre essas regiões foram também determinadas em termos de caracterIsticas de basofilia e espectros de absorção de Feulgen. Sugere-se semelhança em nú-mero e proximidade de fosfatos livres do DNA e um teor em sequências de DNA repetitivo não sensivelmente diferente, quando se comparam tais regiões entre si / Abstract: The two types of heterochromatin described. For Drosophi1a nebulosa by pavan, in 1946 (heterochromatin of the centromeric regions of the X, Y and III chromosomes that of the 11 chrornosome) were estudied cytochemically and cytophysio1ogically. Mitotic chrorno50mes of neura1 gang1ia and po1ytene chromosomes of sa1ivary glands of third instar larvae were subjected to C- and G- banding procedures and incubated in a medium containing the 33258 Hoechst compound. Patterns of basophilia and Feu1gen spectral absorption curves were al 50 determined for the polytene chrornosomes, the chromocenter region (mostly, heterochrornatin of the 11 chromosome) being compared w1th the euchrornatin. The resu1ts did not enhance differences bet-ween the centromeric heterochromatin of the mitotic chromo-somes X and 11. The centrorneric heterochromatin of the auto-somes and X chromosome respondedpositive1y to C- and G- bandind methods and moderately decondensed after being treated with Hoechst compound, always differing in relation to euchromatic regions. . It is suggested that the AT content should not be strong1y higher than the CG one in these heterochro-matic regions. Differences in proteins,which could possib1y .affect the banding patterns or the decondensation due to the 33258 Hoechst compound, a1so do not appear to exist. When the Y chromosome was compared with the other chromosomes in neura1 ganglia, differences in composi-tion were found. Both arms of the Y chromosome display AT- rich areas slightly shifted from the centromere and telome-res. Different proteins are supposed to be associated to chromatin, when the two chromosome arms are compared to each other. If the complex responses to c- and G- banding and to decondensation with the Hoechst compound, found in phylogenetically high Drosophila species could be considered an evolved character, the relatively homogeneous pattern de- picted by the heterochromatlc areas of the nebulosa would be in agreement with its position in the phylogenetic tree pro-posed for these flies. The denaturation-renaturation data indicate asimilarity between heterochromatin of the chromocenter and the euchromatin, of the polytene chromosomes, possibly due to qualitative and quantitative changes in DNA types and/or chromosome proteins which are supposed to occur when diploid chromosomes turn into polytene chromosomes. These chromosome-regions do not also differ in characteristics of basophilia and Feulgen absorption spectrum. The number and proximity of the DNA free phosphate groups and the quantity of repetitive DNA sequences are sug-gested not to De markedly different, when these regions are compared to each other / Mestrado / Mestre em Biologia

In this study it has been demonstrated that Drosophila immigrans females begin laying fertile eggs on the third or fourth day following eclosion, with productivity reaching a peak between the fifth and sixth days of adult life. A delay in mating of even four days decreases the rate as well as the volume of productivity. Based on the evidence in the literature, it is suggested that the stimulus to oviposition may be mechanical or chemical on the corpora allata via the ventral nerve cord.