An ecomorphological analysis of the determinants of mating success

Investigating the factors affecting the strength of sexual selection is important for understanding the evolution of sex-specific morphological and behavioural traits. Traditionally, sexual selection studies focus on male ornaments, although recent evidence indicates that sexual selection mechanisms also target organismal performance. In the present study, we investigated the role of sexually dimorphic morphological and performance traits of the common (viviparous) lizard (Zootoca vivipara, Jacquin 1787) with respect to determining mating behaviour. Using an experimental set-up controlling for size differences, we found that males with longer tails had a higher probability of mating a female. Unexpectedly, males with lower bite forces had an advantage over males with higher bite forces, whereas males with bigger heads copulated for a longer time with the female. This shows that predicting mating success is not straightforward and is sometimes counterintuitive because a longer tail appears to be beneficial, whereas biting harder is not, for male Z. vivipara in a male-female interaction context

Permanent demand excess as business strategy: an analysis of the Brazilian higher-education market

Many Higher Education Institutions (HEIs) establish tuition below the equilibrium price to generate permanent demand excess. This paper first adapts Becker’s (1991) theory to understand why the HEIs price in this way. The fact that students are both consumers and inputs on the education production process gives rise to a market equilibrium where some firms have excess demand and charge high prices, and others charge low prices and have empty seats.Second, the paper analyzes this equilibrium empirically. We estimated the demand for undergraduate courses in Business Administration in the State of São Paulo. The results show that tuition, quality of incoming students and percentage of lecturers holding doctorates degrees are the determining factors of students’ choice. Since the student quality determines the demand for a HEI, it is calculated what the value is for a HEI to get better students; that is the total revenue that each HEI gives up to guarantee excess demand. Regarding the “investment” in selectivity, 39 HEIs in São Paulo give up a combined R$ 5 million (or US$ 3.14 million) in revenue per year per freshman class, which means 7.6% of the revenue coming from a freshman class.

Division of labour and worker size polymorphism in ant colonies: the impact of social and genetic factors

Division of labour among workers is central to the organisation and ecological success of insect societies. If there is a genetic component to worker size, morphology or task preference, an increase in colony genetic diversity arising from the presence of multiple breeders per colony might improve division of labour. We studied the genetic basis of worker size and task preference in Formica selysi, an ant species that shows natural variation in the number of mates per queen and the number of queens per colony. Worker size had a heritable component in colonies headed by a doubly mated queen (h(2)=0.26) and differed significantly among matrilines in multiple-queen colonies. However, higher levels of genetic diversity did not result in more polymorphic workers across single- or multiple-queen colonies. In addition, workers from multiple-queen colonies were consistently smaller and less polymorphic than workers from single-queen colonies. The relationship between task, body size and genetic lineage appeared to be complex. Foragers were significantly larger than brood-tenders, which may provide energetic or ergonomic advantages to the colony. Task specialisation was also often associated with genetic lineage. However, genetic lineage and body size were often correlated with task independently of each other, suggesting that the allocation of workers to tasks is modulated by multiple factors. Overall, these results indicate that an increase in colony genetic diversity does not increase worker size polymorphism but might improve colony homeostasis.

Business Exits entail greater future levels of entrepreneurship? An empirical analysis at country level

Using Global Entrepreneurship Monitor data for 41 countries this study investigates the impact of business exit on entrepreneurial activity at the country level. The paper distinguishes between two types of entrepreneurial activity according with the motive to start a new business: entrepreneurs driven by opportunity and necessity motives. The findings indicate that exits have a positive impact on future levels of entrepreneurial activity in a country. For each exit in a given year, a larger proportion of entrepreneurial activity the following year. Moreover, this e ffect turns out to be higher for opportunity entrepreneurs. The findings indicate that both types of entrepreneurial activity rates are influenced by the same factors and in the same direction. However, for some factors we find a di fferential impact on the entrepreneurship. The results show some important implications given that business exit may be overcome when there is a necessity motivation. This has important implications for both researchers and policy makers. JEL codes: L26. Keywords: Entrepreneurship, business exit, social values

Iniciativa emprenedora i immigració: característiques diferenciadores i factors d'èxit

 L’emprenedoria és una de les àrees de recerca que han tingut un major creixement en les dècades recents. En aquest camp, l’anàlisi del comportament dels emprenedors immigrants ha estat reconeguda com un dels temes amb un important increment d’estudis relacionats. En aquests moments, el fenomen de la immigració és un dels processos socials més importants i amb una major repercussió en el continent europeu, i el fet que hi hagi més iniciatives emprenedores liderades per immigrants que per nadius fa que l’anàlisi i l’exploració d’aquest tema tinguin un atractiu especial. Malgrat tot, i encara que en els darrers anys el nombre d’estudis que pretenen donar una explicació a aquest fenomen ha incrementat, la majoria dels estudis l’han analitzat des d’un punt de vista qualitatiu i centrant-se en situacions regionals específiques i grups concrets, sense que se n’hagin pogut extreure conclusions generals sobre el comportament emprenedor immigrant. De manera que uns dels aspectes clau que un estudi en profunditat requereix són ressaltar aquells factors que contribueixen a distingir el comportament emprenedor immigrant del nadiu, així com aquells factors que podrien motivar l’èxit o el fracàs d’aquest tipus d’iniciatives i com aquests factors condicionarien la resta del teixit empresarial. En aquest context, el principal objectiu d’aquest projecte consisteix en l’anàlisi de les característiques distintives del procés emprenedor dels immigrants. Es pretén abordar aquest objectiu desenvolupant diferents metodologies i combinant diferents fonts d’informació que permetin captar la situació i assolir una comprensió més rica del fenomen estudiat. Els principals resultats obtinguts ens han portat a entendre aspectes que afavoreixen l’emprenedoria immigrant, tals com una menor aversió al risc i un major control percebut. A més, s’han posat de manifest algunes barreres legals amb les que s’han d’enfrontar els emprenedors immigrants a Catalunya.

The Rapid Rise of China’s Dairy Sector: Factors Behind the Growth in Demand and Supply, May 2005

With the rapid growth in China’s dairy industry, a number of recent papers have addressed either the supply or the demand trends for dairy products in China. None, however, presents a systematic explanation for the recent growth in both the supply and demand for dairy products. The goal of this paper is to sketch a more comprehensive picture of China’s dairy sector and to assess the nature of the sector’s development in the coming decades. Drawing upon several empirical studies, we examine the trends in dairy product consumption to create a composite picture of the factors underlying the recent growth. We also empirically investigate the sources of production gains in milk supply and assess the relative importance of expanding herd size, changes in the nature of production, technological change, and improvements in efficiency to the overall growth of milk production.

Competències i factors clau per a l’èxit educatiu des de la perspectiva dels estudiants universitaris fills/es dels immigrants

L’estudi realitzat ha abordat quines són les competències i els factors clau que estudiants universitaris d’origen immigrant consideren que han estat claus per arribar a la universitat, assolint així l’èxit educatiu. S’han escollit estudiants que haguessin fet l’escolaritat obligatòria total o parcialment a Catalunya.Per dur a terme la recerca s’ha treballat amb relats de vida (un total de 13 escrits) i narracions audiovisuals (amb un total de 4 produccions), essent finalment 17 les evidències vàlides. Finalment, s’ha elaborat, administrat i processat un qüestionari d’opinió que s’ha remès a 2472 estudiants de la Universitat de Barcelona, dels quals hem aconseguit 128 respostes considerades vàlides. Els relats s’han analitzat amb un procediment inductiu, procedint a una lectura exhaustiva de les paraules dels participants i anant identificant quines són les competències i els factors clau que ells consideraven que els havien ajudat a arribar a la universitat o que, tot i no ser ells conscients, nosaltres identificàvem com a tals. Pel que fa a les narracions audiovisuals, es va dur a terme una anàlisi tant del contingut, tenint com a referència els resultats obtinguts als relats escrits, com d’aspectes més tècnics, centrats en la imatge i el so. Per acabar, els qüestionaris s’han analitzat a partir de processos bàsics d’estadística descriptiva. Pel que fa als resultats obtinguts, respecte a l’eix de competències, la més destacada és la d’autonomia i iniciativa personals, lligada a la responsabilitat i autoexigència. Respecte a l’eix d’èxit educatiu, destaca el paper del professorat, tant pel suport que els ofereixen com per les expectatives que dipositen en ells. I, per acabar, respecte a l’eix d’inclusió social, els aspectes que l’afavoreixen es centren sobretot en el recolzament de la família, en l’entorn més immediat i en el fet d’entendre la possibilitat de viure amb altres cultures com un enriquiment.

O empreendedorismo. O perfil do empreendedor da Ilha de Santiago Cabo Verde

Este trabalho apresenta um estudo qualitativo, desenvolvido através de pesquisa exploratória, bibliográfica e de campo, feito a trezentos e noventa e nove empreendedores e empresários da Ilha de Santiago, tendo em consideração o cenário económico actual e a preocupação à volta do sector privado. Procurou-se através de pesquisa junto às empresas activas, e cujo número de pessoas ao seu serviço não ultrapassa vinte, identificar três pontos fundamentais relacionados com os empreendedores: investigar os factores que levaram as pessoas a tornarem-se empreendedores; investigar as características principais do empreendedor de sucesso; identificar as características imprescindíveis para se atingir o sucesso empresarial relacionadas com o conhecimento, competências, atitude e talento, sequenciadas por ordem de importância. Para um melhor entendimento destas questões foi utilizado um referencial teórico que aborda o empreendedorismo. A pesquisa de campo foi realizada através de utilização de questionários – entrevistas às empresas estabelecidas nesta ilha, e o método de recolha de dados foi o de entrevista directa. Os resultados obtidos mostraram que os empreendedores enfatizam a importância dos factores comportamentais no sucesso das pequenas e médias empresas e evidenciaram que os factores mais significativos e limitativos do sucesso dos empreendedores no Município da Praia, ilha de Santiago, se referem ao ambiente interno do negócio. Considerando todos estes factores e de acordo com as pesquisas desenvolvidas e analisadas, este trabalho recolheu informações específicas dos empreendedores de sucesso da ilha de Santiago e que podem ser úteis para os que almejam o sucesso empresarial e para eventuais programas de capacitação e formação empreendedora na ilha. This work presents a qualitative study developed through exploratory, bibliographic and field research to three hundred and ninety nine managers and entrepreneurs from Santiago Island, taking into consideration the present economical scenario and main concerns linked to private sector. Through a research in active enterprises and whose staff number doesn’t exceed twenty, the goal was to identify three main issues related to entrepreneurs: look into the factors that encouraged people to become entrepreneurs; examine the main characteristics of a successful entrepreneur and identify, sequenced by order of importance, the most critical characteristics related to knowledge, skills, attitude and talent, that allow entrepreneurial success achievement. For a better understanding of these questions, a theoretical approach to entrepreneurship was exploited. Field research was carried on through the use of questionnaires in enterprises located in Praia, and the data collection method was direct interviews. Results obtained showed that entrepreneurs emphasize the importance of behavioral factors in the success of small and medium enterprises and they evidenced that the most significant and restrictive factors of entrepreneurs’ success in Santiago Island are related to internal business environment. Considering these factors, and according to research developed and analyzed, the work has collected specific information of successful entrepreneurs in Santiago that can be useful for those, in the island, who seek entrepreneurial success and for eventual capacity building and entrepreneurial training programs.

O empreendedorismo. O perfil do empreendedor da Ilha de Santiago Cabo Verde

Este trabalho apresenta um estudo qualitativo, desenvolvido através de pesquisa exploratória, bibliográfica e de campo, feito a trezentos e noventa e nove empreendedores e empresários da Ilha de Santiago, tendo em consideração o cenário económico actual e a preocupação à volta do sector privado. Procurou-se através de pesquisa junto às empresas activas, e cujo número de pessoas ao seu serviço não ultrapassa vinte, identificar três pontos fundamentais relacionados com os empreendedores: investigar os factores que levaram as pessoas a tornarem-se empreendedores; investigar as características principais do empreendedor de sucesso; identificar as características imprescindíveis para se atingir o sucesso empresarial relacionadas com o conhecimento, competências, atitude e talento, sequenciadas por ordem de importância. Para um melhor entendimento destas questões foi utilizado um referencial teórico que aborda o empreendedorismo. A pesquisa de campo foi realizada através de utilização de questionários – entrevistas às empresas estabelecidas nesta ilha, e o método de recolha de dados foi o de entrevista directa. Os resultados obtidos mostraram que os empreendedores enfatizam a importância dos factores comportamentais no sucesso das pequenas e médias empresas e evidenciaram que os factores mais significativos e limitativos do sucesso dos empreendedores no Município da Praia, ilha de Santiago, se referem ao ambiente interno do negócio. Considerando todos estes factores e de acordo com as pesquisas desenvolvidas e analisadas, este trabalho recolheu informações específicas dos empreendedores de sucesso da ilha de Santiago e que podem ser úteis para os que almejam o sucesso empresarial e para eventuais programas de capacitação e formação empreendedora na ilha. This work presents a qualitative study developed through exploratory, bibliographic and field research to three hundred and ninety nine managers and entrepreneurs from Santiago Island, taking into consideration the present economical scenario and main concerns linked to private sector. Through a research in active enterprises and whose staff number doesn’t exceed twenty, the goal was to identify three main issues related to entrepreneurs: look into the factors that encouraged people to become entrepreneurs; examine the main characteristics of a successful entrepreneur and identify, sequenced by order of importance, the most critical characteristics related to knowledge, skills, attitude and talent, that allow entrepreneurial success achievement. For a better understanding of these questions, a theoretical approach to entrepreneurship was exploited. Field research was carried on through the use of questionnaires in enterprises located in Praia, and the data collection method was direct interviews. Results obtained showed that entrepreneurs emphasize the importance of behavioral factors in the success of small and medium enterprises and they evidenced that the most significant and restrictive factors of entrepreneurs’ success in Santiago Island are related to internal business environment. Considering these factors, and according to research developed and analyzed, the work has collected specific information of successful entrepreneurs in Santiago that can be useful for those, in the island, who seek entrepreneurial success and for eventual capacity building and entrepreneurial training programs.

Lake Darling: A Snapshot of Success, 2006

Before improvements were made, a number of factors were hurting the water quality in Lake Darling and driving people toward other lakes.

Pharmacokinetic and pharmacogenetic factors influencing plasma and cellular antiretroviral drug disposition

Abstract: The improvement in antiretroviral drug therapy has transformed HIV infection into a chronic disease. However, treatment failure and drug toxicity are frequent. Inadequate response to treatment is clearly multifactorial and, therefore, dosage individualisation based on demographic factors, genetic markers and measurement of cellular and plasma drug level may enhance both drug efficacy and tolerability. At present, antiretroviral drugs levels are monitored in plasma, whereas only drugs penetrating into cells are able to exert an antiviral activity, suggesting that cellular drug determination may more confidently reflect drug exposure at the site of pharmacological action. The overall objective of this thesis is to provide a better understanding of the Pharmacokinetic and pharmacogenetic factors influencing the plasma and cellular disposition of antiretroviral drugs. To that endeavour, analytical methods for the measurements of plasma and cellular drug levels have been developed and validated using liquid chromatography methods coupled with ultraviolet and tandem mass spectrometry detection, respectively. Correlations between plasma and cellular exposures were assessed during observational and experimental studies. Cytochrome (CYP) 2B6, efflux transporters (ABCB1, ABCC1, ABCC2 and ABCG2) and orosomucoid (ORM) polymorphisms were determined and were related to plasma and cellular exposures, as well as toxicity of antiretroviral drugs. A Pharmacokinetic population model was developed to characterise inter- and intra-patient variability of atazanavir pharmacokinetics, and to identify covariates influencing drug disposition. In that context, a Pharmacokinetic interaction study between atazanavir and lopinavir, both boosted with ritonavir, has beén conducted to assess the safety and pharmacokinetics of this boosted double-protease inhibitors regimen. Well to moderately-correlated cellular and plasma drug levels are .observed or protease inhibitors, whereas for efavirenz and nevirapine these correlations are weak. Cellular exposure, and CYP2B6 genotype (516G>T) are predictors of efavirenz neuropsychological toxicity. Nevirapine plasma exposure is also influenced by CYPZB6 polymorphism. Nelfinavir cellular exposure appears to be significantly associated only with ABCB1 genotype (3435C>T and intron 26 + 80T>C). Indinavir and lopinavir clearance and lopinavir cellular/plasma exposure ratio are influenced by the concentration of the variant S of ORM, suggesting-a specific binding of these drugs to this variant. Nelfinavir and efavirenz are not influenced by ORM concentration and phenotype. The Pharmacokinetic parameters of atazanavir are adequately described by our population model. The atazanavir-lopinavir interaction study indicates no influence on plasma and cellular atazanavir pharmacokinetics, while limited decrease in lopinavir concentrations was observed after atazanavir addition. The residual variability unexplained by the considered variables suggests that other covariates either uncontrolled at present or remaining to be identified, such as genetic and environmental factors influence antiretroviral drug pharmacokinetics, with substantial impact on treatment efficacy and tolerability. In that context, a comprehensive approach taking into account drug pharmacokinetics and patient genetic background is expected to contribute to increase treatment success, and to reduce the occurrence of adverse drug reactions by stratifying patients in an individualised antiretroviral therapy approach. Résumé Facteurs pharmacocinétiques et pharmacogénétiques influençant l'exposition plasmatique et cellulaire des antirétroviraux Les progrès de la thérapie antirétrovirale ont transformé l'infection par le VIH d'une affection mortelle à une maladie chronique. En dépit de ce succès, l'échec thérapeutique et la toxicité médicamenteuse restent fréquents. Une réponse inadéquate au traitement est clairement multifactorielle et une individualisation de la posologie des médicaments qui se baserait sur les facteurs démographiques et génétiques des patients et sur les taux sanguins des médicaments pourrait améliorer à la fois l'efficacité et la tolérance de la thérapie. Par ailleurs, seules les concentrations plasmatiques sont actuellement considérées pour le suivi thérapeutique des médicaments, alors que les taux cellulaires pourraient mieux refléter l'activité de ses médicaments qui agissent au niveau intracellulaire. L'objectif global de cette thèse était de mieux comprendre les facteurs pharmacocinétiques et pharmacocénétiques influençant l'exposition plasmatique et cellulaire des médicaments antirétroviraux. A cet effet, des méthodes pour quantifier les concentrations plasmatiques et cellulaires des antirétroviraux ont été développées et validées en utilisant la chromatographie liquide couplée à la détection ultraviolette et la spectrométrie de masse en tandem, respectivement. La corrélation entre l'exposition cellulaire et plasmatique de ces médicaments a été étudiée lors d'études observationnelles et expérimentales. Les polymorphismes du cytochrome (CYP) 2B6, ainsi que des transporteurs d'efflux (ABCB1, ABCC1, ABCC2 et ABCG2) et de l'orosomucoïde (ORM) ont été déterminés et corrélés avec l'exposition plasmatique et cellulaire des antirétroviraux, ainsi qu'à leur toxicité. Un modèle de pharmacocinétique de population a été établi afin de caractériser la variabilité inter- et intra-individuelle de l'atazanavir, et d'identifier les covariables pouvant influencer le devenir de ce médicament. Dans ce contexte, une étude d'interaction entre l'atazanavir et le lopinavir a été effectuée afin de déterminer la sécurité et le profil pharmacocinétique de ce régime thérapeutique. Des corrélations modérées à bonnes ont été observées entre les taux cellulaires et plasmatiques des inhibiteurs de protéase, alors que pour l'efavirenz et la névirapine ces corrélations sont faibles. L'exposition cellulaire, ainsi que le génotype du CYP2B6 (516G>T) sont des indices de la toxicité neuropsychologique de l'efavirenz. L'exposition plasmatique de la névirapine est également influencée par le polymorphisme du CYPZB6. L'exposition cellulaire du nelfinavir est significativement associée au génotype du ABCB1 (3435C>T et intron 26 + 80T>C). La clairance de l'indinavir et du lopinavir, ainsi que le rapport entre exposition cellulaire et plasmatique du lopinavir sont influencés par la concentration du variant S de l'ORM, suggérant une liaison spécifique de ces médicaments à ce variant. La clairance du nelfinavir et de l'efavirenz n'est pas influencée ni par la concentration ni par le phénotype de l'ORM. Les paramètres pharmacocinétiques de l'atazanavir ont été décrits de façon adéquate par le modèle de population proposé. De plus, le lopinavir n'influence pas les concentrations plasmatiques et cellulaires de l'atazanavir; alors que celui-ci conduit à une baisse limitée des taux de lopinavir. L'importante variabilité pharmacocinétique des antirétroviraux suggère que d'autres facteurs génétiques et environnementaux -qui restent encore à découvrir- influencent également leur disponibilité. Dans un proche futur, une prise en charge qui tienne. compte de la pharmacocinétique des médicaments et des caractéristiques génétiques du patient devrait permettre d'individualiser le traitement, contribuant certainement à une amélioration de la réponse thérapeutique et à une diminution de la toxicité. Résumé grand public Facteurs pharmacocinétiques et pharmacogénétiques influençant l'exposition plasmatique et cellulaire des antirétroviraux Les progrès effectués dans le traitement de l'infection par le virus de l'immunodéficience humaine acquise (VIH), ont permis de transformer une maladie avec un pronostic sombre, en une maladie chronique traitable avec des médicaments de plus en plus efficaces. Malgré ce succès, de nombreux patients ne répondent pas de façon optimale à leur traitement et/ou souffrent d'effets indésirables médicamenteux entraînant fréquemment une modification de leur thérapie. Actuellement, le suivi de la réponse au traitement s'effectue par la mesure chez les patients de la quantité de virus et du nombre des cellules immunitaires dans le sang, ainsi que par la concentration sanguine des médicaments administrés. Cependant, comme le virus se réplique à l'intérieur de la cellule, la mesure des concentrations médicamenteuses au niveau intracellulaire pourrait mieux refléter l'activité pharmacologique au site d'action. De plus, il a été possible de mettre en évidence la grande variabilité des concentrations plasmatiques de médicaments chez des patients prenant pourtant la même dose de médicament. Comme cette variabilité est notamment due à des facteurs génétiques qui sont susceptibles d'influencer la réponse au traitement antirétroviral, des analyses génétiques ont été également effectuées chez ces patients. Cette thèse a eu pour objectif de mieux comprendre les facteurs pharmacologiques et génétiques influençant l'activité et la toxicité des médicaments antirétroviraux afin de réduire la variabilité de la réponse thérapeutique. A cet effet, une méthode de dosage permettant la quantification des médicaments anti-HIV au niveau intracellulaire a été développée. Par ailleurs, nos études ont également porté .sur les variations génétiques influençant la quantité et l'activité des protéines impliquées dans le métabolisme et dans le transport des médicaments antirétroviraux. Enfin, les conséquences de ces variations sur la réponse clinique et la toxicité du traitement ont été évaluées. Nos études ont mis en évidence des associations significatives entre les variations génétiques considérées et la concentration sanguine, cellulaire et la toxicité de quelques médicaments antirétroviraux. La complémentarité des connaissances pharmacologiques, génétiques et virales pourrait aboutir à une stratégie globale permettant d'individualiser le traitement et la dose administrée, en fonction des caractéristiques propres de chaque patient. Cette approche pourrait contribuer à une optimisation du traitement antirétroviral dans la perspective d'une meilleure- efficacité thérapeutique à long terme et d'une diminution des effets indésirables rencontrés.

The Swiss Business Elite (1980-2000): How the Changing Composition of the Elite Explains the Decline of the Swiss Company Network

In this paper we analyse the decline of the Swiss corporate network between 1980 and 2000. We address the theoretical and methodological challenge of this transformation by the use of a combination of network analysis and multiple correspondence analysis (MCA). Based on a sample of top managers of the 110 largest Swiss companies in 1980 and 2000 we show that, beyond an adjustment to structural pressure, an explanation of the decline of the network has to include the strategies of the fractions of the business elites. We reveal that three factors contribute crucially to the decline of the Swiss corporate network: the managerialization of industrial leaders, the marginalization of law degree holders and the influx of hardly connected foreign managers.

High-growth cooperatives: Financial profile and key factors for competitiveness

Given the current economic environment, high-growth companies are particularly relevant for their contribution to employment generation and wealth.This paper discusses the results of a survey that was conducted in order to gain a deeper understanding of high-growth cooperatives through analyzing their financial profiles and then identifying key contributing factors to their growth. To do this, we compared this particular sample with other cooperatives and other high-growth mercantile companies.The results show the main drivers related to high-growth companies success. They are the competitive advantages based on the surveyed group, modern management techniques, quality and productivity, innovation and internationalization. Additionally, we have observed some financial strengths and weaknesses. In this sense, they are under capitalized companies with an unbalanced growth.

Gazelle companies: Growth drivers and an evolution analysis

Gazelle companies are relevant because they generate much more employment than other companies and deliver high returns to their shareholders. This paper analyzes their behavior in the years of high growth and their evolution in the following years. The main factors that explain their success are competitive advantages based on human resources, innovation, internationalization, the excellence in processes and a conservative financial policy. Nevertheless, as time goes by they can be divided in two groups: a group which continues having growth, but most of them with lower growth rates; and the rest which face great problems or even disappear. The present study identifies several key factors that explain this different evolution.

Age and multiple mating effects on reproductive success of Grapholita molesta (Busck) (Lepidoptera, Tortricidae)

The reproductive success of the oriental peach moth was evaluated in four experiments: 1) assessment of the mating duration, fecundity, fertility and longevity of females paired with virgin and immediately mated males; 2) mating duration, spermatophore size, fecundity, fertility and longevity in females paired with virgin and up to four times mated males; 3) receptivity of females to additional copulations after mating with virgin or mated males, and the effects of this behavior in female fecundity, fertility and longevity; 4) influence of insects age in the reproductive output. Males (33%) could copulate immediately after a previous copula. They were fertile until the fourth mating, but only in the first copula they transferred the longest (1.43 ± 0.10 mm) and widest (0.83 ± 0.11 mm) spermatophore, presenting the fastest mating duration (34.8 ± 2.62 min). A high proportion of females copulated by non-virgin males (84%) was receptive to other copulas, in comparison to those copulated by virgin males (32.4%). However, the fecundity, fertility, and longevity were similar among females that copulate once or more. The age was the most important factor affecting reproductive variables, where one and three day old insects had a significant higher fecundity, fertility and presented a shorter mating duration in comparison with older individuals. Results pointed out that the reproductive capacity of Grapholita molesta changes a little with respect to the analyzed factors, highlighting the elevated biotic potential of the species.