Submitted by Nathália Faria da Silva (nathaliafsilva.ufv@gmail.com) on 2017-07-28T14:21:26Z No. of bitstreams: 1 texto completo.PDF: 359561 bytes, checksum: e76fd23ea8e153e98766f8431f0a7c31 (MD5) / Made available in DSpace on 2017-07-28T14:21:26Z (GMT). No. of bitstreams: 1 texto completo.PDF: 359561 bytes, checksum: e76fd23ea8e153e98766f8431f0a7c31 (MD5) Previous issue date: 2001-08-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Com o objetivo de avaliar os efeitos de obstáculos naturais na estruturação de populações em espécies de peixes de pequeno porte, foram analisados os padrões de semelhança molecular (marcadores do tipo RAPD- PCR) e morfológica (caracteres morfométricos e merísticos) em cinco amostras (cada uma de N=50) isoladas por cachoeiras ou barragens da espécie Astyanax bimaculatus (lambari-de-rabo-amarelo, tambiú), em dois afluentes do rio Doce, Minas Gerais (rios Casca e Matipó). Uma amostra adicional em outro afluente do rio Doce (rio Santo Antônio) foi realizada como controle para estimar os parâmetros de divergência genética na bacia. O padrão de variação de 28 loci permitiu caracterizar uma perda de alelos (25% dos loci) no rio Casca e conseqüente diminuição da variabilidade intrapopulacional (menor índice de heterozigosidade e porcentagem de loci polimórficos) em relação aos outros afluentes. No nível interpopulacional foi observado uma diferenciação genética significativa entre todos os três afluentes do rio Doce analisados (p<0,00001), com 21% da variância total obtida na AMOVA observada entre esses três afluentes (p<0,01806). Apenas uma das barreiras geográficas analisadas (localizada no rio Casca) foi efetiva populações à jusante e à montante (p<0,0016). na diferenciação das No rio Matipó, as populações localizadas à jusante e à montante da barragem são geneticamente similares (p<0,6469), e subsidiam a recomendação de adoção de mecanismos de transposição naquele empreendimento, para permitir a continuidade de fluxo gênico. No rio Casca, o padrão de variação de dois caracteres merísticos corroboraram os resultados das análises moleculares. Contudo, a Análise Discriminante Independente do Tamanho realizada com os 15 caracteres morfométricos não foi capaz de diferenciar claramente as populações, o que sugere a presença de apenas uma espécie do complexo A. bimaculatus na bacia do rio Doce. Com base nos dados, pode-se concluir que a diferenciação genética e morfológica de A. bimaculatus do rio Doce não está necessariamente associada à presença de cachoeiras, e que depende de fatores demográficos e/ou históricos dos obstáculos geográficos. / To evaluate the effects of natural barriers in the process of population structure of small-sized species, it was carried out analyses on molecular similarity (with RAPD-PCR markers) and morphologic patterns (morphometric and meristic characters) in five samples (each 2n=50) isolated by waterfalls and dams Astyanax of bimaculatus (lambari-de-rabo-amarelo, tambiú) in two tributaries of the rio Doce basin, State of Minas Gerais (rio Casca and rio Matipó). An additional sample from Santo Antonio was added to the analysis for a broader overview of genetic divergence in the basin. The rio Casca was characterized by 25% loss of alleles (out of 28 loci), with decrease of within population levels of variation (lower heterozigosity polymorphic loci) relative to the other samples. index proportion of Genetic differentiation among tributaries was significative (p<0,00001) and represented 21% of total variance (p<0,01806). We concluded that only one of the analyzed barriers (in rio Casca) was an effective factor for the differentiation of populations (p<0,0016). In rio Matipó, the populations were genetically similar (p<0,6469) suggested the need for maintenance of high levels of gene flow. and In rio Casca, the patterns of variation of meristic characters was consistent with molecular data. As a whole, however, the size-independent discriminant analysis based on 15 morphometric characters did not differentiate the populations, showing the existence of only one species of the A. bimaculatus species complex in the rio Doce basin. The pattern of variation of data suggested that the genetic and morphologic variation of A. bimaculatus in the rio Doce basin was not necessarily associated to waterfalls and that they instead result as an interaction of demographic and historic factors associated to geographic obstacles.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2018-03-28T11:50:50Z No. of bitstreams: 1 texto completo.pdf: 984989 bytes, checksum: ba36d6145762101ded33bc8964abbe9a (MD5) / Made available in DSpace on 2018-03-28T11:50:50Z (GMT). No. of bitstreams: 1 texto completo.pdf: 984989 bytes, checksum: ba36d6145762101ded33bc8964abbe9a (MD5) Previous issue date: 2017-03-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A utilização de águas públicas para a criação de peixes pode resultar em menor desempenho produtivo quando estas águas estão poluídas por compostos tóxicos, como o arsênio. A toxicidade do arsênio ocorre principalmente pela geração de espécies reativas de oxigênio. A contaminação pelo arsênio pode acumular nos tecidos e prejudicar a saúde dos seres humanos que consomem estes peixes. Dessa forma, são necessárias técnicas para reduzir a acumulação e a toxidade do arsênio em peixes. Uma possibilidade de redução/prevenção destes danos é a utilização de aditivos nas dietas, como o orégano, em função de sua alta capacidade antioxidante. Com o presente estudo objetivamos avaliar o potencial do óleo de orégano como atenuador dos danos causados pela exposição ao arsênio em Astyanax aff. bimaculatus. Após 30 dias de alimentação com dietas contendo óleo de orégano (0,0; 1,5 e 2,5 g/kg de óleo de orégano), os peixes foram expostos a uma solução de arsenato de sódio (Na 2 HAsO 4 .7H 2 O) na concentração de 5,0 mg/L de arsênio durante sete dias. Previamente foi realizado um pré- experimento que mostrou que o uso de óleo de orégano em dietas para A. aff bimaculatus é seguro e que o mesmo é capaz de neutralizar espécies reativas de nitrogênio. O experimento foi conduzido em delineamento inteiramente casualisado com três níveis de óleo de orégano na dieta (0,0; 1,5 e 2,5 g/kg de óleo de orégano) e quatro repetições. Fêmeas adultas de A. aff. bimaculatus (6,42 g ± 0,89) foram alimentadas três vezes ao dia durante 30 dias com as dietas experimentais. Ao final desse período, os peixes foram eutanasiados para coleta de amostras. Foram avaliadas as concentrações das enzimas aspartato aminotransferase (AST) e alanina aminotransferase (ALT) no plasma e alterações histopatológicas e estresse oxidativo nas brânquias e no fígado. Nos peixes expostos ao arsênio não foi observada mortalidade em nenhum dos tratamentos avaliados. A atividade da enzima SOD nas brânquias dos peixes alimentados com óleo de orégano (1,5 e 2,5 g/kg) foi maior que no grupo controle, indicando que o orégano tem efeito protetor contra o estresse oxidativo. Nas brânquias dos peixes alimentados com óleo de orégano foi observada maior frequência de hipertrofia de células mucosas (1,5 e 2,5 g/kg) e de necrose (2,5 g/kg) em relação ao tratamento controle. A atividade da enzima ALT no plasma foi maior nos peixes alimentados com 2,5 g/kg de óleo de orégano, indicando dano hepático. Apesar de o orégano apresentar efeito redutor do estresse oxidativo em brânquias, tanto na presença como na ausência de arsênio, não é recomendado seu uso como atenuador dos danos causados pelo arsênio em A. aff bimaculatus devido este causar danos hepáticos e necrose branquial de forma dose dependente. Danos hepáticos e branquiais causados pelo orégano (2,5 g/kg), apenas na presença de arsênio indicam efeito sinérgico entre eles. / The use of public waters for fish farming may result in lower productive performance when these waters are polluted by toxic compounds such as arsenic. The toxicity of arsenic occurs mainly by the generation of reactive oxygen species. Arsenic contamination can accumulate in tissues and harm the health of humans who consume these fish. Thus, techniques are needed to reduce the accumulation and toxicity of arsenic in fish. One possibility of reduction/prevention of damages is the use of additives in diets, such as oregano, due to its high antioxidant capacity. With the present study we aimed to evaluate the potential of oregano oil as an attenuator of the damages caused by exposure to arsenic in Astyanax aff. bimaculatus. After 30 days of feeding with the diets with oregano oil (0.0, 1.5 and 2.5 g / kg of oregano oil), fish were exposed to a solution of sodium arsenate (Na 2 HAsO 4 .7H 2 O) in the concentration 5.0 mg/L arsenic for seven days. A preliminary experiment was carried out which showed that the use of oregano oil in diets for A. aff bimaculatus is safe and that it is capable of neutralizing reactive nitrogen species. The experiment was conducted in a completely randomized design with three levels of dietary oregano oil (0.0, 1.5 and 2.5 g/kg of oregano oil) and four replicates. Adult females of A. aff. bimaculatus (6.42 g ± 0.89) were fed three times a day for 30 days with the experimental diets. At the end of this period fish were euthanized for sample collection. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes and histopathological and oxidative stress in gills and liver were evaluated. In fish exposed to arsenic, no mortality was observed in any of the evaluated treatments. Activity of SOD enzyme in the gills of fish fed with oregano oil (1.5 and 2.5 g/kg) was higher than control group, indicating that the oregano has protective effect against oxidative stress. In the fish gills fed oregano oil, a higher frequency of mucous cells hypertrophy (1.5 and 2.5 g/kg) and necrosis (2.5 g/kg) was observed in relation to control treatment. Plasma ALT activity was higher in fish fed with 2.5 g/kg of oregano oil, indicating liver damage. Although oregano has a reducing effect on oxidative stress in gills, both in the presence and absence of arsenic, its use as an attenuator of arsenic damage in A. aff bimaculatus is not recommended because it causes liver damage and gill necrosis in a dosage form dependent. Liver and gill damage caused by oregano (2.5 g/kg), only in the presence of arsenic indicate a synergistic effect between them.

Animal personality can be defined as a set of physiological and behavioral characteristics that differ between individuals, but are consistent over time and across situations. The evolution of individual differences in behavior that are consistent over time and situations is still not clear. Our understanding of why animals have personality can be improved by investigating the underlying physiological mechanisms of animal behavior. Serotonin is a key monoamine that serves as a physiological modulator of animal behavior. Selective serotonin reuptake inhibitors are a group of chemicals that increase levels of serotonin in the brain. Fluoxetine is one such chemical and is used to treat depression in humans. In the field cricket (Gryllus bimaculatus), increased levels of serotonin have been linked to higher activity and boldness, which are both personality traits. In the current study, the effects of induced serotonin on activity, exploration, boldness and aggression was investigated. My results show that injecting fluoxetine causes substantial changes in behavioral traits used to describe personality in field crickets. This result is opposite to previous studies, as serotonin induced individuals were less active, less explorative, and won less fights, compared to control individuals. This could be due to serotonin existing naturally within the circulatory system of the field cricket, whereas fluoxetine is a manufactured chemical intended for human receptors, or that fluoxetine has a similar effect in modulating personality in field crickets as in humans. Since fluoxetine acts similarly in field crickets as in humans, an increased understanding of the effects of induced serotonin on different behaviors in field crickets could be beneficial for treating psychological illnesses.

Submitted by Reginaldo Soares de Freitas (reginaldo.freitas@ufv.br) on 2015-11-30T13:58:01Z No. of bitstreams: 1 texto completo.pdf: 1894710 bytes, checksum: a62d3888b479312d917dfb64dcfda3b8 (MD5) / Made available in DSpace on 2015-11-30T13:58:01Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1894710 bytes, checksum: a62d3888b479312d917dfb64dcfda3b8 (MD5) Previous issue date: 2014-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior. / No território da Serra do Brigadeiro, importante pela rica biodiversidade, paisagens singulares e grande potencial agroecológico, inúmeras pesquisas sistematizaram e apontaram muitos benefícios do manejo agroecológico, em especial com sistemas agroflorestais. Estes benefícios foram também apontados pelas próprias famílias agricultoras, após anos de transição agroecológica. Dentre os benefícios, destacam‐se o aumento da quantidade e qualidade da água nas nascentes e cursos d’água de propriedades em transição agroecológica. Entretanto, ainda muitas propriedades permanecem com manejo convencional. O presente estudo foi desenvolvido buscando diagnosticar as principais fontes de poluição da água nas comunidades rurais dessa região e verificar os benefícios do manejo agroecológico na dinâmica da água. Inicialmente diagnosticou‐se a atual situação do saneamento básico nas comunidades localizadas no entorno do Parque Estadual da Serra do Brigadeiro (PESB), que influencia diretamente a qualidade da água e do solo. O estudo abrangeu todas as comunidades localizadas em uma área de 2 km ao redor dos limites do parque. O acesso aos serviços de saneamento básico são precários e podem estar afetando negativamente a qualidade da água de afluentes de rios importantes como o Doce e o Paraíba do Sul, na solução do problema de saneamento, especialmente em áreas rurais, devem ser consideradas soluções individuais, como algumas tecnologias sociais, que são acessíveis economicamente e tecnicamente eficazes. Em uma das Bacias Hidrográficas na área de amortecimento do Parque (a Bacia do São Joaquim) analisou‐se a qualidade da água, com o objetivo de determinar o índice de qualidade da água (IQA) em seis pontos. Dois destes pontos estão localizados em microbacias influenciadas pelo manejo tido como convencional e dois pelo manejo agroecológico, estando os outros dois pontos localizados à montante e à jusante da bacia hidrográfica. Relacionou‐se os IQAs obtidos com os diferentes tipos de manejo dos solos adotados na bacia. Os resultados encontrados permitem concluir que o sistema de manejo agroecológico adotado na bacia do rio São Joaquim contribuiu para conservação e recuperação da qualidade da água. Entretanto, por ainda não ser praticado em todas as propriedades, o manejo agroecológico não influenciou a qualidade da água da bacia hidrográfica como um todo. Ainda nesta Bacia determinou‐se a qualidade da água, indiretamente, através da análise histológica de lesões em peixes, um ótimo bioindicadores de poluição. As análises feitas também indicaram diferenças entre as microbacias agroecológicas e convencionais, e os resultados apontaram sinais de degradação da qualidade da água nas bacias convencionais, provavelmente influenciados pela contaminação das águas dessas propriedades por agrotóxicos. Todo estudo foi desenvolvido através de metodologias participativas, onde o diálogo entre o saber popular e científico foi importante na construção de um novo saber prático, acessível e, portanto, capaz de contribuir para solucionar problemas de poluição ambiental inerentes ao manejo convencional. Para isto é importante apoiar o processo de transição agroecológica já em curso em algumas propriedades do entorno do Parque. / In the Serra do Brigadeiro territory, important due to its biodiversity, unique sights and enormous agroecological potential, several studies systematized and pointed out the benefits of the agroecological management, especially using agroforestry systems, after years of agroecological transition. These benefits were also pointed by the family’s farmers. Among the benefits, we highlight the improvement in water quality and quantity of the springs and streams located in the farms in agroecological transition. However, several farmers keep the conventional management in their proprieties. This study was developed to diagnose the main source of the water pollution in the rural communities and verify the benefits of agroecological management in the water dynamics. First, we diagnosed the the sanitation condition in the communities, in the surrounding of the State Park Serra do Brigadeiro (PESB), that directly influence the water and soil qualities. The study covered all the communities within 2km of around the park (PESB) limit. The basic sanitation access are precarious and can negatively affect the water quality of important influent river such as Doce and Paraíba do Sul. In one of the watershed of the Park buffer zone (São Joaquim Basin) the quality of water was analyzed and the Water Quality Index (WQI) was calculated in six locations. Two of them, located in a watershed conventionally managed, two of them located in a watershed agroecologically managed and the last two points were located upstream and downstream of the whole watershed. The WQI was related to the soil management of the watershed. The result shows that agroecological management used at the São Joaquim river contributed for the preservation and quality of the water. However, the majority of the farmers still adopt conventional management and because of that the agroecological management did not affected the water quality in the São Joaquim Basin Histological analyses were carried out also in São Joaquim Basin. The fishes injuries are great pollution bioindicators. The results showed differences among agroecological and conventional watersheds. The fishes tissues showed more injuries in the conventional farmers, probably due to contamination of water with pesticides. All studies were carried out using participatory methodologies. The dialogue between popular and scientific knowledge is necessary to build knowledge that are practical and accessible and can solve environmental pollution problems, caused by conventional management. For this, it is important to support the, already on going on, agroecological transition in some of the surrounding Park properties.

A wide variety of factors are predicted to influence the intensity and outcome of agonistic interactions in animals, including the resource holding potential of the opponents and the nature and value of the resource over which the individuals are competing. Field crickets (Orthoptera: Gryllidae) have been used extensively as model organisms with which to study animal contests, but relatively few studies have examined the effect of mandible size or structure, or the level of contact with females on the intensity and outcome of agonistic interactions. To do so was the aim of the present thesis, using Gryllus bimaculatus as the study species. The first finding of this study was that there is a significant degree of sexual dimorphism for anterior components of the anatomy in G. bimaculatus. The mandibles, head and pronotum of male crickets were all relatively larger than those of females. This indicates that these traits may be acted upon by intrasexual selection. In many animal species that show sexual dimorphism, a trade-off in development sees enhanced weapon growth at the expense of testes size, but no such relationship was seen in this species. A comparison of the mandible structure of males that either won or lost at flaring and or wrestling showed that a relatively wider mandible span was a significant predictor of success during mandible displays. It was also found that specific components of tooth structure, namely the length of the incisor and length to distal tip, were significantly associated with victory at the jaw flaring stage. This is the first time that mandible shape has been shown to affect fight outcome in the Gryllidae, and also the first confirmed identification of a visual cue component of fighting behaviour. Despite the effectiveness of their weapons in fighting, body mass is a primary predictor of victory in combat between G. bimaculatus males, with the greater the degree of asymmetry in weight the more likely the heavier fighter will win. However, a study of fighting behaviour between asymmetrically matched opponents found that even males who were out-weighed by 40% were still likely to escalate the fight to grappling. Furthermore, males who were able to fend off their larger opponent in their first clash were significantly more likely to win their overall encounter. This hyper-aggressive response may therefore represent an adaptive mechanism to extreme odds and is worthy of further study. Female contact is known to be a significant promoter of male aggression and fighting enthusiasm, and mate guarding aggression is well documented in G. bimaculatus. A recreation of two contradictory studies, including one which concluded that mating makes males lose fights, highlighted that female contact after spermatophore transfer can overcome the loser effect and cause a male to re-engage with a previously dominant opponent. Fighting behaviour in this species is therefore highly flexible and factors affecting the outcome of contests are complex. There is much scope for further studies on this topic.

Made available in DSpace on 2015-03-26T13:42:34Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1695521 bytes, checksum: 9a0915b224b9fc02033cedd8cfc42515 (MD5) Previous issue date: 2014-07-30 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The species of the genus Astyanax are widely distributed in the Neotropical region and have few morphological, ecological and behavioral differences, which complicates the taxonomic classification of this taxon. The nominal species Astyanax bimaculatus was described by Linnaeus in 1758 and currently species with two oval spots that occur in several Neotropical basins are considered as belonging to bimaculatus complex. The objective of this study was to determine the cytogenetic and molecular characteristics (mitochondrial DNA) of 19 populations currently assigned to Astyanax bimaculatus from complex coastal basins of southeastern Minas Gerais using conventional staining, nucleolar organizer regions Ag-NORs, C-band, DAPI, FISH and the gene cytochrome oxidase I - COI. Data were compared with other species of the complex. The karyotype 6m +20 sm +18 st +6 t occurred in all populations, with Ag-NORs ranging from two to eight stained chromosomes. The C-banding showed centromeric and pericentromeric markings, evidenced by the fluorochrome DAPI. Fluorescent 18S and 5S rDNA probes marked one chromosome pair respectively. The phylogeny obtained with the COI gene indicated the presence of two haplogroups with large molecular distance between them: haplogroup I was more closely related to the populations of the São Francisco River Basin, while haplogroup II was subdivided into a group which was more related to populations from the upper Paraná (IIA) and another group formed exclusively by coastal haplotypes (IIB). The karyotype uniformity of coastal populations is greater than the recognized Astyanax altiparanae, suggesting the persistence of large populations. Polymorphisms involving C-band patterns indicate that the addition and reduction of heterochromatin blocks are compatible with intraspecific variation. The molecular data suggest that coastal basins received migrants from continental basins, with more recent geodispersion of a coastal haplogroup, probably related to the dynamic confluence of coastal basins during glacial periods. The genetic similarity between São Francisco River Basin and coastal basins indicates that the nominal species Astyanax lacustris does not represent a valid taxon. While the Upper Paraná Basin maintained a molecular identity consistent with the existence of the nominal taxon Astyanax altiparanae that, agreeing with the cytogenetic data, also occurs in the Paraíba do Sul River Basin. It is concluded that the bimaculatus complex in southeastern Brazil is composed by three lineages, including only two species Astyanax aff. bimaculatus present in São Francisco and coastal basins and A. altiparanae present in the Upper Paraná. / As espécies do gênero Astyanax apresentam ampla distribuição na região neotropical e apresentam poucas diferenças morfológicas, ecológicas e comportamentais, o que dificulta a classificação taxonômica desse táxon. A espécie nominal Astyanax bimaculatus foi descrita em 1758 por Linnaeus e, atualmente, espécies com duas manchas ovaladas que ocorrem em diversas bacias neotropicais são consideradas como pertencentes ao complexo bimaculatus. O objetivo deste trabalho foi determinar as características citogenéticas e moleculares (DNA mitocondrial) de 19 populações consideradas como pertencentes ao complexo Astyanax bimaculatus das bacias costeiras do sudeste de Minas Gerais utilizando coloração convencional, regiões organizadoras de nucléolos Ag-NOrs, banda C, DAPI, FISH e o gene citocromo oxidase I - COI. Os dados foram comparados com outras espécies do complexo. O cariótipo 6m+20sm+18st+6t ocorreu em todas as populações, com Ag-NORs variando de dois a oito cromossomos marcados. A banda C mostrou marcações centroméricas e pericentroméricas, evidenciadas pelo fluorocromo DAPI. As sondas 18S e 5S marcaram apenas um par cromossômico respectivamente. A filogenia obtida com o gene COI indicou a presença de dois haplogrupos com grande distância molecular: o haplogrupo I mais aparentado com populações da bacia do rio São Francisco, enquanto o haplogrupo II subdividiu-se em um grupo mais aparentado com populações do alto Paraná (IIA) e outro grupo formado exclusivamente por haplótipos costeiros (IIB). A uniformidade cariotípica das populações costeiras é maior que a reconhecida em Astyanax altiparanae, sugerindo a persistência de grandes populações. Polimorfismos envolvendo padrões de banda C indicam que a adição e redução de blocos de heterocromatina são consideradas variações intraespecíficas. Os dados moleculares sugerem que as bacias costeiras receberam aporte de bacias continentais, com geodispersão mais recente de um haplogrupo costeiro, provavelmente relacionado com a dinâmica de confluência de bacias costeiras durante os períodos glaciais. A similaridade genética entre a bacia do rio São Francisco e as bacias costeiras indica que a espécie nominal Astyanax lacustris não representa um táxon válido. Enquanto a bacia do alto Paraná manteve uma identidade molecular condizente com a existência do táxon nominal Astyanax altiparanae que, condizente com os dados citogenéticos, também ocorre na bacia do rio Paraíba do Sul. Conclui-se que o complexo bimaculatus no sudeste brasileiro é composto de três linhagens, englobando apenas duas espécies: Astyanax aff. bimaculatus presente no São Francisco e nas bacias costeiras e A. altiparanae presente no alto Paraná.

No description available.

This thesis represents a comprehensive examination of the phonotactic behaviour (i.e. attraction to sound) of the female Gryllus bimaculatus under laboratory conditions. Chapter 2 is the first study to analyze the effect of substrate texture on walking performance in crickets. Substrate texture is found to play an essential role in the phonotactic responses of G. bimaculatus. Smooth substrate texture has a detrimental effect due to slipping, whereas a rough texture results in optimal walking performance due to the friction with the walking legs. Chapter 3 represents the first detailed lifetime study analysing phonotaxis in crickets. My results demonstrate that the optimal age to test phonotaxis in G. bimaculatus females is from day 7 to 24 after the final moult. I also found that selectiveness was persistent with age. These findings contradict the female choosiness hypothesis. This study is also the first to describe the effect of senescence on phonotaxis in insects, as responsiveness decreases with age. Chapter 4 compares the phonotactic behaviour of female crickets from different laboratory-bred colonies. From six tested cricket lab colonies, I found three groups statistically different from each other. Females raised under laboratory conditions at the University of Cambridge and Anglia Ruskin University were most reponsive at a frequency of 4.5 kHz, whereas females bred in Tokushima University in Japan were tuned towards a higher frequency of 5 kHz. These results suggest a degree of artificial allopatric speciation. Comparisons with crickets bred under low-quality conditions in a local pet shop demonstrate a loss of responsiveness, indicating that breeding conditions have a direct effect on phonotactic responsivity. Chapter 5 is the first study to report the presence of phonotaxis in males of G. bimaculatus. Previously it was unknown if G. bimaculatus males were able to perform phonotaxis, given that they were only recognised as endurance signal producers. In the present study, only 20% of the studied males (N=70) performed a weak phonotactic response. This finding has potential ecological implications in terms of male cricket territory establishment, and male-male interactions in the wild, which are discussed. Chapter 6 explores the song pattern recognition of the female G. bimaculatus by changing the duration of either the first, second or third pulse of the chirps. A long first pulse decreased the phonotactic response whereas phonotaxis remained strong when the third pulse was long. Chirps with three pulses of increasing duration of 5, 20 and 50 ms elicited phonotaxis, but the chirps were not attractive when played in reverse order. The data are in agreement with a mechanism in which processing of a sound pulse has an effect on the processing of the subsequent pulse, as outlined in the flow of activity in a delay-line and coincidence-detector circuit.