Ecology of Veliidae and Mesoveliidae (Hemiptera: Heteroptera: Gerromorpha) was studied in selected European species. The research of these non-gerrid semiaquatic bugs was especially focused on voltinism, overwintering with physiological consequences and wing polymorphism with dispersal pattern. Hypotheses based on data from field surveys were tested by laboratory, mesocosm and field experiments. New data on life history traits and their ecophysiological consequences are discussed in seven original research papers (four published journal papers, two submitted papers and one communication in conference proceedings), creating core of this thesis.

O objetivo deste trabalho foi elucidar aspectos morfológicos, ecológicos e comportamentais dos percevejos castanhos. Foram realizados estudos de levantamento populacional, dimorfismo sexual, polimorfismo alar e comunicação sonora com diferentes espécies de Scaptocoris. O levantamento populacional e a distribuição vertical no solo foi realizado com S. carvalhoi. As ninfas foram predominantes durante todo o período, não sendo influenciadas pela precipitação média mensal. O número de adultos foi dependente das chuvas, ocorrendo uma maior incidência destes com o incremento da precipitação. Ninfas e adultos mantiveram-se nas camadas mais superficiais do solo no período chuvoso e aprofundaram-se nos períodos de deficiência hídrica. Os adultos foram menos tolerantes ao estresse hídrico e aprofundaram-se logo no início da época seca, enquanto as ninfas o fizeram somente no final desse período. No estudo de dimorfismo sexual, as genitálias externas de machos e fêmeas de S. carvalhoi, S. buckupi e S. castanea foram extraídas e analisadas. As fêmeas se diferenciaram dos machos por apresentarem placas genitais. Nas fêmeas de S. carvalhoi o laterotergito 8 é dividido em duas partes, ao invés da placa única que forma a genitália de S. castanea e S. buckupi. Nos machos, a genitália é formada pelo 9º segmento abdominal da qual se projetam o 10º segmento abdominal e os parâmeros, sendo esta característica semelhante nas três espécies. No estudo de polimorfismo alar foram mensurados o comprimento do corpo, escutelo, asas anteriores e posteriores, comprimento da membrana, e distância entre a inserção da asa e o ápice do abdome em S. carvalhoi. Uma análise de agrupamento demonstrou a existência de dimorfismo alar, serparando-os em indivíduos de asas curtas (braquípteros) e longas (macrópteros). Nos braquípteros as asas não recobriram os últimos tergitos e nos macrópteros elas ultrapassaram o ápice do abdome. As razões entre o comprimento do corpo e das asas anteriores (RAC) e posteriores (RPC), foram superiores a 0,8 e 0,6, respectivamente, para os indivíduos macrópteros. Os braquípteros predominaram no solo durante todo o ano, apresentando menor mobilidade e asas não são funcionais. Os macrópteros ocorreram, principalmente, no início das chuvas e após um longo período seco, apresentando maior mobilidade e reação de vôo em 67% dos casos. A maior freqüência de macrópteros na camada mais superficial do solo (até 20 cm), coincidiu com a época de revoada nestes insetos e os adultos coletados após a revoada foram todos macrópteros, demonstrando a importância destes indivíduos na dispersão para novas áreas. O estudo da morfologia do aparato estridulatório localizado nos abdomes e asas posteriores de S. carvalhoi e S. castanea apresentou diferenças entre os sexos e espécies. O registro dos sons produzidos por estas estruturas e a sua dispersão através do substrato (solo e planta), confirmou que machos e fêmeas de cada espécie produzem sons distintos, e que a propagação deste som no solo ocorre somente a curtas distâncias. / The objective of this study was to elucidate morphological, ecological and behavioral aspects of the burrowing bugs (Scaptocoris). Population dynamic studies, sexual dimorphism, wing polymorphism, and acoustic communication were investigated on different species of Scaptocoris. Studies on population dynamics and vertical distribution in the soil were carried out with S. carvalhoi. Nymphs occurred during the entire length of the study, and their abundance was not influenced by monthly rainfall. Adult population augmented with the increase of rainfall. Nymphs and adults were located in the top layer of the soil during the rainy season and they were found deeper in the soil during droughts. Adults were less tolerant to droughts than nymphs. External male and female genitalia of S. carvalhoi, S. buckupi and S. castanea were extracted for sexual dimorphism studies. Females differed from males by presenting genital plates. Females of S. carvalhoi have the laterotergite 8 separated in two parts, differently from S. castanea e S. buckupi that have only one plate. Male genitalia present the 10th abdominal segment and paramers linked to the 9th segment. This characteristic is similar among the three species. The wing polymorphism was compared by measuring body length, scutellum, anterior and posterior wings, membrane length and distance from the point of insertion of the wing to the apical part of the abdomen of S. carvalhoi. Cluster analysis allowed the identification of two groups based on the wing dimorphism. It was possible to classify each group, according to wing length as brachypterous (short wings) and macropterous (long wings). Wings of brachypterous specimens do not cover the last tergites and the wings of macropterous surpass the apical part of the abdomen. The ratio of the body length and anterior wings (RAC) e posterior wings (RPC) was greater than 0.8 and 0.6, respectively, for macropterous specimens. Brachypterous insects were more prevalent on the soil than macropterous. They were less active and their wings were not functional. Macropterous stinkbugs occurred predominantly during the onset of the rainfall and after long droughts. They were more active flying in 67% of the times when touched. The higher frequency of macropterous stinkbugs in the top soil layer (first 20 cm), occurred during swarm when they were the only group of adult stinkbugs collected, demonstrating their importance on dispersion to new areas. Morphological differences of the stridulatory apparatus, located at the abdomen near the posterior wings, were detected for S. carvalhoi and S. castanea and also between males and females. The sounds produced by these insects and its propagation across the substrate (soil and plant) varied between species and sexes. The sounds propagate only within short distances.

Wing polymorphism of semiaquatic bugs is affected by environmental factors as temperature, photoperiod, population density or permanency of habitat. The heritability has its own specific part, too. A lot of field studies suggest that crucial effect on wing polymorphism has temperature, but laboratory experiments often do not confirm this hypothesis. The main aim of this thesis was to describe the effect of environmental factors (photoperiod, temperature and permanency of habitat) on wing polymorphism of Microvelia reticulata, additionally of Gerris lacustris. The partial tasks included description of effect of mentioned abiotic factors on mortality and rate of development. The individuals of both species were kept at combinations of two levels of temperature, photoperiod and permanency of habitat (overall at eight treatments) from first larval instar to adult. All adults of Microvelia reticulata emerged as apterous, so there was no response of wing polymorphism to tested environmental factors. The main influence of heritability is presumable. Only ten individuals of G. lacustris developed into the adult stage, so it was impossible to describe the influence of abiotic factors on wing polymorphism, mortality and lenght of development in this species. Mortality of individuals of M. reticulata was significantly influenced by the type of substrate. Only 3.5% of individuals survived when reared on wet filter paper, while 80.5% on the water surface. Both other factors (temperature, photoperiod) had no effect on total mortality. There was no difference between mortality of males and females, so it is impossible to note sexual dependent mortality. The lenght of development did not differ between sexes either. Lenght of development was significantly affected by temperature, as low temperature reduces development of M. reticulata. The fastest development showed nymphs of second instar and slowest development nymphs of fifth instar at all treatments. Since the effect of abiotic factors on wing polymorphism was not found in M. reticulata, it would be sufficient to study the effect of heritability on development of wings in this species in the future.

O objetivo deste trabalho foi elucidar aspectos morfológicos, ecológicos e comportamentais dos percevejos castanhos. Foram realizados estudos de levantamento populacional, dimorfismo sexual, polimorfismo alar e comunicação sonora com diferentes espécies de Scaptocoris. O levantamento populacional e a distribuição vertical no solo foi realizado com S. carvalhoi. As ninfas foram predominantes durante todo o período, não sendo influenciadas pela precipitação média mensal. O número de adultos foi dependente das chuvas, ocorrendo uma maior incidência destes com o incremento da precipitação. Ninfas e adultos mantiveram-se nas camadas mais superficiais do solo no período chuvoso e aprofundaram-se nos períodos de deficiência hídrica. Os adultos foram menos tolerantes ao estresse hídrico e aprofundaram-se logo no início da época seca, enquanto as ninfas o fizeram somente no final desse período. No estudo de dimorfismo sexual, as genitálias externas de machos e fêmeas de S. carvalhoi, S. buckupi e S. castanea foram extraídas e analisadas. As fêmeas se diferenciaram dos machos por apresentarem placas genitais. Nas fêmeas de S. carvalhoi o laterotergito 8 é dividido em duas partes, ao invés da placa única que forma a genitália de S. castanea e S. buckupi. Nos machos, a genitália é formada pelo 9º segmento abdominal da qual se projetam o 10º segmento abdominal e os parâmeros, sendo esta característica semelhante nas três espécies. No estudo de polimorfismo alar foram mensurados o comprimento do corpo, escutelo, asas anteriores e posteriores, comprimento da membrana, e distância entre a inserção da asa e o ápice do abdome em S. carvalhoi. Uma análise de agrupamento demonstrou a existência de dimorfismo alar, serparando-os em indivíduos de asas curtas (braquípteros) e longas (macrópteros). Nos braquípteros as asas não recobriram os últimos tergitos e nos macrópteros elas ultrapassaram o ápice do abdome. As razões entre o comprimento do corpo e das asas anteriores (RAC) e posteriores (RPC), foram superiores a 0,8 e 0,6, respectivamente, para os indivíduos macrópteros. Os braquípteros predominaram no solo durante todo o ano, apresentando menor mobilidade e asas não são funcionais. Os macrópteros ocorreram, principalmente, no início das chuvas e após um longo período seco, apresentando maior mobilidade e reação de vôo em 67% dos casos. A maior freqüência de macrópteros na camada mais superficial do solo (até 20 cm), coincidiu com a época de revoada nestes insetos e os adultos coletados após a revoada foram todos macrópteros, demonstrando a importância destes indivíduos na dispersão para novas áreas. O estudo da morfologia do aparato estridulatório localizado nos abdomes e asas posteriores de S. carvalhoi e S. castanea apresentou diferenças entre os sexos e espécies. O registro dos sons produzidos por estas estruturas e a sua dispersão através do substrato (solo e planta), confirmou que machos e fêmeas de cada espécie produzem sons distintos, e que a propagação deste som no solo ocorre somente a curtas distâncias. / The objective of this study was to elucidate morphological, ecological and behavioral aspects of the burrowing bugs (Scaptocoris). Population dynamic studies, sexual dimorphism, wing polymorphism, and acoustic communication were investigated on different species of Scaptocoris. Studies on population dynamics and vertical distribution in the soil were carried out with S. carvalhoi. Nymphs occurred during the entire length of the study, and their abundance was not influenced by monthly rainfall. Adult population augmented with the increase of rainfall. Nymphs and adults were located in the top layer of the soil during the rainy season and they were found deeper in the soil during droughts. Adults were less tolerant to droughts than nymphs. External male and female genitalia of S. carvalhoi, S. buckupi and S. castanea were extracted for sexual dimorphism studies. Females differed from males by presenting genital plates. Females of S. carvalhoi have the laterotergite 8 separated in two parts, differently from S. castanea e S. buckupi that have only one plate. Male genitalia present the 10th abdominal segment and paramers linked to the 9th segment. This characteristic is similar among the three species. The wing polymorphism was compared by measuring body length, scutellum, anterior and posterior wings, membrane length and distance from the point of insertion of the wing to the apical part of the abdomen of S. carvalhoi. Cluster analysis allowed the identification of two groups based on the wing dimorphism. It was possible to classify each group, according to wing length as brachypterous (short wings) and macropterous (long wings). Wings of brachypterous specimens do not cover the last tergites and the wings of macropterous surpass the apical part of the abdomen. The ratio of the body length and anterior wings (RAC) e posterior wings (RPC) was greater than 0.8 and 0.6, respectively, for macropterous specimens. Brachypterous insects were more prevalent on the soil than macropterous. They were less active and their wings were not functional. Macropterous stinkbugs occurred predominantly during the onset of the rainfall and after long droughts. They were more active flying in 67% of the times when touched. The higher frequency of macropterous stinkbugs in the top soil layer (first 20 cm), occurred during swarm when they were the only group of adult stinkbugs collected, demonstrating their importance on dispersion to new areas. Morphological differences of the stridulatory apparatus, located at the abdomen near the posterior wings, were detected for S. carvalhoi and S. castanea and also between males and females. The sounds produced by these insects and its propagation across the substrate (soil and plant) varied between species and sexes. The sounds propagate only within short distances.