Spelling suggestions: "subject:"angulata"" "subject:"angulados""
1 |
Composi??o ictiofaun?stica e estrat?gias reprodutivas de quatro esp?cies de peixes nativos da Bacia Hidrogr?fica Piranhas - Assu, Rio Grande do NorteAraujo, Andrea Soares de 03 July 2012 (has links)
Made available in DSpace on 2014-12-17T15:36:38Z (GMT). No. of bitstreams: 1
AndreaSA_TESE - Pag 1 a 116.pdf: 8811201 bytes, checksum: d0d8579460a5a3ff98a9e4d091cdaca3 (MD5)
Previous issue date: 2012-07-03 / This study focuses on the fish fauna composition and reproductive strategies of
four native fish species in relation to environmental variables of the Piranhas-Assu
hydrographic basin of the Caatinga biome, Rio Grande do Norte, Brazil. Fish and
environmental data were collected monthly during the period September 2008 to
February 2010, in the Marechal Dutra reservoir and River Acau? a tributary of Piranhas-
Assu. The fish were measured, weighed and dissected, and the gonads were removed,
weighed and examined macroscopically for identification and determination of gonad
maturation stages. The results of this work generated seven articles. The first article is
about the fish fauna composition of the Piranhas-Assu hydrographic basin, Rio Grande
do Norte. The 602 fish samples captured were distributed in four orders (Characiformes,
Perciformes, Siluriformes and Synbranchiformes), 11 families and 22 species, of which
17 are endemic to the Caatinga ecoregion. The order Characiformes was more
representative followed by Perciformes, Siluriformes and Synbranchiformes. The
second article is about the length-weight relationship and growth of seven native fish
species Crenicichla menezesi, Cichlasoma orientale, Triportheus angulatus,
Psectrogaster rhomboides, Pimelodella gracilis, Prochilodus brevis and Leporinus piau
from a semiarid Brazilian reservoir. The third article is about the reproductive aspects of
Crenicichla menezesi. Males were larger, heavier and with a slight predominance as
compared to females. Four stages of gonadal development were characterized, being
immature, maturing, mature and spent. The females reached sexual maturity earlier than
males, with an average fecundity of 398 oocytes per batch. The spawning was partial
with a long reproductive period. The fourth article deals with the reproductive strategy
of Leporinus piau a neotropical freshwater fish in semi-arid region of Brazil. The
population of L. piau (n = 211) showed a slight predominance of males (55%), with
larger and heavier females. The males matured earlier than the females. This species
presented total spawning, with an average fecundity of 55,000 mature oocytes. Rainfall
and concentration of dissolved oxygen acted as influential factors during the spawning
season. L. piau shows a seasonal reproductive strategy. The fifth article is related to the
morphometric-meristic characteristics and reproductive aspects of freshwater sardine,
Triportheus angulatus from River Acau? of the Caatinga biome. There was a
predominance of larger females, reaching first maturation before males. There was total
spawning during the rainy period of the region. The sixth article reports on the
reproductive strategy of Psectrogaster rhomboides. The sex ratio was 1M: 1F, with
negative allometric growth. Males reached sexual maturity earlier than females Females
and males showed four stages of gonadal development and spawned during the rainy
season. The fecundity was low and this species presented total spawning. The seventh
article reports on the dynamics of territorial behavior of Crenicichla menezesi. Ten
agonistic behaviors displayed by the males were observed: frontal and lateral threat,
chasing, circular chasing, perpendicular, lateral and mouth attacks, escape, parallel
positioning and stationary. The formation of four social groups was observed among
males: without interaction; interaction with submission and escape; with frontal and
lateral agonistic interactions. In social interactions between males and females, it was
observed that the larger males interacted more among themselves and with the larger
females. The large male established its territory and the two small males along with the
small female were excluded from the other groups. These studies clarified the fish fauna
composition and reproductive strategies of four native species Crenicichla menezesi,
Leporinus piau, Triportheus angulatus and Psectrogaster rhomboides of the Piranhas-
Assu hydrographic basin of the Caatinga biome, Rio Grande do Norte, Brazil. / O presente estudo trata da composi??o ictiofaun?stica e das estrat?gias
reprodutivas de quatro esp?cies nativas de peixes em rela??o ?s vari?veis ambientais da
bacia hidrogr?fica do rio Piranhas-Assu no bioma Caatinga, Rio Grande do Norte,
Brasil. As amostras dos peixes e os dados ambientais foram coletados mensalmente,
durante o per?odo de setembro de 2008 a fevereiro de 2010. Os peixes foram medidos,
pesados, dissecados e as g?nadas foram removidas, pesadas e examinadas para
identifica??o do sexo e determina??o do est?dio de matura??o das g?nadas. Os
resultados desse trabalho geraram sete artigos. O primeiro artigo ? sobre a composi??o
ictiofaunistica em um trecho da bacia Piranhas-Assu, Rio Grande do Norte. Foram
capturados 602 peixes, distribu?dos em quatro ordens (Characiformes, Perciformes,
Siluriformes e Synbranchiformes), 11 fam?lias e 22 esp?cies, das quais 17 s?o
end?micas da Caatinga. A ordem Characiformes foi mais representativa, seguida por
Perciformes, Siluriformes e Synbranchiformes. O segundo artigo trata sobre a rela??o
peso-comprimento e crescimento de sete esp?cies de peixes nativos Crenicichla
menezesi, Cichlasoma orientale, Triportheus angulatus, Psectrogaster rhomboides,
Pimelodella gracilis, Prochilodus brevis e Leporinus piau de um reservat?rio do
semi?rido brasileiro. O terceiro artigo ? sobre os aspectos reprodutivos do jacund?,
Crenicichla menezesi. Os machos foram maiores, mais pesados e com leve
predomin?ncia com rela??o ?s f?meas. Foram caracterizados quatro est?dios de
desenvolvimento gonadal, sendo: imaturo, em matura??o, maduro e esvaziado. As
f?meas atingiram a primeira matura??o sexual antes que os machos, com fecundidade
m?dia de 398 ov?citos por lote. A desova foi parcelada com um longo per?odo
reprodutivo. O quarto artigo trata da estrat?gia reprodutiva de Leporinus piau um peixe
de ?gua doce neotropical da regi?o semi?rida do Brasil. A popula??o amostrada de L.
piau (n = 211) mostrou uma ligeira predomin?ncia de machos (55%), com f?meas
maiores e mais pesadas. A primeira matura??o sexual dos machos ocorreu antes que as
f?meas. Esta esp?cie apresentou desova total, com fecundidade m?dia de 55.000
ov?citos maduros. As chuvas e a concentra??o de oxig?nio dissolvido atuaram como
fatores influentes durante a ?poca de desova. L. piau apresenta uma estrat?gia
reprodutiva sazonal. O quinto artigo ? sobre caracter?sticas morfom?tricas-mer?sticas e
aspectos reprodutivos da sardinha de ?gua doce, Triportheus angulatus do rio Acau? do
bioma Caatinga. Houve uma predomin?ncia de f?meas maiores, atingindo a primeira
matura??o gonadal antes que os machos. Houve desova total no per?odo de chuvas da
regi?o. O sexto artigo relata a estrat?gia reprodutiva da branquinha, Psectrogaster
rhomboides. Constatou-se uma propor??o sexual de 1:1, com tipo de crescimento
alom?trico negativo. Os machos atingiram a maturidade sexual antes que as f?meas. As
f?meas e os machos apresentaram quatro est?dios de desenvolvimento gonadal com o
per?odo de desova no per?odo de chuva. A fecundidade foi baixa e a esp?cie apresentou
desova total. O s?timo artigo relata a din?mica do comportamento territorial de
Crenicichla menezesi. Foram observados dez comportamentos agon?sticos exibidos
pelos machos, sendo amea?a frontal e lateral, persegui??o, persegui??o circular, ataque
perpendicular, lateral e bucal, fuga, posicionamento paralelo e perman?ncia. Foi
observada a forma??o de quatro grupos sociais entre os machos: sem intera??o, com
intera??o de submiss?o e fuga, com intera??o agon?stica frontal e lateral. Nas intera??es
sociais entre machos e f?meas foi observado que os machos maiores interagiram mais
entre si e com as f?meas maiores. O macho maior estabeleceu seu territ?rio e os dois
machos menores juntamente com a menor f?mea foram exclu?dos dos demais grupos.
Estes trabalhos esclareceram sobre a composi??o ictiofaun?stica e estrat?gias
reprodutivas de quatro esp?cies Crenicichla menezesi, Leporinus piau, Triportheus
angulatus e Psectrogaster rhomboides nativos da bacia hidrogr?fica piranhas-assu do
bioma Caatinga, RN, Brasil.
|
2 |
Response of selected non-target Lepidoptera, Coleoptera and Diptera species to Cry1Ab protein expressed by genetically modified maize / Annemie ErasmusErasmus, Annemie January 2010 (has links)
The environmental impacts of genetically modified (GM) crop plants such as Bt (Bacillus
thuringiensis) maize have not yet been fully assessed in South Africa. Bt maize designed
to express Bt endotoxin for control of Busseola fusca (Fuller) (Lepidoptera: Noctuidae)
and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is planted on approximately
1.103 million hectares in South Africa. The monitoring of GM crops after release is
important in order to assess and evaluate possible environmental effects. No risk
assessment for Bt maize was done in South Africa before its release in 1998 and no
targeted post-release monitoring of possible resistance development or impact on non-target
species have been done. Awareness has risen in South Africa through research
highlighting the possible effects GM crops may have. The aim of this study was to
determine, through feeding experiments, the effects of Bt maize on selected non-target
Lepidoptera, Coleoptera and Diptera species that occur in maize agro-ecosystems in
South Africa. Results provide information for use in future risk assessment studies on Bt
maize and indicate which species could possibly be of importance in post-release
monitoring of Bt maize. Priority insect species were identified and laboratory- and semifield
experiments were conducted to evaluate the effect of Bt maize on these species. In
the light of the reportedly lower toxicity of Bt maize to certain noctuid borers, the effect
of Bt maize was evaluated on Sesamia calamistis (Hampson), Agrotis segetum (Denis &
Schiffermüller), and Helicoverpa armigera (Hubner). Feeding studies were also
conducted to determine the effect of Bt maize on non-target Coleoptera, i.e.
Heteronychus arator Fabricius (Coleoptera: Scarabaeidae) and Somaticus angulatus
(Fahraeus) (Coleoptera: Tenebrionidae). The effect of indirect exposure of the stem borer
parasitoid Sturmiopsis parasitica (Curran) (Diptera: Tachinidae) to Bt toxin was
evaluated to determine if there is any effect when it parasitizes Bt-resistant B. fusca
larvae that have fed on Bt maize. Results from the study conducted with S. calamistis
indicated that Bt maize of both events (Bt11 and MON810) were highly toxic to S.
calamistis. The behavioural characteristic of S. calamistis to feed behind leaf sheaths and
to enter stems directly did not result in escape of exposure to the toxin. Larval feeding on
leaf sheaths therefore resulted in the ingestion of sufficient toxin to kill larvae before they entered maize stems. Results showed that the effect of Cry1Ab toxin on the biology of A.
segetum larvae and moths were largely insignificant. Whorl leaves were observed to be
an unsuitable food source for H. armigera larvae and larval growth was poor. No larvae
survived to the pupal stage on any of the Bt maize treatments. When feeding on maize
ears H. armigera larval mass increased on non-Bt maize whereas no increase occurred on
Bt maize. The feeding study conducted with Coleoptera showed that the effect of Bt
maize on H. arator and S. angulatus was insignificant and no differences were observed
in any of the parameters measured for the two species. Although not always significant,
the percentage parasitism of Bt-consuming host larvae by S. parasitica was always higher
compared to host larvae that fed on non-Bt maize. It could be that Bt toxin affects B.
fusca fitness to such an extent that the immune systems of host larvae were less effective.
The different parameters tested for S. parasitica indicated only one case where fly
maggots originating from diapause host larvae feeding on non-Bt maize had a greater
mass compared to host larvae that fed on Bt maize. The same applied to S. parasitica
pupal length. For other parameters tested there were no significant differences. Sesamia
calamistis is stenophagous and occurs in mixed populations with other borer species. It
was therefore concluded that the ecological impact of local extinctions of S. calamistis
caused by Bt maize is not expected to be great. Bt maize will most likely not have any
significant effect on the control of A. segetum under field conditions. The feeding study
conducted with H. armigera quantified the effects of Bt maize on this species and
provided important information on the potential of Bt maize as protection against this
polyphagous pest. However, the likelihood of H. armigera becoming an important
secondary pest is high. It can be concluded that the Cry1Ab toxin targeting lepidopteran
pests will not have adverse effects on H. arator or S. angulatus. Although some adverse
effects were observed on S. parasitica mass and pupal length it is most likely that this
will not contribute to adverse effects in the field, but that there rather be synergism
between Bt maize and S. parasitica. An ecological approach was followed in which the
potential effects of exposure of priority species to Bt toxin in maize was investigated. A
series of selection matrixes were developed in which each of the above mentioned
species was ranked for its maximum potential exposure to Bt toxin by assessing it
occurrence, abundance, presence and linkage in the maize ecosystem. Through the use of these selection matrixes, knowledge gaps were identified for future research and to guide
the design of ecologically realistic experiments. This study contributes to knowledge
regarding the possible effects of Bt maize on the most economically important non-target
pests in South Africa. There is, however, a need to evaluate other non-target species in
feeding studies, as well as in field studies. From this study it can be concluded that some
species can be eliminated from further testing since Bt maize had no adverse effect while
more research have to be conducted on other species. / Thesis (Ph.D. (Environmental Science)--North-West University, Potchefstroom Campus, 2010.
|
3 |
Response of selected non-target Lepidoptera, Coleoptera and Diptera species to Cry1Ab protein expressed by genetically modified maize / Annemie ErasmusErasmus, Annemie January 2010 (has links)
The environmental impacts of genetically modified (GM) crop plants such as Bt (Bacillus
thuringiensis) maize have not yet been fully assessed in South Africa. Bt maize designed
to express Bt endotoxin for control of Busseola fusca (Fuller) (Lepidoptera: Noctuidae)
and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is planted on approximately
1.103 million hectares in South Africa. The monitoring of GM crops after release is
important in order to assess and evaluate possible environmental effects. No risk
assessment for Bt maize was done in South Africa before its release in 1998 and no
targeted post-release monitoring of possible resistance development or impact on non-target
species have been done. Awareness has risen in South Africa through research
highlighting the possible effects GM crops may have. The aim of this study was to
determine, through feeding experiments, the effects of Bt maize on selected non-target
Lepidoptera, Coleoptera and Diptera species that occur in maize agro-ecosystems in
South Africa. Results provide information for use in future risk assessment studies on Bt
maize and indicate which species could possibly be of importance in post-release
monitoring of Bt maize. Priority insect species were identified and laboratory- and semifield
experiments were conducted to evaluate the effect of Bt maize on these species. In
the light of the reportedly lower toxicity of Bt maize to certain noctuid borers, the effect
of Bt maize was evaluated on Sesamia calamistis (Hampson), Agrotis segetum (Denis &
Schiffermüller), and Helicoverpa armigera (Hubner). Feeding studies were also
conducted to determine the effect of Bt maize on non-target Coleoptera, i.e.
Heteronychus arator Fabricius (Coleoptera: Scarabaeidae) and Somaticus angulatus
(Fahraeus) (Coleoptera: Tenebrionidae). The effect of indirect exposure of the stem borer
parasitoid Sturmiopsis parasitica (Curran) (Diptera: Tachinidae) to Bt toxin was
evaluated to determine if there is any effect when it parasitizes Bt-resistant B. fusca
larvae that have fed on Bt maize. Results from the study conducted with S. calamistis
indicated that Bt maize of both events (Bt11 and MON810) were highly toxic to S.
calamistis. The behavioural characteristic of S. calamistis to feed behind leaf sheaths and
to enter stems directly did not result in escape of exposure to the toxin. Larval feeding on
leaf sheaths therefore resulted in the ingestion of sufficient toxin to kill larvae before they entered maize stems. Results showed that the effect of Cry1Ab toxin on the biology of A.
segetum larvae and moths were largely insignificant. Whorl leaves were observed to be
an unsuitable food source for H. armigera larvae and larval growth was poor. No larvae
survived to the pupal stage on any of the Bt maize treatments. When feeding on maize
ears H. armigera larval mass increased on non-Bt maize whereas no increase occurred on
Bt maize. The feeding study conducted with Coleoptera showed that the effect of Bt
maize on H. arator and S. angulatus was insignificant and no differences were observed
in any of the parameters measured for the two species. Although not always significant,
the percentage parasitism of Bt-consuming host larvae by S. parasitica was always higher
compared to host larvae that fed on non-Bt maize. It could be that Bt toxin affects B.
fusca fitness to such an extent that the immune systems of host larvae were less effective.
The different parameters tested for S. parasitica indicated only one case where fly
maggots originating from diapause host larvae feeding on non-Bt maize had a greater
mass compared to host larvae that fed on Bt maize. The same applied to S. parasitica
pupal length. For other parameters tested there were no significant differences. Sesamia
calamistis is stenophagous and occurs in mixed populations with other borer species. It
was therefore concluded that the ecological impact of local extinctions of S. calamistis
caused by Bt maize is not expected to be great. Bt maize will most likely not have any
significant effect on the control of A. segetum under field conditions. The feeding study
conducted with H. armigera quantified the effects of Bt maize on this species and
provided important information on the potential of Bt maize as protection against this
polyphagous pest. However, the likelihood of H. armigera becoming an important
secondary pest is high. It can be concluded that the Cry1Ab toxin targeting lepidopteran
pests will not have adverse effects on H. arator or S. angulatus. Although some adverse
effects were observed on S. parasitica mass and pupal length it is most likely that this
will not contribute to adverse effects in the field, but that there rather be synergism
between Bt maize and S. parasitica. An ecological approach was followed in which the
potential effects of exposure of priority species to Bt toxin in maize was investigated. A
series of selection matrixes were developed in which each of the above mentioned
species was ranked for its maximum potential exposure to Bt toxin by assessing it
occurrence, abundance, presence and linkage in the maize ecosystem. Through the use of these selection matrixes, knowledge gaps were identified for future research and to guide
the design of ecologically realistic experiments. This study contributes to knowledge
regarding the possible effects of Bt maize on the most economically important non-target
pests in South Africa. There is, however, a need to evaluate other non-target species in
feeding studies, as well as in field studies. From this study it can be concluded that some
species can be eliminated from further testing since Bt maize had no adverse effect while
more research have to be conducted on other species. / Thesis (Ph.D. (Environmental Science)--North-West University, Potchefstroom Campus, 2010.
|
Page generated in 0.036 seconds