ABSTRACT
Cornops aquaticum (Bruner) has Eichhornia crassipes, E. azurea, Pontederia cordata and P. lanceolata (Pontederiaceae) as the known host plants. This grasshopper species is cited as a possible agent of biological control for native aquatic macrophytes E. azurea and E. crassipes. This study, carried out from March, 2006 to February, 2007, aimed to evaluate the phenology and age structure of the population of C. aquaticum associated with E. azurea in Piuval bay, Pantanal of Poconé, MT, and to identify possible relationships of its life cycle to abiotic factors such as insolation, temperature and precipitation. Monthly collections of 50 individuals were carried out according to the protocol defined by the "Host - Insect Coevolution on Waterhyacinth" project. Adults and nymphs were separated and the females dissected in order to evaluate ovary maturation. The population presented adults and nymphs during the whole year, suggesting the occurrence of more than one reproductive period. The nymphs from the first stage predominated in August 2006 and the adults in September and October 2006, synchronized with the dry period and beginning of the flooding period, respectively. The highest relative abundance of the females with mature ovaries occurred in July 2006 (50 percent), indicating that this may be a more propitious period for reproduction. The data suggest that C. aquaticum is a species in continual reproduction in Piuval bay and its cycle is associated with the environmental conditions guided by the flood pulse in the Pantanal of Mato Grosso.
Subject(s)
Animals , Female , Male , Grasshoppers/growth & development , Pontederiaceae/parasitology , Brazil , Life Cycle Stages , WetlandsABSTRACT
Variação do peso fresco em Cornops aquaticum (Bruner) (Orthoptera, Acrididae) associado a Eichhornia azurea (Sw) Kunth (Pontederiaceae) em uma baía no Pantanal de Poconé, Mato Grosso. Cornops aquaticum (Bruner, 1906) (Orthoptera, Acrididae) desenvolve seu ciclo de vida sobre macrófitas aquáticas da família Pontederiaceae. Como os gafanhotos são capazes de responder às mudanças sazonais, a alternância de períodos que ocorre no Pantanal pode refletir em sua biologia. Este estudo foi desenvolvido no Pantanal de Poconé - MT, com o objetivo de avaliar possíveis variações no peso fresco dos adultos e ninfas de C. aquaticum. Durante o período de março/2006 a fevereiro/2007 coletaram-se mensalmente, 50 indivíduos de C. aquaticum. Um total de 600 indivíduos foi avaliado, sendo 43,5 por cento adultos e 56,5 por cento ninfas. Os maiores valores de peso fresco total ocorreram nos meses de setembro (9,106g; 0,182g/indivíduo) e outubro/2006 (8,865g; 0,177g/indivíduo) e os menores em março/2006 (3,413g; 0,068g/indivíduo). Nos indivíduos adultos os maiores pesos frescos foram registrados em setembro/2006 (8,680g; 0,223g/indivíduo) e outubro/2006 (8,654g; 0,234g/indivíduo), no final do período de seca, e o menor em março/2006 (1,792g; 0,138g/indivíduo), durante o período de cheia. As ninfas tiveram o maior peso fresco em abril/2006 (2,913g; 0,076g/indivíduo) início da vazante, enquanto o menor peso fresco ocorreu em outubro/2006 (0,211g; 0,016g/indivíduo) início da enchente. Apenas a variação no peso fresco médio das fêmeas foi significativa (f = 6,43; p = 0,001), com os maiores registros durante o período de enchente, o que pode evidenciar uma estratégia reprodutiva.
Cornops aquaticum (Bruner, 1906) (Orthoptera, Acrididae) develops its life cycle on aquatic macrophyte of the Pontederiaceae family. As grasshoppers are able to respond to the seasonal changes, the alternation of periods that occurs in the Pantanal may reflect in their biology. This study was carried out in the Pantanal of Poconé- MT, with the aim of evaluating possible variations in the fresh weight of the adults and nymphs of C. aquaticum. From March/2006 to February/2007, 50 individuals of C. aquaticum were collected each month. A total of 600 individuals was assessed, 43.5 percent of which were adults and 56.5 percent nymphs. The highest values of total fresh weight occurred in September (9.106g; 0.182g/individual) and October/2006 (8.865g; 0.177g/individual) and the lowest in March/2006 (3.413g; 0.068g/individual). Among the adult individuals the highest fresh weight was registered in September/2006 (8.680g; 0.223g/individual) and October/2006 (8.654g; 0.234g/individual), at the end of the dry period, and the lowest in March/2006 (1.792g; 0.138g/individual) during the flood period. The nymphs had the highest fresh weight in April/2006 (2.913g; 0.076g/individual) at the beginning of the draining period, whereas the lowest fresh weight occurred in October/2006 (0.211g; 0.016g/individual) at the beginning of the flood period. Only the variation in the average fresh weight of females was significant (f = 6.43; p = 0.001) with the highest recordings occurring during the flood period, what may show a reproductive strategy.
ABSTRACT
Seis indivíduos de Attalea phalerata Mart. foram amostrados durante o período de cheia (fase aquática) no pantanal mato-grossense (fevereiro/2001), empregando-se a metodologia de nebulização de copas com o objetivo de analisar a composição, estrutura e biomassa da comunidade de artrópodes associada à copa dessa espécie vegetal, bem como a influência do regime hídrico sobre a comunidade. Cada palmeira foi nebulizada uma única vez e realizadas três coletas subseqüentes. O total de 63.657 artrópodes (643,0 ± 259,87 indivíduos/m²) foi amostrado, representando 25 ordens dentre as classes Insecta, Arachnida, Diplopoda e Crustacea. Os grupos dominantes foram Acari (40.0 por cento; 257.2 ± 116,50 indivíduos/m²), Coleoptera (12,0 por cento; 77,5 ± 64,93 indivíduos/m²), Psocoptera (9,2 por cento; 59,0 ± 38,00 indivíduos/m²), Diptera (8,4 por cento; 54,1 ± 18,72 indivíduos/m²), Collembola (8,3 por cento; 53,4 ± 26,24 indivíduos/m²) e Hymenoptera (7,9 por cento; 50,6 ± 21,40 indivíduos/m²), sendo a maioria Formicidae (49,2 por cento). A biomassa de Arthropoda correspondeu a 8,86 g de peso seco total e 0,18 mg/m². Coleoptera, Blattodea, Orthoptera, Araneae e Hymenoptera foram os táxons mais representativos. O regime hídrico (pulso de inundação) bem como a sazonalidade afetam fortemente a composição e estrutura dessa comunidade.
Six trees of the palm species Attalea phalerata Mart. were sampled during high water (aquatic phase) of the Pantanal of Mato Grosso (February 2001), by canopy fogging. The composition, structure, and biomass of the arthropod community associated with their canopies were analysed, as well as the influence the flood pulse renders on it. Each tree was fogged once, followed by three consecutive collections. A total of 63,657 arthropods (643.0 ± 259.87 ind/m²) were collected, representing 25 orders in the classes Insecta, Arachnida, Diplopoda and Crustacea. The dominant groups were Acari (40.0 percent; 257.2 ± 116.50 ind./m²), Coleoptera (12.0 percent; 77.5 ± 64.93 ind./m²), Psocoptera (9.2 percent; 59.0 ± 38.00 ind./m²), Diptera (8.4 percent; 54.1 ± 18.72 ind./m²), Collembola (8.3 percent; 53.4 ± 26.24 ind./m²) and Hymenoptera (7.9 percent; 50.6 ± 21.40 ind./m²), the latter mostly represented by Formicidae (49.2 percent). Arthropod biomass amounted to 8.86 g dry weight and 0.18 mg/m². Coleoptera, Blattodea, Orthoptera, Araneae and Hymenoptera were the most representative taxa. The hydrological regime (flood pulse), as well as seasonality, appear to strongly affect the composition and structure of this canopy community.