E. M. G. Fontes

Movimentos de migração e dispersão de adultos da cigarrinha-das-pastagens

The effect of adults of the spittlebug (Deois flavopicta Stal) movement in their population dynamics was evaluated in pastures of Brachiaria ruziziensis in Brasilia, DF, Brazil. Plastic panels containing adesive trap were used to monitorate the movement rates. The data suggest a lack of pattern related to the geographical position of the traps. Vegetation landscapes similar to pastures fields around the study area seemed to favour the dispersion, whilst Cerrados or wood vegetation in the neighborhood inhibted insect dispersion toward this direction and increased return rate of spittlebugs to the pasture. Spittlebugs moved mainly by short, low jumping flights (bellow 1 m). A proportion of 4:1 male:female was captured in the traps, indicating that males move more than females. The movement of marked and recaptured populations was monitored with non-toxic fluorescent powder. Speed rates lower than 5 m/day was observed. Adult dispersion movement, apparently, does not contribute significantly to the loss or recruitment of individuals to populations of D. flavopicta. Consequently, there is no need to consider this movement in modeling this insect population dynamics. Migration may have a role in this dynamics except in some cases, such as outbreaks and local extinction.O efeito do movimento de adultos da cigarrinha-das-pastagens (Deois flavopicta Stal) em sua dinâmica populacional foi avaliado em pastagens de Brachiaria ruziziensis na regiao do Distrito Federal, Brasil. Foram utilizados paineis de plastico com cola adesiva para monitorar as taxas de movimentacao. Os dados sugerem a ausencia de um padrao predominante de movimentacao em relacao a posicao geografica das armadilhas. A ocorrencia de vegetacao baixa, semelhante as pastagens em volta da area estudada, aparentemente favoreceu a dispersao, ao passo que a ocorrencia de cerrados ou matas na vizinhanca inibiu o movimento nesta direcao e aumentou a taxa de retorno da cigarrinha as pastagens. O inseto se deslocou principalmente mediante saltos ou voos curtos e baixos (abaixo de 1 m). Uma proporcao aproximada de 4:1 (macho:femea) foi capturada nas armadilhas, indicando que os machos movimentam-se mais que as femeas. A velocidade media de movimentacao, de populacoes marcadas com po fluorescente atoxico e recapturadas apos periodos variaveis de liberacao, foi inferior a 5 m por dia. O movimento de dispersao de adultos nao contribui significativamente para a perda ou recrutamento de adultos em populacoes de D. flavopicta, a nao ser em casos de explosoes populacionais ou extincao local.

Pachycondyla obscuricornis as natural enemy of the spittlebug Deois flavopicta

The objective of this work was to evaluate the potential control of the ant Pachycondyla obscuricornis Emery (Hymenoptera: Formicidae) on populations of nymphs of the spittlebug, Deois flavopicta Stal (Hemiptera: Cercopidae). Foraging behavior and prey consumption rate of P. obscuricornis were evaluated. Field data revealed that P. obscuricornis does not show aggressive behavior against individuals of the same species, when they are not carrying a prey; they can patrol distances larger than 10 m searching for prey, and they can build their nest as close as 1 m from each other. The ant has a solitary patrolling habit, there is no recruitment behavior, and individuals dislocate fast, browsing on soil and vegetation for prey. Predation rate on spittlebug nymphs increased relative to the spittlebug abundance, reaching 93.8% of captured prey. Pachycondyla obscuricornis is a voracious predator and may control the population of spittlebugs in cultivated pastures.

Movements of migration and dispersion of adult spittlebugs

The effect of adults of the spittlebug (Deois flavopicta Stal) movement in their population dynamics was evaluated in pastures of Brachiaria ruziziensis in Brasilia, DF, Brazil. Plastic panels containing adesive trap were used to monitorate the movement rates. The data suggest a lack of pattern related to the geographical position of the traps. Vegetation landscapes similar to pastures fields around the study area seemed to favour the dispersion, whilst Cerrados or wood vegetation in the neighborhood inhibted insect dispersion toward this direction and increased return rate of spittlebugs to the pasture. Spittlebugs moved mainly by short, low jumping flights (bellow 1 m). A proportion of 4:1 male:female was captured in the traps, indicating that males move more than females. The movement of marked and recaptured populations was monitored with non-toxic fluorescent powder. Speed rates lower than 5 m/day was observed. Adult dispersion movement, apparently, does not contribute significantly to the loss or recruitment of individuals to populations of D. flavopicta. Consequently, there is no need to consider this movement in modeling this insect population dynamics. Migration may have a role in this dynamics except in some cases, such as outbreaks and local extinction.O efeito do movimento de adultos da cigarrinha-das-pastagens (Deois flavopicta Stal) em sua dinâmica populacional foi avaliado em pastagens de Brachiaria ruziziensis na regiao do Distrito Federal, Brasil. Foram utilizados paineis de plastico com cola adesiva para monitorar as taxas de movimentacao. Os dados sugerem a ausencia de um padrao predominante de movimentacao em relacao a posicao geografica das armadilhas. A ocorrencia de vegetacao baixa, semelhante as pastagens em volta da area estudada, aparentemente favoreceu a dispersao, ao passo que a ocorrencia de cerrados ou matas na vizinhanca inibiu o movimento nesta direcao e aumentou a taxa de retorno da cigarrinha as pastagens. O inseto se deslocou principalmente mediante saltos ou voos curtos e baixos (abaixo de 1 m). Uma proporcao aproximada de 4:1 (macho:femea) foi capturada nas armadilhas, indicando que os machos movimentam-se mais que as femeas. A velocidade media de movimentacao, de populacoes marcadas com po fluorescente atoxico e recapturadas apos periodos variaveis de liberacao, foi inferior a 5 m por dia. O movimento de dispersao de adultos nao contribui significativamente para a perda ou recrutamento de adultos em populacoes de D. flavopicta, a nao ser em casos de explosoes populacionais ou extincao local.

Migration and dispersal movement of adult spittlebugs.

The effect of adults of the spittlebug (Deois flavopicta Stal) movement in their population dynamics was evaluated in pastures of Brachiaria ruziziensis in Brasilia, DF, Brazil. Plastic panels containing adesive trap were used to monitorate the movement rates. The data suggest a lack of pattern related to the geographical position of the traps. Vegetation landscapes similar to pastures fields around the study area seemed to favour the dispersion, whilst Cerrados or wood vegetation in the neighborhood inhibted insect dispersion toward this direction and increased return rate of spittlebugs to the pasture. Spittlebugs moved mainly by short, low jumping flights (bellow 1 m). A proportion of 4:1 male:female was captured in the traps, indicating that males move more than females. The movement of marked and recaptured populations was monitored with non-toxic fluorescent powder. Speed rates lower than 5 m/day was observed. Adult dispersion movement, apparently, does not contribute significantly to the loss or recruitment of individuals to populations of D. flavopicta. Consequently, there is no need to consider this movement in modeling this insect population dynamics. Migration may have a role in this dynamics except in some cases, such as outbreaks and local extinction.O efeito do movimento de adultos da cigarrinha-das-pastagens (Deois flavopicta Stal) em sua dinâmica populacional foi avaliado em pastagens de Brachiaria ruziziensis na regiao do Distrito Federal, Brasil. Foram utilizados paineis de plastico com cola adesiva para monitorar as taxas de movimentacao. Os dados sugerem a ausencia de um padrao predominante de movimentacao em relacao a posicao geografica das armadilhas. A ocorrencia de vegetacao baixa, semelhante as pastagens em volta da area estudada, aparentemente favoreceu a dispersao, ao passo que a ocorrencia de cerrados ou matas na vizinhanca inibiu o movimento nesta direcao e aumentou a taxa de retorno da cigarrinha as pastagens. O inseto se deslocou principalmente mediante saltos ou voos curtos e baixos (abaixo de 1 m). Uma proporcao aproximada de 4:1 (macho:femea) foi capturada nas armadilhas, indicando que os machos movimentam-se mais que as femeas. A velocidade media de movimentacao, de populacoes marcadas com po fluorescente atoxico e recapturadas apos periodos variaveis de liberacao, foi inferior a 5 m por dia. O movimento de dispersao de adultos nao contribui significativamente para a perda ou recrutamento de adultos em populacoes de D. flavopicta, a nao ser em casos de explosoes populacionais ou extincao local.