Extração de Alimento por Cosmoclopius nigroannulatus Stål (Hemiptera: Reduviidae) de Ninfas de Spartocera dentiventris (Berg) (Hemiptera: Coreidae)

Abstract

-The food extraction by Cosmoclopius nigroannulatus Stål from first-instar nymphs of Spartocera dentiventris (Berg) was evaluated. The experiment was conducted in laboratory. Ten newly emerged and individualized adults of each sex were used, for each of the five quantities of prey tested (5.1; 14.7; 29.8; 36.6; 44.8 mg, for males and 5.5; 14.7; 31.1; 37.4; 48.5 mg for females). During five days, the weight of the adults, the total amount of nymphs consumed and the weight of the remaining nymphs, the time spent to ingest the food, estimating the amount and the proportion of food extracted from each nymph, the amount extracted per minute, the remaining food, and the relative consumption rate were measured every 24h. For both sexes, there was an increase in the total consumption of nymphs, in the mean weight of the predator, in the remaining food and in the relative consumption rate, with increase of the amount of food and a decrease in the proportion of total consumption, the food quantity, the proportion extracted per prey and the amount of food extracted per minute. The total consumption and food quantity extracted per prey were 29.8 mg and e 31.1 mg, respectively, for males and for females. There was no correlation between time of ingestion and number of nymphs. Females consumed and gained more weight than males, ingesting more quickly. Our findings suggest that the feeding behavior of predator is directly related to the quantity of prey available.KEY WORDS: Predation, food consumption, handling time RESUMO -Avaliou-se a extração de alimento por Cosmoclopius nigroannulatus Stål, de ninfas de primeiro ínstar de Spartocera dentiventris (Berg). O experimento foi conduzido em laboratório, utilizando-se 10 adultos de cada sexo de C. nigroannulatus, recém-emergidos, em cada quantidade de ninfas de (5,1, 14,7, 29,8, 36,6 e 44,8 mg oferecidas aos machos e 5,5, 14,7, 31,1, 37,4 e 48,5 mg oferecidas às fêmeas). A cada 24h, por cinco dias, registrava-se o peso dos adultos, a quantidade total de ninfas consumidas, o peso das ninfas remanescentes, tempo gasto em ingerir o alimento, estimandose a quantidade e o percentual de alimento extraído de cada ninfa, a quantidade extraída por minuto, as sobras e a taxa de consumo relativa. Em ambos os sexos, houve um aumento no consumo total de ninfas ingeridas, no ganho de peso, nas sobras de alimento e na taxa de consumo, com o aumento da quantidade de ninfas oferecidas e uma diminuição na taxa de consumo total, na quantidade e no percentual de alimento extraído e na quantidade extraída por minuto. O consumo total e a quantidade de alimento extraído por presa estabilizaram-se a cerca de 29,8 g e 31,1 mg, respectivamente para os machos e para as fêmeas, não sendo evidenciada correlação do tempo de ingestão com o número de ninfas. As fêmeas consumiram e ganharam mais peso que os machos, ingerindo o alimento mais rapidamente. Os resultados sugerem que o comportamento alimentar do predador está diretamente relacionado com a quantidade de presas disponíveis.PALAVRAS-CHAVE: Preda...

Food extraction by the males of Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) from cotton leafworm larvae

“…1). Rocha et al (2002) also found similar results, showing an increase in the amount of food consumed and a decrease in the percentage of prey consumed by the females of Cosmoclopius nigroannulatus (Stal) (Hemiptera: Reduviidae) as the density of nymphs Spartocera dentiventris (Berg) (Hemiptera: Coreidae) from the 1st instar increased. According to Mukerji and LeRoux (1969), the increase in daily consumption of nymphs of P. maculiventris was proportional to the amount of prey available.…”

“…The effect of the prey density on the percentage of prey consumed by P. nigrispinus males depended of the adult age (F (age x density) = 3.98; P= 0.05) ( Table 2). Predator age also affected the consumption rates of predator C. nigroannulatus between their first and fifth days of life (Rocha et al, 2002). This could be due to physiological changes, and therefore, it was not dependent on the quantity of food consumed (Morris, 1963).…”

“…Holling (1966) found similar results when evaluating the consumption of larvae of D. melanogaster by the females of the predator H. crassa throughout 18 days. According to Rocha et al (2002), the consumption by the males of the Reduviidae C. nigroannulatus from 1st to 5th day of life was affected by the density and the age of the prey. This could be related to the demand of energy required for the development of reproductive structures and sexual activity, leading them to eventually ingest a greater quantity of food, resulting on a greater gain of weight (Holling, 1966).…”

Population fluctuation, immature mortality and adult longevity of Spartocera dentiventris (Berg) (Hemiptera: Coreidae) on Nicotiana tabacum (Solanaceae)

“…has also been observed by Silva et al (1968). Rocha (2002), in study on the food extraction from S. dentiventris nymphs by C. nigroannulatus, concluded that the reduvid can be considered a eficient predator on nymphs, showing a high potential as a biological control agent on tobacco crops.…”

“…Casual observations in the field indicated the presence of the predator Cosmoclopius nigroannulatus Stål (Heteroptera: Reduviidae) in high numbers in the system. Population dynamics and the funcional response of this reduvid were the focuses of the works of Jahnke et al (2002) and Rocha (2002), respectively. This knowledge is adding to build a very detailed picture of the system, which will eventually allow a well fundamented theoretichal analysis.…”