The density of females of Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) affects their reproductive performance on pupae of Bombyx mori L. (Lepidoptera: Bombycidae)

Palmistichus elaeisis Delvare and LaSalle (Hymenoptera: Eulophidae) is a gregarious and polyphagous parasitoid mainly of Lepidoptera pupae. The objective of this paper as to study the developent of parasitoid on Bombyx mori L. (Lepidoptera: Bombycidae) pupae exposed to one, nine, 18, 27, 36, 45 or 54 female P. elaeisis, respectively. The females of the parasitoid remained in contact with pupae for 24 hours in glass tubes (14.0 x 2.2 cm), packed in a climatic chamber regulated at 25 ± 2°C, 70 ± 10 percent relative humidity and photo phase of 12 hours. With the exception of density 1:1 (72.72 percent), in other densities parasitism was 100 percent. Adults of P. elaeisis did not emerge from pupae at densities of 1:1 and 9:1, but 100.0 percent of parasitoid emergence was observed at the density of 45:1 and 54.54 percent at 54:1. The duration of the life cycle of this parasitoid ranged from 20 to 28 days. P. elaeisis produced 49 to 589 descendants per pupa of B. mori. The sex ratio of P. elaeisis ranged from 0.93 ± 0.01 to 0.97 ± 0.01 without differences with 18, 27, 36, 45 and 54 females/host. This parasitoid should be reared with the density of 45 females per pupa of B. mori.

Palmistichus elaeisis Delvare e LaSalle (Hymenoptera: Eulophidae) é um parasitóide polífago, que inviabiliza, principalmente, pupas de lepidópteros. O objetivo desse trabalho foi estudar o desenvolvimento do parasitóide em pupas de Bobyx mori L. (Lepidoptera: Bombycidae) expostas a uma, nove, 18, 27, 36, 45 ou 54 fêmeas de P. elaeisis, respectivamente. As fêmeas do parasitóide permaneceram em contato com as pupas por 24 horas em tubos de vidro (14,0 x 2,2 cm), acondicionadas em câmara climatizada regulada a 25 ± 2°C, 70 ± 10 por cento de UR e fotofase de 12 horas. Com exceção da densidade 1:1 (72,72 por cento), nas demais densidades o parasitismo foi 100 por cento. Adultos de P. elaeisis não emergiram nas densidades de 1:1 e 9:1, mas observou-se 100 por cento de emergência do parasitóide na densidade 45:1 e 54,54 por cento em 54:1. A duração do ciclo de vida desse parasitóide variou de 20 a 28 dias. P. elaeisis produziu de 49 a 589 descendentes por pupa de B. mori. A razão sexual de P. elaeisis variou de 0,93 ± 0,01 a 0,97 ± 0,01 sem diferenças nas densidades de 18, 27, 36, 45 e 54 fêmeas/hospedeiro. Esse parasitóide deve ser criado na densidade de 45 fêmeas por pupa de B. mori.

Note on gynandromorphism in the eucalyptus defoliator Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae)

The brown moth Thyrinteina arnobia (Stoll, 1872) (Lepidoptera: Geometridae) is an important pest in Brazilian eucalyptus plantations. A gynandromorph individual of T. arnobia was found in a population of this pest in a laboratory rearing and it is described.

A mariposa marrom Thyrinteina arnobia (Stoll, 1872) (Lepidoptera: Geometridae) é uma praga importante em plantios de eucalipto no Brasil. Um indivíduo ginandromorfo de T. arnobia foi encontrado em uma população desta praga em criação de laboratório e descrito nesta nota.

Main lepidopteran pest species from an eucalyptus plantation in Minas Gerais, Brazil

Lepidoptera species were monitored in a plantation of Eucalyptus grandis in the Municipality of Bom Despacho, State of Minas Gerais, Brazil from March 1987 to February 1992. A total of 547 species were collected and divided in: primary pests: 13; secondary pests: 20; species without defined importance to eucalyptus: 79; and non-identified species: 435. These four groups had a mean of 5231.29; 338.18; 438.16 and 2222.87 individuals with a total of 8229.87 individuals collected per trap. The number of species without defined importance to eucalyptus, and non-identified species, increased during the collecting period of five years while those of primary and secondary pests showed similar numbers in all years. The most collected primary pests Thyrinteina arnobia Stoll and Stenalcidia sp. (Geometridae) showed higher frequencies during the driest and coldest periods of the year, whereas Psorocampa denticulata Schaus (Notodontidae) was most frequent during periods of higher rainfall. Species of groups III and IV increased in diversity with eucalyptus age. This area has a high probability of outbreaks of eucalyptus defoliating caterpillars, especially T. arnobia. For this reason, lepidopteran pests should be monitored in this plantation during the driest and coldest periods of the year, when they can reach population peaks.

De marzo de 1987 a febrero de 1992 se realizó un monitoreo con trampas luminosas en plantaciones de Eucalyptus grandis en Bom Despacho, Minas Gerais, Brasil. Se recolectaron 547 especies del orden Lepidoptera: plagas primarias: 13; plagas secundarias: 20; especies sin importancia definida para el cultivo de eucalipto: 79; y especies no identificadas: 435. Estos cuatro grupos tuvieron medias de 5231.29; 338,18; 438.16 y 2222.87 individuos por trampa respectivamente, para un total de 8229.87 lepidopteros recolectados por trampa. Durante los cinco años hubo un aumento del número de especies de los grupos III y IV. Las plagas primarias con mayor número de individuos fueron Thyrinteina arnobia Stoll y Stenalcidia sp. (Geometridae), con las mayores frecuencias para los meses más secos y fríos del año. Psorocampa denticulata Schaus (Notodontidae) fue más abundante en los periodos más lluviosos. La probabilidad de brotes de larvas desfoliadoras de eucalipto, principalmente T. arnobia, es alta en la región. Se recomienda hacer el monitoreo de lepidópteros plaga en los periodos más secos y fríos del año, cuando pueden presentar picos poblacionales.

Fertility and life expectancy of the predator Supputius cincticeps (Heteroptera: Pentatomidae) exposed to sublethal doses of permethrin

The stinkbug Supputius cincticeps (Stål) (Heteroptera: Pentatomidae) can be found in agricultural and forest ecosystems feeding primarily on larvae of Coleoptera and Lepidoptera, where it can be exposed to insecticide applications. This study therefore aimed to evaluate the reproductive potential of'S. cincticeps after exposition to sublethal doses of permethrin (5.74 x 10-3, 5.74 x 10-2, 5.74 x 10-1, 5.74 and 57.44 ppb) through the use of a fertility life table. The development cycle of this predator was determined in order to calculate its net reproductive rate (R0), the infinitesimal (rm) and finite (λ) rates of increase in addition to mean generation time (T). The net reproductive (18.31), infinitesimal (rm) (0.050) and finite (λ) (1.051) rates of increase were higher, while generation time (57.93 days) was shorter for S. cincticeps exposed to 5.74x10-1 ppb of permethrin than in the control. This indicates a higher rate of population increase of this predator when exposed to this permethrin dose.

Lepidoptera pests collected in Eucalyptus urophylla (Myrtaceae) plantations during five years in TrÛs Marias, State of Minas Gerais, Brazil

Lepidoptera pest species from eucalyptus were collected in Eucalyptus urophylla plantations in the region of TrÛs Marias, State of Minas Gerais, Brazil, every 15 days from June 1989 to June 1994 with five light traps. Twelve primary and 15 secondary pest species were collected in the period with an average of 13,387 and 812 individuals per light trap, respectively. Most collected primary pest species were Stenalcidia grosica (Geometridae), Iridopsis subferaria (Geometridae), Eupseudosoma aberrans (Arctiidae) and Psorocampa denticulata (Notodontidae), totalizing for the study period an average of 5,450, 2,162, 2,436 and 1,458 individuals per light trap, respectively. Idalus admirabilis (Arctiidae) was the most collected secondary pest species, averaging 652 individuals/trap. Most primary pest species were collected during the dry season, from April to July, whereas most secondary pest species were collected during the rainy season, from January to March. These differences on seasonal occurrence between the two groups could be due to the fact that many secondary pest species of Eucalyptus in Brazil pupate in the soil, and they need humidity to complete its pupal stage.