As vespas sociais são predadoras de muitas espécies de insetos e o estudo de suas presas pode revelar seu potencial para programas de controle biológico de pragas. Foram realizadas 240h de coleta de presas em 32 colônias de Polistes versicolor (Olivier) no município de Juiz de Fora, MG, de março de 2000 a fevereiro de 2001. As presas capturadas por P. versicolor foram, principalmente, das ordens Lepidoptera (95,4%) e Coleoptera (1,1%) além de 3,4% de indivíduos não identificados. A espécie mais coletada foi Chlosyne lacinia saundersii Doubleday & Hewitson (13,5%) (Lepidoptera: Nymphalidae) e o número total estimado de presas capturadas por colônia de P. versicolor foi de 4.015 indivíduos por ano. Isso mostra que a espécie pode ser utilizada em programas de manejo integrado de pragas de insetos herbívoros, principalmente lagartas desfolhadoras.

The social wasps are predators of many insect species and the study of their preys can reveal the potential of these natural enemies in biological control programs. A total of 240h of collections of preys in 32 nests of Polistes versicolor (Olivier) was carried on in Juiz de Fora, Minas Gerais State, Brazil, from March 2000 to February 2001. The preys captured by P. versicolor were mainly those from the orders Lepidoptera (95.4%) and Coleoptera (1.1%) while 3.4% of them were not identified. Chlosyne lacinia saundersii Doubleday & Hewitson (Lepidoptera: Nymphalidae) was the most collected prey (13.5%). The total of 4,015 preys was estimated to be captured per colony of P. versicolor during one year. The species can be used in integrated pest management of herbivorous insects, especially defoliating caterpillars.

As vespas sociais são predadoras de várias espécies de insetos e, portanto, o estudo de suas presas pode revelar seu potencial para programas de controle biológico de pragas. Durante o período de setembro de 2000 a janeiro de 2002, foram realizadas 70h de coleta de presas capturadas em doze ninhos de Polybia platycephala Richards, localizados em áreas urbanas do município de Juiz de Fora, MG. As presas capturadas por P. platycephala compreenderam cinco ordens de insetos: Diptera (33,4%), Lepidoptera (28,6%), Hemiptera (12,0%), Hymenoptera (9,4%) e Coleoptera (7,2%). O peso médio da carga protéica transportada pelas vespas foi 1,9 ±1,6 mg (n = 34, 0,3 - 6,2 mg), e a taxa média de proteína transportada por dia foi 22,8 mg. De acordo com os resultados, pode-se estimar a captura de 4.380 presas por ano por uma única colônia de P. platycephala. Desta forma, a espécie pode ser utilizada em programas de manejo em ambientes urbanos contribuindo para o controle de insetos pragas como larvas de pernilongos, lagartas desfolhadoras de plantas de jardins, pulgões e formas aladas de formigas.

The social wasps are predators of several species of insects and the study of their preys can reveal their potential for programs of biological pest control. During the period of September 2000 to January 2002, were accomplished 70h of collections of the preys captured in twelve nests of Polybia platycephala Richards, placed in urban areas of Juiz de Fora municipality, Minas Gerais State, Brazil. The preys captured by P. platycephala include five orders of insects: Diptera (33.4%), Lepidoptera (28.6%), Hemiptera (12.0%), Hymenoptera (9.4%) e Coleoptera (7.2%). The mean weight of protein charge carried by the wasps was 1.9 ±1.6mg (n = 34, 0.3 - 6.2 mg), and the mean of protein transported per day was 22.8 mg. According to the results, we could estimate that 4,380 preys are captured by a single colony of P. platycephala during one year. Thus, this species could be used in management programs of urban pests, helping the equilibrium of this environment.

Realizaram-se estudos sobre as formas de reprodução de Stenolobium stans (Juss.) Seem e determinou-se a diversidade, freqüência e constância dos insetos visitantes nas flores em diferentes horas, durante quatro anos. As flores de S. stans começam a se abrir nas primeiras horas do dia entre 5 e 6h, com duração de 3 a 8h. Quando o estigma está receptivo, o pólen tem 90% de viabilidade. Além do pólen, a flor possui outros atrativos para os insetos visitantes, ou seja, os osmóforos responsáveis pelo odor adocicado, luz ultravioleta refletida e néctar com 25% de açúcar. A planta é autocompatível, reproduzindo-se por autogamia, geitonogamia ou xenogamia o que determina a necessidade de polinizadores externos e justifica ser a espécie vegetal em estudo uma séria invasora de campos e pastagens. Grande diversidade de insetos foi verificada visitando as flores, com predominância das abelhas. Os polinizadores foram Centris collaris Lepeletier, Bombus morio (Swederus), Eulaema nigrita Lepeletier e Epicharis sp. No meio rural houve menor incidência das espécies nativas do que no ambiente urbano, com predominância da abelha introduzida Apis mellifera L. Fatores ambientais, principalmente a temperatura, luminosidade, umidade relativa do ar e velocidade do vento, influenciaram a atividade forrageadora dos insetos.

Studies on the different ways of reproduction of Stenolobium stans (Juss.) Seem and on the diversity, frequency and constancy of flower-visiting insects at different hours were carried out during four years. The S. stans flowers open between 5 and 6 am during 3 to 8h, with 90% pollen viability. Besides the pollen, the flower has other features that are attractive to the visiting insects, like osmophores responsible for a sweet odor, ultra-violet reflected light and nectar at 25% of sugar. The plant is autocompatible and reproduces by autogamy, geitonogamy or xenogamy. This behavior demands external pollination and justifies the species to be a serious invasor of grounds and pastures. Large diversity of insects were observed visiting the flowers, with predominance of bees. The pollinators species were Centris collaris Lepeletier, Bombus morio (Swederus), Eulaema nigrita Lepeletier and Epicharis sp. The incidence of native species was lower at the rural area than at the urban one, with predominance of the exotic Apis mellifera L. The environmental factors, mainly temperature, light, relative humidity and wind speed, influenced the foraging activity of the insects.

Inspite of Etythrina species exhibit morphologic attributes for adaptation to pollination by nectarivorous birds mentioned in the literature, E. speciosa is pollinated by lots of bees (Apinae and Meliponinae) which show a great urban occurrence. Systems of E. speciosa floral reproduction, fenology, diversity, frequency and constancy of insects visiting at different hours and flowering periods were studied. E. speciosa is Biocompatible, but xenogamy is the predominant system of reproduction. A large diversity of insects visiting the inflorescences was observed, with predominance of bees. The bee species showed a higher frequency: Apis mellifera Linnaeus, 1758 (45,0 %), Trigona spinipes (Fabricius, 1793) (28,6%), Trigona hyalinata (Lepeletier, 1836) (12,2 %) and the ant Zacryptoceruspusillus Klug, 1824 (2,8 %). Constant but not frequent were the bees (Apidae) Plebeia droryana (Friese, 1900), Friesella schrottkyi (Friese, 1900), Nannotrigona testaceicornis (Lepeletier, 1836), Tetragonisca angustula (Latreille, 1811), the wasps (Vespidae) Polybia paulista Ihering, 1896, Protopolybia exigua (de Saussure, 1854), Agelaia pallipes (Olivier. 1791), the ant (Formicidae) Pseudomyrmex sp. and the beetle (Chrysomelidae) Diabrotica speciosa (Germar, 1824). E. speciosa flowers were visited by hummingbirds (Trochilidae): Eupetomena macroura (Gmelin, 1788), Clorostilbon aureoventris (d'Orbigny & Lafresnaye, 1838) and Amazilia sp. The birds Passer domeslicus (Linnaeus, 1758) (Ploceidae) and Coereba flaveola (Linnaeus, 1758) (Emberizidac), also are present. The frequency and insect distribution were influenced by ambiental factors. Temperature, light, time, barometric pressure, relative humidity and wind velocity were significantly correlated with insect numbers. There is a visit sequence, by floral resource disponibility during the day, conditioned by transport ability, insect numbers and colony necessity, which begins by A. mellifera followed by meliponid bees. These bees make the pollination when they collect the pollen. There is a great animal variety which are sustained by flowers. It is suggested that E. speciosa is one important food source for urban fauna in winter, and so it should be utilized more frequently in streets, parks and gardens arborization.

Realizaram-se estudos sobre sistemas de reprodução de Cassia spectabilis (L.) D C. (Leguminosae) observando-se a diversidade, freqüência e constância dos insetos visitantes em diferentes horários. Também testou-se a influência dos fatores ambientais em relação às visitas. Os resultados de polinização manual sugerem que C. spectabilis é autocompatível, porém, a xenogamia é o sistema de reprodução predominante. As inflorescências foram visitadas por uma grande quantidade de insetos, havendo predominância de abelhas. O horário de maior ocorrência dos insetos nas flores de C. spectabilis foi das 8 às 14 h e de menor ocorrência entre 7 e 8 h e das 17 às 18 h. Quanto ao comportamento dos insetos em relação à flor de C. spectabilis, observou-se que Xylocopa frontalis Olivier, X. suspecta Camargo & Moure, Bombus morio Swederus e Centris scopipes Friese possuem comportamento e morfologia adequados aos polinizadores legítimos; C. similis F., Oxaea flavescens Klug e Epicharis rustica flava Cockerell foram considerados polinizadores ocasionais. Pseudaugochloropsis graminea (F.), Tetragonisca angustula Latreille e A. mellifera L. foram considerados pilhadores. A polinização por vibração é o método usado pelas abelhas para coleta de pólen.

Studies on reproduction of Cassia spectabilis (L.) and on diversity, frequency and constancy of the insects visiting the Leguminosae at different hours were carried out. Observations in the field concerned insect behavior and were followed by their captures, and influence of the abiotic factors was recorded. A pollen viability test showed that 98% was positive. A test for manual pollination suggested that C. spectabilis is autocompatible, but xenogamy is the predominant system of reprodution. Inflorescences were visited by a large number of insects, with predominance of bees. The visiting time of flowers of C. spectabilis by insects had a peak between 8 and 14 h and the lowest ocurrence period were between 7 and 8 h and 17 and 18 h. While Xylocopa frontalis Olivier, X. suspecta Camargo & Moure, Bombus morio Swederus and Centris scopipes Friese have the morphology and the behavior adapted for pollinators legitimate; C. similis F., Oxaea flavescens Klug and Epicharis rustica flava Cockerell were considered occasional pollinators. Pseudaugochloropsis graminea (F.), Tetragonisca angustula Latreille and A. mellifera L. were considered pirates or robbers. The "buzz pollination" is the method used by the bees to pollen collect.

The corn is a plantation attacked by a lot of pests, mainly by Caterpillar Spodoptera frugiperda (Smith), producing serious damages in the plants, occasioning unproductiveness. Thus, the goal of this research was to verify the predation of Polistes simillimus (Zikán, 1951) wasps on this pest of a corn plantation using the wasps colonies as a efficient form of this pest management. The present research was developed in a area in the Piracicaba county, São Paulo (22º43'S, 47º38'W), during the period of november/1995-march/1996, introducing 20 P. simillimus colonies in artificial wood shelters around of 5 plots of com, to accompany the foraging activity of the wasps and the development of the wasps colonies. Spodoptera frugiperda (23,07%) was the main prey captured by the wasps and the average rate of capture was 1,54 preys/h. These data gave an estimation of reduction in the occurrence of S. frugiperda (77,16%), due mainly to the wasps action.