ABSTRACT
O Brasil tem excelentes condições climáticas para a exploração comercial da goiabeira Psidium guajava L. (Myrtaceae); porém, em todo o país, a cultura é atacada por insetos-praga, sendo Triozoida limbata Enderlein, 1918 (Hemiptera: Triozidae) uma das pragas dessa cultura. Como o controle químico dessa praga é muito oneroso e, muitas vezes, indesejável, a utilização de parasitoides é uma excelente alternativa, pois pode atuar eficientemente na regulação das populações dos seus hospedeiros. Assim, este trabalho objetivou identificar as espécies de parasitoides ocorrentes e seus índices de parasitismo natural em T. limbata no cultivo da goiabeira, em Ivinhema, MS. Foram realizadas coletas quinzenais de março a outubro de 2010, sendo coletados dez ramos terminais das plantas com ninfas de T. limbata, por coleta, sempre no início da manhã. Estes ramos tinham suas bases enroladas em algodão hidrófilo, introduzidas em frascos de vidro (5mL) com água e acondicionados em copos transparentes de acrílico justapostos, e assim mantidos até que ocorresse a emergência dos parasitoides adultos. Para identificação, foram calculadas a porcentagem e o índice de parasitismo natural. Do total de 349 espécimes de parasitoides encontrados, 91,11% foi Psyllaephagus trioziphagus Howard, 1885 (Hymenoptera: Encyrtidae), com 20,96% de parasitismo natural, e 8,89% foram representantes do gênero Signiphora, com 2,04% de parasitismo natural.
Brazil has an excellent climate for commercial use of guava Psidium guajava L. (Myrtaceae). However, guava crops throughout Brazil are severely attacked by the insect Triozoida limbata Enderlein, 1918 (Hemiptera: Triozidae), one of the pest of guava crops. The control of this pest with chemicals is costly and often undesirable, whereas parasitoids are a great alternative because they can efficiently regulate their host populations. This study aimed to identify the parasitoid species in T. limbata occurring in a guava plantation and their rates of parasitism, in Ivinhema, MS, Brazil. Data were collected every two weeks early in the morning from March to October 2010, collecting 10 terminal branches from plants with T. limbata nymphs. The base of the branches were wrapped in cotton wool, placed in 5-mL glass vials with water, packed in transparent acrylic glasses, juxtaposed, and maintained until adult parasitoids emerged. These samples were used to calculate the percentage and index of parasitism. From the 349 parasitoid specimens found, 91.11% were Psyllaephagus trioziphagus Howard, 1885 (Hymenoptera: Encyrtidae) with 20.96% of parasitism, whereas 8.89% were from the genus Signiphora with 2.04% of parasitism.
ABSTRACT
Introduction In Triatominae, reproductive efficiency is an important factor influencing population dynamics, and a useful parameter in measuring a species' epidemiological significance as a vector of Trypanosoma cruzi (Chagas, 1909). The reproductive efficiency of triatomines is affected by food availability; hence, we measured and compared the effects of feeding frequency on the reproductive parameters of Triatoma patagonica (Del Ponte, 1929) and Triatoma infestans (Klug, 1934), and the effects of starvation on T. patagonica. Methods Couples from both species were fed weekly, or every 3 weeks; in addition, females in couples of T. patagonica were not fed. Each couple was observed weekly and reproductive efficiency was assessed on the following parameters: fecundity (eggs/female), fertility (eggs hatched/eggs laid), initiation and end of oviposition, initiation of mating, number of matings/week, and number of reproductive weeks. Relative meal size index (RMS), blood consumption index (CI), and E values (eggs/mg blood) were also calculated. Results Changes in feeding frequency affected the reproductive parameters of T. patagonica only, with a decrease in fecundity and number of reproductive weeks for those fed every 3 weeks, or not fed. The reproductive period, RMS index, and CI were lower for T. patagonica than T. infestans. However, despite the lower fecundity of T. patagonica, this species required less blood to produce eggs, with an E values of 2 compared to 2.94 for T. infestans. Conclusions Our results suggest that the differences in fecundity observed between species reflect the availability of food in their natural ecotopes. .
Subject(s)
Animals , Female , Male , Feeding Behavior/physiology , Insect Vectors/physiology , Triatoma/physiology , Insect Vectors/classification , Population Dynamics , Reproduction/physiology , Starvation , Sexual Behavior, Animal/physiology , Triatoma/classificationABSTRACT
La calidad de las plantas ornamentales se relaciona estrechamente con su estado fitosanitario, que se ve afectado por la actividad de los insectos. Entre los principales insectos plagas se destacan los pulgones o áfidos. La fauna asociada con los áfidos que colonizan plantas ornamentales, incluye hormigas melívoras (Hymenoptera: Formicidae) que establecen relaciones de mutualismo; además, los microhimenópteros parasitoides de áfidos (Hymenoptera: Braconidae, Aphidiinae) contribuyen al control de estos insectos plaga. Se conoce muy poco sobre estos grupos de insectos en plantas ornamentales de Córdoba, Argentina. El objetivo de este trabajo es dar a conocer los áfidos que colonizan plantas ornamentales, como así también las hormigas melívoras y parasitoides asociados. Para ello, brotes, hojas y/o flores de las plantas ornamentales colonizadas por áfidos fueron colectadas semanalmente en el Jardín Botánico Municipal de la ciudad de Córdoba, desde Octubre 2003 a Noviembre 2004. También se colectaron las hormigas melívoras asociadas y las "momias" de áfidos parasitados. Se registraron 132 asociaciones áfido-planta ornamental, de las cuales el 64,4 por ciento no se conocían en el país. Los áfidos fueron atendidos por hormigas melívoras en el 33,3 por ciento de las asociaciones, mientras que en el 16,7 por ciento se registró la presencia de parasitoides. Las especies involucradas incluyen 95 de plantas ornamentales colonizadas por 41 de áfidos, mientras que seis de hormigas melívoras atendieron a 10 de áfidos. Los parasitoides estuvieron representados por cuatro especies que estuvieron relacionadas con 11 de áfidos.
The quality of the ornamental plants is closely related to their phytosanitary state, that, in turn, is affected by the activity of some insect groups. Aphids are common pests of nearly all kinds of plants, ornamental plants among them. The fauna associated with aphids that colonize ornamental plants includes honey ants (Hymenoptera: Formicidae) that establish mutualistic relations, and some parasitoids (Hymenoptera: Braconidae, Aphidiinae) that contribute to the control of the aphid population. Very little is known about the aphids and their associated fauna living on ornamental plants of Cordoba, Argentina. The goal of this work was to identify the aphids that colonize ornamental plants, as well as their associated honey ants and parasitoids. Samples of sprouts, leaves and/or flowers of aphid-colonized ornamental plants of the Jardín Botánico Municipal of Cordoba city were collected weekly, from October 2003 to November 2004. Whenever found, the associated honey ants and "mummies" of aphids atacked by parasitoids were also collected. One hundred and thirty two aphid-plant associations were registered, 64.4 percent of which were unknown in the country. In 33.3 percent of these associations, the aphids were tended by honey ants whereas the presence of aphid parasitoids was registered in 16.7 percent. Ninety five species of ornamental plants were colonized by 41 aphid species, whereas six ant species tended 10 aphid species. Aphid parasitoids were represented by four species related to 11 aphid species.