Tipos de resistência a Alabama Argillacea (Huebner, 1818) (Lepidoptera: Noctuidae) envolvidos em genótipos de algodoeiro: II. Antibiose

Cotton genotypes resistance to Alabama argillacea (Huebner, 1818) due to antibiosis has been evaluated in laboratory trials (at 27 ± 2°C, 70 ± 10% relative humidity and 14 hours photoperiod). Six different genetic materials (T 1122-13-1, STO 285 N, JPM 157, T 953-13-4-2, CNPA 9211-21, and CNPA 9211-31) have been tested in a completely randomized experimental design, with ten replications, each one with ten larvae/genotype. Larvae have been supplied with leaves daily. The following variables have been scored: time length of several insect stages (from larvae to adult), average mass of larvae and pupae as well as average larval, pre-pupal and pupal mortality rates. All genotypes have revealed longer overall average time length of stage duration from larvae to adult, as compared to STO 285 N; however, CNPA 9211-31 and CNPA 9211-21 have shown the smallest average mass of pupae along with high frequencies of pre-pupae and larvae to adult mortalities. The results strongly suggest that antibiosis is one of the resistance mechanisms to A. argillacea in that two cotton genotypes.

Feeding ecology, density and biomass of the freshwater turtle, Phrynops geoffroanus, inhabiting a polluted urban river in south-eastern Brazil

This study examines the ecology of a population of Geoffroy's side-necked turtle Phrynops geoffroanus inhabiting a polluted urban river in Ribeirão Preto city, São Paulo state, south-eastern Brazil. Adult turtles fed mainly on Chironomidae larvae and pupae (Chironomus cf. plumosus, 100% of occurrence frequency) and domestic waste, but they also consumed terrestrial items (cockroach, snails) and carrion. Juvenile turtles showed more feeding diversity than the adults and exhibited a trend for predation on Chironomidae pupae, but this is not reflected in resource partitioning. The elevated number of turtles (170-230 turtles/ha of river) and biomass (255-345 kg/ha of river) inhabiting this urban river is probably the result of the abundance of sewage and organic waste produced by humans, the absence of predators, and increased availability of nesting areas. Such factors convert this area into an environment highly advantageous for the survival of Geoffroy's side-necked turtle.

Ultrastructural and Cytochemical Aspects of Metamorphosis in the Midgut of Apis mellifera L. (Hymenoptera: Apidae: Apinae)

The midgut of Apis mellifera is remodeled during metamorphosis. The epithelium and, to a lesser extent, the muscular sheath degenerate between the end of the last larval instar and the onset of pupation (prepupa).The larval epithelium is shed to the midgut lumen and digested, while a new epithelium is reconstructed from larval regenerative cells. During pupation, some reorganization still occurs, mainly in brown-eyed pupae. In pharate adult, the midgut wall shows the characteristics of adult, although some cells have pycnotic nuclei. The localization of alkaline and acid phosphatases showed that these enzymes were not involved in the reabsorption of the midgut wall.

Influência de cultivares de batata-doce resistentes e suscetíveis a Euscepes postfasciatus fairmaire (Coleoptera: Curculionidae) sobre o parasitismo, sobrevivência e a biologia de Catolaccus grandis burks (Hymenoptera: Pteromalidae)

The influence of four resistant and two susceptible genotypes of sweet potato to Euscepes postfasciatus Fairmaire on parasitism and biology of Catolaccus grandis Burks were evaluated under laboratory conditions. Six sweet potato roots of each genotype were infested with E. postfasciatus adults during 40 days. After this period the larvae were taken, weighted and encapsulated in parafilm. Five larvae were offered in free choice and no choice tests to C. grandis pregnant females for 12h. Five replications were used. The parasitized larvae and the eggs of the parasitoid were counted. Three daily observations were made to determine the developmental time of phases and parasitoid survival. C. grandis females can distinguish E. postfasciatus larvae reared on susceptible and resistant roots, prefering to parasitize larvae reared on susceptible roots. C. grandis survival was higher when the parasitoid was reared on larvae originated from susceptible roots and the number of emerged females was higher on larvae reared on hosts originated from susceptible roots.

Variation of genetic expression during development, revealed by esterase patterns in Aedes aegypti (Diptera, Culicidae)

Polyacrylamide gel electrophoresis was used to analyze esterase patterns during development of Aedes aegypti from the cities of Marília and São José do Rio Preto (SJRP), Brazil. The zymograms showed a total of 23 esterase bands, 22 of which were in the specimens from Marília and 19 in those from SJRP. These esterase bands were considered to be the product of 23 alleles distributed tentatively in eight genetic loci. Most of the alleles were developmentally regulated. The larval stage expressed the greatest number of them (19 alleles, from the eight loci, in Marília; and 17 alleles, from seven loci, in SJRP). The pupal stage expressed 10 alleles from seven loci, in both populations, and the adult stage expressed 8 alleles from five and six loci in SJRP and Marília, respectively. Some alleles that were active in every stage were developmentally controlled at the level of expression (amount of product). A single allele was constitutively and highly expressed, in larvae, pupae, and adults, in both populations. Differences in esterase synthesis among stages are probably due to regulatory mechanisms acting in agreement with the requirements of a variable number of processes in which esterases are involved. The larval stage is the most active in developmental processes and shows very intense intake of food and very high mobility. These features may demand increased esterase production at that stage. Comparison of the two populations examined showed (besides the existence of alleles that they do not share) that they exhibit differences in the control of expression of other alleles. Such findings may reflect genetic differences between founders in each population, but the possibility of involvement of the intensive use of insecticides in SJRP is also discussed.

Spatial pattern of parasitism in Diatraea saccharalis Fab. (Lep., Crambidae) populations at two different spatial scales in sugarcane fields in Brazil

The biological control of Diatraea saccharalis is regarded as one of the best examples of successful classical biological control in Brazil. Since the introduction of the exotic parasitoid, Cotesia flavipes, the decrease in D. saccharalis infestation in sugarcane fields has been attributed to the effectiveness of this agent. Native Tachinidae fly parasitoids (Lydella minense and Paratheresia claripalpis) have also been implicated in the success. Quantitative data confirming the actual contribution of these agents to the control of D. saccharalis are, however, rather scant. The purpose of this study was to investigate the spatial pattern of parasitism of these parasitoids in D. saccharalis populations at two large spatial scales (fields and zones). To investigate this subject, a large data set comprising information collected from a sugarcane mill located in the state of São Paulo, Brazil (São João sugarcane mill) was analysed. When regressions between the proportion parasitism against host density were computed, the percentage of significant regressions with either a positive or a negative slope was very small at both spatial scales for both parasitoid species. Regressing the densities of tachinid-parasitized hosts against host densities per field showed that these parasitoids presented a 'moderate aggregative' response to host densities, as 53.33% of the regressions were positively significant. Cotesia flavipes was 'weakly aggregated' on host densities at the field level, because only 33.33% of the regressions were positively significant. At the zone level, neither aggregative nor spatial proportion parasitism responses were evident for either parasitoid species due to the small percentage of significant regressions computed.

Tabela de vida ecológica do minador-dos-citros, Phyllocnistis citrella stainton (Lepidoptera: Gracillariidae)

The construction of ecological life tables is a useful tool to understand the population dynamics of insects in the field. In this work, ecological life tables were developed for Phyllocnistis citrella (Stainton) in an orchard of Citrus sinensis situated in Santa Rita do Passa Quatro, Sao Paulo State, during 2002. The occurrence of generation overlay in the field was avoided by obtaining the eggs from infestation on young citrus plants (Citrus limonia) kept under controlled conditions. The samples were taken every other day and the number of live, dead, predated and parasitized individuals were recorded. The occurrence of arthropod predators was determined through visual search on the plants of the orchard. The key factors of mortality acting on P.citrella populations were: pupae parasitism caused by Ageniaspis citricola (Logvinovskaya), action of uncertain factors on prepupae and predation of 3rd-instar larvae. The most abundant arthropod predators belonged to the families Formicidae, Chrysopidae, Coccinellidae, Reduviidae e Araneae. In two of five generations of P. citrella, approximately 4% of A. citricola pupae were hyperparasitized by Galeopsomyia fausta (LaSalle) (Hymenoptera: Eulophidae).

On the immature stages of the crazy ant Paratrechina longicornis (Latreille 1802) (Hymenoptera: Formicidae)

The ant Paratrechina longicornis is a cosmopolitan ant species that has been accidentally spread by commerce around the world, and now is a pest of houses and hospitals. The morphology of its larval stages has been previously described without knowledge of the number of instars. The present study revisits the original description of P. longicornis larvae by adding differences observed among the three larval instars. Compared to other Paratrechina species studied so far, P. longicornis presents smaller larvae, less evident variation in mandible morphology, and clear variation in the morphology of head hairs between the analysed specimens of the second and third instar larvae. Ultrastructural images of the eggs, larval spiracle ornamentation, and pupae are also presented for the first time. Copyright © 2007 - Magnolia Press.

Nest defense behavior against the attack of ants in colonies of pre-emergent Mischocyttarus cerberus (hymenoptera, vespidae)

The study was carried out at the UNESP Rio Claro campus (SP), where biotests consisting of simulated ant attacks were performed in colonies of Mischocyttarus cerberus. The behaviors of the wasps were recorded with a camcorder, for further analysis. This analysis was done using the Mann-Whitney U test and the Principal Component Analysis. In the pre-emergence development stage, colonies with a single foundress defend the nest only after the first larvae appear. When there are only eggs in the nest, the wasp abandons the nest. Before leaving, the wasp rubs its gaster against the nest, releasing the ant repellent secretion. When the nest contains larvae or larvae and pupae, the foundress defends the colony, vibrating its wings, pumping her abdomen and biting the ant.

Microdon tigrinus (Diptera, Syrphidae): Populational fluctuations and specificity to the nest of Acromyrmex coronatus (Hymenoptera: Formicidae)

This study was performed in the southern and southeastern regions of Brazil, visiting numerous municipalities, over a period of 25 years, excavating nests of 12 species of leaf-cutting ants of the Acromyrmex genus. Larvae and pupae of Microdon tigrinus were found only in nests of the leaf-cutting ant Acromyrmex coronatus, indicating high specificity. Observation showed that larvae and pupae were well accepted in the nests and the adults, immediately after puparia eclosion and prior to wing distension, were not attacked by the workers, suggesting that they produce semiochemicals for a short time period until they arrive outside the Acromyrmex coronatus nest. It was postulated that these larvae feed on the organic detritus of the nest, as shown for Microdon larvae of other species.

Management of vomplex systems: Modeling the biological pest control

The aim of this paper is to study the cropping system as complex one, applying methods from theory of dynamic systems and from the control theory to the mathematical modeling of the biological pest control. The complex system can be described by different mathematical models. Based on three models of the pest control, the various scenarios have been simulated in order to obtain the pest control strategy only through natural enemies' introduction. © 2008 World Scientific Publishing Company.

Drosofilídeos e seus himenópteros parasitoides em coffea arabica L

The objective of this study was to evaluate the occurrence of Drosophilidae and their parasitoids in coffee fruits in Cravinhos, SP, Brazil. The fruits were collected directly from the tree, and a portion was exposed under the canopy. Fifty-nine drosophilid pupae were collected in all, of which 31 adults (including two Ganaspis exemplars) emerged. The survival rate of all pupae was 49.2%. Thirty-five drosopholid pupae were obtained from the fruit trees, 24 of which later emerged, three different species: Zaprionus indianus Gupta, Drosophila nebulosa Sturtevant and D. simulans Sturtevant. From the fruits under the canopy of plants were obtained 24 pupae of four different species: Z. indianus, D. cardini Sturtevant, D. immigrans Sturtevant and D. willistoni Sturtevant. The emergence of two Ganaspis sp. (Hymenoptera: Figitidae) examples, with a parasitism rate of 8.3%, was also observed. Half of the drosophilids collected are introduced species and represented 79% of the adults emerged. Associations between Z. indianus, D. cardini, D. immigrans, D. nebulosa, D. simulans and D. willistoni and the coffee crop are reported herein.

Impacts of enemy-mediated effects and the additivity of interactions in an insect trophic system

In this study, we used data from both experiments and mathematical simulations to analyze the consequences of the interacting effects of intraguild predation (IGP), cannibalism and parasitism occurring in isolation and simultaneously in trophic interactions involving two blowfly species under shared parasitism. We conducted experiments to determine the short-term response of two blowfly species to these interactions with respect to their persistence. A mathematical model was employed to extend the results obtained from these experiments to the long-term consequences of these interactions for the persistence of the blowfly species. Our experimental results revealed that IGP attenuated the strength of the effects of cannibalism and parasitism between blowfly host species, increasing the probability of persistence of both populations. The simulations obtained from the mathematical model indicated that IGP is a key interaction for the long-term dynamics of this system. The presence of different species interacting in a tri-trophic system relaxed the severity of the effects of a particular interaction between two species, changing species abundances and promoting persistence through time. This pattern was related to indirect interactions with a third species, the parasitoid species included in this study. © 2012 The Society of Population Ecology and Springer Japan.

Classification of crucifer cultivars based on the life-history of diamondback moth (Plutella xylostella)

We compared different cultivars and hybrids of crucifers in relation to development and life-history of diamondback moth (Plutella xylostella) to classify the plants according to their resistance to the pest. The plants used were Manteiga da Geórgia kale, Bola de Neve cauliflower, Ramoso Piracicaba Precoce broccoli, Chato-de-quintal cabbage, and the hybrid cabbages Midori, TPC668, TPC308, and TPC681. We evaluated performance daily until the pupal stage. Pupae were assessed individually to determine the pupal weight, performance, and pupal period. We determined the sex ratio, fecundity, fertility, and longevity of the emerged adults and calculated their reproductive potential. Cabbage hybrids TPC668, TPC308, and TPC681 do not support the development and reproduction of the diamondback moth. These hybrids show a level of resistance that is similar to that found the commercially available hybrid Midori and cultivar Chato de Quintal, which are known to be resistant to the diamondback moth. This finding implies that the capitata (cabbage) cultivars are the most suitable for planting because they are more resistant to pest than the cultivar's moth, acephala (kale). © 2013 Copyright Taylor and Francis Group, LLC.

Efeito de cultivares de repolho e doses de extrato aquoso de nim na alimentação e biologia de Plutella xylostella (linnaeus) (lepidoptera: Plutellidae)

The isolated and associated effects of cabbage cultivars Ruby Ball and Chato de Quintal and aqueous extract of seeds of fruits of neem (Azadirachta indica A. Juss.) were evaluated in the concentrations of 5 and 10% on Plutella xylostella (L.) attractiveness, feeding and development. In free-choice no-preference for feeding test, leaf discs of each treatment were placed in Petri dishes where three caterpillars/treatment were released while in no-choice test two caterpillars were placed in Petri dishes with one leaf disc in each dish. In the biology test, neonate larvae were transferred to Petri dishes in the proportion of one per dish, whereas the biological parameters were evaluated: larvae mortality after 1, 3 and 5 days; pupae mortality; total mortality; six day-old larvae weight; 24 hour-old pupae; and adult longevity. Cultivar Ruby Ball showed lower attractiveness to the caterpillars in free-choice test. Neem extract in both concentrations was repellent to the caterpillars in free-choice test. There were no differences in the dry mass consumed by the caterpillars in free-choice and no-choice tests. There were no differences in larval, pupal and total mortality between the cultivars. Both doses of neem extract were equally efficient in the mortality of the diamondback moth. There were no differences in caterpillars and pupae weight and in the longevity of the adults of P. xyostella between the cultivars.