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Search Results: 1 - 10 of 494 matches for " predation "
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Aedes aegypti survival in the presence of Toxorhynchites violaceus (Diptera: Culicidae) fourth instar larvae
Albeny, Daniel S;Martins, Gustavo F;Andrade, Mateus R;Krüger, Rodrigo F;Vilela, Evaldo F;
Zoologia (Curitiba) , 2011, DOI: 10.1590/S1984-46702011000400017
Abstract: the mosquito aedes aegypti (linnaeus, 1762) is the main vector of dengue and yellow fever viruses. different methods have been used to control a. aegypti, including chemical and biological tools. however, chemical control can lead to a subsequent increase in the mosquitoes' insecticide resistance, and biological control represents an important method as an alternative to insecticide usage. larvae from the toxorhynchites genus (diptera: culicidae) are predators of other mosquitoes and represent a potential natural biocontrol agent of a. aegypti larvae. in the present work, a. aegypti larval survival was studied in the presence of the neotropical toxorhynchites violaceus (wiedemann, 1821) fourth instar larvae. toxorhynchites violaceus consumption of a. aegypti increased during the 192 hours of the experiment and was more marked in the intervals between 96 and 120 hours and between 168 and 192 hours, when the a. aegypti survival reached 0%. during the fourth instar, t. violaceus increased its predation on a. aegypti larvae, possibly in order to increase its nutrient storage prior to pupation. otherwise, low prey consumption can lead to a nutritional deficit for the larvae, delaying the adult's sexual development and reducing its egg production. here we show that a. aegypti survival can be reduced by the t. violaceus fourth larvae predation under laboratory conditions
Reciprocal Trophic Interactions and Transmission of Blood Parasites between Mosquitoes and Frogs
Laura V. Ferguson,Todd G. Smith
Insects , 2012, DOI: 10.3390/insects3020410
Abstract: The relationship between mosquitoes and their amphibian hosts is a unique, reciprocal trophic interaction. Instead of a one-way, predator-prey relationship, there is a cyclical dance of avoidance and attraction. This has prompted spatial and temporal synchrony between organisms, reflected in emergence time of mosquitoes in the spring and choice of habitat for oviposition. Frog-feeding mosquitoes also possess different sensory apparatuses than do their mammal-feeding counterparts. The reciprocal nature of this relationship is exploited by various blood parasites that use mechanical, salivary or trophic transmission to pass from mosquitoes to frogs. It is important to investigate the involvement of mosquitoes, frogs and parasites in this interaction in order to understand the consequences of anthropogenic actions, such as implementing biocontrol efforts against mosquitoes, and to determine potential causes of the global decline of amphibian species.
Wolbachia screening in spiders and assessment of horizontal transmission between predator and prey
Yun, Y;Peng, Y;Liu, FX;Lei, C;
Neotropical Entomology , 2011, DOI: 10.1590/S1519-566X2011000200002
Abstract: recent studies have revealed that the prevalence of wolbachia in arthropods is attributable not only to its vertical transmission, but also to its horizontal transfer. in order to assess the horizontal transmission of wolbachia between predator and prey, arthropods belonging to 11 spider families and six insect families were collected in the same field of rice. the distribution of wolbachia in these arthropods was detected by diagnostic pcr amplification of the wsp (wolbachia outer surface protein gene) and 16s rdna genes. nurscia albofasciata strand (araneae: titanoecidae), propylea japonica thunberg (coleoptera: coccinellidae), paederus fuscipes curtis (coleoptera: staphylinidae), and nilaparvata lugens stal (homoptera: delphacidae) were infected with wolbachia. this is the first report of infection of n. albofasciata and p. fuscipes by wolbachia. no direct evidence indicated the existence of horizontal transmission of wolbachia between predator and prey.
Diversidad de insectos capturados por ara?as tejedoras (Arachnida: Araneae) en el agroecosistema cacao en Tabasco, México
Pérez-de La Cruz, Manuel;Sánchez-Soto, Saúl;Ortíz-García, Carlos F.;Zapata-Mata, Raúl;Cruz-Pérez, Aracely de la;
Neotropical Entomology , 2007, DOI: 10.1590/S1519-566X2007000100011
Abstract: the aim of this work was to know the diversity of insects captured by weaver spiders in a plantation of cocoa (theobroma cacao l.) of 6 ha in the state of tabasco, mexico. the study was carried out from july 2004 to june 2005 by means biweekly samples of the insects captured on the spiders webs. the total of 3,041 webs of 54 species of spiders belonging to seven families (araneidae, theridiidae, tetragnathidae, uloboridae, pholcidae, dyctinidae and linyphiidae) were revised. we found 1,749 specimens belonging to 10 orders of insects, represented by 93 families, the majority of coleoptera, diptera and hemiptera that constituted 74% of the identified families. the biggest number of specimens of all orders was captured by araneidae, except of isoptera, whose specimens were captured mainly by the family theridiidae. the index of diversity (h'), evenness (j') and similarity (is), applied to know the diversity of families of insects captured among families of spiders, varied from 0.00 to 3.24, 0.00 to 0.81, and 0.04 to 0.522, respectively. we conclude that there is a wide diversity of insects predated by the weaver spiders in the cocoa agroecosystem, and that there are species that can be promising for the biological control of pests.
Feeding dynamics of Cichla kelberi Kullander & Ferreira, 2006 introduced into an artificial lake in southeastern Brazil
Villares Junior, Gilberto Aparecido;Gomiero, Leandro Muller;
Neotropical Ichthyology , 2010, DOI: 10.1590/S1679-62252010005000008
Abstract: the objective of this study was to characterize the seasonally of the diet of cichla kelberi in an artificial lake in leme-sp, determining the food items and their relation to the sex and gonadal maturity of the fish sampled. the diet of c. kelberi presents a dynamic in three different periods: winter months were characterized by low feeding activity and a high concentration of undetermined fish; increase in feeding activity occurred in the spring, with tilapia sp. being the dominant food item; and a high rate of cannibalism was observed in the summer and early fall. the plasticity in the composition of the diet was marked by quantity of prey available during the different periods of the year, and the reproductive period.
First report of predation on floral visitors by crab spiders on Croton selowii Baill. (Euphorbiaceae)
Novo, Reinaldo Rodrigo;Souza, Jefferson Thiago;Castro, Cibele Cardoso de;
Acta Botanica Brasilica , 2010, DOI: 10.1590/S0102-33062010000200029
Abstract: in the literature it has been extensively mentioned that crab spiders (araneae: thomisidae) prey on floral visitors of several plant species. here we present observations of croton selowii baill. (euphorbiaceae), a monoecious species harboring individuals of crab spiders in an area of coastal vegetation of pernambuco state, brazil. the species is visited by several invertebrate orders, and some of them were preyed upon by the spiders, mainly diptera species. the spiders rubbed the forelimbs within the flowers, which may constitute a strategy to camouflage these structures. croton selowii seems to represent a suitable foraging site for the spiders, because it has a generalist pollination system (thus being visited by a wide range of invertebrate species) and blooms in a period of low flower resource availability in the area.
Dial behavioral responses of Metamysidopsis elongata atlantica (Crustacea, Mysida) to gradients of salinity and temperature
Gama, Andréa M. da S;Calazans, Danilo;Fontoura, Nelson F;
Iheringia. Série Zoologia , 2011, DOI: 10.1590/S0073-47212011000100014
Abstract: metamysidopsis atlantica elongata (bascescu, 1968) is a common mysid in the surf zone of sandy beaches from the state of rio grande do sul, brazil, where it is frequently recorded forming dense aggregations. trough laboratory trials, behavioral responses to salinity (10, 20, 25, 28, 30, 40 e 45), temperature (10, 15, 20, 30±1oc) and light (yes/no) were tested using adult males, adult females and juveniles. although there was no response to temperature, the species showed clear response to salinity and light. in the presence of light, organisms remained in the bottom of the aquaria, but moved to surface when bottom salinities were increased. in the absence of light, adults moved to the surface. however, juveniles moved down to or remained on the bottom, maybe as a response to avoid adult predation.
Resposta funcional de Scymnus (Pullus) argentinicus (Weise) (Coleoptera: Coccinellidae) a diferentes densidades do pulg?o verde Schizaphis graminum (Rond. ) (Homoptera: Aphididae)
Vieira, Gilvania F.;Bueno, Vanda H. P.;Auad, Alexander M.;
Anais da Sociedade Entomológica do Brasil , 1997, DOI: 10.1590/S0301-80591997000300012
Abstract: the functional response, search time and handling time of the predator scymnus (pullus) argentinicus (weise) were evaluated. nymphs of 3rdand 4th instars of the greenbug, schizaphis graminum (rond.), were provided as food. the statistical design was randomly in a factorial 3 x 5, with three densities of the greenbug (10, 25, 35 nymphs) and four instars and adult of the predator, in 10 replications. tests were conducted in an environmental chamber at 25± 1oc, 70± 10% rh and 14 hours photophase. for both larvae and adults of s. (pullus) argentinicus the amount of predated nymphs increased with the increment of aphid densities, until reaching a plateau (functional response type ii). predation in the 4th instar was higher and greater for the density of 35 nymphs compared to the densities of 10 and 25 nymphs. the increment in predation increased, from density 10 to 25, but decreased at density 25 to 35 nymphs. the search time incresead gradually with the age of the predator, while the handling time decreased with the age. adult females presented higher predation and searched faster for prey than males. searching time decreased with the increase in aphid density.
Hábitos alimentares e uso de abrigos por Chrotopterus auritus (Chiroptera, Phyllostomidae)
Witt,André Alberto; Fabián,Marta Elena;
Mastozoolog?-a neotropical , 2010,
Abstract: chrotopterus auritus (peters, 1856) (phyllostomidae, chiroptera) is the only species of carnivorous bat recorded in rio grande do sul state. in this work we identified the diet ítems and observed their spatial distribution within roosting sites at daytime. we monitored seven caves, every fifteen days, from may/2002 to april/2003, in machadinho and barracáo counties, rio grande do sul state, brazil. the diet was inferred from fecal samples (n=67) and food remains (n=63). mammals, birds and arthropods, composed the diet of the c. auritus. c. auritus did not show preference by food ítems, such as mammals, birds or arthropods, because there were no significant differences among them in fecal samples. the result was similar when comparing the presence of these ítems between seasons. rodents, passeriformes and coleopterans were the prevailing ítems in the diet of the c. auritus. fruits were consumed occasionally, about 5.9% of the total of the samples. c. auritus was, during the whole study period, present in the studied caves, varying in number of individuáis and shelters. cohabitation with desmodus rotundus and myotis nigricans was observed.
Factors influencing predation of the Waterbugs Sphaerodema annulatum (Fab.) and S. rusticum (Fab.) on the Disease Transmitting Snail Lymnaea (Radix) luteola (Lamarck)
Roy, J. K.;Raut, S. K.;
Memórias do Instituto Oswaldo Cruz , 1994, DOI: 10.1590/S0074-02761994000100003
Abstract: variations in the rate of predation of the waterbugs sphaerodema annulatum and s. rusticum on the snails lymnaea (radix) luteola have been noted in respect to the morphs of the waterbugs, size of the prey individuals, densities of prey and predators, temperature and surface area of the waterbody concerned and the seasons. consumption rate was highest (7.2 and 2.2 individuals per day per individual of s. annulatum and s. rusticum, respectively) in prereproductive ages of the waterbugs. this was followed by a gradual decline with the increase in age of the predators. the consumption rate was gradually higher with the increase of temperature from 20 °c to 35 °c. the bugs failed to survive beyond 35 days at 35 °c. though the bugs prey upon the snails of all sizes preference for 6.5 ÷ 4.5 mm to 8 ÷ 5 mm individuals by s. annulatum and for 5 ÷ 3 mm to 6.5 ÷ 4.5 mm individuals belonged to 3 ÷ 2 - 4 ÷ 3 mm size group maximum when supplied separately. the rate of predation gradually declined with the rise of predator's desity irrespective of waterbug species. predation rate increased with increasing prey density. this was level off when the prey snails were 1100 and 700 in number for s. annulatum and s. rusticum respectively. an adult s. annulatum and s. rusticum consumed 5.04, 3.7, 1.43 and 3.36, 2.49, 1.04 snails per day respectively in summer, monsoon and winter.
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