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Search Results: 1 - 10 of 174 matches for " herbivory "
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Effects of phyllophaga (phytallus) hoegei larval density (coleoptera:melolonthidae) on plant and herbivore growth
Ramírez-Corona,Fabiola; Morón-Ríos,Alejandro;
Interciencia , 2007,
Abstract: the belowground herbivory has received relatively little attention. the plant response to belowground herbivory is variable and partially mediated by the identity and density of the root feeder. this study evaluated 1) the effects of belowground herbivory by two densities of the common root feeder, phyllophaga (phytalus) hoegei on the plant biomass, the nitrogen content of tillers and roots of the native, dominant grass muhlenbergia quadridentata; and 2) the effects of these two larval densities on the survival and growth of this species. the experiment was performed in a pine forest area at 3200masl. plants were established in pots in the field and subjected to belowground herbivory (three levels) in a completely random design with ten replicates per treatment. high densities of the root feeder significantly decreased root biomass and the root/shoot ratio, but the herbivores did not affect the nitrogen concentration of plant tissues. survivorship of phyllophaga hoegei larvae was not affected by growth density, but at high density the root feeder larvae decreased the relative growth rate and the weight gained
Natural history and biology of Chlamisus minax Lacordaire (Chrysomelidae: Chlamisinae)
Reu Jr., Wilson F.;Del-Claro, Kleber;
Neotropical Entomology , 2005, DOI: 10.1590/S1519-566X2005000300001
Abstract: although very abundant in the neotropics, there is little information about the biology, ecology and natural history of brazilian chlamisinae beetles. in the present study we investigated directly in the cerrado vegetation the aspects of natural history and biology of chlamisus minax lacordaire. the results showed that the species has annual cycle and the adults are present in the field during the spring and summer when the reproduction occurs. the females cover their eggs with a mantle, and later on the rests of the egg and faeces are added by the larva to the mantle to produce a protective case. the six larval morpho-stages are herbivorous and feed on floral buds of heteropterys pteropetala a. juss. (malpighiaceae). the larvae pupate in the host plants and after that they fall on the ground remaining in diapause between april and october. this is the first study to investigate the biology and natural history of a brazilian chlamisinae beetle directly in the field.
Host Plants of the Grasshopper Cornops aquaticum (Bruner) (Orthoptera: Acrididae) in the Wetland of Poconé, MT, Brazil
FERREIRA, SORAIA A.;VASCONCELLOS-NETO, JO?O;
Neotropical Entomology , 2001, DOI: 10.1590/S1519-566X2001000400003
Abstract: the grasshopper cornops aquaticum (bruner) lives permanently on aquatic macrophytes in floodplains of tropical south america. its host plants and feeding preference were determined by field observations, crop analysis and feeding tests in the laboratory. macrophytes were sampled and their petioles were examined for potential egg deposition in order to reveal host plant specificity. sub-samples were dissected in the laboratory and eggs were counted directly whereas the rest of the sample was kept in net-covered water tanks aiming to verify hatching of nymphs. c. aquaticum fed and oviposited on eichhornia azurea and pontederia cordata (pontederiaceae) in the field. out of 140 fore-guts analyzed from free-living grasshoppers, 75% contained pontederiaceae tissues. in the laboratory, however, it accepted plant species from other families. tests of acceptance revealed that from 19 plant species offered, one by one, 16 were accepted. the seven plant species, which were accepted with highest frequency, were selected for tests of feeding rates. these rates were equal for all seven species. when four or five food plant species were offered simultaneously, the host species were not always preferred. the fact that in the laboratory more host-plant species were accepted than in the field indicates that the host range in the field is determined by other ecological factors than the plant chemistry. host plant selection by c. aquaticum can be related to the relative abundance of the macrophyte species in the field and to the protection, which they offer against predation. considering the emerging parts of the macrophytes, e. azurea represents the most abundant resource in the floodplains. moreover, the cryptic coloration of the grasshopper on e. azurea lessens predation risk. that is why, apart from being potentially polyphagous, c. aquaticum presents a considerable oligophagy in the field, feeding on few species of pontederiaceae.
Ecología alimentaria de Parodon tortuosus (Pisces, Characiformes) en el río de la Suela (Córdoba, Argentina)
Pelegrin,Nicolás; Haro,José G;
Ecolog?-a austral , 2004,
Abstract: the feeding of 71 parodon tortuosus individuals from de la suela river, córdoba province, argentina, was analized. the diet was mostly composed by algae (chlorophyta, cyanophyta and chrisophyta which comprise 92.1% of the total dry weight of the stomach contents), with a few animal items (7.9%) such as diptera (chironomidae and simuliidae), ephemeroptera and trichoptera. there were no significant differences in the diet between cold and warm seasons neither between juveniles and adults. parodon tortuosus is an algae-eating fish that lives in small waterfalls with rocky substrates. it behaves as a browser or as a grazer according to its needs, but it can eventually ingest animal food mixed with the algae.
Temperature and foliage quality affect performance of the outbreak defoliator Ormiscodes amphimone (F.) (Lepidoptera: Saturniidae) in northwestern Patagonia, Argentina
PARITSIS,JUAN; VEBLEN,THOMAS T;
Revista chilena de historia natural , 2010, DOI: 10.4067/S0716-078X2010000400012
Abstract: in the temperate forests of chile and argentina the phytophagous moth ormiscodes amphimone (f.) causes severe defoliation on the southern beech tree nothofagus pumilio (poepp. & endl.) krasser. the recent increase in defoliation frequency in some áreas appears to be influenced by a warmer climate. to evalúate the effects of temperature and the spatial heterogeneity of foliage quality on the performance and relative consumption rate of o. amphimone in northwestern patagonia, argentina we conducted a factorial experiment. larval performance was measured as relative growth rate, developmental time, larval survival, and pupal weight. larvae of o. amphimone were reared under two constant temperature regimes (15 °c and 20 °c) and fed with two n. pumilio foliage types (from a mesic and from a xeric site). larvae at the higher temperature and fed with leaves from the mesic site showed higher performance and consumption rate than larvae in the other treatments. higher temperature and mesic foliage had positive effects on o. amphimone's relative growth rate, development time and relative consumption rate. however, pupal weight was positively influenced by mesic foliage but not by temperature, and larval survival did not show significant differences among treatments. our results preliminarily suggest that o. amphimone performance and consumption rate may increase under higher temperature conditions, especially in the mesic portions of the precipitation gradient. however, these findings should be carefully interpreted as further research is necessary to assess the influence of higher temperatures on the foliar quality of n. pumilio.
Riqueza de galhas entomógenas em áreas antropizadas e preservadas de caatinga
Carvalho-Fernandes, Sheila Patricia;Almeida-Cortez, Jarcilene Silva de;Ferreira, Andre Luiz Nunes;
Revista árvore , 2012, DOI: 10.1590/S0100-67622012000200008
Abstract: gall-inducing insects, also called cecidogens, are regarded as more specialized because they present direct interaction with internal tissues of the plant, modifying them in its benefit and because of that, becoming more dependent of the host species. the present study investigated the fauna of gall-inducing insects in plants from environments with different intensities of anthropic action in the caatinga. the areas were selected according to an ecological succession scale (preserved, intermediate and anthropic areas), with three replicates each, totaling nine areas. eight 10 m2 plots were sampled in each area, separated by an interval of 10 m. it was found 25 morphotypes of galls in 18 host species of eight plant families. the family fabaceae bears the largest number of morph-species of gall, with six morphotypes and caesalpinia pyramidalis tul. presents four morphotypes. the majority of galls was found on leaves (68%) followed by stems (28%) and bud flowers (4%). the galls occurred isolated (84%), glabrous (56%), most are spherical (32%), amorf (28%), discoids (12%) and globoids (12%). the greatest richness of galls was found in the tree layer, with sixteen morphotypes followed by shrub (7) and herbaceous (2). the richness of galls was influenced by the degree of conservation of the studies areas. there were differences between the preserved and anthropic areas.
A curious case of herbivory in the common toad Rhinella arenarum during hibernation in captivity conditions
Jungblut, Lucas David,Pozzi, Andrea Gabriela,Paz, Dante Agustín
Cuadernos de Herpetología , 2012,
Abstract: El objetivo de la presente nota es documentar un comportamiento curioso ocurrido con un grupo de animales adultos de Rhinella arenarum que fueron mantenidos en condiciones de hibernación artificial en el laboratorio durante abril-julio del 2012.
Insect herbivory along environmental gradients  [PDF]
Nigel R. Andrew, Isobel R. Roberts, Sarah J. Hill
Open Journal of Ecology (OJE) , 2012, DOI: 10.4236/oje.2012.24024
Abstract: There is a general assumption in the literature that insect herbivory increases towards the tropics, but decreases with increasing altitude. Similar generalities have been identified along other environmental gradients, such as resource, temperature, climatic and biotic gradients. However there is growing evidence in the scientific literature that such generalities are not consistent. This could be due to a number of reasons including the lack of consistency in the way herbivory is assessed such as different methodologies used by researchers, or fundamental differences in leaf damage caused by different types of insect herbivores. Here we assess 61 publications researching insect herbivory along a range of environmental gradients (both biotic and abiotic) and review the methods that researchers have used to collected their data. We found leaf chewing from samples collected in North America dominated the field and most studies assessed herbivory on a single host plant species. Thirty three percent of the studies assessed latitudinal gradients, while 10% assessed altitudinal gradients. Insect herbivory was most commonly expressed as percentage leaf damage using point herbivory. Fewer studies measured a range of different types of herbivory (such as sap sucking, leaf mining, galling, and root feeding) as leaves aged. From our synthesis, we hope that future research into insect herbivory along environmental gradients will take into account herbivory other than just leaf chewing, such as sap sucking, which may cause more damage to plants. Future research should also assess herbivory as a rate, rather than just a single point in time as damage to a young leaf may be more costly to a plant than damage to a mature or senescing leaf. Measurements of plant traits will also assist in comparing herbivory across habitats, plant species, and within species physiological variation. The true impacts that insects have on plants via herbivory along environmental gradients are still poorly understood.
Revealing an Endemic Herbivore-Palm Interaction in Remote Desert Oases of Baja California  [PDF]
Elisabet V. Wehncke, Xavier López-Medellín, Michael Wall, Exequiel Ezcurra
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.42A060
Abstract:

In the Central Desert of northern Baja California, blue fan palm populations (Brahea armata) are found as isolated oases on mountaintops and along canyons with ephemeral flow conditions. Here, the effect of the interaction between the larva of an endemic moth, Litoprosopus bajaensis, and this endemic blue fan palm was documented for the first time. We registered the phenology of palms by counting the number of shoots with flowers or fruits, assessing their damage and calculating the reproductive success per individual palm within three populations: San Pedro Martir, Catavi?a, and La Libertad. Palm populations were severely impacted by this larva, causing high damage to the inflorescences. No differences were found in the number of inflorescence stems produced and damaged among study sites; but the reproductive success of palms was significantly higher in Catavi?a than in the other sites during the entire sampling period, and consequently an important proportion of stems escaped from the herbivore predation. We suggest that differences among sites may be explained by the fact that Catavi?a is the only alluvial canyon and can be considered an area of high nutrient uptake, resource availability, and rooting depths. In contrast the other two are bedrock canyons, where water runs intensely, sweeping away great portions of the nearby vegetation. Catavi?a received the highest precipitation during the winter season of 2010 allowing a continuous production of inflorescence stems and fruits. This preliminary study reveals a new endemic interaction, it occurrence at population and regional levels, and highlights the role of desert oases as resource patches and connectivity pathways for mobile insects. Finally, it also highlights the effects of different water flow dynamics and water pulses in providing an opportunity window of escape from predation for host plant species living in desert environments.

Induced responses in the subtropical evergreen, broad-leaf tree Schima superba: Effects of simulated herbivory on leaf quality and subsequent insect attack during leaf expansion
Liu,ZG; Cai,YL; Li,K;
Phyton (Buenos Aires) , 2010,
Abstract: induced responses to herbivory are physical, nutritional, and allelochemical traits that change in plants following disturbances, and reduce the performance and/or preference of leaf tissues on herbivores. this study gave evidence to the induced defense theory through the simulated herbivory in schima superba, one of common dominant trees in subtropical evergreen, broadleaf forests in southern china. results showed that leaves damaged at the beginning of leaf expansion would develop into having a larger area, higher toughness and higher tannin concentrations, but a lower water content compared with control leaves. as a result, they experienced lower herbivory rates than controls. these results indicate that simulated herbivory on leaves of s. superba (1) reduced leaf nutrition, and (2) increased the leaf physical and biochemical defense as a result of a localized induction to herbivory, therefore altering insect herbivore attacks.
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