Search

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In marine invertebrates, the modes of development at early stages are related to the type and capacity of larval feeding to achieve growth. Therefore, studying the factors that determine larval feeding strategies can help to understand the diversity of life histories and evolution of marine invertebrates. The polychaete Boccardia wellingtonensis is a poecilogonous species that encapsulates and incubates its offspring. This species produces two types of larvae: (1) larvae that do not feed within the capsule and hatch as planktotrophic larvae (indirect development), and (2) adelphophagic larvae that feed on nurse eggs and other larvae inside the capsule to hatch as advanced larvae or juveniles (direct development). Otherwise, the larval types are indistinguishable at the same stage of development. The non-apparent morphological differences between both types of larvae suggest that other factors are influencing their feeding behavior. This work studied the potential role of the activity of 19 digestive enzymes on the different feeding capacities of planktotrophic and adelphophagic larvae of B. wellingtonensis. Also, differences in larval feeding structures and the larval capacity to feed from intracapsular fluid were evaluated by electron and fluorescence microscopy. Results showed that both types of larvae present similar feeding structures and had the capacity to ingest intracapsular fluid protein. Adelphophagic larvae showed overall the highest activities of digestive enzymes. Significant differences between larval types were observed in nine enzymes related to the use of internal and external nutritional sources. Given that larval feeding is closely related to larval development in species with encapsulation, this work supports that the study of the digestive enzymatic machinery of larvae may contribute to understanding the evolution of developmental modes.

In marine invertebrates, the modes of development at early stages are related to the type and capacity of larval feeding to achieve growth. Therefore, studying the factors that determine larval feeding strategies can help to understand the diversity of life histories and evolution of marine invertebrates. The polychaete Boccardia wellingtonensis is a poecilogonous species that encapsulates and incubates its offspring. This species produces two types of larvae: (1) larvae that do not feed within the capsule and hatch as planktotrophic larvae (indirect development), and (2) adelphophagic larvae that feed on nurse eggs and other larvae inside the capsule to hatch as advanced larvae or juveniles (direct development). Otherwise, the larval types are indistinguishable at the same stage of development. The non-apparent morphological differences between both types of larvae suggest that other factors are influencing their feeding behavior. This work studied the potential role of the activity of 19 digestive enzymes on the different feeding capacities of planktotrophic and adelphophagic larvae of B. wellingtonensis. Also, differences in larval feeding structures and the larval capacity to feed from intracapsular fluid were evaluated by electron and fluorescence microscopy. Results showed that both types of larvae present similar feeding structures and had the capacity to ingest intracapsular fluid protein. Adelphophagic larvae showed overall the highest activities of digestive enzymes. Significant differences between larval types were observed in nine enzymes related to the use of internal and external nutritional sources. Given that larval feeding is closely related to larval development in species with encapsulation, this work supports that the study of the digestive enzymatic machinery of larvae may contribute to understanding the evolution of developmental modes. [ABSTRACT FROM AUTHOR]

We examined dietary self-selection and rules of compromise for protein (P) and digestible carbohydrate (C) intake by fifth-instar Vanessa cardui L. ( Lepidoptera: Nymphalidae: Nymphalini). We presented six fat-free diet pairs to larvae in a choice trial to determine the 'intake target'. In addition, we fed larvae seven fat-free single diets differing in dietary nutrient ratio in no-choice trials to determine the rules of compromise they exhibit when constrained to a singular, sub-optimal dietary source. In choice trials, caterpillars regulated nutrient intake to a ratio of 1 protein to 1.09 carbohydrate (1P:1.09C), exhibiting tighter regulation of protein than of carbohydrate. Furthermore, larvae from different diet pair treatments did not differ in pupal mass or stadium duration. In no-choice experiments, larvae reduced consumption on increasingly protein-biased diets and increased consumption on increasingly carbohydrate-biased diets, relative to a 1P:1C ratio diet. Differences in carbohydrate consumption were much greater between no-choice treatments than differences in protein consumption. Dietary nutrient ratio affected pupal mass when accounting for initial larval mass. Pupal mass decreased as nutrient ratio was shifted off of 1P:1C, but to a greater extent when the ratio was skewed toward carbohydrate. Stadium duration increased as nutrient ratio diverged from 1P:1C, being more pronounced when shifted toward carbohydrate than toward protein. Regulation to near 1P:1C is consistent with results found for other Lepidoptera, and the rule of compromise exhibited by V. cardui is consistent with that expected for a generalist herbivore. [ABSTRACT FROM AUTHOR]

This is the first report of Elaphria agrotina (Guenée, 1852) and Elaphria deltoides (Möschler, 1880) (Lepidoptera: Noctuidae) feeding on maize ( Zea mays L.). The specimens were collected in maize fields during the crop season of 2012 and 2013 in three municipalities in Mato Grosso State, Brazil. Larvae were collected while feeding at the ear base, which often resulted in ears dropping to the ground. Larvae also were observed feeding on kernels in fallen ears. Ear injury often leads to reduced grain quality, and when the ears fall to the ground, reduced yield. A previous report of Striacosta albicosta (Smith, 1888) feeding on maize in Brazil was probably a misidentification of an E. agrotina male, which has wing pattern and coloration similarities with S. albicosta. [ABSTRACT FROM AUTHOR]

Rice plants are vulnerable to the yellow stem borer, Scirpophaga incertulas (Walker), during the booting phase, when infestations cause the greatest yield loss. Although the moth is ubiquitous in rice-growing regions, S. incertulas feeding patterns on booting plants have been poorly characterized. We studied the early-instar feeding patterns of S. incertulas on wild and cultivated rice accessions to determine where larvae feed and if feeding route influences larval survival and development. Three cultivated (Taichung Native 1, IR64, and IR72) and three wild rice accessions (two accessions of Oryza nivara and one accession of O. rufipogon) were chosen for the study. Larvae were introduced onto booting plants and sampled after 6 h, 1 d, 2 d, 4 d, and 7 d. Approximately 2.5% more larvae survived on cultivated accessions than on wild accessions. Larvae were also 15% more likely to feed on the panicle of cultivated accessions than wild accessions, and panicle-feeding improved larval survival and development. Stem borer feeding route depended on plant phenology; larvae were more likely to feed on the panicle than on vegetative structures on booting, heading, and flowering tillers. Because all stems were cut by the seventh day if larvae fed on the panicle, resistance during the booting phase may be effective if it reduces the likelihood of panicle feeding or if strong antibiotic resistance can be found in the panicle. [ABSTRACT FROM AUTHOR]

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia pomonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth. [ABSTRACT FROM AUTHOR]

The effect of linear furanocoumarins and Bacillus thuringiensis subsp. ai;,awai toxins on feeding behavior of beet armyworm, Spodoptera exigua (Hiibner), larvae was quantified by giving larvae a choice between a control diet and a treated diet (diets contained linear furanocoumarins, B. thuringiensis, or linear furanocoumarins plus B. thuringiensis). Linear furanocoumarins were tested at concentrations found in the outer leaves of celery, Apium graveolens L., plants. Diet consumption and diet preference were quantified by recording the position of the larvae twice daily for 4 d and analyzed using analysis of variance and loglinear models of a 2 x 2 factorial with B. thuringiensis and linear furanocoumarins as main effects. Both main effects and their interaction were significant for diet consumption and preference data. The interaction between these 2 factors on larval diet preference indicated a mildly antagonistic effect causing increased deterrenceand reduced diet consumption by S. exigua larvae; however, by not asmuch as predicted if B. thuringiensis and linear furanocoumarins acted independently. These laboratory results document the combined effect of secondary plant compounds and an entomopathogen on larval behavior. Our results indicate the importance of considering the behavioral ecology of insect herbivores in estimating the compatibility of secondary plant compounds and entomopathogens for the development of integrated pest management programs. [ABSTRACT FROM AUTHOR]