Carlos Frederico

Reproductive and Fat Body Cycles of the Tropical Sand Lizard (Liolaemus lutzae) of Southeastern Brazil

The reproductive and fat body cycle of the tropidurid lizard Liolaemus lutzae was studied in the tropical seasonal habitat of Restinga da Barra de Marici Rio de Janeiro, southeastern Brazil. Females have a marked seasonality in reproduction (September to March), possibly correlated with rainfall. Females store fat in fat bodies during drought periods, investing it in the production of the first clutch in the beginning of the reproductive season. Recruitment of juveniles began in the middle of December and ended in May-June of the following year. The minimum size at maturity for females (51.5 mm SVL) was smaller than that of males (61.1 mm SVL). Clutch size varied from one to four eggs, most frequently two. Female body size explained only a small part of the variation in clutch size. The simultaneous occurrence of yolking follicles and corpora lutea in some females together with the abdominal palping of marked females in the field suggests that at least two clutches may be produced per reproductive season.

Reproductive Cycle and Life-History Traits of the Viviparous Skink Mabuya frenata in Southeastern Brazil

The reproductive and fat body cycles and some life-history traits of the viviparous skink Mabuya frenata were studied in a seasonal habitat in the state of Sao Paulo, southeastern Brazil. Reproductive activity is markedly cyclical in both sexes. Females reach sexual maturity at juvenile body sizes, have an extended gestation period lasting 9-12 months, and give birth to 2-8 young (mean 4.9 ? 1.1), mainly during August through October. Fat stored in fat bodies during the wet season is used up during gestation in females and during increased spermatogenic activity in males. Females reach a larger adult body size than males, but males have relatively larger heads. The reproductive and life-history traits observed for M. frenata are similar to those of other South American Mabuya.

An ant-membracid-plant interaction in a cerrado area of Brazil

In the Cerrado of Itirapina, Brazil, 34% of the shrubs of Didymopanax vinosum (Araliaceae) were colonized by the honeydew-producing homopteran Aconophora teligera (Membracidae) which was found exclusively on this species of plant. Correlations were made between membracid density and ant frequency, as well as between these parameters and plant damage. We found that: (1) ant frequency was higher on branches with membracids and both were more frequently found near apical meristems; (2) herbivore damage was lower on apical meristems where the membracids concentrate than on ones where they are absent; (3) the presence of membracids on the plant was correlated with a reduction in the occurrence of other potential herbivores, especially on the branches housing membracids; (4) plants with more tillers tended to have a larger number of membracids. The data suggest that the presence of A. teligera and associated ants probably reduce herbivory on apical meristems of D. vinosum .

Larval Diet in Bromeliad Pools: A Case Study of Tadpoles of Two Species in the Genus Scinax (Hylidae)

Many species of frogs that breed in bromeliads exhibit parental care as females deposit unfertilized eggs to feed the tadpoles. Treefrogs of the genus Scinax are not known to exhibit this behavior, even though they have exotrophic tadpoles. The purpose of this study was to describe qualitatively and quantitatively the diets of tadpoles of hylids S. littoreus and S. perpusillus developing in the phytothelm of Alcantarea glaziouana (Bromeliaceae). We evaluate if there are seasonal and spatial differences (between tadpoles living in the central tank and the lateral tanks) in the diet, and to test for food selectivity of the species. The most abundant items in the diet of tadpoles of both species were, respectively, algae, fungi, and protozoa. Detritus and plant debris were present in the diet of more than 90% of the tadpoles of the two species. The trophic niche breadth for S. littoreus was 1.26, whereas that for S. perpusillus was 1.54. The tadpole diets were seasonally conservative for both tadpole species and spatially similar only for S. perpusillus. Tadpoles of Scinax littoreus showed differences in diet, depending on the microhabitat in which they developed in the bromeliad, and showed electivity favorable for fungi but negative for copepods. Our data suggest that tadpoles of S. perpusillus are, in general, non-selective omnivores feeding on items in a similar proportion to their occurrence in the environment, while tadpoles of S. littoreus are more selective-feeders, avoiding animal items. Muitas espécies de anuros que se reproduzem em bromélias apresentam cuidado parental com fêmeas depositando ovos não fertilizados para alimentar os girinos no fitotelma. Os hilídeos do gênero Scinax não apresentam este comportamento, mesmo apresentando girinos exotróficos. O objetivo do presente estudo foi descrever quali-quantitativamente a dieta dos girinos das espécies S. littoreus e S. perpusillus que se desenvolvem no fitotelma da Alcantarea glaziouana (Bromeliaceae). Avaliamos se há diferenças sazonais e espaciais (entre girinos que residem no vaso central e nos vasos laterais da bromélia) na dieta, além de testar a existência de seleção de itens alimentares pelas espécies de anuros. Os itens mais abundantes na dieta de ambos os girinos foram respectivamente: algas, fungos e protozoários. Detrito e restos vegetais estavam presentes em mais de 90% dos estômagos de ambas as espécies. A amplitude de nicho trófico para S. littoreus foi 1,26 enquanto para S. perpusillus foi 1,54. As dietas foram sazonalmente conservativas para ambas as espécies e espacialmente similar apenas para S. perpusillus. Os girinos de Scinax littoreus apresentaram diferenças na dieta de acordo com o microhabitat em que se desenvolviam na bromélia além de apresentar eletividade positiva para fungos e negativa para copépodos. Nossos dados sugerem que S. perpusillus é, em geral, um onívoro não seletivo, alimentando-se de itens em proporção similar da que estes ocorrem no fitotelma, enquanto os girinos de S. littoreus são mais seletivos evitando itens animais.