Water balance and locomotor performance in three species of neotropical toads that differ in geographical distribution

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Restriction fragment analysis of the ribosomal DNA of Paratelmatobius and Scythrophrys species (Anura, Leptodactylidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Comparative cytogenetic studies of eleven species of the Tropidurus torquatus group (Sauria, Tropiduridae), with banding patterns

The chromosomes of 173 specimens representing eleven species of the Tropidurus torquatus group, from 33 localities in Brazil, were analysed after Giemsa staining, C-banding, NORs, and replication banding techniques. A karyotype with 2n = 36, including 12 macrochromosomes and 24 microchromosomes (12 M + 24 m), and sex determination of the XY:XX type were found in Tropidurus cocorobensis, T. erythrocephalus, T. etheridgei, T. hispidus, T. hygomi, T. montanus, T. mucujensis, T. oreadicus, and T. torquatus. The two other species, T. itambere and T. psammonastes, presented 2n = 36 (12 M + 23 m) karyotype only in females while males had 2n = 35 (12 M + 23 m), due to the sex determination of the X(1)X(2)Y:X(1)X(1)X(2)X(2) type. Other interspecific differences as well as some intraspecific variation regarding the NORs and C-banding patterns have been observed, mainly in the microchromosome set. on the contrary, the macrochromosomes were highly conservative. Although consistent karyotypic diversity occurred in the torquatus group, the cytogenetic data obtained up to now did not allow us to clarify the phylogenetic relationships of the species. Nevertheless, the geographical distribution of the distinct cytotypes in T. hispidus and T. torquatus suggested that more than one species might be involved in each case.

Energetic and physiological correlates of prey handling and ingestion in lizards and snakes

In this review, we summarize the energetic and physiological correlates of prey handling and ingestion in lizards and snakes. There were marked differences in the magnitude of aerobic metabolism during prey handling and ingestion between these two groups, although they show a similar pattern of variation as a function of relative prey mass. For lizards, the magnitude of aerobic metabolism during prey handling and ingestion also varied as a function of morphological specializations for a particular habitat, prey type, and behavior. For snakes, interspecific differences in aerobic metabolism during prey handling seem to be correlated with adaptations for prey capture (venom injection vs. constriction). During ingestion by snakes, differences in aerobic metabolism might be due to differences in cranial morphology, although allometric effects might be a potentially confounded effect. Anaerobic metabolism is used for prey handling and ingestion, but its relative contribution to total ATP production seems to be more pronounced in snakes than in lizards. The energetic costs of prey handling and ingestion are trivial for both groups and cannot be used to predict patterns of prey-size selection. For lizards, it seems that morphological and ecological factors set the constraints on prey handling and ingestion. For snakes, besides these two factors, the capacity of the cardio-respiratory system may also be an important factor constraining the capacity for prey handling and ingestion. © 2001 Elsevier B.V.

Modelos dinâmicos de assembléia

The structure of an ecological community is shaped by several temporally varying mechanisms. Such mechanisms depend in a large extent on species interactions, which are themselves manifestations of the community's own structure. Dynamics and structure are then mutually determined. The assembly models are mathematical or computational models which simulate the dynamics of ecological communities resulting from a historical balance among colonizations and local extinctions, by means of sequential species introductions and their interactions with resident species. They allow analyzing that double relationship between structure and dynamics, recognizing its temporal dependence. It is assumed two spatiotemporal scales: (i) a local scale, where species co-occur and have their dynamics explicitly simulated and (ii) a regional scale without dynamics, representing the external environment which the potential colonizers come from. The mathematical and computational models used to simulate the local dynamics are quite variable, being distinguished according to the complexity mode of population representation, including or not intra or interspecific differences. They determine the community state, in terms of abundances, interactions, and extinctions between two successive colonization attempts. The schedules of species introductions also follow diverse (although arbitrary) rules, which vary qualitatively with respect to species appearance mode, whether by speciation or by immigration, and quantitatively with respect to their rates of introduction into the community. Combining these criteria arises a great range of approaches for assembly models, each with its own limitations and questions, but contributing in a complementary way to elucidate the mechanisms structuring natural communities. To present such approaches, still incipient as research fields in Brazil, to describe some methods of analysis and to discuss the implications of their assumptions for the understanding of ecological patterns are the objectives of the present review.

Coloration of the testicular peritoneal sheath as a synapomorphy of triatomines (Hemiptera, Reduviidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de transcriptomas por RNAseq em tecidos de cabeça e glândula salivar de Rhodnius montenegrensis e Rhodnius robustus (Hemiptera, Reduviidade, Triatominae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Intraspecific, interspecific, and seasonal differences in the diet of three mid-sized carnivores in a large neotropical wetland

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Interspecific chromosomal divergences in the genus Characidium (Teleostei: Characiformes: Crenuchidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A comparative tunnelling network approach to assess interspecific competition effects in termites

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Interspecific variation in the defensive responses of obligate plant-ants: experimental tests and consequences for herbivory

The aggressive behavior of ants that protect plants from herbivores in exchange for rewards such as shelter or food is thought to be an important form of biotic defense against herbivory, particularly in tropical systems. To date, however, no one has compared the defensive responses of different ant taxa associated with the same plant species, and attempted to relate these differences to longer-term efficacy of ant defense. We used experimental cues associated with herbivory-physical damage and extracts of chemical volatiles from leaf tissue-to compare the aggressive responses of two ant species obligately associated with the Amazonian myrmecophyte Tococa bullifera (Melastomataceae). We also conducted a colony removal experiment to quantify the level of resistance from herbivores provided to plants by each ant species. Our experiments demonstrate that some cues eliciting a strong response from one ant species elicited no response by the other. For cues that do elicit responses, the magnitude of these responses can vary interspecifically. These patterns were consistent with the level of resistance provided from herbivores to plants. The colony removal experiment showed that both ant species defend plants from herbivores: however, herbivory was higher on plants colonized by the less aggressive ant species. Our results add to the growing body of literature indicating defensive ant responses are stimulated by cues associated with herbivory. However, they also suggest the local and regional variation in the composition of potential partner taxa could influence the ecology and evolution of defensive mutualisms in ways that have previously remained unexplored.

Study of acrosome formation, interspecific and intraspecific, in the testicular lobes of some pentatomid species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Possible interspecific origin of the B chromosome of Hypsiboas albopunctatus (Spix, 1824) (Anura, Hylidae), revealed by microdissection, chromosome painting, and reverse hybridisation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)