RESUMO

BACKGROUND: Plant-pollinator mutualistic networks show non-random structural properties that promote species coexistence. However, these networks show high variability in the interacting species and their connections. Mismatch between plant and pollinator attributes can prevent interactions, while trait matching can enable exclusive access, promoting pollinators' niche partitioning and, ultimately, modularity. Thus, plants belonging to specialized modules should integrate their floral traits to optimize the pollination function. Herein, we aimed to analyze the biological processes involved in the structuring of plant-hummingbird networks by linking network morphological constraints, specialization, modularity and phenotypic floral integration. METHODS: We investigated the understory plant-hummingbird network of two adjacent habitats in the Lacandona rainforest of Mexico, one characterized by lowland rainforest and the other by savanna-like vegetation. We performed monthly censuses to record plant-hummingbird interactions for 2 years (2018-2020). We also took hummingbird bill measurements and floral and nectar measurements. We summarized the interactions in a bipartite matrix and estimated three network descriptors: connectance, complementary specialization (H2'), and nestedness. We also analyzed the modularity and average phenotypic floral integration index of each module. RESULTS: Both habitats showed strong differences in the plant assemblage and network dynamics but were interconnected by the same four hummingbird species, two Hermits and two Emeralds, forming a single network of interaction. The whole network showed low levels of connectance (0.35) and high specialization (H2' = 0.87). Flower morphologies ranged from generalized to specialized, but trait matching was an important network structurer. Modularity was associated with morphological specialization. The Hermits Phaethornis longirostris and P. striigularis each formed a module by themselves, and a third module was formed by the less-specialized Emeralds: Chlorestes candida and Amazilia tzacatl. The floral integration values were higher in specialized modules but not significantly higher than that formed by generalist species. CONCLUSIONS: Our findings suggest that biological processes derived from both trait matching and "forbidden" links, or nonmatched morphological attributes, might be important network drivers in tropical plant-hummingbird systems while morphological specialization plays a minor role in the phenotypic floral integration. The broad variety of corolla and bill shapes promoted niche partitioning, resulting in the modular organization of the assemblage according to morphological specialization. However, more research adding larger datasets of both the number of modules and pollination networks for a wider region is needed to conclude whether phenotypic floral integration increases with morphological specialization in plant-hummingbird systems.

RESUMO

Neotropical toads from the Rhinella margaritifera species group have been considered a taxonomic puzzle for a long time. Because of the high morphological similarity and an unknown number of undescribed taxa among the species of this group, we did an extensive search for character distribution within all nominal taxa. Herein we describe Rhinella parecis sp. nov. a new species from Southern Brazilian Amazon. We provide a morphological diagnosis, morphometric comparisons with similar species, and a molecular phylogenetic hypothesis on the relationships of the new species. Rhinella parecis sp. nov. is assigned to the R. margaritifera group and differs from others species by snout-vent length ranging 40.7-53.5 mm in males (n=12) and 44.9-54.8 mm in females (n=4), snout rounded in dorsal view, acute with fleshy ridge extending to tip of snout in lateral view, canthal and pre-orbital crests absent, supra-orbital, parietal and supra-tympanic crests present and low, dorsolateral row of tubercles present, bony protrusion at the angle of jaws absent, tympanum evident, vertebral apophyses absent and toes half-webbed. The new species is the 20th species associated to the R. margaritifera group distributed in the Chapada dos Parecis, a probable center of endemism in states of Rondônia and Mato Grosso, Brazil.

Assuntos

Anuros , Animais , Brasil , Bufonidae , Feminino , Masculino , Filogenia

RESUMO

This is the first record of the family Nemestrinidae in the Amazon Basin, based on three females identified as Atriadops macula (Wiedemann, 1824). The specimens were collected in the canopy using flight interception traps. This species was previously known to inhabit understory open areas. The canopy, the new habitat record, is an open area stratum with higher insolation, higher temperature and less humidity. As the adults of A. macula have the mouthparts greatly reduced, they probably do not feed and their occurrence in the canopy probably is more likely related to the distribution of their hosts as well as the environmental factors.

Assuntos

Dípteros , Animais , Ecossistema , Feminino

RESUMO

A new genus and five new species of odiniids (Odiniidae: Traginopinae) are described from the Brazilian Amazon and Cerrado biomes: Inpauema mirador gen. nov. et sp. nov. (type species), I. catarinae sp. nov., I. gaimarii sp. nov., I. raimundoluizi sp. nov., and I. xavieri sp. nov. The genus is being characterized by a unique combination of diagnostic characters: body predominantly dark brown to black, with silvery-gray pruinose spots on inner margin of eyes, longitudinally along middle of lunule and face, on notopleuron and mesopleuron; postcranium concave from dorsal view; one pair of stout proclinate ocellar setae; postocellar setae absent; lunule shorter than frons; gena lacking upturned seta; antennae separated by a maximum distance of 2X the diameter of a single antennal socket and gonocoxal apodemes directed upward, forming an arch. A key to separate Helgreelia Gaimari, 2007 from Inpauema gen. nov. and for the new species is provided.

Assuntos

Dípteros , Distribuição Animal , Estruturas Animais , Animais , Brasil , Ecossistema

RESUMO

For animals with spatially complex behaviours at relatively small scales, the resolution of a global positioning system (GPS) receiver location is often below the resolution needed to correctly map animals' spatial behaviour. Natural conditions such as canopy cover, canyons or clouds can further degrade GPS receiver reception. Here we present a detailed, high-resolution map of a 4.6 ha Neotropical river island and a 8.3 ha mainland plot with the location of every tree >5 cm DBH and all structures on the forest floor, which are relevant to our study species, the territorial frog Allobates femoralis (Dendrobatidae). The map was derived using distance- and compass-based survey techniques, rooted on dGPS reference points, and incorporates altitudinal information based on a LiDAR survey of the area.