Consumption of Melopsittacus undulatus (Shaw, 1805) (Psittaciformes, Psittacidae) by Sapajus cay Illiger, 1815 (Primates, Cebidae) in Midwest region of Brazil

The interaction between native and exotic species can cause changes both in the food-chain and in aspects of competition for trophic resources, such as predation. Predatory events are common in nature, but difficult and usually recorded opportunistically. Here we present the first report of trophic interaction involving a species of exotic bird (Melopsittacus undulatus) and a species of native primate (Sapajus cay). Capuchin monkeys have already been recorded feeding on a wide variety of vertebrates, including frogs, lizards, birds, mammals, and even other species of primates. Although the record of the non-native M. undulatus in the state of Mato Grosso do Sul indicates a possible domestic escape, the record of predation may represent a beneficial trophic interaction for the ecosystem, preventing M. undulatus from becoming an invasive alien species. Studies are needed to assess what risks are posed by domestic species being preyed upon by native species.

Mathematics of sustainable and profitable management of fisheries resources

The ecological and economic management of the fishery is a major issue. However, one reads contradic-tory discourses about it depending of the interest that animates it. Using mathematical models, I attempt tounderstand how to rationalize public policies in this multi-stakeholder area. It was a question of seeing, frommathematical models, how to optimize the fishery, that is to say, to allow fishermen and women to have maxi-mum gains while preserving the resource. We will see that these objectives are far from being incompatible andeven go hand in hand.I study first with biological models, then with bio-economic models, a fishery where only one species is con-sidered exploited. I then propose models of exploitation of several species in trophic interaction by two differ-ent approaches: one with systems of coupled differential equations, the other by game theory with a stochasticepidemic model.We will be careful to formulate the assumptions and presuppositions of each model. We will also indicatepossible improvements suggested by the literature.

A novel approach to quantifying trophic interaction strengths and impact of invasive species in food webs

Measuring ecological and economic impacts of invasive species is necessary for managing invaded food webs. Based on abundance, biomass and diet data of autochthonous and allochthonous fish species, we proposed a novel approach to quantifying trophic interaction strengths in terms of number of individuals and biomass that each species subtract to the others in the food web. This allowed to estimate the economic loss associated to the impact of an invasive species on commercial fish stocks, as well as the resilience of invaded food webs to further perturbations. As case study, we measured the impact of the invasive bass Micropterus salmoides in two lake communities differing in food web complexity and species richness, as well as the biotic resistance of autochthonous and allochthonous fish species against the invader. Resistance to the invader was higher, while its ecological and economic impact was lower, in the more complex and species-rich food web. The percid Perca fluviatilis and the whitefish Coregonus lavaretus were the two species that most limited the invader, representing meaningful targets for conservation biological control strategies. In both food webs, the limiting effect of allochthonous species against M. salmoides was higher than the effect of autochthonous ones. Simulations predicted that the eradication of the invader would increase food web resilience, while that an increase in fish diversity would preserve resilience also at high abundances of M. salmoides. Our results support the conservation of biodiverse food webs as a way to mitigate the impact of bass invasion in lake ecosystems. Notably, the proposed approach could be applied to any habitat and animal species whenever biomass and diet data can be obtained.

PREDATORY INTERACTION BETWEEN TWO ANURAN SPECIES WITH Thamnodynastes chaquensis (COLUBRIDAE) IN THE BRAZILIAN CERRADO

Although predatory events are uncommon to be recorded in nature, these data are important tools for understanding prey-predator interaction of the involved species. Snakes of genus Thamnodynastes are known for having an anuran diet, including some species of hylid frogs in their diet. Despite this, this pattern does not include T. chaquensis since there are no records on predation or trophic interaction with hylid frogs.Here, we report the first predatory interaction between T. chaquensis and two hylid frogs in Brazilian Cerrado. The first predation event with treefrog Boana caiapo occurred with success but, the second with B. albopunctatadid not. Connecting trophic links within an ecosystem requires in-depth knowledge of its species and their intraspecific interactions. In this context, records of the predation and predation attempts such as these may help to connect unknown trophic links, which helps to understand aspects of the natural history of the species involved.

Insect Communities Associated with Siam Weed: Evaluation after Three Decades of Cecidochares connexa Release as Biocontrol Agent

Chromolaena odorata is well known as an invasive weed, and its existence in agricultural habitats causes an undesirable effect on crop plants. The invasion of C. odorata alters local biodiversity and shapes the new trophic interaction with local herbivores and other insects. This research was conducted to study the insect communities associated with C. odorata and evaluate the success of the release of Cecidochares connexa, the natural enemy of C. odorata. Field research was conducted in two different geographical regions in Bogor Regency (Java) and South Lampung Regency (Sumatera), Indonesia. In each region, we selected five villages that have two land-use types (oil palm plantations and open area) and contain a high population of C. odorata. Observation of insects and natural enemies of C. odorata was conducted in each land-use type using two methods: suction sampling and gall collection, which were performed in 30 plants as sampling units. In total, we found 255 species of insects associated with C. odorata. The difference of region affected the abundance of insects but not their species richness. The species composition of insects showed difference between regions as well as between land-use types. There was a positive correlation between elevation and species richness of insects. In addition, the population of C. connexa (gall numbers) was significantly affected by regions and was found to be higher in Bogor and Lampung. The same pattern also was shown for its parasitoids (based on parasitized galls). We found a negative relationship between the number as well as parasitize galls and elevation. In conclusion, the presence of C. odorata, as well as its natural enemies, shape the new trophic interaction with local insects, and as consequence, its introduced natural enemies may not be effective to control the population of C. odorata.

The effect of synthetic microbial spatial self-organization on the fate of antibiotic resistance genes

<p>Biofilms are considered as hotspots for the transfer of antibiotic resistance genes (ARGs), but very few studies have investigated the fate of ARGs (e.g. proliferation or elimination) in situ given different microbial spatial self-organization (SSO). SSO refers to a pervasive process during biofilm formation when microbes arrange themselves non-randomly across surfaces. So far the causes of SSO have been uncovered in a sense, however, the consequences of SSO were largely overlooked. Here, I hypothesize that the magnitude of inter-species intermixing, as one fundamental character of SSO, will determine the fate of ARG-carrying conjugative plasmid in both absence and presence of antibiotic selection. I evaluated this by performing range expansion experiments on agar plates to develop an artificial biofilm using a synthetic microbial community consisting of two isogenic Pseudomonas Stutzeri <em>A1501</em> who are facultative denitrifiers in anaerobic condition. By knocking out different functional genes responsible for different steps of denitrification I am able to modify the metabolic interactions between these two strains from competing (without trophic interaction) to cross-feeding (with trophic interaction), which will further result in different magnitude of inter-species intermixing. Competing group has lower magnitude due to demixing of two, while cross-feeding group has higher magnitude due to mixing. I observed that in the absence of antibiotic selection plasmid experienced faster pace of elimination in competing group than cross-feeding group, whereas in the presence of antibiotic selection plasmid proliferated more efficiently in cross-feeding group than competing group. These results suggest that SSO is a determining factor of the fate of ARGs in biofilms, which provides a novel perspective of better understanding ARGs-related pressing problems facing our society.</p>