Background choice and immobility as context dependent tadpole responses to perceived predation risk.

The association of immobility and camouflage is widespread as a defensive mechanism in prey from varied taxa. However, many experiments assessing the reaction of prey to predator cues are conducted under artificial laboratory conditions. In a previous experiment we observed the tadpoles of Ololygon machadoi (Hylidae) to respond to predator visual and/or chemical cues by choosing backgrounds that improve their disruptive properties, but detected no associated reduction of movement. Here we experimentally demonstrate this response in the species' natural habitat, on backgrounds where the tadpoles are likely to achieve their best camouflage. We also tested whether previous experiences could influence both background choice and immobility in O. machadoi tadpoles. These novel experimental results suggest that a defensive behavior-i.e., reduction of movement-in these tadpoles is more strongly expressed under the natural conditions where they evolved, compared to laboratory conditions where prey and predator were brought into closer contact. Besides, previous experiences are likely to play an important role in expressed defensive responses.

Tadpoles respond to background colour under threat.

The ability to respond to background colour is an important feature of species that might benefit from background matching camouflage. Tadpole colour patterns vary and could be associated with several functions, including defense. Because tadpoles are exposed to a wide array of visually oriented predators, they represent good models to study defensive colouration and associated behaviours. We tested whether a potentially disruptively camouflaged tadpole with a dark body crossed by yellow bars (Ololygon machadoi) is able to respond differently to matching light and dark natural background colours and an artificial blue contrasting background. We used a syntopic contrasting black tadpole (Bokermannohyla martinsi) as a control, expecting it not to respond to background colour in search for camouflage. Ololygon machadoi tadpoles chose light over blue backgrounds under threat, as expected, however they did not show preferential use of dark vs. blue backgrounds. Bokermannohyla martinsi did not respond to any combination of background colours. Our results suggest that O. machadoi tadpoles are able to respond to background colour, and may favor matching backgrounds under some circumstances. The potentially disruptive colouration of O. machadoi tadpoles may increase their repertoire of escape strategies, background matching being one of the options to escape predation.

Formal education, previous interaction and perception influence the attitudes of people toward the conservation of snakes in a large urban center of northeastern Brazil.

BACKGROUND: The attitudes and perceptions of people toward animals are influenced by sociodemographic factors, such as formal education and gender, and by personal experience. Understanding these interactions is critical for the establishment of conservation strategies for animals that have conflictual relationships with humans, such as snakes. Our study aims to explain how perceptions and the human fear of snakes vary and are influenced by formal education and gender. In addition, it aims to show how prior interaction with these animals influence these perceptions and the human fear toward snakes and how these perceptions and fear influence the importance of conservation of these animals. METHODS: We collected data from June 2010 to December 2013 using questionnaires given to 1142 visitors of a scientific serpentarium (Núcleo Regional de Ofiologia da Universidade Federal do Ceará) in the municipality of Fortaleza, northeastern Brazil. RESULTS AND DISCUSSION: Negative perceptions toward snakes were less frequent according to an increase in levels of schooling. Women had more negative perceptions and were more afraid of snakes than were men. Prior interaction with snakes decreased the occurrence of negative perceptions and reduced the level of human fear of these animals. People with negative perceptions classified the conservation of snakes as not important and were more afraid of these animals. Understanding the relationship between sociodemographic factors, prior experiences, perceptions, fear, and the importance given to conservation can help to better understand human attitudes toward snakes. CONCLUSIONS: Environmental education activities considering gender differences, involving preliminary interaction with snakes and focusing on priority targets identified in our study, such as people with low formal education, can increase the efficiency of measures for the conservation of these animals.

Assessing the influence of geographic distance in parasite communities of an exotic lizard.

The decay of similarity between biological communities with increasing geographical distance is a well-established pattern in ecology, but there are more complex factors acting on host population connections that influence this association for parasite communities, such as parasites' colonization ability and degree of connectivity between host populations. Here we aim to determine the helminth communities associated with different populations of the host lizard Hemidactylus mabouia, testing if the similarity of parasite communities decreases as the distance between them increases. For this, we collected samples of lizard populations in seven sites from Northeastern coast of Brazil and identified parasite species of helminths and pentastomids in each host, calculated the Sørensen indices of presence/absence and abundance of each pair of communities and related them to the geographical distance. We did not find a relationship of decaying similarity with increasing distance between the parasite communities of the host populations. This can be explained by factors such as the characteristics of the contact between the host populations, and by modes of transmission of most parasite species. Furthermore, it may be related to the exotic nature of the host in Brazil so that parasite communities have not reached equilibrium.