Ecology and neurophysiology of sleep in two wild sloth species

Study Objectives: Interspecific variation in sleep measured in captivity correlates with various physiological and environmental factors, including estimates of predation risk in the wild. However, it remains unclear whether prior comparative studies have been confounded by the captive recording environment. Herein we examine the impact of predation pressure on sleep in sloths living in the wild. Design: Comparison of two closely related sloth species, one exposed to predation and one free from predation. Setting: Panamanian mainland rainforest (predators present) and island mangrove (predators absent). Participants: Mainland (Bradypus variegatus, 5 males and 4 females) and island (Bradypus pygmaeus, 6 males) sloths. Interventions: None. Measurements and Results: EEG and EMG activity were recorded using a miniature data logger. Although both species spent between 9 and 10 hours per day sleeping, the mainland sloths showed a preference for sleeping at night, whereas island sloths showed no preference for sleeping during the day or night. EEG activity during NREM sleep showed lower low-frequency power, and increased spindle and higher frequency power in island sloths when compared to mainland sloths. Conclusions: In sloths sleeping in the wild, predation pressure influenced the timing of sleep, but not the amount of time spent asleep. The preference for sleeping at night in mainland sloths may be a strategy to avoid detection by nocturnal cats. The pronounced differences in the NREM sleep EEG spectrum remain unexplained, but might be related to genetic or environmental factors.

Chemosensory ecology: deceiving Drosophila.

The Solomon's lily arum mimics the odours of yeast to attract drosophilid flies as unrewarded pollinators.

Water scarcity, social power and the production of an elite suburb: the political ecology of water in Matadepera, Catalonia

This article investigates the history of land and water transformations in Matadepera, a wealthy suburb of metropolitan Barcelona. Analysis is informed by theories of political ecology and methods of environmental history; although very relevant, these have received relatively little attention within ecological economics. Empirical material includes communications from the City Archives of Matadepera (1919-1979), 17 interviews with locals born between 1913 and 1958, and an exhaustive review of grey historical literature. Existing water histories of Barcelona and its outskirts portray a battle against natural water scarcity, hard won by heroic engineers and politicians acting for the good of the community. Our research in Matadepera tells a very different story. We reveal the production of a highly uneven landscape and waterscape through fierce political and power struggles. The evolution of Matadepera from a small rural village to an elite suburb was anything but spontaneous or peaceful. It was a socio-environmental project well intended by landowning elites and heavily fought by others. The struggle for the control of water went hand in hand with the land and political struggles that culminated – and were violently resolved - in the Spanish Civil War. The displacement of the economic and environmental costs of water use from few to many continues to this day and is constitutive of Matadepera’s uneven and unsustainable landscape. By unravelling the relations of power that are inscribed in the urbanization of nature (Swyngedouw, 2004), we question the perceived wisdoms of contemporary water policy debates, particularly the notion of a natural scarcity that merits a technical or economic response. We argue that the water question is fundamentally a political question of environmental justice; it is about negotiating alternative visions of the future and deciding whose visions will be produced.

The resistance of seeds of cowpea (Vigna unguiculata) to the cowpea weevil (Callosobruchus maculatus)

Cowpea (Vigna unguiculata) seeds are heavily damaged during storage by the bruchid Callosobruchus maculatus. Seeds of some Nigerian varieties showed a strong resistance to this bruchid. By utilizing biochemical and entomological techniques we were able to rule out the paticipation of proteolytic enzyme (trypsin, chimotrypsin, subtilisin and papain) inhibitors, lectins, and tannins in the resistance mechanisms. Fractionation of the seed meal of a resistant variety suggests that the factor(s) responsible for the effect is (are) concentrate in the globulin fraction.

Ecology of phlebotomine sand flies (Diptera: Psychodidae)in a focus of Leishmania (Viannia) brasiliensis in northeastern Colombia

The phlebotomine sand fly fauna of two coffee plantations in a Leishmania-endemic area of Norte de Santander, Colombia was studied. Regular insect collections using a variety of methods were made for three and a half years. Information was obtained on diurnal resting sites, host range and seasonal abundance for 17 species, of wich five (Lutzomyia spinicrassa, Lu. serrana,Lu. shannoni, Lu. ovallesi and Lu. gomezi) were far more numerous than the others, anthropophilic and present throughout the year. The behaviour of these and the remaining 12 species is discussed in relation to their potential role in transmission of Leishmania (Viannia) brasiliensis in the area.

Ecology of malaria vectors in the Americas and future direction

The resurgence of malaria in the Americas has renewed interest in Anopheles biology. Anopheles darlingi, An. albimanus, An. nuneztovai and An aquasalis are reconfirmed as major malaria vectors and other species are playing important roles in regional malaria transmission. Adultbiting activity and larval ecology are discussed in detail. Seasonal abundance and daily biting activity of Anopheles vary considerably among species and geographically for the same species. Anopheles albimanus has the least amount of variation in biting activity over its range and An. darlingi has the greatest. All species studied are more exophilic and exophagic than endophilic and endophagic. Anopheles darling is more antropophilic, endophilic and endophagic than other Anophelines. Larval studies remain more descriptive than comprehensive. Research on Anophelines is becoming more integrated and biologists are using new biochemical techniques and ecological principles to answer critical questions. This "pluralization" will help us understand species complexes, population dynamics and malaria transmission. integrated control programs will require more regional, in-depth ecological studies.

The political ecology of Jatropha plantations for biodiesel in Tamil Nadu, India

Jatropha curcas is promoted internationally for its presumed agronomic viability in marginal lands, economic returns for small farmers, and lack of competition with food crops. However, empirical results from a study in southern India revealed that Jatropha cultivation, even on agricultural lands, is neither profitable, nor pro-poor. We use a political ecology framework to analyze both the discourse promoting Jatropha cultivation and its empirical consequences. We deconstruct the shaky premises of the dominant discourse of Jatropha as a “pro-poor” and “pro-wasteland” development crop, a discourse that paints a win-win picture between poverty alleviation, natural resource regeneration, and energy security goals. We then draw from field-work on Jatropha plantations in the state of Tamil Nadu to show how Jatropha cultivation favors resource-rich farmers, while possibly reinforcing existing processes of marginalization of small and marginal farmers.

Sand fly vectorial ecology in the state of São Paulo

Ecological aspect of sand fly distribution in the state of São Paulo, Brazil are described. The main man-biting species are Lutzomyia whitmani, Lu.pessoai, Lu.intermedia, Lu.migonei and Lu.fischeri. Their primary habitat is the forest but latter three of the above species are also encountered in domiciliary environment. Sylvatic species such as Lu.flaviscutellata bite man only rarely and Psychodopygus ayrozai seems to be more anthropophilic. The survival of sand flies in the residual forest and in cultivated areas where man has nearly destroyed the forest almost completely is analyzed. Over the last ten years the incidence of human American cutaneous leishmaniasis (ACL) has been increasing: human cases occurring within several municipalities in which there is overlapping with the distributon of domiciliary Lu.intermedia. New ACL microfoci are appearing in the state of São Paulo and these call for further study.

Ecology of Triatoma rubrovaria (Hemiptera, Triatominae) in wild and peridomestic environments of Uruguay

This paper describes population structure, spatial distribution and habitat selection of wild and peridomestic populations of Triatoma rubrovaria (Blanchard, 1843). Field studies were carried out at Las Piedras and La Bolsa in the Northern Department of Artigas, Uruguay. A semicircular sampling area, divided in seven or eight triangular sectors was sequentially examined from October 1990 to November 1991. At Las Piedras (typical wild habitat) 1063 T. rubrovaria bugs were collected from 84 of the rocky outcroops ("pedregales"). Abundance varied by season peaking in October-November (spring). Throughout the year, most of the population was made up of third, fourth and fifth instar nymphs; adults were found from October to March. In the peridomestic environment of La Bolsa, however T. rubrovaria was less common and showed a more irregular instar distribution. Colonized ecotopes, were those close to houses. In both sites T. rubrovaria was mainly associated with the geckonid Homonota uruguayensis and the cockroach Blaptica dubia.

Urban ecology of Triatoma infestans in San Juan, Argentina

This study was performed in an urban neighborhood of the capital city of the province of San Juan, Argentina. Erected as a housing complex, the place consists of 768 flats distributed in buildings of three and seven floors each. A survey was carried out in 33% of the dwellings, enquiring about the number of Triatoma infestans found indoors, stage of the bug development - nymph or adult - and how these insects had entered their homes. Adult T.infestans were found on all floors; 163 people (64%) had found them at least once, and 130 (51%) several times. Dispersal flight seems to have been the main mechanism of infestation by adult bugs in this area, and a total of 51% of the surveyed inhabitants reported that the insects had flown into their flats.