Interaction between Musca domestica L. and its predator Muscina stabulans (Fallén) (Diptera, Muscidae): effects of prey density and food source abundance

Interaction between Musca domestica L. and its predator Muscina stabulans (Fallén) (Diptera, Muscidae): Effects of prey density and food source abundance. The objective of this work was to evaluate the influence of prey density and food source abundance on the predatory behavior of Muscina stabulans over M. domestica. Three predator/prey proportions were evaluated (1:1, 1:3 and 1:6), using 100 third instar predator larvae against second instar prey larvae. Each proportion was maintained using three different levels of food substrate (25, 50 and 100 g). The experiments were carried out in triplicate in BOD incubators (25ºC, UR 70% ± 10% and 12 h photoperiod). The mortality of the M. domestica larvae was 100% under all conditions, except in the 1:6 predator/prey proportion, at the 50g and 100g food substrate levels, where it was 99.99% and 99.22%, respectively. There was a significant increase in the development period of M. stabulans in relation to the increase in prey density and decrease in quantity of food substrate. An increase in the proportion of individuals and a reduction in the amount of resource slowed down larval development. Muscina stabulans pupal weight was proportional to the increase in prey density and the amount of food substrate. The proportion or the density influenced the survival of M. stabulans, with no difference in relation to the amount of food source and consequently in the interaction of the factors. There was no difference between the 1:1 and 1:3 predator-prey densities, with both differing from the 1:6 density

Exigências térmicas de pré-oviposição e incubação para populações de Periplaneta americanaLinnaeus, 1758 (Blattaria, Blattidae) da região Sul do Brasil

Colônias de Periplaneta americanaLinnaeus, 1758 foram estabelecidas e mantidas sob condições de laboratório, a partir de espécimes coletados na área urbana do município de Pelotas, RS, Brasil, de janeiro/1996 a dezembro/1997 para estimativa das exigências térmicas dos estágios de pré-oviposição e incubação. Tais espécimes foram alimentados com ração peletizada comercial apropriada para coelhos e água ad libitum. Trinta casais e 30 ootecas foram expostos a temperaturas entre 15 e 40ºC, com intervalos de 5°C, em câmara climatizada com umidade relativa ³80% e fotofase de 12 horas. O período de pré-oviposição de P. americana variou de 6 a 45 e de incubação de 27,7 a 102 dias, na faixa de temperatura de 20 a 35ºC. A viabilidade de ootecas variou de 43,3% a 83,3% e de ovos de 87,1 a 98,4%. A temperatura base (Tb) e a constante térmica (K) para pré-oviposição e incubação foram de 13,8°C, 160,1 GD e 13,9°C, 554,6 GD, respectivamente. A faixa de temperatura ótima para oviposição e incubação de P. americanaem condições de laboratório foi de 20 a 35ºC, com influência considerável e inversamente proporcional na duração do período de oviposição e de incubação, mas não na viabilidade dos ovos

12,500+ and counting: biodiversity of the Brazilian Pampa

Knowledge on biodiversity is fundamental for conservation strategies. The Brazilian Pampa region, located in subtropical southern Brazil, is neglected in terms of conservation, and knowledge of its biodiversity is fragmented. We aim to answer the question: how many, and which, species occur in the Brazilian Pampa? In a collaborative effort, we built species lists for plants, animals, bacteria, and fungi that occur in the Brazilian Pampa. We included information on distribution patterns, main habitat types, and conservation status. Our study resulted in referenced lists totaling 12,503 species (12,854 taxa, when considering infraspecific taxonomic categories [or units]). Vascular plants amount to 3,642 species (including 165 Pteridophytes), while algae have 2,046 species (2,378 taxa) and bryophytes 316 species (318 taxa). Fungi (incl. lichenized fungi) contains 1,141 species (1,144 taxa). Animals total 5,358 species (5,372 taxa). Among the latter, vertebrates comprise 1,136 species, while invertebrates are represented by 4,222 species. Our data indicate that, according to current knowledge, the Pampa holds approximately 9% of the Brazilian biodiversity in an area of little more than 2% of Brazil’s total land. The proportion of species restricted to the Brazilian Pampa is low (with few groups as exceptions), as it is part of a larger grassland ecoregion and in a transitional climatic setting. Our study yielded considerably higher species numbers than previously known for many species groups; for some, it provides the first published compilation. Further efforts are needed to increase knowledge in the Pampa and other regions of Brazil. Considering the strategic importance of biodiversity and its conservation, appropriate government policies are needed to fund studies on biodiversity, create accessible and constantly updated biodiversity databases, and consider biodiversity in school curricula and other outreach activities