ABSTRACT. Entropy estimation in Muscina stabulans (Fallén) (Diptera, Muscidae) under laboratory conditions. Entropy (H) as a concept in demography was adapted from that of physics to quantify the impact of mortality on life expectancy and to quantitatively demonstrate mortality tendencies in experimental populations. Entropy was estimated for 160 pairs of Muscina stabulans (Fallén, 1817) in a climate-controlled chamber (24.8ºC ± 0.6ºC, relative humidity 70 -80%, 12 h photophase). Both sexes had H values intermediate to those theoretically expected (0.0 -0.5), showing that the survival curve is rectangular. The age-specific mortality distribution shows that mortality affects adults of this species in two ways. First, mortality is higher for 10 days from pupal emergence. Second, mortality again increases between 20-30 days after emergence. Small differences in mortality rates cause a greater overall impact on the survival of females.KEYWORDS. Life expectancy; mortality; population dynamics; survival.RESUMO. Estimativa de entropia de Muscina stabulans (Fallén) (Diptera, Muscidae) em condições artificiais. O conceito de entropia (H) foi adaptado da mecânica estatística para a demografia para quantificar o impacto da mortalidade na expectativa de vida e demonstrar quantitativamente a tendência da mortalidade em populações experimentais. Isto foi verificado para 160 casais de Muscina stabulans (Fallén, 1817) mantidos em câmara climatizada a 24,8ºC ± 0,6ºC, umidade relativa do ar entre 70 e 80% e fotofase de 12 horas. Nestas condições, machos e fêmeas apresentaram valores de H intermediários aos valores teóricos de H = 0 e H = 0,5 demonstrando que para esta espécie, a curva de sobrevivência é do tipo retangular. A distribuição da mortalidade por idade específica indicou que a força desse parâmetro age de dois modos sobre os adultos desta espécie. Em um, a mortalidade tem maior força nos intervalos compreendidos entre a emergência dos adultos e o 10° dia após este processo. No segundo modo, a força de mortalidade é maior entre o 20º e 30°d ias após a emergência, sendo que pequenas variações na mortalidade causam maior impacto na sobrevivência das fêmeas do que nos machos.PALAVRAS-CHAVE. Expectativa de vida; dinâmica populacional; mortalidade; sobrevivência.Muscina stabulans (Fallén, 1817) (Diptera, Muscidae) é uma espécie anautógena (Tirone et al. 1996), cosmopolita, com maior freqüência na Região Neotropical . No Brasil foi encontrada na Bahia, Paraná e São Paulo com preferência por ambientes urbanos (Linhares 1981;Carvalho et al. 1984), importante para a entomologia forense em países subtropicais (Liu & Greenberg 1989;Centeno et al. 2002)

This is the first published report concerning reproduction and survival using lifeMuscina stabulans (Fallén, 1817) (Diptera, Muscidae), commonly known as the false stable fly, is a cosmopolitan, synanthropic, anautogenous species most often founded in the Neotropical Region. In Brazil it has been reported from the states of Bahia, Paraná, Rio Grande do Sul and São Paulo, preferring urban environments (CARVALHO et al., 2002). This species is epidemiologically important because it is capable of transmitting several pathogens to humans and other animals as well as causing myiasis (GREENBERG, 1971). In poultry farms they can drastically reduce populations of Musca domestica Linnaeus, 1758 (Diptera, Muscidae), because M. stabulans third instars are facultative predators of housefly first and second instars (SKIDMORE, 1985). This species is also forensically important since its larvae can colonize decomposing carcasses from first to 10 days following the death of the individual, thus serving in the estimation of the post-mortem interval (PMI) (CENTENO et al., 2002;SOUZA et al., 2008).Muscina stabulans is a species with a very rapid developmental rate, especially between 20° and 30°C (KHZYWINSKI, 1993; MARCHENKO, 2001;MASCARINI & PRADO, 2002). In spite of this, little is known of its reproduction and survival of specific ages. This work had the objective of describing the mortality and reproduction of M. stabulans using survival analysis and calculated variables obtained using fertility life tables.-NOTE- A colony of M. stabulans was established under laboratory conditions in order to obtain eggs, larvae and pupae. The adults were maintained in 30X30X30cm cages and fed powdered milk, sugar and fish meal at a ratio of 2:2:1, respectively (RIBEIRO et al., 2000b). Water was provided in cups with polyester sponges placed on the surface of the water. Feed and water were provided ad libitum. Following oviposition, egg masses were obtained from a culture medium in the form of a paste consisting of fish meal, sawdust and water in the proportion of 2:2:1, respectively. The egg masses were transferred to a receptacle with the same medium used for their collection inside a collection funnel.After eclosion in this medium the larvae fed until the 3 rd instar, abandoned the funnel and fell into a container with moist sawdust (between 65 and 90% RH) to pupate. The pupae were transferred to glass containers and maintained until adult emergence. Some of these pupae were used to maintain the replacement cages in the laboratory. The colony was maintained during the entire experiment in an environmental chamber at a temperature of 24.8°C±0.6°C, relative air humidity between 70% and 80%, and a12:12 hour photophase.Life span and reproduction were determined with the establishment of 40 pairs in each cage. The four cages used were established starting with 320 randomly chosen pupae and handled in the same manner as described for the stock colony. The cages were observed daily to remove dead insects and eggs.