Seasonal dynamics of a drosophilid (Diptera) assemblage and its potencial as bioindicator in open environments

Abstract

ABSTRACT. Drosophila Fallen, 1823 (Diptera, Drosophilidae) is for long a well-established model organism for genetics and evolutionary research. The ecology of these flies, however, has only recently been better studied. Recent papers show that Drosophila assemblies can be used as bioindicators of forested environment degradation. In this work the bioindicator potential of drosophilids was evaluated in a naturally opened environment, a coastal strand-forest (restinga). Data from nine consecutive seasonal collections revealed strong temporal fluctuation pattern of the majority of Drosophila species groups. Drosophila willistoni group was more abundant at autumns, whereas D. cardini and D. tripunctata groups were, respectively, expressive at winters and springs, and D. repleta group at both seasons. The exotic species D. simulans Sturtevant, 1919 (from D. melanogaster group) and Zaprionus indianus Gupta, 1970 were most abundant at summers. Overall, the assemblage structure did not show the same characteristics of forested or urban environments, but was similar to the forests at winters and to cities at summers. This raises the question that this locality may already been under urbanization impact. Also, this can be interpreted as an easily invaded site for exotic species, what might lead to biotic homogenization and therefore can put in check the usage of drosophilid assemblages as bioindicators at open environments.KEYWORDS. Drosophila, seasonality, bioindicators, restinga, Brazil.RESUMO. Dinâmica sazonal de uma assembléia de drosofilídeos (Diptera) e seu potencial como bioindicadora em ambientes abertos. Drosophila Fallen, 1823 (Diptera, Drosophilidae) é, há muito tempo, um organismo modelo em pesquisas de genética e evolução. A ecologia destas moscas, no entanto, apenas recentemente foi melhor estudada. Trabalhos recentes apontam que as assembléias de Drosophila podem ser utilizadas como bioindicadoras de degradação de ambientes florestais. Neste trabalho, foi avaliado o potencial bioindicador dos drosofilídeos em um ambiente de restinga, naturalmente aberto. Dados de nove coletas sazonais consecutivas revelaram um forte padrão de flutuação temporal na maioria dos grupos de espécies de Drosophila. O grupo D. willistoni foi mais abundante nos outonos, enquanto os grupos D. cardini e D. tripunctata foram, respectivamente, expressivos nos invernos e primaveras, e o grupo D. repleta em ambas as estações. As espécies exóticas D. simulans Sturtevant, 1919 (do grupo D. melanogaster) e Zaprionus indianus Gupta, 1970 foram mais abundantes nos verões. Em geral, a estrutura desta assembléia não mostrou as mesmas características de ambientes florestais ou urbanos, mas mostrou-se similar às florestas nos invernos e aos urbanizados nos verões. Isto demonstra que esta localidade já pode estar sofrendo impacto da urbanização. Também, este pode ser interpretado como um local facilmente invadido por espécies exóticas, o que pode levar à homogeneização biótica e, portanto, pode por em cheque o uso de assembléias de drosofilídeo...

Comparison of Drosophilidae (Diptera) assemblages from two highland Araucaria Forest fragments, with and without environmental conservation policies

“…Among the Neotropical indigenous species, the subgroup willistoni showed differences of more than 70% between areas (Table 3) Regarding the ecological indexes, PMA in 2006 (H' = 2.601) and the autumn in 2006 in both areas (PMA: H' = 2.941; FBL: H' = 2.626) had higher diversity than already detected, but in general, the diversity indexes (H') were mostly similar (but sometimes higher than) to those found in other works (Silva et al, 2005a;Tidon, 2006;Toni et al, 2007;Gottschalk et al, 2007;Bizzo et al, 2010;Schmitz et al, 2010;Poppe et al, 2012). No seasonal pattern was detected in both areas.…”

Phenology of Drosophila species across a temperate growing season and implications for behavior

“…In disturbed areas of the tropics, exotic species dominate and displace native species [17, 23–26], a pattern also seen in temperate zones [27]. Thus Drosophila can serve as indicator species for environmental disturbance with major changes in community composition across years as a signal of environmental degradation [28].…”

Effects of seasonality on drosophilids (Insecta, Diptera) in the northern part of the Atlantic Forest, Brazil

“…Several studies have produced evidence of the seasonal changes in abundance, richness, composition and diversity of tropical insects (Janzen & Schoener, 1968; Pinheiro et al ., 2002; Basset et al ., 2003; Grimbacher & Stork, 2009; Neves et al ., 2010; Ferreira et al ., 2015). A specific group of insects, drosophilids, have become the object of considerable research addressing seasonal variations in the southern part of the Atlantic Forest in Brazil (Dobzhansky & Pavan, 1950; Saavedra et al ., 1995; De Toni et al ., 2007; Bizzo et al ., 2010; Garcia et al ., 2012), where marked temperature and rainfall changes are observed throughout the year, characterized by four distinct seasons. The seasonality of drosophilids inhabiting the northern part of the Brazilian Atlantic Forest has been little investigated, despite the influence of rainfall on the region's seasonal features, while the temperature range is less extensive.…”