Crepuscular period is one of the factors that may influence the biting activity of mosquitoes. Many of these insects have a peak activity in this period. The purpose of this study was to investigate the afternoon crepuscular activity of Culicidae in a remaining area of Atlantic Forest in western Santa Catarina, southern Brazil. Moreover, the possible influence of abiotic factors, the abundance and species richness were verified. In order to better analyze the influence of crepuscular period in specific composition and abundance of mosquitoes, the dusk was divided into three periods: pre-sunset, sunset and post-sunset. At the end of the study, nine hundred and eight four specimens distributed in 12 genera and 23 species were collected. Trichoprosopon pallidiventer (Lutz, 1905) (59.76%), Aedes crinifer (Theobald, 1903) (8.13%), Ae. scapularis (Rondani, 1848) (5.89%) were the most abundant species. Spring time presented the greatest abundance and species richness. During the study, among the three periods evaluated, pre-sunset had the greatest abundance and post-sunset the lowest. Pre-sunset and sunset had the greatest similarity between species. Regarding to the abiotic factors evaluated seven and 15 days before sampling, they did not present significant correlation for the three most abundant species. However, temperature had a positive correlation to these species. Moreover, the correlation between collected species and its possible role as vectors of etiological agents of diseases was discussed.Keywords: abiotic factors, Culicidae, Diptera, Hematophagy, Santa Catarina state. Mosquitos (Diptera

RESUMO: O presente estudo teve como objetivo identificar as espécies de mamíferos de médio e grande porte mortos por atropelamento em trechos de cinco rodovias, totalizando 110 km de extensão, na região oeste de Santa Catarina, Brasil. Foi analisada a sazonalidade, as diferenças na quantidade de atropelamentos nas diferentes rodovias e nas diferentes fitofisionomias ao longo destas. Foram realizadas expedições mensais, de junho de 2013 a maio de 2014, sendo encontrados 66 mamíferos atropelados, pertencentes a nove espécies, com uma taxa de atropelamento 0,05 ind./km/dia. As espécies com maior quantidade de indivíduos atropelados foram Didelphis albiventris com 25,75% dos atropelamentos, seguido de Cerdocyon thous com 16,66%, Nasua nasua com 9,10%, Dasypus novemcinctus com 7,57%. Não houve variação significativa de animais atropelados sazonalmente e nem relação entre a vegetação e o local de atropelamento, porém, locais considerados antropizados tiveram maior quantidade de atropelamentos. A diferença na variância de mamíferos atropelados entre as rodovias foi significativa (H = 13,78, p < 0,01). A Análise de Agrupamento demonstrou que a composição da mastofauna atropelada em campo sujo, capoeira e floresta foram similares entre si. Também o foram as áreas de floresta e áreas de Pinus sp. e agrícolas.

Recently, the number of Aedes aegypti foci has increased in west of Santa Catarina, south Brazil, which has increased concern regarding mosquito-borne disease outbreaks such as dengue fever, Zika virus, and chikungunya. Therefore, it is important to monitor genetic resistance to insecticides through "knockdown resistance". Homozygosity (Ile/Ile) at position 1016 in the coding region of a voltage-dependent sodium channel gene (Na) may induce resistance to pyrethroid insecticides. We evaluated the frequency of these alleles in A. aegypti in west Santa Catarina. In total, 349 specimens were obtained from the microregions of Joaçaba (31), Concórdia (35), Chapecó (154), and São Miguel do Oeste (129). We found that 109 individuals (31.0%) were homozygous for Val/Val, 102 (29.0%) were heterozygous for Val/Ile, and 138 (40.0%) were homozygous for Ile/Ile. The allele frequencies were similar for Val (0.455) and Ile (0.545). Joaçaba and Concórdia had the highest mutant allele frequencies (0.825 and 0.685, respectively). Therefore, these populations should be monitored for increases in pyrethroid resistance. The São Miguel do Oeste and Chapecó populations had similar frequencies of Val and Ile and were not in Hardy-Weinberg equilibrium, suggesting that a selection pressure or other evolutionary force has occurred. In conclusion, the observed frequency of Ile/Ile homozygous individuals in the region studied requires attention, because the implementation of controls using pyrethroid may increase the frequency of the mutant allele through the selection of resistant populations.

Landscapes composed of small rural properties may support highly heterogeneous habitat, because they often cover distinct types of land uses adjacent to surrounding forest fragments. Many butterfly species may benefit from this kind of landscape, as very distinct microhabitats can be found in a very restricted spatial scale. To better understand how different microhabitats are related to fragmentation in rural landscapes the present study collected the butterfly fauna in 18 sampling point sites, representing distinct types of forest edges and forest interiors. Although closely located, these sites showed no spatial autocorrelation. Instead, a major distinction in species richness and composition was found among forest interior and edge habitats while no significant difference was found in species composition among distinct edge types. Therefore, the high segregation of butterfly assemblages found in a very restricted geographic scale suggests the presence of two different groups of butterflies that respond independently to forest fragmentation, the forest interior assemblages and forest edge assemblages. This distinction of butterfly assemblages related to forest interior and forest edges were already reported, but our results highlights that these differences are found mostly due to species turnover between those habitats. In other words, both microhabitat types present a high number of specialized species compared to a smaller fraction of generalist species that may occurs in both microhabitats. In the case of Atlantic Forest, the species of special conservation concern are those true specialized in forest interior habitats and not those specialized in forest edges, thus the present study corroborates the importance of sampling different microhabitats when studying fragmentation processes, both inside and outside of fragments. Although forest edges may present different kinds of habitat types, species present along border tend to be as heterogeneous as species present in different locations inside the forest. This information should be considered in sampling designs of biodiversity essays that focus on a more consistent representation of local diversity.

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