Oviposition of Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus in city with dengue transmission, state of São Paulo, Brazil

Abstract

 The objective was to study the distribution and abundance of Ae. aegypti and Ae. albopictus eggs, the       co-occurrence of species and aspects of oviposition behavior in the traps. During 4 days in every month,       80 traps were exposed in the peri- and intra domiciliary environments of 40 urban residences in 22       blocks sorted out in Sebastião, SP, from February, 2011 to February, 2012. It was analyzed the monthly       distribution of the ovitraps positivity indexes (IPO) and eggs average per ovitrap (MOA) of Ae. aegypti       and Ae. albopictus, by using the Kruskal-Wallis test, followed by the Dwass-Steel-Chritcholow- Flinger       test. The Spearman correlation and simple linear regression test was used to assess the association between       meteorological variables with the number of traps with eggs and number of eggs. The standard of evasion       and superoviposition in the ovitraps with Ae. aegypti was analyzed per comparison of class categories of       number of eggs, by applying Kruskal-Wallis test, followed by the Dwass-Steel-Chritchlow-Fligner test, for       multiple comparisons. In the comparison analysis of IPO values in the traps of the species co-occurrences,       in indoors and outdoors sites, as well as in the MOA analysis, the Mann-Whitney test was used. To evaluate       the infestation intensity per species was utilized the estimator of Kernel density. The Ae. aegypti IPO and       MOA were higher in the peri- domiciliary environment, p=0,03 ; p=0,03, respectively. It was verified       the positive correlation among temperature and number of ovitraps with eggs and number of eggs of this       species, in domiciliary environments. There was no difference in the IPO (p=0,33) and MOA (p=0,57)       of Ae. albopictus between the environments. There was positive correlation between temperature and       positivity of ovitraps with Ae. albopictus in the peri- domiciliary environment. It was verified higher IPO       of Ae. aegypti compared to Ae. albopictus, in the peri- (p=0,00) and intra domiciliary sites (p=0,00). The       MOA of Ae. aegypti was higher than the Ae. albopictus in the peri- (p=0,00) and in the intra domiciliary       (p=0,01). No significant difference was showed in the number of positive ovitraps of the different class       categories of number of eggs. (T = 3.48; p = 0,32). The number of eggs registered in the class categories       was different (H = 10.86; p = 0,01), presenting in the class 31 to 60, when compared to ≤ 30 (p=0,03),       and in the class ≥ 91, this one compared to ≤ 30 (p=0,00). The comparison of the species distribution in       ovitraps of co-occurrence, per domicilie environment, has not showed significant difference (H = 4.61; p       = 0,20). The spatial distribution of eggs ovitraps revealed higher intensity of infestation by Ae. aegypti in       the south area of the study, a highly urbanized area. Regarding Aedes albopictus, the conglomeration of       occurrence places of the species was in the north coast, place of little population concentration. There was       a temporal and spatial patterns of distribution and abundance of species, Ae. aegypti and Ae. albopictus       predominating over revealing peridomiciles your priority space in the selection of oviposition site. These       species occupy urban space differently indicating segregation of habitat which may have contributed for       the co-occurrence found. Overcrowding was found in the traps which suggests little availability of suitable       breeding sites in the environment.