This study represents an analysis of Ae. albopictus behavior from its first registration in Havana, 1995, up to 2018. It highlights results on its dispersion and initial evidence of their domiciliation in the last years. There is a sustained increase in the number of Ae albopictus breeding sites shared / mixed with Ae. aegypti, known dominant specie in the urban ecosystem in Havana province [10].
A limitation of this study is that surveillance data from the routine Ae. aegypti and Ae. albopictus Control Program were used. This program carried out control measures such as the use of Temephos (Abate) and Bactivec® (Bacillus thuringiensis H-14) permanently in water containers detected by vector operators who perform the inspection in homes, workplaces and vacant lots. In addition, the inspection frequency is generally monthly but sometimes the frequency is increased up to 11-days surveys in case of high Ae. aegypti infestation or epidemiological alerts. These variations are the same for all municipalities; hence no differential impact is expected.
Aedes albopictus expanded geographically from 2010 to 2018 to 14 of the 15 municipalities that the province of Havana possesses, which shows, in addition to its introduction, its dispersal power. It should be noted that in the first years of its introduction (1995–1997) an attempt was made to eliminate Ae. albopictus mainly through chemical measures, but the objective was, obviously, not achieved. This could be due to various factors such as those of an operational nature in the control carried out (being more targeted to indoor spaces, where the main Ae. aegypti breeding sites are localized) or due to ignorance about Ae. albopictus insecticide, widely used in national control actions, susceptibility and / or resistance status [17]. On the other hand, different authors argue that the control of Ae. albopictus, in particular, is excessively difficult by living often far from the dwellings which implies a more extensive coverage needed than for Ae. aegypti [23].
The scanty presence of Ae. albopictus in the municipalities Habana Vieja and Diez de Octubre and their absence during the period studied in Centro Habana can be explained by the lack of areas with abundant vegetation in these urban municipalities. The presence of vegetation is important for this mosquito, since it has been shown that it is rarely found in rural areas where vegetation is eliminated [24].
It is known that Ae. aegypti is abundant in urban areas and Ae. albopictus in rural areas and that both can coexist in semi-urban areas [7], breeding mainly in artificial and natural breeding sites. They can even be found in slightly polluted waters [25, 26] which explains the observed association with Cx. quinquefasciatus mosquito, which prefer these type of breeding sites, but can also be found together with Aedes in used car tires [6] [26–28].
Aedes mediovittatus the other species with one of the highest percentages of association is present mainly in the Caribbean area with preference for rearing in tree holes [22] [29]. During the intensive phase with insecticides that took place in Cuba during 1981, the presence of Ae. aegypti was drastically reduce in the urban ecosystem which favored an increase in the presence of Ae. mediovittatus until the introduction of Ae. albopictus [4] [10] where this species has since been subjected to strong pressure and where in recent years it has been displaced by Ae. albopictus [17].
No similar patterns were found regarding the number of exclusive Ae. albopictus breeding sites in the province, mostly found in the peri-urban municipalities (Boyeros, Cotorro, Guanabacoa and Arroyo Naranjo) followed by Habana del Este and La Lisa belonging to mixed urbanization group, while the urban municipalities presented the highest number of mixed Ae. albopictus breeding sites with other culicids.
Studies conducted with Ae. aegypti and Ae. albopictus showed that the last one has a greater longevity in adult phase at different temperatures and humidity, which determined the influence of these climatic factors on the geographical distribution of these species [30]. These parameters that favor the occurrence of microclimates in certain areas of the province of Havana mainly in peri-urban areas with greater vegetation and in vegetative patches within the center of the province guarantee the appropriate conditions for a greater presence of Ae. albopictus in certain areas and favors the coexistence of both species.
Coexistence between Ae. aegypti and Ae. albopictus could also be favored under the Cuban conditions of strong insecticide pressure, to which the Ae. aegypti populations are subjected from 1981 up to today in Havana [10] [31]. The finding of Ae. albopictus in breeding sites inside the houses, although in an incipient but stable way, indicate towards an initiation of a domiciliation of the species.
It is known that there is hybridization between both species where the male of Ae. albopictus mates with the female Ae. aegypti resulting in a descendant of permanent sterilization in females resulting from this crossing and influencing the displacement of one species by another. [32, 33], However, a 15-year study in Rio de Janeiro, Brazil [34] suggested that the two species can achieve relative coexistence in the absence of strong competitive displacement by Ae. albopictus males for mating with Ae. aegypti females suggesting the low potential of hybridization and the lack of displacement between both species for these reasons [11]. On the other hand, another Brazilian study showed that even with high seasonal densities the effects of inter specific competition with Ae. aegypti was not enough to displace Ae. albopictus [12].
In Cuba, there is only evidence of hybridization between Ae. aegypti and Ae. albopictus at the laboratory level [35]. At the field level, it was determined that until 2012 only one coexistence between both species could be demonstrated [17], a result that we continue to support in this study until 2018. We do not doubt that the Cuban populations of these species exhibit the same behavior, as observed in Brazil in terms of hybridization, although in the Cuban situation there is an important difference of an influencing condition, namely the maintained chemical control with the use of Temephos in the water-holding containers in the houses. This last indication whose objective is to control Ae. aegypti populations in Havana until now has not avoided that this species continuing to be the dominant species in the urban ecosystem of this province in Cuba.
[35].