**3.2 Average biological cycle time and total adults of** *A. aegypti* **from Manaus, Amazonas, in environmental rooms that simulate the climatic conditions provided by the IPCC**

The averages of climatic variations during the experiment in °C, increase in ppm of CO2 and percentage (%) of humidity for the different environmental rooms are represented in **Table 2**.

**Figure 1.**

*Egg hatch percentage of* A. aegypti *from Londrina, Paraná, in incubator chambers (BOD) with different temperatures with ±2°C limits and ambient temperature (16.7–24.1°C), observed for 10 days.*


*+ Equal letters on the same line do not differ from each other by the Kruskal-Wallis p = 0.0261, H = 11.0428.*

#### **Table 1.**

*Emergence of* Aedes aegypti *adults with eggs incubated for 10 days at different temperatures and placed for post-embryonic development at a temperature of 25 ± 2°C.*


#### **Table 2.**

*Averages of temperature °C, increase in ppm of CO2 and percentage (%) of humidity for the different environmental rooms.*

There was a statistical difference (p < 0.05) between the average time of the biological cycle of *A. aegypti* in the different environments, with room 4 being the environment that had the greatest influence on the life cycle of mosquitoes, since they developed more faster than the insects kept in the other environmental rooms (**Table 3**).

In the room 1, it was found that adults emerged on the sixth and seventh day, with 45.79% females and 54.20% males. In the room 2, adults emerged on the sixth day, with 58.88% of females and 41.11% of males. In the room 4, adults began to emerge on the fifth and sixth day of the experiment, with 60.34% females and 39.66% males. The mortality percentage in the different instars for rooms 1, 2 and 4 was: 14.4; 28 and 53.6%, respectively.

#### **4. Discussion**

Temperature is one of the main environmental variables responsible for changes in the biology of the mosquito *A. aegypti*, directly influencing the reproductive cycle of this species [27–31]. The exposure of *A. aegypti* eggs to temperatures out of their normal range can cause physiological stress, interrupting the development [32]. Therefore, the temperature must be in a suitable range, in order to the larvae hatch and the generations develop and multiply.

**127**

*Post-Embryonic Development of* Aedes *(*Stegomyia*)* aegypti *Linnaeus, 1762 at Different…*

**Parâmeters Room 1 (TA) Room 2 (TM) Room 4 (TE)** Averages 7.3430a,\* 6.6780b,\* 6.0510c,\* Standard deviation 0.43756 0.65009 0.60656 Standard error 0.13837 0.20558 0.19181 *TA = ambient temperature; TS = mild temperature; TE = extreme temperature. For the Tukey test, the averages were transformed into a root of x + 0.5\*. Different letters on the same line, indicate a statistically significant difference* 

In this study, the high hatching rate of larvae (48%) maintained at a temperature of 25°C, in Londrina, Paraná, corroborates what was observed in the laboratory by Farnesi et al. [33] and Mohammed and Chadee [34], who verified larvae hatching rates above 90% at this temperature. In addition, it is in accordance with the optimal temperature range for the development of the *A. aegypti* mosquito, mentioned

*Average life cycle time of adults kept in different environmental rooms that simulate the climatic conditions* 

Beserra et al. [35] observed that this range is between 21 and 29°C, when studying the thermal requirements of the species in four bioclimatic regions of Paraíba, Brazil. Later, Beserra et al. [36] observed that the optimal temperature for the development of *A. aegypti* is between 22 and 32°C, when studying the mosquito's biological cycle in air-conditioned chambers with six different temperatures. For Marinho [37], the ideal temperature range for the development of the vector is between 22°C and 36°C, according to results obtained after analyzing the influence of climatic factors on the pattern of oviposition, distribution and population development of *A. aegypti* in the field and the laboratory. More recently, Galavíz-Parada et al. [29] conclude that hatching and survival of *A. aegypti* in Mexico can occur in a temperature range between 15°C and 32°C under

Thus, the third highest rate of hatching of larvae (35%), as well as the lowest mortality of larvae (2.2%) occurring at ambient temperature (16.7–24.1°C) in Londrina, is also in line with the range optimal temperature for the development of *A. aegypti*, mentioned in the literature, and corroborates with a study by Yang et al. [38], where they observed that the mortality rate of adult females of *A. aegypti* was lower between 15°C and 30°C and increases rapidly at temperatures below or above this range, thus corroborating with the mortality rate observed at 0°C (22.2%) in Londrina. On the other hand, Costa et al. [39] reported that the longevity in *A. aegypti* decreased from 25 to 35°C, corroborating with the second highest mortality

Assessing the influence of ambient temperature on the longevity and fertility of *A. aegypti* in the city of Guarapuava, Paraná, Ajuz et al. [40] found that the vector's survival zone is wide and that only the minimum temperatures below 5°C limit the proliferation and super infestation of the species in the city. Thus, it is evident that the life cycle of the mosquitoes in Londrina is also affected only in extreme temperatures, in view of the greater number of emergencies of adults of *A. aegypti* observed at 5°C (44.80%), as well as a relatively low mortality rate on this temperature (6.6%). The ability of *A. aegypti* larvae and adult to tolerate low temperatures

The low hatching of larvae (7%) and emergence of adults (5.6%) at 0°C, as well as the absence at 45°C observed in Londrina, is justified by the fact of extreme temperatures (very low or very high) are harmful to the development of *A. aegypti*,

*DOI: http://dx.doi.org/10.5772/intechopen.93100*

*according to the Tukey test (p < 0.05), CV = 4%; F = 12.64 and DMS = 0.120.*

in the literature.

*provided by the IPCC.*

**Table 3.**

laboratory conditions.

rate, observed at 25° C (16.6%) in Londrina.

also was demonstrated in the study by Jass et al. [41].

*Post-Embryonic Development of* Aedes *(*Stegomyia*)* aegypti *Linnaeus, 1762 at Different… DOI: http://dx.doi.org/10.5772/intechopen.93100*


*TA = ambient temperature; TS = mild temperature; TE = extreme temperature. For the Tukey test, the averages were transformed into a root of x + 0.5\*. Different letters on the same line, indicate a statistically significant difference according to the Tukey test (p < 0.05), CV = 4%; F = 12.64 and DMS = 0.120.*

**Table 3.**

*Life Cycle and Development of Diptera*

**Adult emergence rate**

There was a statistical difference (p < 0.05) between the average time of the biological cycle of *A. aegypti* in the different environments, with room 4 being the environment that had the greatest influence on the life cycle of mosquitoes, since they developed more faster than the insects kept in the other environmental rooms

1 27.23 434.4 77.01 2 29.74 864.6 78.66 4 32.18 1279.87 76.96

*Equal letters on the same line do not differ from each other by the Kruskal-Wallis p = 0.0261, H = 11.0428.*

*Emergence of* Aedes aegypti *adults with eggs incubated for 10 days at different temperatures and placed for* 

*Averages of temperature °C, increase in ppm of CO2 and percentage (%) of humidity for the different* 

**Temperature (°C) CO2 (ppm) Humidity (%)**

**Temperature (±2°C) 0°C 5°C 25°C 45°C Ambient** 

**Replicas M F M F M F M F M F** 1 4 1 8 7 10 4 0 0 6 5 2 0 1 5 4 8 6 0 0 0 0 3 0 0 8 4 5 2 0 0 0 0 4 0 1 9 7 12 3 0 0 10 6 5 0 0 4 0 0 0 0 0 9 8 Total 4 3 34 22 35 15 0 0 25 19 **Total M-F\* 7a+ 56a 50a 0b 44a Total % 5.60% 44.80% 40% 0% 35.20%**

**(16.7–24.1°C)**

**Rooms Climate variations**

*post-embryonic development at a temperature of 25 ± 2°C.*

In the room 1, it was found that adults emerged on the sixth and seventh day, with 45.79% females and 54.20% males. In the room 2, adults emerged on the sixth day, with 58.88% of females and 41.11% of males. In the room 4, adults began to emerge on the fifth and sixth day of the experiment, with 60.34% females and 39.66% males. The mortality percentage in the different instars for rooms 1, 2 and

Temperature is one of the main environmental variables responsible for changes

in the biology of the mosquito *A. aegypti*, directly influencing the reproductive cycle of this species [27–31]. The exposure of *A. aegypti* eggs to temperatures out of their normal range can cause physiological stress, interrupting the development [32]. Therefore, the temperature must be in a suitable range, in order to the larvae

**126**

(**Table 3**).

**Table 2.**

*\**

*+*

**Table 1.**

*M-F: M = male and F = female.*

*environmental rooms.*

**4. Discussion**

4 was: 14.4; 28 and 53.6%, respectively.

hatch and the generations develop and multiply.

*Average life cycle time of adults kept in different environmental rooms that simulate the climatic conditions provided by the IPCC.*

In this study, the high hatching rate of larvae (48%) maintained at a temperature of 25°C, in Londrina, Paraná, corroborates what was observed in the laboratory by Farnesi et al. [33] and Mohammed and Chadee [34], who verified larvae hatching rates above 90% at this temperature. In addition, it is in accordance with the optimal temperature range for the development of the *A. aegypti* mosquito, mentioned in the literature.

Beserra et al. [35] observed that this range is between 21 and 29°C, when studying the thermal requirements of the species in four bioclimatic regions of Paraíba, Brazil. Later, Beserra et al. [36] observed that the optimal temperature for the development of *A. aegypti* is between 22 and 32°C, when studying the mosquito's biological cycle in air-conditioned chambers with six different temperatures. For Marinho [37], the ideal temperature range for the development of the vector is between 22°C and 36°C, according to results obtained after analyzing the influence of climatic factors on the pattern of oviposition, distribution and population development of *A. aegypti* in the field and the laboratory. More recently, Galavíz-Parada et al. [29] conclude that hatching and survival of *A. aegypti* in Mexico can occur in a temperature range between 15°C and 32°C under laboratory conditions.

Thus, the third highest rate of hatching of larvae (35%), as well as the lowest mortality of larvae (2.2%) occurring at ambient temperature (16.7–24.1°C) in Londrina, is also in line with the range optimal temperature for the development of *A. aegypti*, mentioned in the literature, and corroborates with a study by Yang et al. [38], where they observed that the mortality rate of adult females of *A. aegypti* was lower between 15°C and 30°C and increases rapidly at temperatures below or above this range, thus corroborating with the mortality rate observed at 0°C (22.2%) in Londrina. On the other hand, Costa et al. [39] reported that the longevity in *A. aegypti* decreased from 25 to 35°C, corroborating with the second highest mortality rate, observed at 25° C (16.6%) in Londrina.

Assessing the influence of ambient temperature on the longevity and fertility of *A. aegypti* in the city of Guarapuava, Paraná, Ajuz et al. [40] found that the vector's survival zone is wide and that only the minimum temperatures below 5°C limit the proliferation and super infestation of the species in the city. Thus, it is evident that the life cycle of the mosquitoes in Londrina is also affected only in extreme temperatures, in view of the greater number of emergencies of adults of *A. aegypti* observed at 5°C (44.80%), as well as a relatively low mortality rate on this temperature (6.6%). The ability of *A. aegypti* larvae and adult to tolerate low temperatures also was demonstrated in the study by Jass et al. [41].

The low hatching of larvae (7%) and emergence of adults (5.6%) at 0°C, as well as the absence at 45°C observed in Londrina, is justified by the fact of extreme temperatures (very low or very high) are harmful to the development of *A. aegypti*, according to Buriol et al. [42], who stated that temperatures below 5°C and above 40°C are lethal to mosquito development. Similar data were observed by De Majo et al. [43], Marinho et al. [44], Mohammed and Chadee [34] in studies about the effect of different temperatures on the development of *A. aegypti*. More recently, Sukiato et al. [32] also noted in their study that there was no hatching of *A. aegypti* eggs at 40°C, and the larval and pupal mortality was higher at 37°C, compared to other lower temperatures (34, 31 and 28°C).

In Manaus, Amazonas, the greatest influence of the room 4 (with the highest temperature - 32.18°C) on the life cycle of the mosquitoes, where they developed faster than mosquitoes kept in other lower temperature environmental rooms, is in line with Carrington et al. [45], who found that temperatures around 30°C are ideal for the development of *A. aegypti* and that the development was faster under a temperature of 35°C and impaired above this range. Similar results were also obtained by Brady et al. [46], when evaluating the survival of the species at different temperatures, located between 0°C and 40°C. Sukiato et al. [32] also observed that the *A. aegypti* development time was shorter at higher temperatures (37 and 34°C).

In relation to the mortality rate, the lower mortality (14.4%) that occurred at the room 1, where the temperature was lower, as well as the higher mortality (53.6%) of different instars that occurred at the room 4, also corroborate with the results reported by Yang et al. [38] and Sukiato et al. [32] already compared with the results obtained in Londrina. A study by Farjana et al. [47] also demonstrated that the mortality of *A. aegypti* increased at a higher temperature (35°C).

The lowest and the highest mortality rate at the rooms 1 and 4, respectively, may have happened due to the influence of CO2 concentration—which was lower at the room 1 (similar to the current atmospheric concentration) and much higher at the room 4—because CO2 atmospheric is also related to the biological cycle of living beings, influencing their ecological interactions. High CO2 rates have an impact on ecological communities, causing a reduction in nitrogen concentration. Furthermore, it can reduce the quality and quantity of food in breeding sites, compromising larval growth and survival [48].

However, in a study by Azevedo et al. [49], higher concentrations of CO2 had no significant influence on the results obtained in relation to the biological cycle of *A. aegypti.*
