1. Effect of temperature and nutrition on the development and inter specific relationship of Aedes aegypti and Ae. albopictus (Diptera: Culicidae)
Thahsin Farjana and Nobuko Tuno
Laboratory of Ecology, Kanazawa University, Japan

2. Background
More than one-third of the world’s population living in areas at risk for
dengue transmission (CDC-2010)
Dengue Map
Province or local level
Country level
Areas of ongoing transmission risk   
Map courtesy: CDC-Health Map collaboration, 2010

3. artificial containers Artificial containers
Two competent vectors for dengue and DHF
Aedes aegypti
indoor and outdoors:
artificial containers
2. Aedes albopictus
urban
Artificial containers
Natural containers
Rural
Sub-urban
Vegetated urban

4. Aedes aegypti: Global distribution
Ae. aegypti infested areas with dengue epidemic activity
Ae. aegypti infested areas
Map courtesy: CDC dengue map, 2006

5. Ae. albopictus: Global distribution
Map Courtesy: Landcare Research, 2004

6. geographic distribution
of vector borne diseases.
Global climate change
Regional temperature and photoperiod may affect the distribution of these two species (Hawley, 1988)
Vegetation/Detritus type may affect the outcomes of inter specific competition in sympatric areas (Murrell & Juliano, 2008)

7. Interspecies competition
Our questions:
Combined effect of temperature & nutrition
??????
Larval growth
Interspecies competition

8. Materials and Methods Laboratory stocks:
Aedes aegypti Tanzania strain (Mosi, Tanzania)
Ae. albopictus Japan strain (Nagasaki, Japan)
Adults maintenance;
25±1°C, humidity (70-90%), 14L/10D photoperiod
3% sucrose solution
Mouse blood (once per week).

9. Manipulated conditions:
1. Temperature (20, 25, 30, 35°C)
2. Nutrition (Poor vs Rich)
Poor: mg for 1st and 2nd instars
0.1 mg for 3rd and 4th instars
Rich: 0.2 mg for 1st and 2nd instars
0.5 mg for 3rd and 4th instars
200 ml water + 20 larvae
Species size
Single species: 20 larvae x 5 replicates
Mixed species: Ae. aegypti 10: Ae. albopictus 10 x 10 replicates

10. Larval developments, survival, molting and pupation were checked daily
Wing length of emergent adults were measured (Van Den Heuvel, 1963).
Measured parameters:
Mortality at developmental stages
Development period from 1st instars to adult (♀ and ♂)
Wing length of adults (♀ and ♂)
Interspecies competition among 2 species

11. Per capita performance, Index I
With Modification from Livdahl and Sugihara 1984
Ln(1/N0)(∑ wx3)
I =
∑x wx3 / ∑ wx3
No, is the initial number of larvae in an experimental treatment
wₓ, is the wing length of females that emerged on day x

12. Mortality from first instars to emergence
Results and Discussion
Mortality from first instars to emergence
Ae. aegypti
Ae. albopictus
Significantly different between poor and rich nutrition

13. Effect of temperature, diet and mixed species on the mortality
Factors
Effects (ANOVA Results)
Ae. aegypti
Ae. albopictus
Temperature
Yes
Nutrition No
Mixed species
Temperature x Nutrition
Temperature x Mixed species
Significant=Yes, Non Significant=No

14. Development time from 1st instars to emergence in mixed species
Female
Male

15. Wing length of adult Ae. aegypti and Ae
Wing length of adult Ae. aegypti and Ae. albopictus at 20, 25, 30 and 35 °C temperature
Ae. aegypti ♀
Ae. albopictus ♀

16. Effects (MANOVA Results)
Effects of temperature and diet on the development time and wing size in mixed species
Factors
Effects (MANOVA Results)
Ae. aegypti
Ae. albopictus
Female
Male
Temperature
Yes
Nutrition
Temperature x Nutrition No
Significant=Yes, Non Significant=No

17. Sex ratio of Ae. aegypti and Ae. albopictus

18. In case of Ae. albopictus, more female in mixed and poor
diet may compensate for the declining intrinsic rate of
increase under these unfavorable conditions.

19. Per Capita Performance index (I) with 1:1 sex ratio

20. Estimated per capita performance index I in mixed species with absolute sex ratio
Ae. albopictus was favored at 20°C - 25°C
Ae. aegypti was favored at 25°C- 30°C.
At 35°C, the population growth of both species was declined.

21. Comparative I in A. Poor Diet B. Rich Diet

22. Comaprative I in different diet conditions

23. Concluding remarks
Population growth of Ae. albopictus was more stable, regardless of diet and temperature.
Population growth of Ae. aegypti varied more with these two factors.
These species-specific attributes may help explain the latitudinal distribution of the mosquitoes and degree of species dominance where they are sympatric.