**4. Cytogenetic study**

*Life Cycle and Development of Diptera*

antenna of the female is pilose [14].

parts to develop completely.

personal protection [28–38].

The adult's length is between 3.96 and 4.25 mm (**Figure 5**), and it is are made up of a head with two large compound eyes, a thorax, a pair of scaled wings, and six jointed legs. The thorax, legs, and wings are covered with dark brown scales. The abdomen is covered with black scales and some of which are white, and the anal cercus is withdrawn. The adults rest on the surfaces in such a way that the thorax and head are parallel to the surface and the hose may form a small angle with the surface. The antenna of the male is plumose, easily visible near the eye and the

Male mosquitoes last less than a week and the females may live for a couple of months and that is only with ideal conditions depending on how much warmth and moisture. Sometimes females have to wait for about a day for their reproductive

The role of mosquitoes life cycle to manage their populations is vital throughout the world and especially in the tropics because these spread many diseases. Generally, mosquitoes control operations are targeted against three different problems; nuisance mosquitoes bother people around homes, in parks, and recreational areas; economically important mosquitoes reduce real estate values consisting of land and the buildings, adversely affecting tourism and related business interests; and public health is the focus when mosquitoes are vectors or transmitters of infectious diseases [22–27]. Therefore, mosquitoes prevention and control involves a basic understanding of their life cycle, removal of potential egg laying sites, removal of any sources of standing water, keeping of weeds and other vegetation mowed and trimmed to minimize shelter for adult mosquitoes, considering stocking of mosquitoes eating fish for areas with ponds, control of adult mosquitoes, and

**78**

**Figure 5.**

*Female adult of* Culex quinquefasciatus*.*

During the last so many years, there has been a renewed emphasis upon basic research in mosquito biology. The dramatic development of resistance over the world and the unequivocal demonstration of the genetic basis of this resistance have underlined the need for more research and increasingly intensive research on the genetics and cytogenetics of mosquitoes, and today, relatively little is known in this field.

The study shows that the chromosomes karyotyping of this species consists of three pairs of chromosomes (i.e., 2n = 6). There are one pair of sexual chromosomes and two pairs of autosomal chromosomes (**Figure 6**).

The average length for autosomal chromosomes collected from Baghdad province is 5.87 and 6.99 μM for chromosome 2 and chromosome 3, respectively, and the length of sexual chromosome is 4.46 μM, the average length for autosomal chromosomes collected from Babylon province is 5.51 and 6.96 μM for chromosome 2 to chromosome 3, respectively, and the length of sexual chromosome is 4.33 μM; while the average length for autosomal chromosomes collected from Wasit province is 5.5 and 6.97 μM for chromosome 2 and chromosome 3, respectively, and the length of sexual chromosome is 3.89 μM (**Table 1**).

When measuring the arm ratio for the autosomal and sexual chromosomes, it shows that the metacentric chromosomes show the average arm ratio for the chromosomes of the Baghdad province as 1.21, 1.28, and 1.25 μM for chromosomes 1, 2, and 3, respectively; the ratio of arm to autosomal and sexual chromosomes of Babylon as 1.18, 1.15, and 1.20 μM from chromosome 1 to chromosome 3, respectively; and the ratio of arm of the autosomal and sexual chromosomes of the Wasit province as 1.27, 1.20, and 1.30 μM from chromosome 1 to chromosome 3, respectively (**Table 2**).

In regard to the relative length for the autosomal chromosomes, the average length of the relative chromosomes of the Baghdad is 33.98 and 40.18% for chromosome 2 and chromosome 3, respectively, and the relative length of the sexual chromosome is 25.8%, while the relative length of the chromosomes of the Babylon is 32.32 and 41.42% in the case of chromosome 2 and chromosome 3, respectively; the relative length of the sexual chromosome is 25.77%. As for the Wasit province, the relative length of chromosomes is 33.61 and 42.6% in case of chromosome 2 and chromosome 3, respectively, and the rate of relative length of sexual chromosome is the 23.78% (**Table 3**).

When measuring the average ratio of centromere index for this insect of Baghdad province, it is 43.8 and 44.35 μM for chromosome 2 and chromosome 3, respectively, while the average ratio of the centromere index is 45.1 μM for the sexual

**Figure 6.** *Three pairs of chromosomes of* Culex quinquefasciatus*.*


*\*\*Mean autosomal chromosomes.*

#### **Table 1.**

*The average total length (μM) of chromosomes collected from different province in Iraq.*


#### **Table 2.**

*The average arm ratio for the chromosomes of the different provinces in Iraq.*


*\*\*Mean autosomal chromosomes.*

#### **Table 3.**

*The average length of the relative chromosomes of the* Culex quinquefasciatus*.*

chromosome. The average ratio of the centromere index of the Babylon insect is 46.5 and 46.6 μM for chromosome 2 and chromosome 3, respectively, while the chromosome reached 45.72 μM for the sexual chromosome, and the average centromere index of the Wasit province is 45.1 and 43.32 μM for chromosome 2 and chromosome 3, respectively, and for sexual chromosome, it is 44 μM (**Tables 4** and **5**).

**81**

**5. Conclusion**

*Sexual chromosomes. \*\*Autosomal chromosomes.*

*Life Cycle and Cytogenetic Study of Mosquitoes (Diptera: Culicidae)*

**Region Ch. No. Ch. I\* M± S.D**

a

a

a

*The average ratio of centromere index chromosomes of the* Culex quinquefasciatus*.*

**Region Ch. No.**

Metacentric

Metacentric

Metacentric

**Ch. II\*\* M± S.D**

43.8% ± 10 a

46.5% ± 10 a

45.1% ± 10 a

p = 0.924 p = 0.980 p = 0.951

**Ch. l\* Ch. ll\*\* Ch. lll\*\***

M Metacentric

M Metacentric

M Metacentric **Ch. III\*\* M± S.D**

44.35% ± 10 a

46.6% ± 10 a

43.32% ± 10 a

M Metacentric

M Metacentric

M Metacentric

These results provide important genetic information for understanding the chromosomal structure of *C. quinquefasciatus* mosquito from some regions of Iraq. This work opens the ways toward the creation of useful in detail studies of the

*Classification of chromosomes of the* Culex quinquefasciatus *from some regions of Iraq by arm ratio and* 

While all mosquitoes need standing water to reproduce, some of the other species have evolved so specifically that they will only lay their eggs in natural or artificial containers. The larvae of most mosquito species hang suspended from the water surface because they need air to breath. An air tube, called a siphon, extends from the larva's posterior to the water surface. Pupae are also physically active and employ a rolling or tumbling action to escape to deeper water, which is why they are commonly referred to as "tumblers." The pupal stage lasts from 1.5 to 4 days, after which the pupa's skin splits along the back allowing the newly formed adult to slowly emerge and rest on the surface of the water. The present study shows that the chromosomes karyotyping of C. *quinquefasciatus* species consists of three pairs of chromosomes (i.e., 2n = 6). Certainly much of this information is of a descriptive sort and easy to obtain by present techniques. Life cycle and karyotype studies in additional species

can be simply done and should be carried out in a standardized way.

chromosomes in additional mosquito species.

*DOI: http://dx.doi.org/10.5772/intechopen.93219*

Baghdad 45.1% ± 10

Babail 45.72% ± 10

Wasit 44% ± 10

Baghdad M

Babail M

Wasit M

*centromere index by Levan et al. [38].*

*SM: arm ratio = 1.50–2.99. Centromere index = 40.0–25.1. M: arm ratio = 1.00–1.49. Centromere index = 50.0–40.1.*

*\*Sexual chromosomes. \*\*Mean autosomal chromosomes.*

**Table 4.**

*\**

**Table 5.**

#### *Life Cycle and Cytogenetic Study of Mosquitoes (Diptera: Culicidae) DOI: http://dx.doi.org/10.5772/intechopen.93219*


*\*\*Mean autosomal chromosomes.*

#### **Table 4.**

*Life Cycle and Development of Diptera*

Baghdad 4.46 ± 1

Babail 4.33 ± 1

Wasit 3.89 ± 1

**Region Ch. No. Ch. I\* M± S.D**

**Region Ch. No. Ch. I\* M± S.D**

a

a

a

a

*The average total length (μM) of chromosomes collected from different province in Iraq.*

a

a

*The average arm ratio for the chromosomes of the different provinces in Iraq.*

**Region Ch. No. Ch. I\* M± S.D**

a

a

a

*The average length of the relative chromosomes of the* Culex quinquefasciatus*.*

Baghdad 1.21 ± 1

Babail 1.18 ± 1

Wasit 1.27 ± 1

Baghdad 25.8% ±10

Babail 25.77% ± 10

Wasit 23.78% ± 10

*\*Sexual chromosomes. \*\*Mean autosomal chromosomes.*

*\*Sexual chromosomes. \*\*Mean autosomal chromosomes.*

**Table 3.**

*\*Sexual chromosomes. \*\*Mean autosomal chromosomes.*

**Table 1.**

**Table 2.**

**Ch. II\*\* M± S.D**

**Ch. II\*\* M± S.D**

5.87 ± 1 a

5.51 ± 1.52 a

5.5 ± 1.52 a

P = 0.7721 P = 0.7793 P = 1.0

1.28 ± 1 a

> 1.1 a

1.20 ± 1 a

p = 0.99 p = 0.99 p = 0.99

**Ch. II\*\* M± S.D**

33.98% ±6.08 a

32.79% ±10 a

33.61% ±10 a

p = 0.96 p = 0.83 p = 0.99

**Ch. III\*\* M± S.D**

**Ch. III\*\* M± S.D**

6.99 ± 1 a

6.96 ± 1 a

6.97 ± 1 a

1.25 ± 1 a

1.20 ± 1 a

1.30 ± 1 a

**Ch. III\*\* M± S.D**

40.18% ±8.54 a

41.42% ±8.54 a

> 42.6% ±10 a

**80**

chromosome. The average ratio of the centromere index of the Babylon insect is 46.5 and 46.6 μM for chromosome 2 and chromosome 3, respectively, while the chromosome reached 45.72 μM for the sexual chromosome, and the average centromere index of the Wasit province is 45.1 and 43.32 μM for chromosome 2 and chromosome

3, respectively, and for sexual chromosome, it is 44 μM (**Tables 4** and **5**).

*The average ratio of centromere index chromosomes of the* Culex quinquefasciatus*.*


*Sexual chromosomes. \*\*Autosomal chromosomes.*

#### **Table 5.**

*Classification of chromosomes of the* Culex quinquefasciatus *from some regions of Iraq by arm ratio and centromere index by Levan et al. [38].*

These results provide important genetic information for understanding the chromosomal structure of *C. quinquefasciatus* mosquito from some regions of Iraq. This work opens the ways toward the creation of useful in detail studies of the chromosomes in additional mosquito species.
