Identification of flying insects of aquatic plants was investigated in two ponds: Ngatsouéné and Yo. These ponds are located in the center of Djambala, at 02˚32'42.3" south latitude and 014˚45'6.59" E longitude. It shows two areas: a central area consisting of a grove and an exclusively savannah area in which the survey was conducted. Geographic references of: (location outskirts of center of Djambala, 02˚31'8.39'' South latitude and 014˚46'6.29'' East longitude). Both pools were separated by about 1 km ( Figure 1 ), were characterized by the same vegetation, depth varies between 1m and 1.5 m.

Physico-chemical parameters were measured using an apparatus multiparameter Hanna: the water temperature and the air temperature, the conductivity, the pH (potential of hydrogen), TDS (total dissolved solids). Insects were captured from 23 to 24 December 2012.

The flying insects located on the plants were collected by hand or using the entomological net. Captured insects were photographed and fixed in alcohol 70˚. These insects were identified using the keys proposed by different authors [12] - [15] .

The physico-chemical parameters of the water ranged between the two ponds. In the Yo pound, the pH was 6.1, the conductivity was equal to 29 μS/cm, TDS 14 ppm, the water temperature 28.23˚C and the air temperature 27.23˚C. Physico-chemical parameters values were measured in the Ngantsouéné indicate the following values: air temperature equal to 24.8˚C, water temperature equal to 24.9° C, a pH of 5.61, a conductivity of 18μS/cm, a TDS of 9ppm. The low conductivity of the water of Ngatsouéné and Yo indicates that these two ponds are poor in dissolved minerals. These results are similar to those found by [16] who found an acid pH (5.33) and a low conductivity (8.70 μS /m) in the Léfini River. By cons, in Nkéni River, they found almost the same value, an acidic pH (5.03) and low conductivity (8.68 μS/cm). Similar results were found in the Léfini River a pH of 5.6 and a conductivity of 7.9 [17] . The slight difference observed between pH, conductivity and turbidity values of the two ponds can be explained by the fact that in the Yo pond, is more frequented by populations who come from the fields and use soaps for cleaning their clothes and dishes.

The inventory of flying insects in two ponds Ngatsouéné and Yo, reported 37 species belonging to 17 families and 7 orders. The same species were found in both ponds; this implies that there is an interconnection between these two ponds. Each species is identified by its scientific name and common name in Téké language ( Table 1 ). Some pictures of the insects collected are recorded in Figure 2 .

The proportional distribution of species richness of insects according to the orders is shown in Figure 3 . The order of Orthoptera is the most represented with 10 species or 27.02 %, followed by Hymenoptera (8 species or 21.62%), Coleoptera (7 species or 18.91%), Mantoptera (5 species or 13.51%), Heteroptera (cash or 08.10%). Diptera and Odonata are orders less represented each with 2 species (5.40%). These results differ from those obtained by [15] on the Djoumouna River that identified 34 families of insects belonging to seven orders. Diptera and Coleoptera are the largest orders. This difference may be explained by the fact that the studies were conducted in different ecosystems; Djambala being located on a plateau 789 m above sea level.

Proportional representation of different families depending on the species richness ( Figure 4 ).

In Yo and Ngatsouéné, family of Mantidae is the most abundant species with 5 (13.51%), followed by Acrididae (4 species; 10.81%), the Apidae, the Coccinellidae and Pyrgomorphidae (3 species; 8.10%), the Calliphoridae, the Formicidae, the Pentatomidae, the Gryllidae, the Libellulidae, the Lycidae and Sphecidae (2 species; 5.40%), finally Coreidae, the Meloidae, the Tetrigidae, the Cerambycidae and the Megachilidae each had one species (2.70%).