Diversity of beetles associated with watermelon crops Citrullus lanatus (Thunb.) Mats. in the region of Ouargla (southern Algeria)

Study Extent

The present experiment was carried out in the palm grove of Zaatote at Ouargla. Plots were chosen in cultivated watermelon fields. This palm grove is located on the road between the region of Ouargla and that of El-Goléa (10 km south-east of Ouargla). The region of Ouargla is located in the Saharan bioclimatic zone. It has clay-sandy soils. The winter is temperate and summers are hot and dry.

Sampling

Sampling was carried out in three plots, each of 500 m², using Barber pots from December (transplanting) until June (fruiting and ripening of the first fruits). The pots used were cylindrical cans, 15 cm in diameter and 18 cm in height (Benkhelil, 1991). They were buried vertically so that the opening was at ground level to avoid the barrier effect for small species. We installed 10 traps 5 meters apart per row in each field so that there was no interaction between them. The traps were filled with water to one-third and a few drops of detergent were added to prevent insects from climbing up the walls. The pots were placed on the ground and collected after 24 hours. The contents of each pot were filtered separately on to petri dishes, labelled with number, date and place of capture, and stored in alcohol (70%), for subsequent faunal determinations in the laboratory. The watermelon plots where traps were installed watermelon underwent phytosanitary treatment at various stages crop growth.

Quality Control

Insects were identified by Professor Faiza Marniche at the zoology laboratory at the National Veterinary School of El Alia, and confirmed in the Arthropod section of the Museu de Ciències Naturals de Barcelona by Mr. Amador Viñolas. The identified species were classified according to the trophism of images and grouped into four functional groups: pests, predators, scavengers and miscellaneous in order to determine the role played by each species.

Method steps

1. Recorded data based on identified beetle catches were analysed using software PASTsoftware (PA-leontologicalSTatistics) Version 2.17 (Hammer et al., 2001). The following numerical indices were used: the centesimal frequency (Fc), the Shannon Diversity Index (H’)and the Pielou equity index (E).

1. Coleoptera
   rank: order
2. Tenebrionidae
   rank: family
3. Staphylinidae
   rank: family
4. Scarabaeidae
   rank: family
5. Nitidulidae
   rank: family
6. Elateridae
   rank: family
7. Dermestidae
   rank: family
8. Curculionidae
   rank: family
9. Cryptophagidae
   rank: family
10. Coccinelidae
    rank: family
11. Chrysomelidae
    rank: family
12. Carabidae
    rank: family
13. Anticidae
    rank: family

The present experiment was carried out in the palm grove of Zaatote at Ouargla. This palm grove is located on the road between the region of Ouargla and El-Goléa (10 km south-east of Ouargla). The region of Ouargla is located in the Saharan bioclimatic zone. It has clay-sandy soils. The winter is temperate and summers are hot and dry.