A study of the adaptation of the ant Cataglyphis bicolor in terms of feeding under insular conditions was conducted on the north-eastern coast of Algeria. For this, three pairs of stations (island-continent) were chosen. Analyzing fragments of prey species found in C. bicolor nests, the diet in each station pair was studied. The results obtained indicate that C. bicolor has an opportunistic diet characterised by insectivory. Indeed, more than 95% of the prey consumed in the six study stations were insects with a clear preference for other ants, with frequencies ranging from 52 to 87%. Among the latter, Messor barbarus, Camponotus sp., Camponotus laurenti, Pheidole pallidula and Tetramorium biskrense were the ants most predated by C. bicolor. The diversity of continental prey seemed greater than that of island environments. For the two Cap Sigli stations, the prey richness was 94 species for the continent against only 28 species for the island environment. For Boulimat, there were 27 prey species for the mainland and 20 prey species for the islet. Finally, for the Sahel region, C. bicolor was able to harvest 42 prey species on the mainland and 28 species on the island. The diversity of C. bicolor prey in the island environments seems to be a function of insect richness (prey availability) and floral richness.

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The present paper seeks to study the diversity and ant community composition of some Algerian islands. This study is considered as the first exhaustive survey of ant species of Algerian islands since 1957. The survey was carried out in the spring and summer seasons between April and July of two years 2014 and 2015. Vegetation richness, island area, mainland distance, and elevation variables were measured for each island. Relative abundance (RA), frequency of occurrence (FO), as well as species richness (S), Shannon’s diversity index (H), and equitability (E) for each island were used to compare the diversity pattern among islands. Patterns of species composition and community structure were compared among the sampling islands through ordination analysis (nonmetric multidimensional scaling [NMDS]). SIMPER analysis using a Bray–Curtis similarity index matrix was performed to determine the contribution of each ant species to the dissimilarities among islands. Canonical correspondence analysis (CCA) was performed to highlight the impact of environmental variables on the ant community. All analyses were computed by using PAST software. Two sampling methods (pitfall trap and hand collecting) were used, which led to the identification of 1039 individuals belonging to 16 species. Diversity indexes were different among islands. Ant community was significantly different between islands of the two regions Bejaia and Jijel. Three species contributed to 50.74% of the differences between islands of the two regions. Part of the ant community composition was influenced directly or indirectly by three environmental variables: vegetation richness, island area, and mainland distance. It is important to point out the absence of two invasive ants, Linepithema humile and Paratrechina longicornis, in our islands.