Diet of Cataglyphis bicolor (Hymenoptera-Formicidae) in an insular condition in north-eastern Algeria

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.

Biogeography and Cophylogeny of Paussus favieri(Carabidae, Paussinae) and Pheidole pallidula(Hymenoptera, Myrmicinae)

The myrmecophilous carabid beetle, Paussus favieri, has a circum-Mediterranean distribution and it is completely dependent upon its host ant Pheidole pallidula during all stages of its life history. Using molecular sequence data we inferred the phylogenies of the populations of both the beetle and its ant host to determine if there are signs of co-evolution. A total of 34 P. favieri from France, Spain, Portugal, Morocco and Tunisia and 42 Ph. pallidula workers from the same countries, plus Greece and Italy, were collected and analyzed. Many mitochondrial and nuclear markers were sequenced, but only COI was evolving fast enough to infer the population-level phylogenies of the beetles and the ants. Preliminary analyses suggest that the European populations of P. favieri are derived from a single dispersal event from Africa, while several dispersal events are suggested for Ph. pallidula. We found the topologies of host and parasite trees to be generally congruent, as would be expected if the host and parasite have had a history of co-evolution or co-divergence.

The diversity of arthropods community in dunes and a palm grove (Phoenix dactylifera) in the Touggourt region (Septentrionale Sahara)

An inventory of arthropods was carried out at locations in the desert area of Touggourt, southeast Algeria. Samples were collected from two diverse habitats, a palm grove (agricultural habitat) and dunes (natural habitat). Using the Barber pitfall trap, 1100 specimens, divided into four classes, 15 orders, 44 families and 99 species were obtained. In the palm grove, 660 arthropods were trapped, belonging to four classes and 12 orders. Of these four classes, Insecta dominated followed by Crustacea, Arachnida and Entognata. Insecta accounted for 59.49% of the total capture and was dominated by two orders: Hymenoptera (41.81%) and Amphipoda (34.55%). In the Hymenoptera, Cataglyphis sp. was the most abundant (38.2%), followed by Pheidole pallidula (2.3%). In the dunes, 440 individuals were trapped. Insecta was the most abundant (90.69%), and Crustacea and Arachnida were scarce. Of the dominance by insects, Hymenoptera was most abundant (68.15%), and within that order, Cataglyphis bombycina (35.5%) was the most abundant followed by Monomorium subopacum (8.9%). In the palm grove, 42 species were recorded, compared to 57 in the dunes. The Shannon–Weaver index and equitability varied in both stations. In the palm grove, the diversity was 2.6, and the equitability was 0.5. By contrast in the dunes, the diversity was equal to 4 and the Equitability equal to 0.7. The differences in vegetation between the two sites reflect the differences in species diversity.

Ants (Hymenoptera: Formicidae) of San Marino

A recent catalog of the ants of Europe and surrounding areas listed no ants recorded from San Marino. One afternoon of collecting in urban sites of San Marino yielded 23 ant species: Aphaenogaster subterranea, Camponotus aethiops, Camponotus fallax, Camponotus lateralis, Camponotus piceus, Crematogaster scutellaris, Formica cunicularia, Formica gagates, Hypoponera eduardi, Lasius emarginatus, Lasius lasioides, Lasius paralienus, Messor structor, Pheidole pallidula, Plagiolepis pygmaea, Tapinoma nigerrimum s.l., Temnothorax angustulus, Temnothorax flavicornis, Temnothorax italicus, Temnothorax lichtensteini, Temnothorax tergestinus, Temnothorax unifasciatus, and Tetramorium caespitum. Surprisingly, despite collecting in heavily disturbed urban sites, none of the ants known so far from San Marino are exotic to Europe.

Ants affect the infestation levels but not the parasitism of honeydew and non-honeydew producing pests in citrus

Ants act simultaneously as predators and as hemipteran mutualists, and thereby may affect the composition and population dynamics of a wide arthropod community. We conducted ant-exclusion experiments in order to determine the impact of ants on the infestation levels and parasitism of three of the most important citrus pests of western Mediterranean citrus: the honeydew producer Aleurothrixus floccosus Maskell (woolly whitefly) and the non-honeydew producers Aonidiella aurantii Maskell (California red scale; CRS) and Phyllocnistis citrella (Staiton) (citrus leafminer). The study was conducted in three commercial citrus orchards, each one dominated by one ant species (Pheidole pallidula, Lasius grandis or Linepithema humile) during two consecutive growing seasons (2011 and 2012). We registered a significant reduction of the CRS densities on fruits in the ant-excluded treatment in the three orchards and in the two seasons, ranging from as high as 41% to as low as 21%. Similarly, the percentage of shoots occupied by A. floccosus was significantly lower in the ant-excluded plots in the orchards dominated by P. pallidula and L. humile. No significant differences were registered in the percentage of leaf surface loss caused by P. citrella between ant-allowed and ant-excluded treatments in any case. We found no significant differences in the percent parasitism between ant-allowed and ant-excluded treatments for honeydew and non-honeydew producing herbivores. These results suggest that: (i) ant management should be considered in order to reduce herbivore populations in citrus and (ii) mechanisms other than parasitism (e.g., predation) might explain the differences in herbivore infestation levels between treatments.

Behavior ofPaussus favieri(Coleoptera, Carabidae, Paussini): A Myrmecophilous Beetle Associated withPheidole pallidula(Hymenoptera, Formicidae)

Several specimens of the myrmecophilous beetlePaussus favieriwere reared in ant nests ofPheidole pallidula. Their interactions were recorded and all behaviors observed are described. Duration and frequency of five behaviors ofP. favieriwere analyzed with ANOVA and post hoc Tukey tests; these comprised rewarding, antennal shaking, antennation, escape, and “no contact”. Significant differences both in duration and in frequency among behaviors were detected. The main result is that the rewarding behavior, during which the beetle provides attractive substances to the host, is performed significantly more frequently than all others. This result strongly supports the hypothesis that the chemicals provided by the beetles and licked by the ants are of great importance for the acceptance and the full integration ofP. favieriin the ant society. This result also suggests that, contrary to previous findings and interpretations, the myrmecophilous strategy ofP. favieriis very similar to the symphilous strategy described forP. turcicus. The occasional interactions of some beetle specimens with theP. pallidulaqueen were recorded, illustrated, and discussed, indicating the possibility of a more complex strategy ofP. favieriinvolving a chemical mimicry with the queen. In addition, the courtship performed by the beetle is described for the first time, together with a peculiar “cleaning” behavior, which we hypothesize functions to spread antennal chemicals over the body surfaces.