In this survey conducted in southern Cameroon, we compared ant-Hemiptera associations on plantations treated with insecticides, on plantations 2 years after insecticide treatments ceased, and on control lots that never received insecticide treatments. By eliminating arboreal-nesting ants, insecticides favored the presence of "ecologically dominant" ground-nesting, arboreal-foraging species that occupied the tree crowns. The reinstallation of arboreal ants was slow as 2 yr after insecticide treatment ceased differences with the control lots were significant. This intermediary period also illustrated that arboreal ants can found and develop colonies on trees occupied by ground-nesting species. Certain arboreal species were more frequent during this intermediary period than on the control lots, showing that the period of installation in the trees was followed by competition between arboreal ants. We confirm that ground-nesting ants tend a wide range of hemipteran families, including well known agricultural pests, whereas arboreal ants, particularly dominant species, were mostly associated with Coccidae and Stictococcidae that do not pose problems to the supporting trees. A tree effect was also noted for both ant and hemipteran distribution. We concluded that because of insecticide use, ground-nesting ants pose problems through their associated Hemiptera. On the contrary, dominant arboreal ants, strong predators, benefit their supporting trees by excluding ground-nesting species and tending mostly nonpest Hemiptera. Nevertheless, certain of them, carpenter species or species likely to tend Pseudococcidae, have to be eliminated through integrated management.

No abstract

Parmi les Loranthaceae, l'espèce Phragmanthera capitata s'est mieux adaptée aux conditions du milieu modifié par l'homme et aux arbres cultivés ou spontanés devenant un véritable fléau agronomique. La méthode de lutte ciblée plus prometteuse ne peut être satisfaisante que si les mécanismes qui régulent l'adaptation des Loranthaceae à leurs hôtes cultivés ou spontanés sont identifiés et maîtrisés. Dans cette optique, une étude de la myrmécofaune arboricole a été menée sur trois couples P. capitata/hôte au verger de la chefferie de Ndogbong. Auparavant, un inventaire exhaustif de tous les arbres parasités ou non et de la myrmécofaune du verger de la chefferie de Ndogbong (Douala) a été entrepris et toutes les touffes de P. capitata comptabilisés sur les arbres hôtes qui en possédaient. Tous les arbres du verger sont exotiques excepté Spondias mangifera. Le taux de parasitisme est de 42,85%. Quatre espèces de fourmis (Crematogaster sp. 1, Crematogaster sp.2, Pheidole megacephala et Camponotus sp.) ont une activité fourragère notamment florifère sur les individus de P. capitata. Leur densité varie avec la floraison et semble liée à la chute des boutons floraux et des fleurs. Ces fourmis pourraient constituer des forces d'organisation et d'évolution exploitables dans la lutte biologique contre les Loranthaceae.

The little fire ant, Wasmannia auropunctata, is native to Central America, but has been introduced into many parts of the world. We examined the current distribution of W. auropunctata in Cameroon, tested for aggression between workers from different parts of the country, and examined the genotypes of workers, queens, and males to evaluate the mating system. We found W. auropunctata at 36 sites in three provinces (Centre, East, and South). We found W. auropunctata only in humandisturbed habitats. Its spread appears to be primarily human mediated. Aggressive behaviour was almost non-existent between workers from different sites, indicating that there is only one supercolony in Cameroon. Our genetic analysis found that only one male/female pair of clones was introduced into Cameroon, probably from Gabon. No new male clonal lineage was identified, whereas new sexually derived female clonal lineages were noted. Apart from the genotype of the founding queen, which was well distributed but generally not dominant, a new clonal queen genotype emerged and was both omnipresent and dominant at most sites. These results may be useful in the development of management strategies.

Conclusion and application of results:The Loranthaceae constitute in the littoral region, notably in Logbessou a real calamity against which an energetic struggle compatible with the conservation of the biodiversity assesses for a sustainable development.

The objective of this study was to identify the myrmecofauna fruit trees infected by Loranthaceae orchards Lokomo (East Cameroon). The collection and identification of myrmecofauna was made on an area of 5 ha. The work was conducted from October to December 2010. The orchards consist of a mixture of exotic ornemental trees, fruit trees for consumption and forest species deliberately left in place. Woody species hosts concerned were Albizia adianthifolia, Calliandra susinamensis, Citrus maxima, Entandrophragma cylindricum, Psidium guajava, Macaranga hurifolia, Phyllanthus discoides and Terminalia mantaly. A total of seven ant species grouped in six genera and two subfamilies (Formicinae and Myrmicinae) were identified. In Formicinae, two genera have been identified, Camponotus and Oecophylla. Myrmicinae in turn had three genera, Atopomyrmex, Crematogaster and Tetramorium. The activity of myrmecophilous revealed that ants forage on flowers, fruits and suckers of T. ogowensis and T. preussii. The suckers dried out and degenerated causing the death of the tufts.

Les Loranthaceae sont des plantes parasites qui causent de nombreux dommages sur les plantes hôtes se traduisant par une réduction de la floraison, de la fructification et de la production. Dans le but de trouver une méthode de lutte efficace contre les Loranthaceae, une étude relative à l'activité myrmécophile a été menée au verger de la chefferie de Ndogbong. Un inventaire de la myrmécofaune a été réalisé sur 16 individus de Theobroma cacao dont 9 parasités et 7 non parasités. Trois espèces de Loranthaceae ont été recensées : Phragmanthera batangae (Engler) S. Balle, P. capitata (Sprengel) S. Balle et Tapinanthus preussii (Engler) Van Teghem. Trois sous-familles de fourmis ont été identifiées : les Ponerinae (Odontomachus troglodytes Santschi), les Formicinae (Camponotus sp.) et les Myrmicinae (Crematogaster sp., C. decacrema, C. oxygyne, et Pheidole megacephala Fabricius). Deux espèces de fourmis ont été présentes sur les fleurs et les fruits de P. capitata et T. preussii et contribuent à la lutte biologique contre les Loranthaceae.

According to Holway et al. (2002), six ants are recognized as the most widespread and damaging invasive species: Anoplopepis gracilipes (yellow crazy ant), Linepithelma humile (Argentine ant), Pheidole megacephala (African bigheaded ant), Solenopsis invicta (red imported fi re ant), Solenopsis geminata (tropical fi re ant) and Wasmannia auropunctata (little fi re ant). Wasmannia auropunctata Roger, 1893 is one of the most harmful invasive species in the world (Wetterer & Porter, 2003). Native to Central and South America, W. auropunctata has been introduced throughout the West Indies, Australia, Israel, Italy, Pacifi c islands groups and West Africa (Wetterer, 2013). In Cameroon, W. auropunctata was fi rst reported in cocoa plantations along the Kribi-Ebolowa road (de Miré, 1969). Since then, it has successfully spread into southern and eastern Cameroon (Tindo et al., 2012), where it has severely reduced the abundance and richness of native ant species (Mbenoun et al., 2017). The invasive success of exotic species can vary substantially over time from population explosions to population