Study of two psyllid species (Psylloidea: Liviidae) associated with ants (Hymenoptera : Formicidae) on two Savannah plant species at Koutaba (West Region Cameroon).

Abstract

Jumping plant-louse are a common and diverse group of small sap-sucking insects, with a world-wide distribution. They are found on a large range of plant species/varieties (Ouvrard et al., 2015). Their main effect on plant is sap deprivation. As they feed, they excrete large amounts of honeydew which is actively collected by ants. In turn ants offer to them a sort of protection. So close relationships between ants and hemipterans are well known in aphids, whiteflies, or scale insects, but so far poorly documented in psyllids. In the present study, two psyllid species, belonging to the family Liviidae, were observed in the presence of several species of ants, feeding on two plant species, Psorospermum glaberrimum and Ozoroa paniculosa respectively. The medicinal features of the two plant species are well documented; among others are the deworming and anti-plasmodial effects. The present study aimed at contributing to the psyllid knowledge in Cameroon by providing morphological descriptions which would permit their precise identification, describing their infestation pattern on host-plants, listing their different attendant ant species and finally assessing variations of these psyllids’ populations on the plant structures at different phenological stages. Investigations and samplings took place in the Savannah at Koutaba (West Cameroon) (050 39’72.7”N; 0100 47’18.1” E; 1227 m) from February to June 2019. As results, morphological studies led to the diagnosis of two new species of psyllid, Paurocephala sp.n. on P. glaberrimum, and Diaphorina sp.n. on Ozoroa paniculosa . The first species, Paurocephala sp.n. is similar to Paurocephala insolita Mifsud and Burkhardt 2002 by the whole habitus, especially forewing pattern, but is clearly distinguishable in adult by colouration of thoracic and abdominal segments as well as in immature by the number and distribution of sectasetae on antenna and wing pads and the lack of caudal process. The second species, Diaphorina sp.n., is morphologically close to Diaphorina albomaculata Capener 1970 but differs to it by the genal processes slightly longer, the more elongate forewing with more expanded white patches, the broader parameres, the more produced male proctiger and the form of female subgenital plate. In the immature of Diaphorina sp.n., there are long setae at the rim of the caudal plate while they are lanceolate in D. alomaculata. For the infestation pattern, an unusual behaviour of Paurocephala sp.n. was seen as it turned to colonise older leaves of P. glaberrimum while Diaphorina sp.n., as usual in psyllids,