The habitat functions of vegetation in relation to the behaviour of the desert locust Schistocerca gregaria (Forskål) (Acrididae: Orthoptera) - a study in Mauritania (West Africa)

The functions of vegetation for the behaviour of gregarious desert locust hop- pers (Schistocerca gregaria (ForskaKl)) are considered in respect to different scales: single plant (taxon, life form), plant community (species composition, dominance, density), and patterns in vegetation and landscape. In the semi-desert of Mauritania, two typical desert locust habitats are phytosociologically characterized. The perennial communities of the tree and shrub layer belong to the alliance Acacio-Panicion with an oceanic Euphorbia balsamifera -Salvadora persica community in a dune-wadi complex characterized by Zy- gophyllum waterlotii , and a more continental Acacia ehrenbergiana -Panicum turgidum community in the inselberg landscape of the Mauritanides. The spatial-temporal move- ment of a hopper band was observed. Hopper band movement depends mainly on wind direction, but is also influenced by patterns in vegetation and landscape morphology. Places giving protection and for moulting are provided by perennials and dense vegetation patches. Length of stay is determined by predation, moulting and food availability. Feed- ing behaviour in the natural habitat depends on food plant preference and the availability of palatable plant species within the plant community. In this study, feeding damage is evaluated both qualitatively and quantitatively using the method Density Analysis with Estimation of Feeding Damage.

[1]  S. Ghaout,et al.  What defense doesSchouwia purpurea (Cruciferae) have against the desert locust? , 1991, Journal of Chemical Ecology.

[2]  A. C. Lewis,et al.  Feeding behavior: selection of both wet and dry food for increased growth in Schistocerca gregaria nymphs , 1985 .

[3]  C. Ashall,et al.  Field Studies on diurnal Behaviour, Movement and Aggregation in the Desert Locust (Schistocerca gregaria Forskål). , 1957 .

[4]  D. Greathea..  A brief survey of the effects of biotic factors on populations of the desert locust. , 1966 .

[5]  H. Wilps,et al.  Field investigations on Schistocerca gregaria (Forskål) adults, hoppers and hopper bands , 1997 .

[6]  R. Warnke-Gruttner.  Ökologie der Erde. Band 2: Spezielle Ökologie der Tropischen und Subtropischen Zonen. Von H. Walter und S. W. Breckle. 461 S., 330 Abb., 116 Tab., 4 Karten. Fischer, Stuttgart 1984. UTB Groß Reihe. DM 48,– , 1986 .

[7]  W. J. Bell.  Searching Behavior Patterns in Insects , 1990 .

[8]  T. Boutton,et al.  Insect herbivory on C3 and C4 grasses , 2004, Oecologia.

[9]  A. C. Lewis,et al.  The effect of wilting on palatability of plants to Schistocerca gregaria, the desert locust , 1986, Oecologia.

[10]  D. W. Goodall,et al.  The Sahel zone north of the Equator , 1986 .

[11]  Ökologie der Lebensgemeinschaften , 2001 .

[12]  C. Ashall,et al.  Studies on numbers and mortality in field populations of the desert locust (Schistocerca gregaria Forskål). , 1962 .

[13]  M. M. Rai,et al.  Changing Oviposition Preferences of the Desert Locust, Schistocerca gregaria, Suggest a Strong Species Predisposition for Gregarization , 2000, Journal of Chemical Ecology.

[14]  G. Varley,et al.  Grasshoppers and Locusts , 1967 .

[15]  M. Simmonds,et al.  Food selection by locusts: An analysis of rejection behaviour , 1985 .

[16]  J. Wiens.  Spatial Scaling in Ecology , 1989 .

[17]  H. Wilps.  Ecology of Schistocerca gregaria (Forskål): observations in West Africa from 1990 to 1994 , 1997 .