The relation between the halophyte Aster tripolium and Agapanthia villosoviridescens an insect invader of estuarine salt marshes
Hemminga, M.A.; van Soelen, J.; Markusse, M.M. (1987). The relation between the halophyte Aster tripolium and Agapanthia villosoviridescens an insect invader of estuarine salt marshes, in: Huiskes, A.H.L. et al. (Ed.) Vegetation between land and sea. pp. 214-224
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| Keywords |
Aquatic organisms > Estuarine organisms
Developmental stages > Larvae
Fauna > Aquatic organisms > Aquatic animals > Aquatic insects
Feeding
Growth rate
Halophytes
Seed production
Water bodies > Inland waters > Wetlands > Marshes > Salt marshes
Weight
Agapanthia villosoridescens; Aster tripolium L. [WoRMS]
Marine/Coastal |
| Abstract |
Aspects of the relation between the halophyte Aster tripolium and larvae of Agapanthia vilosoviridescens (Coleoptera, Cerambycidae), which mine the flowering stems of the halophyte, were investigated on three salt marshes along the Wester-schelde estuary. These salt marshes are exposed to estuarine tidal waters of different salinity. Growth of Agapanthia larvae, studied form August-November 1986, was conspicuously different on the three locations. Dry weight increases were more pronounced as the marsh location was progressively further away form the estuarine mouth. Also the ratio larval dry weight: length of stem cavity (caused by larval feeding), was significantly different between the marshes, suggesting varying food converting efficiencies. Probably, these differences are due to effects of the estuarine salt gradient on the host plant, Aster tripolium; as a consequence of osmotic adjustment, the chemical composition of the plant tissue will change with the environmental salt concentration, affecting its quality as a food source for stem boring Agapanthia villosoviridescens larvae. Various aspects of seed production (i.e, achene weight, number of achenes per flowering head, ratio achenes with/without embryo, and number of flowering heads), were studied in two of the salt marshes in relation to different types of insect herbivorous activity, with particular reference to feeding of Agapanthia larvae. It is concluded that stem boring activities only have a marginal effect on seed production in Aster tripolium, with the possible exception of a positive effect on the number of flowering heads per Aster stem on one of the marshes. The present study demonstrates a differentiated animal-plant relation as may be found on salt marshes along estuarine gradients. |
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