Document: SAL-3-43-5

Host plant influence on movement patterns and the subsequent distribution of Lygus rugulipennis (Heteroptera: Miridae) nymphs.

HANNUNEN, S.* ¹ and B.EKBOM ²

University of Helsinki, Finland ¹
Swedish University of Agricultural Sciences, Uppsala, Sweden ²

Abstract:
The objectives of this work were to study: 1.) if host plant species affects movement patterns of nymphs of a highly polyphagous herbivore, Lygus rugulipennis (Heteroptera: Miridae); and 2.) if and how these movement patterns influence the spatial distribution of individuals in heterogeneous landscapes. We observed movement patterns of individual nymphs on two host plant species, wheat (Triticum aestivum) and Tripleurospermum inodorum (scentless mayweed), in laboratory, and we used the observed movement patterns to model redistribution of nymphs with an individual based movement model and with a diffusion approximation of random walk. We tested the predictions of the models by following redistribution of nymphs on small arenas (30 30 cm and 60 60 cm) consisting of the two plant species in the laboratory. Probability of moving (0.71 on wheat and 0.65 on T. inodorum) and the distribution of turning angles did not differ among plants, but the total time spent moving and the net displacements were significantly longer on wheat than on T. inodorum. In the arenas most nymphs (50-100 %) were found on T. inodorum after the period of redistribution (2 and 8 hours in the smaller and larger arenas respectively). Both the simulation model and the diffusion approximation of random walk predicted the redistribution well. The ability of the models to predict distribution in heterogeneous space even though they were parametrized with data collected in homogenous vegetation, suggests that the observed distribution of individuals was actually caused by the differences in movement patterns, and not by e.g. strong attraction to T. inodorum.

Keywords: polyphagous herbivore, Triticum aestivum, Tripleurospermum inodorum, spatial distribution, simulation model, diffusion

This abstract is being presented at: 9:45 AM in session:
Oral Session #4: Herbivore Responses to Plants.