An individual-based model of Trichogramma foraging behaviour: Parameter estimation for single females

Authored by S Blanche, J Casas, F Bigler, KE JanssenVanBergeijk

Date Published: 1996

DOI: 10.2307/2404974

Sponsors: Swiss National Science Foundation (SNSF)

Platforms: No platforms listed

Model Documentation: Other Narrative Flow charts Mathematical description

Model Code URLs: Model code not found

Abstract

1. The aim of this paper is to estimate spatio-temporal parameters of an individual based model of Trichogramma female foraging behaviour in a mass rearing system. The system consists of Trichogramma brassicae (Bezdenko (Hymenoptera: Trichogrammatidae) and the host Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). This paper deals with the analysis of the foraging behaviour of single females. 2. We used direct visual observation for building an ethogram with the following behavioural states: searching, drumming, drilling, oviposition and host-feeding. We estimated the distribution of the time spent in the behavioural states using the gamma distribution and built a transition probability matrix between the behavioural states. 3. The mean time duration for searching, drumming, drilling and oviposition was similar for all behavioural states in our experiments and amounted to half of a minute. Host feeding, however, lasted more than 2 min. 4. An image analysis system was used to record the paths of single Trichogramma females foraging on a spatial lattice arrangement of host eggs. Paths were analysed using a vector autocorrelation function. The velocity vector was analysed separately for the speed and directional components, The analysis showed a short time memory for the directional process and a negligible memory for the speed component. We used a stochastic differential equation, an Ornstein Uhlenbeck-process, for modelling the directional changes. We then combined it with the information about the speed changes and obtained simulated paths. Visual assessment with recorded paths showed good agreement; the characteristic loops and circlings, as well as the longer meanders were faithfully represented. The theoretical and simulated processes overestimated the mean squared displacement in the first few hundred seconds but provided a good fit thereafter.

Tags

Simulation time Walk Hosts Minutum Hym