In seeking new hosts, entomopathogenic nematode foraging strategies are believed to range from sit-and-wait foragers (ambushers) to widely active foragers (cruisers).  This study investigated the behaviour, dispersal and competitive ability of entomopathogenic nematodes of the genera <i>Heterorhabditis </i>and <i>Steinernema </i>in relation to soil habitat. The host finding and competitive ability of <i>Steinernema carpocapsae, </i>an “ambusher” and <i>Heterorhabditis megidis, </i>a “cruiser” in two contrasting soil habitats (sand and peat) showed “habitat-specific” differences in foraging mode between the two species.  In peat, <i>S. carpocapsae </i>outcompeted <i>H. megidis </i>in terms of host finding, whereas the opposite was true in sand.  In the appropriate habitat, both nematodes showed behaviours not predicted by their supposed foraging strategy.  Experiments examining the interspecific interactions between <i>S. carpocapsae </i>and <i>H. megidis </i>also showed significant differences in the population dynamics between the two species in relation to habitat. Nictation behaviour is frequently cited as a host finding strategy in ambush foraging nematodes. The study confirms that ambush foraging species <i>S. carpocapsae </i>and <i>Steinernema scapterisci </i>frequently nictate, but show that habitat is an important factor regulating this behaviour.  This study also demonstrates the ability of the cruise foraging nematode, <i>H. megidis </i>to nictate on habitats not previously examined.

Thesis (Ph.D.)--Aberdeen University, 2009. / Title from web page (viewed on July 14, 2009). Includes bibliographical references.