ancestralSteinernema had low or no standing behaviour and a low
frequency of jumping, occupied epigeal habitats, was of medium size and
had a low level of attraction to host volatiles and no change in behaviour
after host contact (J.F. Campbellet al., unpublished data). The lack of
multiple clades with ambush- or cruise-foraging specialization makes it
difficult to determine whether or not the suite of behavioural traits associ-
ated with each strategy represents adaptations. However, the diversity in
Steinernematidae has probably been undersampled and, as new species
are described, hypotheses about the evolution of foraging strategy can be
further tested and refined.Conclusions
The importance of parasites in ecosystem function and the influence of
parasites on host behavioural ecology have become more widely acknow-
ledged in recent years and we have seen a surge of research in these areas.
However, research on the behavioural ecology of the parasites themselves
is still limited. This is unfortunate. Parasite infective stages make very
useful models for addressing behaviour questions and there are many
important fundamental and applied questions that need to be addressed.
There is a strong foundation of behavioural research that has been
conducted on entomopathogenic nematode infective stages, but many
questions still remain to be addressed. In this chapter we have tried to
cover in a general way the different steps involved in foraging for hosts
within the framework of the ambusher/cruiser continuum. This con-
ceptual framework has proved useful for addressing behavioural
questions for this group and has enabled us to develop adaptive
syndromes for the different foraging strategies. These syndromes still
need to be tested and refined as new species are discovered and new
aspects of the parasite–host interaction are elucidated.References
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