TABLE CONTENTS

Parasites, Vibrations and the Hunt for Hosts
Wilson M.J. (1), S. Heritage (2) & P. Torr (1)
(1) Institute of Biological and Environmental Sciences, University of Aberdeen, Scotland, UK, AB243UU; (2)
Entomology Branch, Forest Research, Northern Research Station, Roslin, Midlothian, EH25 9SY, UK.
Steinernema carpocapsae is thought to be an unsound choice for control of sedentary and
subterranean hosts as its response to chemical stimuli is so poor. However, in repeated field
trials for control of the large pine weevil (Hylobius abietis), the most serious pest in
plantation forest establishment in boreal regions, this nematode has proven to be at least as
efficacious as other commercially available nematodes that show significantly better
chemical response. The target immature stages of the weevil develop in the cryptic habitat of
conifer roots and stumps that grow in peat, a material often used as a biofiltration medium
due to it’s excellent adsorption/absorption properties for volatiles. The volatile binding
efficiency of the peat may act to reduce insect borne volatile gradients and in such an
environment an alternative host cue might be important. We demonstrate that
entomopathogenic nematodes are attracted to vibrations through the substrate, a response to a
host cue never before documented in an insect parasite, and subsequently postulate that in
forest soils vibrational cues may be more important for host detection than those of a
chemical nature.
Phoretic Dispersal of Entomopathogenic Nematodes by Large Pine Weevil
Adults
Kruitbos, L. (1), M.J. Wilson (1) & S. Heritage (2)
(1) School of Biological Sciences. University of Aberdeen., United Kingdom, AB24 3UU; (2) Forest Research,
Roslin, Midlothian, United Kingdom, EH25 9SY
This study investigated whether entomopathogenic nematodes are capable of using the large
pine weevil, Hylobius abietis as a vector for phoretic dispersal. The bioassays tested whether
H. abietis promoted dispersal of Steinernema carpocapsae and Heterorhabditis megidis
between two connected terraria filled with sand and whether transported nematodes were able
to infect a host, G. mellonella. The two terraria were connected by an 18 cm polystyrene
tube, where 30,000 nematodes and 5 H. abietis were placed into Site A and 5 G. mellonella
were placed into Site B (Treatment A). After 7 days, 100% of G. mellonella were found to
be infected with S. carpocapsae and 78% for H. megidis in the presence of H. abietis. In the
absence of H. abietis no G.mellonella were found to be infected for both species (Treatment
B). Thus, we show H. abietis could be a source of facultative phoretic dispersal for
nematodes, and they must be capable of leaving H. abietis and infecting new hosts.
5 th International Congress of Nematology, 2008 305