TY - JOUR
T1 - Effect of insect host age and diet on the fitness of the entomopathogenic nematode-bacteria mutualism
AU - Miranda, Victoria A.
AU - Navarro, Patricia D.
AU - Davidowitz, Goggy
AU - Bronstein, Judith
AU - Stock, S. Patricia
PY - 2013/11
Y1 - 2013/11
N2 - Insect host age and diet were evaluated as potential factors that could affect the fitness of the entomopathogenic nematode-bacterium mutualistic partnership. Two nematode species were considered: Steinernema carpocapsae and Heterorhabditis sonorensis, together with their symbionts Xenorhabdus nematophila and Photorhabdus luminescens, respectively. The tobacco hornworm, Manduca sexta, was used as the insect host. Insect developmental stage was a factor that impacted nematode virulence. Non-wandering 5th instar M. sexta were found to be more susceptible to nematode infection compared to wandering 5th instars. This was more noticeable for S. carpocapsae than for H. sonorensis. The nutritional status of the host also had an effect on the fitness of the two nematode species tested. In general, insects fed with the reduced diet content were less susceptible to nematode parasitism. The least observed mortality (0.5 %) was in those M. sexta larvae exposed to the low H. sonorensis dose. Host diet also had an effect on the production of IJ progeny in the insect cadavers. For both nematode species tested, the highest yield of emerging IJs was observed from those insect hosts fed with the low nutrient diet and exposed to the highest nematode inoculum. However, for both nematode species tested, the nutritional status of the host did not significantly affect time of emergence of IJ progeny or the reassociation with their bacterial symbionts (expressed as cfu/IJ). This is the first study on the effect of insect host physiology on both EPN and their symbiotic bacteria fitness.
AB - Insect host age and diet were evaluated as potential factors that could affect the fitness of the entomopathogenic nematode-bacterium mutualistic partnership. Two nematode species were considered: Steinernema carpocapsae and Heterorhabditis sonorensis, together with their symbionts Xenorhabdus nematophila and Photorhabdus luminescens, respectively. The tobacco hornworm, Manduca sexta, was used as the insect host. Insect developmental stage was a factor that impacted nematode virulence. Non-wandering 5th instar M. sexta were found to be more susceptible to nematode infection compared to wandering 5th instars. This was more noticeable for S. carpocapsae than for H. sonorensis. The nutritional status of the host also had an effect on the fitness of the two nematode species tested. In general, insects fed with the reduced diet content were less susceptible to nematode parasitism. The least observed mortality (0.5 %) was in those M. sexta larvae exposed to the low H. sonorensis dose. Host diet also had an effect on the production of IJ progeny in the insect cadavers. For both nematode species tested, the highest yield of emerging IJs was observed from those insect hosts fed with the low nutrient diet and exposed to the highest nematode inoculum. However, for both nematode species tested, the nutritional status of the host did not significantly affect time of emergence of IJ progeny or the reassociation with their bacterial symbionts (expressed as cfu/IJ). This is the first study on the effect of insect host physiology on both EPN and their symbiotic bacteria fitness.
KW - Heterorhabditis sonorensis
KW - Host age
KW - Host diet
KW - Manduca sexta
KW - Photorhabdus luminescens
KW - Steinernema carpocapsae
KW - Xenorhabdus nematophila
UR - http://www.scopus.com/inward/record.url?scp=84895068945&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84895068945&partnerID=8YFLogxK
U2 - 10.1007/s13199-013-0266-7
DO - 10.1007/s13199-013-0266-7
M3 - Article
AN - SCOPUS:84895068945
VL - 61
SP - 145
EP - 153
JO - Symbiosis
JF - Symbiosis
SN - 0334-5114
IS - 3
ER -