TY - JOUR
T1 - Indirect plant-mediated effects on insect immunity and disease resistance in a tritrophic system
AU - Shikano, Ikkei
AU - Ericsson, Jerry D.
AU - Cory, Jenny S.
AU - Myers, Judith H.
N1 - Funding Information:
We thank Karmen Scott, Christal Nieman, Jing Niu and Shoshana Turner for technical assistance and Patricia Schulte for the use of her spectrophotometer. This research was funded by NSERC.
Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
PY - 2010/2
Y1 - 2010/2
N2 - Host plant quality can significantly influence the growth and condition of phytophagous insects, and consequently their susceptibility to pathogens. This study examined the relationship between host plant quality, insect condition, immune responsiveness and resistance to pathogens in the cabbage looper, Trichoplusia ni. Two baseline and induced immune parameters were estimated, haemocyte numbers and haemolymph phenoloxidase (PO) activity, for larvae on two host plants, broccoli and cucumber. Haemolymph protein concentration was assessed as an indication of insect condition, and the susceptibility of larvae to T. ni single nucleopolyhedrovirus (SNPV) was used as a measure of disease resistance. T. ni growth, survival and condition was much higher on broccoli than cucumber. Haemocyte numbers were significantly higher in broccoli-reared larvae, whereas PO activity was not. An immune challenge induced significantly elevated numbers of haemocytes for larvae reared on both host plants, but did not affect PO activity or protein concentrations. Susceptibility to T. ni SNPV was markedly higher in larvae reared on cucumber than on broccoli. These results clearly indicate that host plant quality can affect both immune response and disease resistance of T. ni larvae and that bottom-up effects could be important in interactions between insects and entomopathogens.
AB - Host plant quality can significantly influence the growth and condition of phytophagous insects, and consequently their susceptibility to pathogens. This study examined the relationship between host plant quality, insect condition, immune responsiveness and resistance to pathogens in the cabbage looper, Trichoplusia ni. Two baseline and induced immune parameters were estimated, haemocyte numbers and haemolymph phenoloxidase (PO) activity, for larvae on two host plants, broccoli and cucumber. Haemolymph protein concentration was assessed as an indication of insect condition, and the susceptibility of larvae to T. ni single nucleopolyhedrovirus (SNPV) was used as a measure of disease resistance. T. ni growth, survival and condition was much higher on broccoli than cucumber. Haemocyte numbers were significantly higher in broccoli-reared larvae, whereas PO activity was not. An immune challenge induced significantly elevated numbers of haemocytes for larvae reared on both host plants, but did not affect PO activity or protein concentrations. Susceptibility to T. ni SNPV was markedly higher in larvae reared on cucumber than on broccoli. These results clearly indicate that host plant quality can affect both immune response and disease resistance of T. ni larvae and that bottom-up effects could be important in interactions between insects and entomopathogens.
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U2 - 10.1016/j.baae.2009.06.008
DO - 10.1016/j.baae.2009.06.008
M3 - Article
AN - SCOPUS:75749133155
SN - 1439-1791
VL - 11
SP - 15
EP - 22
JO - Basic and Applied Ecology
JF - Basic and Applied Ecology
IS - 1
ER -