Relationships Between the Parasitoid Hyposoter exiguae and the Cabbage Looper, Trichoplusia ni : Effects of Host Age on Developmental Rate of the Parasitoid 12

1973 ◽  
Vol 2 (5) ◽  
pp. 759-764 ◽  
Author(s):  
Zane Smilowitz ◽  
Gerard F. Iwantsch
1975 ◽  
Vol 107 (9) ◽  
pp. 927-934 ◽  
Author(s):  
Gerard F. Iwantsch ◽  
Zane Smilowitz

AbstractThe effects of parasitism by Hyposoter exiguae (Viereck) on certain developmental parameters of Trichoplusia ni (Hübner) were influenced by host age at parasitism.Head-capsule growth increments for parasitized Trichoplusia ni became smaller with each successive molt during parasitism so that determination of instar on the basis of head-capsule width became impossible.Parisitized T. ni showed a proportionately smaller gain in weight from time of stinging until parasitoid emergence the older they were when stung (6 times for 3rd instars; 2 times for 4th instars; and no gain for 5th instars). This retardation was evident 24 h after parasitism. Essentially the same results were obtained for dry weight.Percentage dry weight of parasitized larvae tended to increase over control values until the 5th stadium when controls abruptly increased. Values for parasitized 5ths remained below the controls. Values found on the last days reflected those of the parasitoid which composed most of the mass inside the host cuticle.Hemolymph specific gravity in controls and parasitized 3rd instars oscillated with a frequency of one stadium in the 3rd, 4th, and early 5th stadia. Specific gravity of controls then rose to a maximum of 1.0501 in the prespinning phase and dropped by the pharate–pupal phase. Values for parasitized larvae in the 5th stadium rose slightly before leveling off, and parasitized 5th instars rose to a maximum on the next-to-last day. Maximum values attained for hosts parasitized as 3rd and 5th instars never reached that for controls on day 11. This may be related to the complete unacceptability or unsuitability of T. ni larvae for parasitism from day 11 on.


1975 ◽  
Vol 107 (7) ◽  
pp. 689-694 ◽  
Author(s):  
Zane Smilowitz ◽  
Gerard F. Iwantsch

AbstractThe effect of host age of the cabbage looper, Trichoplusia ni (Hübner), on ovipositional rate and successful parasitism by Hyposoter exiguae (Viereck), a solitary endoparasitoid was investigated. Success in parasitism of T. ni was correlated with host age. Successful parasitism of hosts exposed as first, second, or early third instar larvae, ranged from 83 to 88%. A decline in parasitism was observed for the remaining instars with a low of 27% for mid-fifth instar larvae.A different relationship between host age and successful parasitism was observed in tests where all five instars of the host were presented to the parasitoid simultaneously. Successful parasitism was highest among second and third instars, approximately 75% for both, and lowest for fifth and first instars, 10% and 30%, respectively. A significantly higher rate of mortality was found for first instar hosts.The ovipositional rate of H. exiguae was related to host age. The parasitoid deposited an average of 2.3 and 1.3 eggs per 24 h in first and second instar T. ni, respectively The number of eggs/host and degree of superparasitism declined in older individuals and differed statistically for each instar. The percentage parasitism differed statistically for all but first and second instar larvae.


1994 ◽  
Vol 20 (11) ◽  
pp. 2959-2974 ◽  
Author(s):  
P. J. Landolt ◽  
R. R. Heath ◽  
J. G. Millar ◽  
K. M. Davis-Hernandez ◽  
B. D. Dueben ◽  
...  

PLoS ONE ◽  
2011 ◽  
Vol 6 (10) ◽  
pp. e26834 ◽  
Author(s):  
Jatinder S. Sangha ◽  
Wajahatullah Khan ◽  
Xiuhong Ji ◽  
Junzeng Zhang ◽  
Aaron A. S. Mills ◽  
...  

2002 ◽  
Vol 205 (17) ◽  
pp. 2605-2613 ◽  
Author(s):  
Richard B. Gardiner ◽  
Kyrre Ullensvang ◽  
Niels C. Danbolt ◽  
Stanley Caveney ◽  
B. Cameron Donly

SUMMARYGlutamate functions as a neurotransmitter in the central nervous system(CNS) and neuromuscular junctions in insects. High-affinity glutamate transporters are responsible for keeping the resting levels of excitatory amino acids below the synaptic activation threshold by removing them from the extracellular fluid, thereby preventing them from reaching toxic levels. Peptides representing the N- and C-terminal regions of a glutamate transporter cloned from the cabbage looper caterpillar (Trichoplusia ni) were synthesized and used to generate polyclonal antibodies. The antibodies produced immunohistochemical staining in both muscular and nervous system T. ni tissues. Neuromuscular junctions in the skeletal muscles produced the most intense labelling, but no visceral muscle or sensory nerves were labelled. In the CNS, the neuropile of the ganglia, but not the connectives, gave a diffuse staining. Electron microscopical examination of ganglia and neuromuscular junctions showed that the plasma membrane of glial cells, but not that of neurons was labelled, in agreement with the notion that most of the glutamate uptake sites in this insect are in glial cells.


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