RELATIONSHIPS BETWEEN THE PARASITOID HYPOSOTER EXIGUAE AND THE CABBAGE LOOPER, TRICHOPLUSIA NI: EFFECTS ON HEAD-CAPSULE WIDTH, LIVE AND DRY WEIGHTS, AND HEMOLYMPH SPECIFIC GRAVITY OF HOSTS AT DIFFERENT AGES

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.

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The Phenologies of Cotesia-Urabae, Dolichogenidea-Eucalypti (Hymenoptera, Braconidae) and Their Host Uraba-Lugens (Lepidoptera, Noctuidae) in the Adelaide Region

Australian Journal of Zoology ◽

10.1071/zo9900347 ◽

1990 ◽

Vol 38 (4) ◽

pp. 347 ◽

Cited By ~ 9

Author(s):

GR Allen

Keyword(s):

Field Study ◽

Larval Stage ◽

First Generation ◽

Dry Weight ◽

Head Capsule ◽

Head Capsule Width ◽

Two Generations ◽

High Level ◽

Lepidoptera Noctuidae ◽

Host Generation

A field study was undertaken to determine the phenologies of the solitary larval endoparasitoids Cotesia urabae and Dolichogenidea eucalypti in relation to that of their bivoltine host Uraba lugens. C. urabae had two generations within both the summer and the winter generation of U. lugens, and D. eucalypti had two generations in the summer but only one generation in the winter. D. eucalypti parasitised a narrower range of host sizes in the field. Both parasitoids attacked recently hatched (typically 1st instar) or 'small hosts' at the beginning at each host generation. In summer D. eucalypti was the first to emerge from hosts, but both D. eucalypti and C. urabae, emerged from hosts which had modes of 0.85-1.05 mm in head capsule width and 0.9-1.5 mg in dry weight (mid hosts). In winter, C. urabae emerged from hosts which had modes of 1.15 mm in head capsule width and 2.7 mg in dry weight (large hosts). Both species in summer, and C. urabae in winter, then proceeded to parasitise hosts of around these sizes to commence second parasitoid generations. In its second generation in summer and its first generation in winter, D. eucalypti typically emerged after most unparasitised hosts had pupated. Both species of parasitoid overwintered within the larval stage of their host. Levels of parasitisation appeared to be low, and dropped between first and second generations within each host generation. It was concluded that C. urabae and D. eucalypti displayed continuity of generations and a high level of synchronisation with U. lugens in the Adelaide region.

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The Developmental Characteristics for the Head Capsule Width ofMonochamus alternatus(Coleoptera: Cerambycidae) Larvae and Determination of the Number of Instars

Journal of Insect Science ◽

10.1093/jisesa/iez010 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 3

Author(s):

Myeong Su Go ◽

Soon Hwa Kwon ◽

Su Bin Kim ◽

Dong-Soon Kim

Keyword(s):

Head Capsule ◽

Head Capsule Width ◽

Developmental Characteristics

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RELATIONSHIPS BETWEEN THE PARASITOID HYPOSOTER EXIGUAE AND THE CABBAGE LOOPER, TRICHOPLUSIA NI: THE EFFECT OF HOST AGE ON OVIPOSITIONAL RATE OF THE PARASITOID AND SUCCESSFUL PARASITISM

The Canadian Entomologist ◽

10.4039/ent107689-7 ◽

1975 ◽

Vol 107 (7) ◽

pp. 689-694 ◽

Cited By ~ 12

Author(s):

Zane Smilowitz ◽

Gerard F. Iwantsch

Keyword(s):

Trichoplusia Ni ◽

Cabbage Looper ◽

Host Age ◽

Older Individuals ◽

Percentage Parasitism ◽

First Instar ◽

Third Instar Larvae

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.

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

Environmental Entomology ◽

10.1093/ee/2.5.759 ◽

1973 ◽

Vol 2 (5) ◽

pp. 759-764 ◽

Cited By ~ 70

Author(s):

Zane Smilowitz ◽

Gerard F. Iwantsch

Keyword(s):

Trichoplusia Ni ◽

Developmental Rate ◽

Cabbage Looper ◽

Host Age

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Host plant effect on the number of moultings and head capsule width of the gypsy moth caterpillars

Glasnik Sumarskog fakulteta ◽

10.2298/gsf1205127m ◽

2012 ◽

pp. 127-138

Author(s):

Slobodan Milanovic ◽

Sladjan Milanovic

Keyword(s):

Gypsy Moth ◽

Head Capsule ◽

Larval Instars ◽

Head Capsule Width ◽

Sessile Oak ◽

Turkey Oak ◽

English Oak ◽

Host Plant Effect ◽

Oak Leaves

The effect of four oak species: Turkey oak, Hungarian oak, sessile oak and English oak on the number of moultings and head capsule width of the gypsy moth caterpillars was researched. Host plants have a statistically significant effect on the number of both male and female larval instars. The highest number of larval instars was recorded for caterpillars fed on sessile oak leaves, and the lowest number was recorded for those fed on Turkey oak leaves. Females reared on Hungarian oak and English oak leaves had a normal number of larval instars. Except for 1st instar caterpillars, all other larval instars showed a statistically significant host plant effect on the head capsule width. The widest head capsules were found on caterpillars fed on Turkey oak leaves, and those fed on sessile oak leaves had the narrowest head capsules. The study data on head capsule widths can be practically applied in the determination of the optimal ratio of larval instars in the gypsy moth population, i.e. in the determination of terms for aerial spraying actions.

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BIOASSAY OF PROLACTIN

Acta Endocrinologica ◽

10.1530/acta.0.0600091 ◽

1969 ◽

Vol 60 (1) ◽

pp. 91-100 ◽

Cited By ~ 5

Author(s):

Charles S. Nicoll

Keyword(s):

Epithelial Cells ◽

Lipid Content ◽

Dry Weight ◽

Fat Content ◽

Assay Sensitivity ◽

Mucosal Epithelium ◽

Wet Weight ◽

Total Dry Weight

ABSTRACT The response of the pigeon crop-sac to systemically acting prolactin (injected subcutaneously) was evaluated by measuring the wet weight of the responsive lateral lobes of the organ and by determining the dry weight of a 4 cm diameter disc of mucosal epithelium taken from one hemicrop. Of several different injection schedules tested, administration of prolactin in four daily injections was found to yield optimal responses. When compared with a graded series of prolactin doses, measurement of the mucosal dry weight proved to be a better method of response quantification than determination of the crop-sac wet weight with respect to both assay sensitivity and precision. The submucosal tissue of the crop-sac was estimated to constitute about 64 % of the total dry weight of the unstimulated organ and it was found to be relatively unresponsive to prolactin stimulation in comparison with the mucosa. The lipid content of the mucosal epithelium was determined using unstimulated crop-sacs or tissues which showed varying degrees of prolactin-induced proliferation. The fat content of the mucosal epithelial cells increased only slightly more rapidly than the dry weight or the defatted dry weight of the mucosa. Suggestions are made for the further improvement of the systemic crop-sac assay for prolactin.

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