Journal of Orthoptera Research (1999) 8, 237-242

C.F. Hinks and O. Olfert (1999)
Growth and survival of early-instar grasshoppers on selected perennial grasses, with observations on plant constituents which may influence performance
Journal of Orthoptera Research 8, 237-242
Abstract: Hatchlings of Melanoplus sanguinipes (F.) (the lesser migratory grasshopper) were fed for five days on Triticum aestivum L. (wheat cv Katepwa), Avena sativa L. (oats cv Harmon) or one of the following perennial grasses; Andropogon gerardii Vitman (big bluestem), A. scoparius Michx. (little bluestem), Bouteloua gracilis (HBK) Lag. (blue grama), Bromus inermis Leyss. (smooth brome), Festuca ovina 'glauca' L. (sheep's fescue), or F. sulcata Hack. (sheep's fescue). Survival of the grasshoppers fed B. inermis and F. sulcata was comparable to those fed wheat (86%), whereas survival of the grasshoppers fed on the remaining grasses was lower than those fed oats (73%), ranging from 68% on F. ovina down to 27% on B. gracilis. The mean weights of surviving grasshoppers after the five-day feeding interval followed a similar trend, except that all the grass-fed grasshoppers were significantly lighter than those fed either wheat (13.7 mg) or oats (9.6 mg). The mean weights of these grass-fed grasshoppers ranged from 8.5 mg on those fed F. sulcata down to 6.3 mg on B. gracilis. In a spot test for tannins, only the two species of Andropogon tested positive. With the exception of A. scoparius, leaf homogenates from each species were assayed for their capacity to inhibit trypsin and chymotrypsin in grasshopper digestive fluid. Trypsin activity was reduced from 6.6% (F. sulcata) to 40.6% (B. inermis), and chymotrypsin activity was reduced from 13.5% (B. inermis) to 18.9% (Harmon oats), whereas A. gerardii, both species of Festuca and Katepwa wheat homogenates enhanced chymotrypsin activity. The results are discussed in the context of herbivore resistance through known defence mechanisms and their significance to grasshopper management strategies.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Owen Olfert

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
identification/taxonomy

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Melanoplus sanguinipes