Cornops aquaticum
| Cornops aquaticum | |
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| Species: | C. aquaticum
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| Binomial name | |
| Cornops aquaticum | |
Cornops aquaticum is a semi-aquatic species of grasshopper native to the Neotropics. It feeds and breeds exclusively on members of the Pontederiaceae family, especially water hyacinth (Eichhornia crassipes), and is being investigated as a possible biological pest control agent for the water hyacinth in countries where that plant is invasive.
Ecology
The female Cornops aquaticum inserts its ovipositor into the leaf stalk of the host plant and deposits an egg-case containing thirty to seventy eggs; the egg cases are large, measuring an average of 27 by 3 mm (1.1 by 0.1 in). The eggs hatch after about four weeks and the nymphs feed on the leaves of the plant for about seven weeks, passing through six or seven instars, and causing much damage. Adults live for up to twelve weeks; after an initial feeding period of four weeks, females deposit up to seven egg cases at intervals in the host plant tissues. Feeding trials show that besides water hyacinth, nymphs can complete their development on Pontederia cordata (pickerel weed), also in the Pontederiaceae family, and on Canna indica. In the laboratory, nymphs can also feed during starvation trials on certain other plants but the females do not oviposit on these species and the nymphs do not complete their development beyond the third instar on any of them. The adults also consume large amounts of above-water foliage of their plant host and can fly vigorously between plants.[1]
Both nymphs and adult Cornops aquaticum feed on the floating mats of water hyacinth (Eichhornia crassipes). Damage caused to the plant is high compared to damage caused by other grasshoppers, but nevertheless, the insect is unable to keep up with the production of new growth by the plant.[2]
Biological control
In its native South America, the water hyacinth is an aquatic plant in the Pontederiaceae family that is kept under control by its natural enemies. However in countries into which this plant has been introduced, there may be no natural enemies and it can become invasive. Cornops aquaticum is under consideration as a possible biological control agent for this invasive plant. It has been introduced under controlled conditions into South Africa for this purpose.[3]
References
- ^ Hill, M.P.; Oberholzer, I.G. (2000). "Host Specificity of the Grasshopper, Cornops aquaticum, a Natural Enemy of Water Hyacinth". Proceedings of the X International Symposium on Biological Control of Weeds: 349–356.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Franceschini, M.C.; De Wysiecki, M.L.; Poi de Neiff, A.; Galassi, M.E.; Martínez, Fedra S. (2011). "The role of the host-specific grasshopper Cornops aquaticum (Orthoptera: Acrididae) as consumer of native Eichhornia crassipes (Pontederiaceae) floating meadows". Revista de biologia tropical. 59 (3): 1407–1418. PMID 22017141.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Balian, E.V.; Lévêque, C.; Segers, H.; Martens, K. (2008). Freshwater Animal Diversity Assessment. Springer Science & Business Media. p. 542. ISBN 978-1-4020-8259-7.