Tolerance of Heteracris Littoralis (Orthoptera: Acrididae) to the Toxic Plant, Nerium Oleander (Apocynacea)

Abstract

Nerium oleander (Apocynacea) is a highly toxic plant that has never been reported to be selected as a food or even as a resting place by any acridid species. The study tested the competence of Heteracrislittoralis (Orthoptera: Acrididae) to tolerate and survive on this plantfor considerable periods, and to resume normal capacity of development and reproduction when favourable food plant became available. Nymphal survival and development were followed by monitoring three cohorts of freshly hatched hoppers. The first cohort fed oleander leaves; the second one (control) fed clover; while the third cohort fed oleander leaves for 35 days, and then switched to clover. Age specific survivorship and reproductive parameters of the adults were followed by monitoring three cohorts of newly fledged adults fed on the same patterns. Moulting was suspended in nymphs fed oleander; when food plant was switched to clover, the insects resumed normal development and reached the adult stage. Adult cohort reared on N. oleander exhibited a normal age specific survivorship curve, but ovarian development was suspended. Suspension of ovarian development by N. oleander was accompanied by very low indices of food consumption and conversion of digested food into body substance. But, after switching to normal food, clover, the insects resumed normal ovarian development with significant prolonged longevity, and the fecundity was approximately equal to the same parameter in the control cohort. This reflects a strong evolutionary biotic potential against the selective power of plant defense.

Accidental Oleandrum (Nerium Oleander L.) Ingestion: Anatomo-Pathological consequences in livestock species

“…Oleanders areone of the leading causes of poisoning cases and they are potentially lethal to different species of insects, domestic animals, and human be-ings: ingestion, inhalation, and contact with all parts of the plant can cause much adverse toxicities and lethal effects (Langford et al, 1996;Aslani et al 2004;Soto-Blanco et al 2006). El-Shazly, Nassar & El-Sherief (1996) and El-Shazly, Rfeaei & Shaurub (1997) reported that ethanolic extracts of the leaves of Nerium oleander were lethal to the larvae of Muscina stabulans (Diptera-Muscidea) and to the second instar nymphs of Spilostethus pandurus (Heteroptera-Lygaeidae) when incorporated into the diet of these insects. The insecticidal activity of this plant has also been reported by Satphathi & Ghatak (1990), Satphathi, Ghatak & Bhusam (1991), Pushpafatha & Muthukrishnan (1995) and Hiremath, Young, Joon, Kim-Soon & Kim (1997).…”