The effect of parasitism byHyposoter didymator [Hym.: Ichneumonidae] on food consumption and utilization bySpodoptera litura [Lep.: Noctuidae]

Abstract

The effect of parasitism by Hyposoter didymator (Thunb.) [Hym. : Ichneumonidae] on food consumption and utilization by Spodoptera litura (Fb.) [Lep. : Noctuidae] was studied for seven days, during which the parasitoid completed its larval development. Food consumption, weight gained and faeces produced were significantly less in parasitized larvae than in unparasitized larvae after the 4 th day following parasitization. Approximate digestibility was higher in parasitized larvae after the 2 nd day following parasitization. Efficiency of conversion of ingested and digested food into body weight was greater in unparasitized larvae after the 2 n~ day of parasitization. There seems to be a definite immediate advantage to the crop on releasing the parasitoid due to the reduced consumption of food.

The influence of two endoparasitic wasps, Hyposoter didymator and Chelonus inanitus, on the growth and food consumption of their host larva Spodoptera littoralis

“…The first 2 days after parasitisation by H. didymator [egg incubation period is 1.8±0.18 days in this parasitoid according to Kumar et al (1988)], parasitised S. littoralis larvae behaved identically to unparasitised ones, as previously reported by Kumar and Ballal (1992). When the parasitoid egg hatches, there is an initial reduction in food consumption by the parasitised host, which rapidly increases with the development of the parasitoid over very few days.…”

“…On the other hand, extrapolation of results from one parasitoid species to another is very difficult, even though they belong to the same genus, because the host species seem to influence results. As such, Kumar and Ballal (1992) reported that the magnitude of the reduction in food consumption of Spodoptera litura (Fabricius) larvae parasitised by H. didymator was much lower than that when the host was S. littoralis. In conclusion, the effect of parasitism on host food consumption seems to be dependent on the host-parasitoid association, and, consequently, it should be studied case by case.…”

“…It seems that polydnaviruses, among other factors, reduce the uptake of food and increase the concentration of free sugars in the host haemolymph and glycogen in the host larval body, mainly in the last host instar. On the other hand, Kumar and Ballal (1992) reported the effect of parasitism by H. didymator on a different, but very related species, Spodoptera litura (Fabricius), demonstrating that food consumption, weight gain and production of faeces were significantly lower in parasitised larvae compared with unparasitised ones. Both previous studies seem to indicate that the presence of parasitoids is advantageous to the crop, because they have a negative effect on the feeding behaviour of the host.…”

“…Besides, feeding during larval development has rarely been reported for a given host/parasitoid system, because most researchers have only focussed on total feeding (e.g. Kumar and Ballal, 1992;Ohnuma and Kainoh, 1992).…”

Larval parasitism of the autumnal moth reduces feeding intensity on the mountain birch

“…Gregarious species, i.e. where several parasitoid larvae develop within/upon one host, are likely to increase the food consumption of their hosts (Slansky, 1986;Alleyne & Beckage, 1997;Smallegange et al, 2008), whereas solitary species (one parasitoid larva per host) usually have the opposite effect (Guillot & Vinson, 1973;Rohlfs & Mack, 1983;Senthamizhselvan & Muthukrishnan, 1989;Kumar & Ballal, 1992;Harvey, 1996;Bae & Kim, 2004). A few studies have already shown that parasitoid-induced diminished food consumption in herbivorous insects has led to increased plant fitness Fritzsche-Hoballah & Turlings, 2001;Smallegange et al, 2008).…”