Abstract:
Two parasitoids and one predator were recovered from the red llour beetle, Tribolium
castaneum (Herbst) and the confused flour beetle, T. confi,sum Duval infested wheal flours.
lbe larval-pupal parasitoids are Rhahdepyris zeae Waterston and !Iolepyris sylvanidis
Brethes (Hymenoptera: Bethylidae) and the predator is Xylocoris jlavipes (Reuter)
(Hemiptera: Anthocoridae). Some ac;pects of biology of these parasitoids and.predator were
investigated in the laboratory condition on the above two species of Tribolium.
R. zeae although a larval-pupal ectoparasitoid showed a decided preference towards the
fourth instar larvae and early pupae of the host. The developmental time varied in the
male and female adult parasitoids. The male and female of R. zeae completed
<.lt:velopmcnt within 19.06:1:0.59 um.I 20.14±0.58 days in 'I: castmwum while in T.
confu.mm it was 20.10±0.77 and 21 .20±0.92 days, respectively al 30 ± I °C and 70% R.
H. The males are polygamous but the females arc always monogamous. Both the sexes
of R. zeae lived maximum days when host was supplied continuously. The female
deposited maximum number of eggs when hosts were abundant. The sex ratio of R.
zeae always showed female biased and dependent on the size of the host.
Ji sylvanidis is also a primary larval-pupal ecloparasitoid of T. castaneum and T.
confusum. After emergence the male took the initiative in mating and courtship. The
fourth instar larvae were preferred for oviposition. The male of fl. sylva11idis completed
life cycle within I 5.50±0.62 and 16.00±0.47 days in T. castaneum and T. confusum
whereas the female required I 6.66t:0.72 and 17.15±0.80 days. Females are monandrous
while males are polygynous. The hosts fluids were necessary for greater longevity in
both the sexes. H. ,\ylvanidi.\· is arrhenolokous.
Xylocoris jlavipes (Reuter) is a predator of different larval and pupal stages of
Tribolium. The early stage was most preferred than that later stages. The male of X
flavipcs completed life cycle within 16.99±1.86 and 17.80±1.30 days in 7'. castancum
and T. confusum whereas the female required 16.00± 1.63 and 17.00±1.63 days. The
female biased sex ratio of X jlavipes was noticed.-----
Description:
This Thesis is Submitted to the Institute of Biological Sciences (IBSc) , University of Rajshahi, Rajshahi, Bangladesh for The Degree of Master of Philosophy (MPhil)
