reproductive biology of Perillus bioculatus
T. S. Adams
Albrecht Blvd., Fargo, ND 58105-5674, USA
A method is
presented to quantitatively score the degree of ovarian
maturation in a predacious pentatomid with asynchronous follicle
development. Ovarian scores were not influenced by mating
status, but were significantly lower in females fed the
artificial diet. Ovarian follicles start forming when females
are 2.3 days old reaching a peak at 4.5 days. In controls, the
rate of new follicle formation decreases after the onset of
vitellogenesis. By 4.5 days, all control ovarioles contained at
least one vitellogenic follicle and by 9.5 days all ovarioles
had chorionated follicles. In contrast, females fed the
artificial diet had 40% of the ovarioles with a vitellogenic and
chorionated follicle at 10.5 days of age. Mating started when
females were 3.5 days old and correlated with the start of
vitellogenesis. Mating and an adequate diet are prerequisites
for laying a full compliment of eggs in Perillus bioculatus.
Virgins laid an average of 22 eggs compared with 138 in the
multiply mated controls and 84 in singly mated females. Multiply
mated females given an artificial diet only laid 42 eggs.
Oviposition rates were calculated over five-d periods for each
female and presented as eggs/ovariole/d (eod). In all
experimental groups the rates of egg laying decreased as the
females aged approaching 0.07eod by 27.5 d after the start of
oviposition. Two factors affecting egg laying are: 1).
Availability of mature ovarian follicles in the ovariole and 2).
Mating. Unmated females develop mature ovarian follicles, but do
not oviposit many of them. Mated females given the artificial
diet develop fewer mature ovarian follicles, but oviposit them.
Hemolymph vitellogenin titers were determined with an ELISA
technique. Insects given the artificial diet had lower
vitellogenin levels than those given prey. The interaction of
diet with hormones required for ovarian maturation will be
Perillus bioculatus, fecundity, artificial diet,
oviposition rate, vitellogenin.
Copyright: The copyrights of
this abstract belong to the author (see right-most box of
title table). This document also appears in Session 13 –
INSECT PHISIOLOGY, NEUROSCIENCES, IMMUNITY AND CELL BIOLOGY
Symposium and Poster Session, ABSTRACT BOOK II –
XXI-International Congress of Entomology, Brazil, August