| dc.description |
Cotesia are parasitoid wasps (Hymenoptera : Braconidae ) that are used for
biological control of pest moths (Lepidoptera : Noctuidae , Pyralidae ) that damage
agricultural crops . This dissertation investigated courtship acoustics and mating , and
their relevance to biological control , in members of the Cotesia flavipes species
complex , and a noncomplex member , Cotesia marginiventris .
The first study investigated whether courtship acoustics were species specific for
two members of the Cotesia flavipes complex , C . flavipes and C . sesamiae , and for C .
marginiventris . During courtship , male Cotesia fan their wings and produce low
amplitude sounds and substrate vibrations . The airborne and substrate components of
courtship were similar within a species . However , the courtship acoustics of each
species was distinct . The duration and frequency of several courtship acoustic
components distinguished each species , while some components did not differ among
species . The second study investigated mating success and transmission of courtship
vibrations on natural and artificial rearing substrates for Cotesia marginiventris . Mating
success was measured on plastic , glass , corn and bean leaves , and chiffon fabric . Mating
success was lowest on plastic and glass , intermediate on corn and bean leaves , and
highest on chiffon . Substrate influenced transmission of courtship vibrations . Durations
of courtship vibrations were longer on corn , bean and chiffon than on plastic . Frequency
modulation occurred on corn , bean and chiffon , and amplitude was greatest on chiffon .
The mating success of normal and dealated males was higher on chiffon than on glass ,
suggesting that courtship communication relied in part on substrate vibrations .
The third study examined female and male mate choice in a solitary and a
gregarious species , C . marginiventris and C . flavipes , respectively . Females of the
solitary species , C . marginiventris , mated more frequently with large than small males ,
and this did not appear to be the result of male competition . Male choice for female size
was not apparent in C . marginiventris . Females of the gregarious parasitoid , C . flavipes ,
mated with large or small males with similar frequencies , and male -male competition
was not observed . In the male choice experiment , C . flavipes males attempted copulation
and mated more with smaller females , and smaller females accepted males more than
large females . |
|