Abstract:
Mate finding and dispersal from the natal patch in parasitoid Hymenoptera
are influenced by the availability of host resources and interactions with other
organisms. We compared the mating behavior of three solitary aphid parasitoids,
Aphidius ervi Haliday, Lysiphlebus hirticornis Mackauer and Pauesia pini (Haliday)
(Hymenoptera: Braconidae: Aphidiinae) that differ in host resource exploitation and
ant mutualism. In L. hirticornis, which is obligately ant-attended, the residence time
on the natal patch was approximately 4 h compared with less than 2 h in the
facultatively ant-attended P. pini; the sexes did not differ in residence time. Females
of A. ervi, which is not attended by ants, stayed for slightly more than 2 h on the
natal patch while their male siblings remained for only 1 h. In L. hirticornis, 90% of
all siblings in a clutch mated on the natal patch but only 13% in A. ervi and 42% in P.
pini did so. Off-patch matings (23%) were observed only in A. ervi. Males and
females of L. hirticornis were 12-times more likely to mate on the natal patch when
aphids and ants were present than when either of the latter species was removed; and
patch residence time declined from approximately 4 h to approximately 2.5 h in the
absence of either aphids or ants. We propose that, in aphidiine wasps and perhaps
other quasigregarious parasitoids, mating behavior is influenced by the availability
of resources on the natal patch and the presence or absence of trophobiotic ants.
