Mj. Parr et al., INFLUENCE OF SOME FATTY-ACIDS ON OVIPOSITION BY THE BRUCHID BEETLE, CALLOSOBRUCHUS-MACULATUS, Journal of chemical ecology, 24(10), 1998, pp. 1577-1593
The cowpea seed beetle, Callosobruchus maculatus, will lay its eggs on
many potential hosts and inert surfaces. Oviposition on glass beads i
s stimulated by coating them with individual fatty acids. Nevertheless
, female beetles reject mung seeds less frequently than beads treated
with either an extract of mung seeds or, especially, an extract of mun
g seeds plus oleic acid. The addition of oleic acid to the extract res
ulted in a change in the sequence of oviposition behavior, notably an
increase in a raised body position indicative of hosts of low acceptab
ility. Fatty acids are present in the epicuticular waxes of legume see
ds; wax extract of mung bean contains 32.4% fatty acid and 14 alkanes,
whereas a wax extract of chickpea contains 5% fatty acid and Is alkan
es. Thus, chickpea may be a less acceptable host for oviposition than
mung bean because of physical differences and/or because of chemical d
ifferences, including a reduced total level of fatty acid or the high
proportion of oleic acid it is reported to contain. It is concluded th
at an appropriate mixture of fatty acids in the epicuticular waxes sti
mulates oviposition but that an elevated level of oleic acid in conjun
ction with others is deterrent.