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Notes:
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Several sympatric lepidopteran species feed on
maize plants, and the different components of their
species-specific female sex pheromones may play a role
in attracting conspecifics and/or deter heterospecific males.
In this study, we analyzed the content of Mythimna
unipuncta pheromone glands and tested the response of
males to components of their own pheromone blend and
that of Sesamia nonagrioides in the wind tunnel. Whole
pheromone glands, and lures where (Z)-9-hexadecenyl
acetate, Z)-11-hexadecen-1-ol or (Z)-9-hexadecenyl acetate +
(Z)-11-hexadecen-1-ol were added to the major component,
(Z)-11-hexadecenyl acetate, elicited significantly higher
responses by M. unipuncta males than lures with main
component alone, although the levels varied with concentration.
In the field a rather different outcome was observed, as
the addition of other compounds found in the female
pheromone gland did not improve trap catch over lures with
only (Z)-11-hexadecenyl acetate. The addition of (Z)-11-
hexadecenal, a compound of the S. nonagrioides pheromone,
to (Z)-11-hexadecenyl acetate significantly reduced attraction
of M. unipuncta males both in the wind tunnel and in the
field, as well as the number of sympatric clover cutworm,
Discestra trifolii, under field conditions. The addition of
(Z)-9-hexadecenyl acetate, a minor component of the
M. unipuncta pheromone blend, reduced the number of
S. nonagrioides captured in field traps that were baited with
the S. nonagrioides lure. The significance of such inhibition
in the reproductive isolation of sympatric species that attack
maize is discussed
This research was funded by Spanish Research Agency CICYT, AGL2005-06485. |
