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Chemical-mediated effects of predatory fish on chironomid larvae behaviour have been ignored so far. Sediment-dwelling chironomid larvae inhabit protective burrows from which they extend their bodies only to feed on deposited detritus and microalgae from the surrounding sediment. Here, we performed factorial laboratory experiments to study whether fish-borne chemical cues (kairomones) are responsible for behavioural trait changes of chironomid larvae, and whether chironomid larvae are able to assess the densities of fish predators and food resources and the trade-off between them. We exposed naïve Chironomus riparius larvae to the chemical presence of zero, one, and ten predator fish (Rutilus rutilus) and offered two resource levels (low food, high food) for each treatment. Kairomones induced significant inherent behavioural trait changes in chironomid larvae. During the first 120 min after exposing chironomids to fish-conditioned water, we found a significant increase in digging activity with increasing predator density. After 3 days of exposure, the deepest chironomid burrows were found in treatments with the highest predator density. Chironomid larvae were significantly able to adjust their foraging behaviour to different predator densities and food concentrations and trade off between them; that is, when fish predators were more abundant or when more food resources were available, the foraging activities of larvae were significantly reduced. Our data suggest that chemically mediated trait changes (burrowing and foraging behaviour) may cascade through the littoral food web. 相似文献
2.
The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for
interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable
depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored
whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants (cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on
the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both
cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves
offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones. 相似文献
3.
Dickens JC 《Die Naturwissenschaften》2007,94(10):847-852
Chemical signals emitted by insects and their hosts are important for sexual communication and host selection. Plant volatiles
facilitate the location of suitable hosts for feeding and oviposition, and may moderate responses to sex and aggregation pheromones.
While mating has been shown to moderate behavioral responses to pheromones in a number of insects, little is known about the
effects of mating on behavioral responses of insects to plant attractants, and even less is known about the mechanisms involved.
In this study, mating was shown to decrease behavioral responses of the Colorado potato beetle to a host kairomone within
24 h, and attraction to the kairomone recovers only after 72 h. This decrease in responsiveness also occurs when only contact
with the opposite sex is allowed; the effect is not observed with contact among individuals of the same sex. Peripheral olfactory
responses to a component of the kairomone correlate with the observed behavioral responses and suggest involvement of antennal
receptors in the behavioral change. 相似文献
4.
Paolo Lo Bue Stefano Colazza Lisa D. Forster Jocelyn G. Millar Robert F. Luck 《Chemoecology》2004,14(3-4):151-156
Summary. Metaphycus sp. nr.
flavus (Encyrtidae: Hymenoptera)
is a parasitoid species collected from the Mediterranean
region which lays its eggs in the immature stages of several
economically important soft scale insects (Hemiptera:
Coccidae), including brown soft scale, Coccus hesperidum
L. (= host insect). Preliminary tests suggested that the parasitoid
is most successful in producing offspring when it
oviposits in the younger stages of brown soft scale. In
Y-olfactometer bioassays measuring wasp choices and residence
times, naïve parasitoids were significantly more
attracted to yucca leaves infested with 26, 27, or 28 d-old
scale than to uninfested leaves, whereas leaves with older
(29-30 d-old) scale were no more attractive than uninfested
leaves. Parasitoids also spent significantly more time in the
arm with yucca leaves infested with 26 d-old scale than in
the arm with uninfested leaves. These results are consistent
with observations of the parasitoids reproductive success on
scale of different ages, whereby older scale are more likely
to encapsulate the developing eggs of M.
sp. nr. flavusfemales than are younger scale. Further bioassays determined
that yucca leaves that had been infested with 26 d-old
scale but from which the scale had been removed were as
attractive as infested leaves. In contrast, infested yucca
leaves from which scale had been removed and the leaves
subsequently washed with distilled water were less attractive
than infested leaves. Furthermore, the wash water
containing scale residues was attractive to female wasps. In
total, these results suggest that Metaphycussp. nr. flavus
females utilize volatile, water soluble compounds produced
by brown soft scale as cues to locate suitable hosts. 相似文献
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