| 1. |
- Larsdotter-Mellström, Helena, et al.
(författare)
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It's All in the Mix : Blend-Specific Behavioral Response to a Sexual Pheromone in a Butterfly
- 2016
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Ingår i: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Among insects, sexual pheromones are typically mixtures of two to several components, all of which are generally required to elicit a behavioral response. Here we show for the first time that a complete blend of sexual pheromone components is needed to elicit a response also in a butterfly. Males of the Green-veined White, Pieris napi, emit an aphrodisiac pheromone, citral, from wing glands. This pheromone is requisite for females to accept mating with a courting male. Citral is a mixture of the two geometric isomers geranial (E-isomer) and neral (Z-isomer) in an approximate 1:1 ratio. We found that both these compounds are required to elicit acceptance behavior, which indicates synergistic interaction between processing of the isomers. Using functional Ca2+ imaging we found that geranial and neral evoke significantly different but overlapping glomerular activity patterns in the antennal lobe, which suggests receptors with different affinity for the two isomers. However, these glomeruli were intermingled with glomeruli responding to, for example, plant-related compounds, i.e., no distinct subpopulation of pheromone-responding glomeruli as in moths and other insects. In addition, these glomeruli showed lower specificity than pheromone-activated glomeruli in moths. We could, however, not detect any mixture interactions among four identified glomeruli, indicating that the synergistic effect may be generated at a higher processing level. Furthermore, correlations between glomerular activity patterns evoked by the single isomers and the blend did not change over time.
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| 2. |
- Mozuraitis, Raimondas, et al.
(författare)
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Nonvolatile Chemical Cues Affect Host-Plant Ranking by Gravid Polygonia c-album Females
- 2012
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Ingår i: Zeitschrift für Naturforschung C - A Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075 .- 1865-7125. ; 67:1-2, s. 93-102
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Tidskriftsartikel (refereegranskat)abstract
- In a multiple-choice test, the preference of egg-laying Polygonia c-album (comma butterfly) females was studied for oviposition on plants bearing surrogate leaves treated with crude methanol extracts obtained from leaves of seven host-plant species: Humulus lupulus, Urtica dioica, Ulmus glabra, Salix caprea, Ribes nigrum, Corylus avellana, and Betula pubescens. The ranking order of surrogate leaves treated with host-plant extracts corresponded well to that reported on natural foliage, except R. nigrum. Thus, host-plant choice in P c-album seems to be highly dependent on chemical cues. Moreover, after two subsequent fractionations using reversed-phase chromatography the nonvolatile chemical cues residing in the most polar water-soluble fractions evidently provided sufficient information for egg-laying females to discriminate and rank between the samples of more and less preferred plants, since the ranking in these assays was similar to that for natural foliage or whole methanol extracts, while the physical traits of the surrogate leaves remained uniform.
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| 3. |
- Mozuraitis, Raimondas, et al.
(författare)
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Volatiles released from foliar extract of host plant enhance landing rates of gravid Polygonia c-album females, but do not stimulate oviposition
- 2016
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Ingår i: Entomologia Experimentalis et Applicata. - : Blackwell Publishing. - 0013-8703 .- 1570-7458. ; 158:3, s. 275-283
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Tidskriftsartikel (refereegranskat)abstract
- The role of olfactory cues for host search is much less investigated in day-active butterflies than in their relatives, the nocturnal moths. The goal of this study was to investigate whether host-plant volatiles from foliar extracts of hop, Humulus lupulus L. (Cannabaceae), evoke electroantennographic (EAG) responses, increase landing rates, and stimulate egg-laying behavior of gravid Polygonia c-album L. (Lepidoptera: Nymphalidae) females. Eighty-nine volatile compounds were detected in a non-concentrated methanol extract of hop by gas chromatography-mass spectrometry, 11 of which elicited an EAG response. Concentration of the crude extract significantly reduced landing rates on artificial leaves treated with the sample due to loss of volatile compounds, but after landing the oviposition response of gravid females was not affected. A mixture of eight commercially available EAG-active volatiles increased the landing rate of gravid females to their source but did not act as oviposition stimulants. Dividing the volatile compounds into two groups - consisting of (1) hexanal, (E)-2-hexenal, octanal, nonanal, and decanal, and (2) sulcatone, humulene, and benzyl alcohol - obliterated effectiveness, revealing synergism between compounds. Although volatiles did not stimulate oviposition, they significantly contributed to the distribution of eggs by increasing the landing rates on treated artificial leaves.
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