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A positive relationship between ownership and contest success is widespread among territorial butterflies. We tested the hypothesis that owners win simply because they have a longer experience occupying a given territory than do intruders in territorial butterflies. Using the lycaenid butterfly Chrysozephyrus smaragdinus, we staged contests between two males that had experienced different residency periods at the same contested territory, similar to owners and intruders in natural contests. We found that males that had occupied the contested territory for a longer period (a day) always defeated the shorter occupancy males (15 min). Therefore, residency period plays a key role in settling territorial contests. As residency confers advantages in a time-dependent manner, the mechanism of owner dominance could be an increase in motivation to fight as local familiarity increases. Moreover, this result predicts a population-level territorial dynamics. If residency period per se confers advantages in each contest, males arriving at a territory early in their adult season should acquire territorial dominance because they can remain there for a certain period with only a few rivals; late-appearing males do not have this advantage. As predicted, we found that males appearing at territory sites early in the season were more likely to hold their territories. This finding provides new evidence for the evolution of protandry in butterflies. [ABSTRACT FROM AUTHOR]

Summary Oviposition response of Ideopsis similis (L.) (Lepidoptera: Danaidae) was examined for 12 phenanthroindolizidine alkaloids present in its host plant, Tylophora tanakae (Maxim.) (Asclepiadaceae). At least five alkaloids, i.e. (+)-isotylocrebrine (3,4,6,7-tetramethoxyphenanthroindolizidine; l), (+)-3-demethyliso- tylocrebrine (3), (+)-isotylocrebrine N-oxide (5), (+)-6-demethyltylocrebrine (8) and (–)-7-demethyltylophorine (10), were found to individually stimulate oviposition by females. Of these, compounds 1, 3 and 10 were regarded as key components most responsible for host recognition or preference. However, female egg-laying was much higher in response to a mixture of the five alkaloids. In two-choice bioassays, more eggs were deposited on samples comprising the five alkaloids than on samples consisting of a single alkaloid. This suggests strongly that host selection by the butterfly is mediated by the synergistic action of several phenanthroindolizidine alkaloids present in the host plant. [ABSTRACT FROM AUTHOR]

AbstractThe active compounds of oak-sap odour in attracting adults of two butterflies, Kaniska canace (L.) and Vanessa indica (Herbst) (Lepidoptera: Nymphalidae), were identified by chemical analyses, electroantennogram (EAG) and two behavioural assays: proboscis extension reflex (PER) and attraction to artificial tree models. Fourteen compounds were identified from two sap samples collected in 1997 and 1998, of which the major volatiles were ethanol and acetic acid (≈ 900 p.p.m. and 500 p.p.m. in sap, respectively). However, the chemical composition of the minor volatiles varied considerably between the two samples. Among 13 chemicals tested, V. indica showed strong PER to five aliphatic acids (acetic, propionic, butyric, isobutyric and isovaleric), 2-methylpropan-1-ol and 3-hydroxybutan-2-one, whereas the PER-active compounds for K. canace were these seven compounds and also ethanol, 3-methylbutan-1-ol and 1-hydroxypropan-2-one. In two-choice behavioural bioassays, the model scented with a sap-odour mimic, which was an aqueous mixture of the PER-active compounds, was more attractive to the two butterflies than an unscented control. These results demonstrated that the sap odour stimulates foraging behaviour of the butterfly. Although EAG responses of both butterflies to 3-methylbutan-1-ol and that of V. indica to 2-methylpropan-1-ol were positively dose-dependent, responses to other compounds were not strong and not dose-dependent at 1–100 μg doses. These EAG responsiveness suggests that the olfactory receptors for these compounds might be few in the antenna and that the butterflies have enough olfactory sensitivity to the dose of 1 μg. [ABSTRACT FROM AUTHOR]

A series of new amphoteric surfactants, sodium salts of 2-(N-alkyl-N-methylamino)ethanephosphates (alkyl: n-dodecyl, n-tetradecyl and n-hexadecyl) were prepared by reacting alkylbromides with N-methylaminoethanol, followed by addition of phosphoric acid groups and neutralization with sodium hydroxide. The structures of these compounds were confirmed by spectroscopy and elemental analysis. Physical properties such as Krafft point, isoelectric point, critical micelle concentration, occupation area of molecule at surface, foaming power and the effect of pH on surface activity were evaluated. These surfactants were found to exhibit zwitterionic characteristics in the pH range from approximately 5 to 9 and demonstrated good surface-active properties over a wide pH range (pH 4~10). Large occupation areas of the molecule at a surface in comparison with sodium dodecyl sulfate was noted as a characteristic feature of these surfactants. [ABSTRACT FROM AUTHOR]