Yutaka Yoshiyasu

Geographic variation in sex pheromone of Asian corn borer, Ostrinia furnacalis, in Japan.

Geographic variation in the sex pheromone of the Asian corn borer, Ostrinia furnacalis (Guenée), was surveyed in populations sampled at four locations ranging from 39.7°N to 32.9°N in Japan. The sex pheromone of the three northern populations was composed of (E)- and (Z)-12-tetradecenyl acetates with a mean E proportion of 36–39%. The southernmost population (Nishigoshi) had the same components but with a significantly higher E composition of 44%. The frequency distribution of the E ratio in the Nishigoshi population exhibited a small peak near 38% and a major peak near 46%. A family-wise analysis of the sex pheromone of this population confirmed that there were two distinct phenotypes regarding the E ratio. An “≍46% E strain” inhabits southern parts of Japan, in addition to an “≍38% E strain,” which seems to be predominant in other regions of Japan.

Identification of Sex Pheromone of Adzuki Bean Borer,Ostrinia scapulalis

By means of gas chromatography with electroantennographic detection (GC-EAD), gas chromatography–mass spectrometry (GC-MS), and a series of bioassays, (Z)-11-tetradecenyl acetate (Z11–14:OAc) and (E)-11-tetradecenyl acetate (E11–14:OAc) at a ratio of 100:3 were identified as the female sex pheromone of the adzuki bean borer,Ostrinia scapulalis. The average amounts ofZ11–14: OAc andE11–14:OAc in a single sex pheromone gland were 6.6 ± 2.4 ng and 0.2 ± 0.1 ng, respectively. In a wind-tunnel bioassay, the binary blend ofZ11- andE11–14:OAc elicited almost the same male behavioral responses as did virgin females and sex pheromone gland extract. In field trapping experiments, rubber septa impregnated with the binary blend (50 μg/septum) attracted more males than virgin females. The sex pheromone ofO. scapulalis thus turned out to be similar to that of theZ-type European corn borer,O. nubilalis, in both components and their ratio.

Sex pheromone of Ostrinia sp. newly found on the leopard plant Farfugium japonicum

Recently, larvae of Ostrinia were found feeding on the leopard plant Farfugium japonicum (Asteraceae), previously unrecorded as a host plant of this genus. The adult moths that developed from these borers were morphologically similar to, but distinct from, Ostrinia zaguliaevi, a monophagous species specialized for feeding on another Asteraceae plant, the butterbur Petasites japonicus. Although the taxonomical status of the moth feeding on F. japonicum is to be determined, distinct morphological differences in the adults strongly suggest this to be a new species (hereafter referred to as O. sp.). To gain an insight into the reproductive isolation between O. sp. and other members of the genus Ostrinia, the female sex pheromone and the males’ response to it were investigated using samples collected from F. japonicum. (Z)‐9‐tetradecenyl acetate (Z9‐14:OAc), (Z)‐11‐tetradecenyl acetate (Z11‐14:OAc), (E)‐11‐tetradecenyl acetate (E11‐14:OAc), tetradecyl acetate, and (Z)‐11‐hexadecenyl acetate were identified as candidates for sex pheromone components by analyses using gas chromatographs coupled to a mass spectrometer (GC‐MS) and electroantennographic detector (GC‐EAD). A series of bioassays of male responses in a wind‐tunnel and a field cage indicated that the former three compounds are essential for attracting males, and the latter two have no synergistic effect on the attraction. We therefore concluded that Z9‐14:OAc, Z11‐14:OAc and E11‐14:OAc are the sex pheromone components of O. sp. Although the same three compounds are used as the sex pheromone components of O. zaguliaevi and another congener, Ostrinia zealis, the blend proportions differed greatly among the three (Z9‐14:OAc/Z11‐14:OAc/E11‐14:OAc = 18/76/6 in O. sp., 45/50/5 in O. zaguliaevi and 70/6/24 in O. zealis). Differences in sex pheromones could contribute to the reproductive isolation between O. sp. and the other two Ostrinia species if males of each species exhibit a narrow window of response to their own blend ratio.

Relationships Between Nest-Dwelling Lepidoptera and Their Owl Hosts

Abstract Lepidoptera fauna of five owl species nests were investigated in Japan. Seventeen moth species were identified: Niditinea striolella (Tineidae), Agonopterix sp. (Elachistidae) from Blakistons Fish Owl, Ketupa blakistoni, nests; Monopis longella (= pavlovskii), M. flavidorsalis, M. sp., M. congestella, Niditinea baryspilas, N. striolella, N. sp. (Tineidae), Martyringa ussuriella (Oecophoridae), Mabra charonialis (Crambidae), Pyralis regalis (Pyralidae) from Ural Owl, Strix uralensis, nests; Tinea translucens, Niditinea baryspilas (Tineidae) from Brown Hawk-Owl, Ninox scutulata, nests; Opogona sacchari, O. sp., Phaeoses sp. (Tineidae) from Collared Scops Owl, Otus lempiji, nests; and Opogona sacchari, Phaeoses sp., Setomorpha sp. (Tineidae), Endotricha theonalis (Pyralidae) from Ryukyu Scops Owl, Otus elegans, nests. The moth nest fauna varied among owl species. The differences were related to owl prey (fish, small animals and birds, insects) and habitats (urban area, forest), and the tineid species selecting the nest. Tineids are presumed to decompose keratin found in owl nests and help maintain the cleanliness of the nest chamber, and such relationships between tineids and owls may be mutualistic. Rapid burrowing into owl nest materials by tineids may reflect a strategy to avoid being preyed upon by the nest owners.