Canadian Forest Service Publications
Helianthus annuus pollen, an oviposition stimulant for the sunflower moth, Homoeosoma electellum. 1989. Delisle, J.; McNeil, J.N.; Underhill, E.W.; Barton, D. Entomol. Exp. Appl. 50: 53-60.
Issued by: Laurentian Forestry Centre
Catalog ID: 14090
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Females of the sunflower moth, Homoeosoma electellum, laid a total of 242.3 ± 27.4 (X ± SE) eggs when provided oviposition sites of wax paper dusted with pollen from cultivated sunflowers. Fecundity was influenced by the age at which mating occurred but not by the duration of mating. Eggs were laid during both the light and dark portions of a 16L:8D photoperiodic cycle, with an evident peak occurring shortly after the onset of the scotophase.
The fecundity of females provided oviposition sites with a 1 mg equivalent of an ethanolic pollen extract daily (124.2 ± 22.8) did not differ significantly from that of females provided 1 mg of pollen (172.2 ± 28.0). Furthermore, the females showed the same positive dose dependent oviposition response where sites contained different concentrations of either pollen or pollen extract. However, when different oviposition substrates were provided simultaneously, females preferred pollen > ‘reconstituted pollen’ (extract + pollen residue following extraction) = pollen extract > pollen residue = wax paper control. These data confirm the presence of an oviposition stimulant for H. electellum in the sunflower pollen.
Antennectomised females laid as many eggs on sites with pollen residue as on sites with pollen, indicating that the majority of sensillae for detecting the oviposition stimulant are located on the antennae.
The importance of pollen load as an indicator of a suitable host plant, given that previous laid eggs do not inhibit subsequent oviposition, is discussed with respect to larval survival.