Sex‐linked control of sex pheromone behavioral responses in European corn‐borer moths (Ostrinia nubilalis) confirmed with TPI marker gene

Abstract

In two races of European corn-borer moths (ECB), the E-race females emit and males respond to 99:l sex pheromone blend of (€)/(a-11-tetradecenyl acetates, whereas the Z-race females and males produce and respond to the opposite 3:97 pheromone blend of (€)/(a-11-tetradecenyl acetates, respectively. We previously have shown that female production of the final blend ratio i s under control of a major autosomal locus but that the sequence of male upwind flight responses to the blend i s controlled by a sex-linked (Z-linked) locus. This sex-linked control of behavioral responses in crosses of E and Z ECB now is confirmed by use of sex-linked TPI (triose phosphate isomerase) allozyme phenotypes to determine the origin of the sex chromosomes in F2 populations.F1 males from reciprocal E x Z crosses generate similar behavioral-response profiles in wind-tunnel studies, with moderate numbers responding to the Z pheromone and intermediate blends (35%-65% Z), but very few responding to the E pheromone. The F2 behavioral-response profiles indicate that they are composed of 1 :I mixtures of hybrids and paternal profiles. Analysis of TPI allozyme differences allowed us to separate male F2 populations into individuals whoseZchromosomes both originated from their grandfathers, and individuals who had one Z chromosome originating from each grandparent. With these partitioned F2s, the TPI homozygotes exhibited behavioral-response profiles very much like their grandfathers, whereas the TPI hybrids produced response profiles similar to their heterozygous F, fathers. These results demonstrate incontrovertibly that the response to sex pheromone in male ECB is controlled by a sex-linked gene that i s tightly linked to the TPI locus and therefore i s independent of the locus controlling pheromone blend production in females.Acknowledgments: The authors thank M.L. Hessney for rearing the insects used in these studies and J.P. Nyrop (Department of Entomology, NYSAES) and J. Barnard (Laboratory Director of Computer Services, NYSAES) for invaluable advice regarding statistical analysis. We are also indebted to M.R. Nolan and S. Kresovich (Germplasm Resources, National Clonal Repository, NYSAES) and N.F. Weeden (Department of Horticultural Sciences, NYSAES) for advice and encouragement regarding electrophoresis techniques.

Gene Flow Among Three Races of European Corn Borers (Lepidoptera: Pyralidae) in New York State

“…) and sites and also from evidence from flight tunnel data. Studies , Glover et al 1990 of E and Z males tested with the Z pheromone, the E pheromone, and three intermediate ratios (35: 65, 50:50, and 65:35 E to Zl1-14: OAc) in a flight tunnel described by Glover et al (1987), indicate that E borers are much more likely to respond fully to off-blends than are Z borers. Fig.…”

“…Fig. 2, taken from Glover et al (1990), shows that UZ males are highly canalized in their behavioral response. When 30 naive males were flown to each blend, only two insects (one at 50% and one at 65%) responded fully to blends other than the natural Z blend.…”

“…Both male and female adult moths were stored individually at -70°C until they were analyzed via electrophoresis for TPI phenotype. The samples were run on Titan III cellulose acetate plates and stained using the procedures described by Glover et al (1990). In the European corn borer populations examined to date, there are principally two allozymes.…”

“…Homozygous males and hemizygous females exhibit a single band at either the Tpi-l position or the Tpi-2 position (Glover et al 1990). …”

Genetic basis of male sexual behavior

“…Identification of compounds has been based on sensitive bioassays and many chemical structures have been determined (Roelofs, 1995). Receptivity of male moths to particular blends of pheromonal compounds has been traced to one or more sex-linked genetic loci (Roelofs et al, 1987;Glover et al, 1990). In Drosophila, sex pheromone signaling is short-range (less than a few centimeters).…”