MATING FREQUENCY OF THE FEMALE EUROPEAN CORN BORER, OSTRINIA NUBILALIS (LEPIDOPTERA: PYRALIDAE), IN SOUTHWESTERN ONTARIO

1977 ◽  
Vol 109 (1) ◽  
pp. 117-122 ◽  
Author(s):  
W. M. Elliott

AbstractEuropean corn borer moths were caught in an ultraviolet light trap from early June to late October at Harrow, Ont. Two conspicuous peaks of light trap catches occurred each year, corresponding to two generations, but a third generation was deduced from three peaks of occurrence of virgin females. The number of moths which could be caught with nets in the day time correlated with the light trap catch of the previous night (r = 0.7). Most of the moths caught in the light trap or in nets were females but males predominated in the early June, September, and October catches. The shortage of males in the second generation was shown to influence the proportion of females mating, but not the number of spermatophores per female. Most females mated once and the number of matings per female did not differ enough between years to account for differences in adult populations.

1978 ◽  
Vol 110 (5) ◽  
pp. 487-493 ◽  
Author(s):  
W.M. Elliott ◽  
R.J. McClanahan ◽  
J. Founk

AbstractThe formation of a yellow band inside the stalk of each ovariole was a good indicator that a female European corn borer had laid eggs. The absence of these bands was less reliable as an indicator that no eggs had been laid, probably due to the time taken for the bands to form. The numbers of moths accumulating in a light trap over a week at Harrow, Ontario, and the numbers of females estimated to have laid eggs correlated significantly with the numbers of larvae developing in nearby green pepper plots 3, 4, and 5 weeks later during second generation flights. This enabled linear equations for forecasting pepper damage to be developed, in which the dissection data was more useful than the total moth catch alone.


1987 ◽  
Vol 119 (3) ◽  
pp. 291-299 ◽  
Author(s):  
D.L. Struble ◽  
J.R. Byers ◽  
D.G.R. McLeod ◽  
G.L. Ayre

AbstractThe sex pheromone components of European corn borer, Ostrinia nubilalis (Hbn.), from southern Alberta were identified in washes and extracts of abdomen tips from calling female moths. This is a Z strain population as (Z)-11- and (E)-11-tetradecenyl acetates were isolated in a ratio 100:2.4, and a corresponding synthetic blend in a ratio of 100:3 attracted males in the field. Dodecyl alcohol, tetradecyl alcohol and acetate, and (Z)-11-tetradecenol were also identified, but none of these components nor other "pheromone-like" mono-unsaturated C10 to C16 acetates had any effect on increasing the trap catches of male moths under field conditions. However, the addition of (Z)-9-dodecenyl acetate or (Z)-9-tetradecenyl acetate to the synthetic pheromone blend significantly reduced the capture of male moths, even though these compounds were not detectable in the female extracts. Pheromone blends used for monitoring the Z strain of the European corn borer must be essentially free, ca.< 0.1%, of these acetates. A commercially available, sticky-surface, delta-type trap was the most satisfactory of several tested for capturing moths under prairie conditions.


1959 ◽  
Vol 91 (12) ◽  
pp. 798-806 ◽  
Author(s):  
J. A. Mutchmor

In southwestern Ontario the European corn borer, Ostrinia nubilalis (Hbn.), produces two flights annually. The first flight, beginning in June, consists of moths from larvae that have overwintered. The midsummer, or second, flight begins late in July or early in August, and its moths are the progeny of the first flight. Until about 20 years ago the borer produced only one annual flight and was thought to be univoltine. The change in the seasonal history of the borer in Ontario was described by Wressell (1953) and Miller (1956). The literature describing similar changes in parts of the United States has been reviewed by Lees (1955) and Everett et al. (1958). Wressell (1953) summarized light trap collection data of moth flights in the Chatham, Ontario, area for the years 1932 to 1951. The summary includes the percentage of the moths that were from the midsummer flight, and it is evident that the size of this flight varies greatly from year to year. Aside from its intrinsic interest, it would be of some economic value to know what governs the size of the midsummer flight. This is a report of studies undertaken to examine the case, and to relate the findings to the larger problem of why the borer now produces a second flight where formerly it produced only one.


1982 ◽  
Vol 114 (9) ◽  
pp. 769-774
Author(s):  
W. M. Elliott ◽  
J. D. Richardson ◽  
J. Founk

AbstractThe mean post-mating age of mated female moths of the European corn borer, Ostrinia nubilalis (Hübner), from light traps varied from 3.4 to 5.2 days during the June–September flight period at Harrow, Ontario, in a manner consistent with assignment of moths to 3 generations per year. At the beginning of the first generation the mean age was 3.66 days and rose to 5.21 before flights ceased. At the beginning of the second generation the mean age was 3.39 days and rose to 4.47 days. A third generation could be detected in early September by a significant drop in age and an increase in virgin females. The average age of mated females was negatively correlated with the proportion of virgin females in the same week (r = −0.648, P = 0.02), indicating that about 40% of the variance in age of mated females was associated with emergence of new recruits to the population. Females collected with a sweep net from their day time resting places in weeds were either the same age or older than those from the light trap. The mean age of moths from light traps was found to be not meaningful when it was tested as a factor in forecasting damage caused by their progeny in green peppers 3–5 weeks later.


1979 ◽  
Vol 111 (3) ◽  
pp. 233-236 ◽  
Author(s):  
D. G. R. McLeod ◽  
C. Ritchot ◽  
T. Nagai

AbstractThere are now two strains of the European corn borer, Ostrinia nubilalis (Hübner), in Quebec. The strain normally found produces one generation while the more recently introduced strain produces two generations per year. Both strains have been characterized and compared with corn borer strains from Ontario and New York State. The two attributes of the recently introduced strain that promote the development of a second generation are (1) early emergence in the spring with less intense diapause and (2) a lower critical photoperiod for diapause induction. The latter characteristic allows pupation of first generation larvae. Field and laboratory tests on the pheromone response of adult male moths demonstrated that the origin of this recent introduction was New York State.


1979 ◽  
Vol 111 (12) ◽  
pp. 1325-1335 ◽  
Author(s):  
W. M. Elliott ◽  
V. A. Dirks

AbstractThe spermatophores in mated female European corn borers, Ostrinia nubilalis (Hübner), were shown to lose volume (depletion), change colour, and retract their spiral stalks over a period of about 7 days in such a way that postmating age could be estimated from their appearance. Colour changes and stalk retraction occurred more slowly in females that laid fertile eggs than in those that did not, but depletion occurred at the same rate. The average postmating age was estimated as 5.2, 6.3, 3.9, and 2.6 days for small light trap catches of first generation females in 1974, 1975, 1976, and 1977 and 4.4, 3.9, and 3.2 days for larger catches of second generation females in 1974, 1975, and 1977. Catches did not show decreasing numbers in successive age groups but tended to show modal values at < 1 day and at 4–6 days with only 1% living > 7 days. Redistribution of the moths from the date of capture back to the date of mating tended to give a unimodal curve of numbers on time in the 1975 second generation but not in 1974 or 1977. The unimodal curve of redistributed moths in 1975 was significantly different from a normal distribution. The redistribution showed that 58% of the moths mated within the heat unit interval when the second generation was expected to emerge, whereas only 38% of the actual catches occurred in this interval. Redistribution also showed that mating probably occurred even on cold nights when few moths were trapped, and conversely that on some warm nights with large catches most of the moths had mated on earlier nights.


1978 ◽  
Vol 110 (1) ◽  
pp. 51-55 ◽  
Author(s):  
D. G. R. McLeod ◽  
A. N. Starratt

AbstractA study was made of the reason for the fairly rapid loss of attractancy of pheromone traps for the European corn borer, Ostrinia nubilalis (Hübner). This loss in attractancy appeared to be attributable mainly to formation of an inhibitory or repellent substance(s). Although traps with a suspended pheromone dispenser were significantly more attractive than traps with the dispenser placed in contact with the adhesive, they still became relatively unattractive to male corn borers within approximately 1 week.


1999 ◽  
Vol 89 (5) ◽  
pp. 449-454 ◽  
Author(s):  
F. Huang ◽  
R.A. Higgins ◽  
L.L. Buschman

AbstractRealized heritability, h2, of resistance in European corn borer, Ostrinia nubilalis (Hübner), to Bacillus thuringiensisBerliner ssp. kurstaki endotoxins was examined in five resistant laboratory colonies. These colonies were reared on a meridic diet that incorporated a commercial formulation of B. thuringiensis, Dipel ES. Resistance in these colonies reached 42–67× by the seventh to twentieth selected generations and then plateaued. The realized heritability of resistance averaged 0.17–0.31 over all selected generations for the five colonies. In the three Iowa colonies, the highest realized heritability, 0.18–0.33, occurred during the second period of selection (seventh to thirteenth selected generations). In the two Kansas colonies, the highest realized heritability, 0.36 and 0.46, occurred during the first period of selection (first to sixth selected generations). In the absence of selection pressure, resistance in the southwest Kansas colony decreased from 62× to 42× after two generations, and remained at about that level for the next five generations.


1992 ◽  
Vol 124 (1) ◽  
pp. 113-116 ◽  
Author(s):  
Lucie Royer ◽  
Jeremy N. McNeil

AbstractEuropean corn borer males have hair pencils located ventrally on the 8th sternite and these are extruded when a male approaches a calling female. The fact that (i) antennectomized females mated significantly less than both intact controls and individuals subjected to other forms of surgery, and (ii) males with hair pencils removed had a significantly lower mating success than control males, suggests that a male pheromone is involved in the mating system of the European corn borer.


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