Paternity Allocation in a Mutant Heliothis virescens¹Colony

Abstract

Abstract. Tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), females can copulate multiple times creating the possibility for sperm competition. We used a colony lacking wild pigmentation on the wings (albino-type) for an experiment in which females double mated. Females copulated 2 days apart with two, 2-day-old males, one albino-type and one wild-type, or in the opposite sequence. A third of the females produced offspring from the first mate, and this group was significantly biased toward producing albino-type compared to wild-type progeny. A fourth of the females produced offspring from the second male exclusively and within this group was a significant bias toward wild-type compared to albino-type progeny. Almost half of the females produced offspring sired in equal proportions by both males simultaneously or in alternated paternities throughout all the reproductive life. These results suggest that regardless of the order in which moths mated, wild-type sperm had potential superior competitiveness. Therefore, sperm precedence is not the main driving force behind the paternity allocation mechanism in this strain of tobacco budworm. Resumen.Las hembras del gusano tabacalero, Heliothis virescens (F.) (Lepidoptera: Noctuidae), tienen la capacidad de copular varias veces creando la posibilidad de que haya competencia entre el esperma dentro de ellas. Utilizamos una colonia de este insecto la cual no expresa la pigmentación normal en las alas de las palomillas normales (tipo albino) en un experimento en el cual las hembras tuvieron dos cópulas con dos días de separación, con dos machos de dos días de edad, uno de ellos del tipo albino y el otro del tipo normal así como otros tratamientos en los que la secuencia de machos fue contraria. Una tercera parte de las hembras produjeron progenie del primer macho y dentro de este grupo, hubo una tendencia significativa en producir más progenie del tipo albino que del tipo normal. Una cuarta parte de las hembras produjeron exclusivamente progenie del segundo macho, y dentro de este grupo hubo una tendencia significativa al producir más progenie del tipo normal que del tipo albino. Cerca de la mitad de las hembras produjeron progenie en proporciones similares de los machos normales y albinos simultáneamente, así como en patrones en los que alternaban la paternidad de la 253progenie a lo largo de sus vidas reproductivas. Estos resultados sugieren que sin importar la secuencia en que las palomillas fueron apareadas, el esperma de los machos normales mostró un potencial competitivo mayor y que la precedencia de esperma no es el mecanismo más importante en el momento de distribuir la paternidad en esta colonia de H. virescens.

Offspring From Sequential Matings Between <I>Bacillus thuringiensis</I>-Resistant and <I>Bacillus thuringiensis</I>-Susceptible <I>Heliothis virescens</I> Moths (Lepidoptera: Noctuidae)

“…1 and 2). These Þndings add more information to what has been reported previously (LaMunyon 2001, Blanco et al 2008a, that the tobacco budworm does not exhibit sperm precedence in the strict sense of the concept; that is, one of the maleÕs sperm displaces the other almost entirely.…”

“…Among the main obstacles that prevented the successful implementation of this technique on a large scale was the fact that females that copulated with sterile males produced fertile offspring when they had also mated with wild fertile males (Flint andKressin 1968, Pair et al 1977), ruling out the possibility of complete sperm precedence (Flint and Kressin 1968, Pair et al 1977, LaMunyon 2001, Simmons 2005, Blanco et al 2008a. The interaction of different malesÕ sperm in H. virescens indicates that it would be expected that a Bt-resistant female that copulates with a Bt-susceptible as well as with a Bt-resistant male, can produce offspring carrying Bt-resistant and Bt-susceptible alleles.…”

Size and Chemical Composition of Heliothis virescens (Lepidoptera: Noctuidae) Spermatophores

“…Counts of spermatophores inside Þeld-collected H. virescens females indicate that these insects copulate an average of 1.6 (Hendricks et al 1970) to 2.7 (Raulston et al 1975) times, but the use of sperm and/or the mechanism of sperm competition among these two to three males is not thoroughly understood in this species (Pair et al 1977, LaMunyon 2001, Blanco et al 2008. Spermatophore counts in tobacco budworm females (Յ2.7, Raulston et al 1975) are directly inßuenced by the type of substance that the male had access to (Fig.…”

A Life-History Perspective On Sexual Selection in a Polygamous Species

“…Both males and females can mate only once a night [39,43], as each mating lasts on average 3 hours [43] and adults are sexually active only for 3-5 h during the night [44,45]. However, both sexes mate multiple nights [37][38][39][40][41]; this study. The average adult life time is 20 days in the laboratory at 25 °C [46], during which females oviposit ~ 500 -1500 eggs [47]; this study).…”

“…Of this species, much information on its sexual behaviors has been gathered over the past 40 years, because this species is a major pest in North and South America. Specifically, H. virescens males and females are highly promiscuous [37][38][39][40][41]. Field-caught females have been found to contain 7 spermatophores [39] and females mate up to 12 times under laboratory conditions [42].…”