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

Abstract

The tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), is a polyandrous species of economic importance on the American continent. This sexual behavior allows for the presence of multiple spermatophores inside a female and the possibility of different males fertilizing the female's offspring, which can make insecticide resistance management or sterile insect release programs particularly challenging. The presence of spermatophores in a female can greatly influence her behavior, physiology, and offspring production. The role that these reproductive structures have is directly influenced by their size and the amount and type of substances that they contain as they are passed into the female during copulation. In this study, we investigated the role that male feeding has on mating potential, including the basic chemical composition and coloration of three sequentially produced spermatophores by male moths that were fed nothing, water, sucrose solution, or nectar. Male moth feeding had a direct influence on spermatophore weight, which was used as an indicator of polyandrous behavior. Nectar-fed moths produced heavier spermatophores and copulated in greater proportion than moths exposed to the other treatments. The total sugar and protein content of spermatophores was not influenced by the type of male feeding. Red or pink spermatophores were more prevalent in the first-produced spermatophores, diminishing in proportion on the second, and increasing again on the third-produced spermatophore, but this coloration proportion was prevalent of males not fed or fed only water. There were no differences in the chemical composition of the different colored spermatophores. These results indicate that polygynous behavior on H. virescens can be influenced by the type of male feeding.

Condition-dependent ejaculate size and composition in a ladybird beetle

“…Empirical studies involving experimental manipulations of condition generally support this prediction, reporting that highcondition males produce larger ejaculates (Gwynne 1990;Delisle & Bouchard 1995;Watanabe & Hirota 1999;Jia et al 2000;Ferkau & Fisher 2006;Lewis & Wedell 2007;Blanco et al 2009; but see Wedell 1993), transfer more sperm (Fedina & Lewis 2006;McGraw et al 2007;Perez-Staples et al 2008), and produce more ejaculate-derived nuptial gifts (Jia et al 2000; but see Wedell 1993).…”

Experimental evidence for chemical mate guarding in a moth

“…In H. virescens the male appears to invest heavily in his mate: males mate only once per night, and one mating lasts ~3 h during which he transfers a spermatophore that is ~5–10% of his body mass21. Perfuming the female significantly reduces the probability that she will remate (Fig.…”

“…The anti-aphrodisiac pheromone reduced subsequent matings and lessened female fecundity, as twice-mated females oviposited more eggs than once-mated females. Females normally re-mate every night (11 out of 21 in this study) or every other night2124. Therefore, there may be selection pressure on females to accept males with less pheromone or less saturated pheromone components to minimize the chemical mate guarding effects, as unsaturated compounds are more volatile.…”

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

“…Under this concept it is assumed that when Bt-resistant moths emerge, the potential mating of a Bt-resistant female with a Bt-susceptible male will produce Bt-susceptible offspring, therefore preserving Bt-susceptibility in the next generation. An aspect that has not been entirely addressed by this assumption has to do with the fact that tobacco budworm (and other Lepidoptera) mate multiple times (Flint and Kressin 1968, Raulston et al 1975, Blanco et al 2009b). The fact that Ն90% of both sexes of Cry1Ac-resistant tobacco budworm moths emerge within a 3-d period, Ϸ4 d later than the synchronized emergence of a Bt-susceptible colony (C.A.B., unpublished), indicates that there is a greater chance that a Bt-resistant female will encounter a Bt-resistant male than a Btsusceptible male under Þeld conditions.…”