Nuptial Gifts, Resource Budgets, and Reproductive Output in a Polyandrous Butterfly

Abstract

Many female insects receive material during mating, referred to as “nuptial gifts,” that may increase the female’s resource budget. This investigation examines how nuptial gifts influence female nitrogen and carbon budgets in a polyandrous butterfly, Pieris napi. During mating, a virgin male of this species transfers a large and nutritious ejaculate containing 14% nitrogen by dry mass. The amount of nitrogen transferred is equivalent to that in ∼70 eggs. Females use the male‐transferred nutrients to increase their pool of nutrients used for egg production and show a positive relationship between amount of ejaculate material received and lifetime reproductive output. It is clear that for multiply mated females, nitrogen derived from male nuptial gifts is essential for a balanced nitrogen budget. As in earlier studies, female thorax mass decreased with age, indicating that old females of P. napi are able to use more of the resources from their thorax than young females. Since male‐transferred material also increases female longevity, multiply mated females also use more of their resources from the thorax. Consequently, multiply mated females have a relatively higher reproductive investment than singly mated females, i.e., they transform a larger part of their body reserves to egg production. These results are important for studies that involve male‐transferred nutrients in female life history patterns as well as for investigations of links between nuptial gifts and sexual selection theory. When the value of nuptial gifts is determined only on the nutritional value of the gift itself rather than the function within the female, there is an obvious risk for incorrect conclusions.

Effects of no mating on the female adults and embryonic development of Schistocerca gregaria (Orthoptera: Acrididae)

“…This phenomenon was also reported in many species, for example, Gryllus veletis [14], Pieris napi [15]. One of reasons to increase mating female life span is the large number of accessory substances transferred to females with the male ejaculate [14,15]. While the solitary virgin desert locusts could not get any accessory substances from males, this may be cause them had a relatively shorter longevity.…”

Paternal investment directly affects female reproductive effort in an insect

“…This is not simply a function of females converting male nutrients into eggs. The difference in the amount of resources present in a spermatophore between a virgin and a mated male is equivalent to the production of approximately 21 eggs (Karlsson 1998), whereas the smallest difference in the number of eggs laid by females mated to virgin and mated males is almost 100 eggs. This implies that females are increasing their egg laying after receiving larger donations.…”

“…This is because nectar contains mainly carbohydrates and only traces of the amino acids needed for the production of additional eggs (Karlsson & Wickman 1990;Boggs 1997). However, these energy reserves provide carbon skeletons for egg production in some species (Boggs & Ross 1993), and can prolong adult life, enabling sufficient time for the conversion of larval-derived nutrients to reproduction (Boggs 1997;Karlsson 1998). In addition, in species in which males provide nutrients females can obtain more resources by essentially foraging for matings.…”

The Cost of Mating: Influences of Life History Traits and Mating Strategies on Lifespan in Two Closely RelatedYponomeutaSpecies

“…In Lepidoptera mating can have both positive and negative effects on male and female lifespan (e.g., [9,19,[29][30][31][32][33][34]43]). One of our objectives was therefore to investigate if, and how, mating influenced lifespan in Y. padellus and Y. cagnagellus.…”

“…First, in Lepidoptera, positive [19,[29][30][31][32][33], negative [9,34], or no effects [35,36] of mating on lifespan have been observed in either sex or in both sexes. Therefore, the effect of mating itself needs to be considered when investigating sex-specific longevity and relating it to male investment in lifespan.…”