Mating frequency and reproductive success in an income breeding moth, Mnesampela privata

Abstract

The frequency of mating in insects is often an important determinant of female reproductive output and male sperm competition. In Lepidoptera that provide male nutrients to the female when mating, it is hypothesized that polyandry may be more prevalent. This is thought to be especially so among species described as income breeders; that is, in species who do not derive all their nutrients for reproductive output entirely from the resources obtained during the larval stage. We selected the geometrid moth, Mnesampela privata (Guenée) (Lepidoptera: Geometridae), to examine this hypothesis further. We found this species was best characterized as an income breeder with female weight on emergence positively correlated with total egg load but not with the number of eggs laid. Further, in accord with income breeders, females emerged with a partially developed egg load and lifetime fecundity was positively correlated with the number of oviposition days. However, in the laboratory we found that incidence of repeated matings or polyandry was rare. When moths were paired singly over their lifetime, only 4% of mated females multiple mated. When females were paired with three males concurrently, female mating success increased from 60 to 81% with multiple mating among mated females increasing to just 15%. Dissection of wild caught M. privata found that polyandry levels were also low with a maximum of 16.4% of females collected at any one time being multiple mated. In accord with theory, mating significantly increased the longevity of females, but not of males, suggesting that females acquire essential resources from male ejaculates. Despite this, multiple mated females showed a trend toward decreasing rather than increasing female reproductive output. Spermatophore size, measured on death of the female, was not correlated with male or female forewing length but was negatively correlated with the number of fertile eggs laid and female longevity. Smaller spermatophore width may be related to uptake of more nutrients by the female from a spermatophore. We discuss our findings in relation to income breeding and its relationship to polyandry in Lepidoptera.

Delayed mating and reproduction in the autumn gum moth Mnesampela privata

“…The percentage of males transferring a spermatophore (mating) for 1‐day mating delays was in the range 27–46% (Table 1) and was lower than the 60% of pairs mating reported by Walker and Allen (2010) for moths paired immediately after emergence (i.e. 0‐day delay matings).…”

“…The number of single‐pair matings set up in each treatment and age category varied according to colony production but was in the range 15–33. The results of the present study are compared with reproduction data for M. privata as reported by Walker and Allen (2010), where 0‐day‐old males were paired with 0‐day‐old females under the same conditions.…”

“…A colony of M. privata was established in the laboratory as described by Walker and Allen (2010). Colonies were maintained under an LD 12 : 12 h photocycle in a walk‐in temperature room at 21 ± 1 °C and 60–70% relative humidity (RH).…”

“…Although several studies have been conducted on the oviposition behaviour of M. privata (Rapley et al , 2004a, b, c; Steinbauer et al , 2004b; Östrand et al , 2008), the effect of delayed mating on reproduction in M. privata is unknown. We recently reported on the reproductive biology and mating behaviour of M. privata paired immediately after emergence (Walker & Allen, 2010). Mnesampela privata was shown to be more aligned with income breeders than capital breeders because ovulation continues after emergence and fecundity was positively correlated with longevity.…”

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.…”