Differences in mating strategies in two closely related small ermine moth species (Lepidoptera: Yponomeutidae)

Abstract

Abstract. The degree of polyandry in a species is linked to other life history traits such as egg maturation, life span, and male ejaculate size and quality. The study of differences in mating strategies between closely related species can provide a better understanding of the evolution of these strategies and of sperm competition. Mating patterns of two closely related species of small ermine moths (Yponomeuta) were investigated in the laboratory. The average female age at first mating was higher in Y. cagnagellus than in Y. padellus. Both species mated more than once; however, Y. cagnagellus females were more likely to remate in a short time frame. Moreover, Y. cagnagellus had higher life time female mating frequencies than Y. padellus (viz., 3.0 versus 2.0). These differences in mating frequency were confirmed in the field by examining the presence of spermatophores (or their remains) in the bursa as well as sperm in the spermatheca of field-caught females.

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

“…The hypothesis of Wiklund et al [25] implies that males of polyandrous species continue to live International Journal of Zoology after the peak of female receptivity (at least under the condition that females receptivity is synchronous, as is the case in Yponomeuta) and thus live past the moment that most females have mated once. Indeed, our results showed that in both species males live long after the peak of female receptivity: males of both species live on average more than 45 days after eclosion, but Y. cagnagellus females are receptive at 14.6 ± 1.2 (mean ± SE) days and Y. padellus females at 4.9 ± 0.6 days after eclosion [39]. We extended Wiklund's hypothesis to sex-specific lifespan differences between high and low polyandrous species and expected a larger investment in lifespan in Y. cagnagellus males; that is, we predicted a significant sex by species interaction on lifespan.…”

“…In the laboratory, they can mate up to 9 times. The average mating frequency of Y. padellus females is 2.0 ± 0.2, and a majority of females is mating only once [39]. We can therefore conclude that Y. cagnagellus females are highly polyandrous and Y. padellus females have a low degree of polyandry.…”

“…The two species are closely related [40,41] and therefore very much alike in many of their life history traits and behaviour. They do however differ in lifespan, and although both are able to mate more than once, they display significant differences in female mating frequencies [39]. The average mating frequency of Y. cagnagellus females are 3.0 ± 0.3 times (mean ± standard error).…”

“…Yponomeuta padellus females show synchronized sexual maturity (as indicated by female 'calling' behaviour) and have similar age at first mating in the laboratory [38,39]. Yponomeuta cagnagellus females also show synchronized sexual maturity [38] but the age of females mating for the first time can vary widely, and this may indicate that Y. cagnagellus females are choosy [39]. The two species are closely related [40,41] and therefore very much alike in many of their life history traits and behaviour.…”

Experimental evidence for male biased flight‐to‐light behavior in two moth species

“…Females start calling for males only at the age of about 10 days (Hendrikse, 1979). The average age at first mating is 14.6 days, and females may mate with several males (Bakker et al., 2008). Individuals rarely disperse further than 100 m from their place of eclosion (Menken et al., 1992) and gene flow between populations is low (Menken et al., 1980).…”