The relationship between male moth density and female mating success in invading populations of Lymantria dispar

Abstract

The successful establishment of non-native species in new areas can be affected by many factors including the initial size of the founder population. Populations comprised of fewer individuals tend to be subject to stochastic forces and Allee effects (positive-density dependence), which can challenge the ability of small founder populations to establish in a new area. Although the conceptual relationship between initial colony size and establishment success has been previously documented, it is not trivial to estimate precisely the colony size needed to ensure colony persistence. Over the last 40 years, there have been many studies on the probability of mating success of female Lymantria dispar (L.) (Lepidoptera: Lymantriidae) in the USA related to background male moth densities. We were motivated by this wealth of data and sought to combine the results from these prior studies with the goal of estimating a robust measure of the male moth density required to achieve varying levels of female mating success. Although the data are specific to L. dispar, the pheromone communication system in L. dispar is not unique and thus the results of this analysis could be broadly applicable to our general understanding of Lepidoptera mating behavior.

Female Fertilization: Effects of Sex-Specific Density and Sex Ratio Determined Experimentally for Colorado Potato Beetles and Drosophila Fruit Flies

“…In case of Leptinotarsa decemlineata , high transient densities can furthermore be expected when summer generation beetles emerge en masse on chemically untreated potato fields (max: ≈500 adult beetles per plant [Vahl and Boiteau, personal observation]). In addition, studies with atypical conditions may help to understand why some sex ratios and densities rarely occur and to identify conditions under which fertilization of all females should not be expected – a situation that is perhaps surprisingly common in natural populations of insects [49]–[4951].…”

The Effect of Male and Female Age on <I>Lymantria dispar</I> (Lepidoptera: Lymantriidae) Fecundity

“…In L. dispar, female mating success has been consistently shown to be strongly inßuenced by the background male moth density, such that at low male densities, females are rarely mated while at higher densities, nearly all females are mated (Sharov et al 1995;Tcheslavskaia et al 2002;Contarini et al 2009;Tobin et al 2009Tobin et al , 2013. Consequently, it is not surprising that L. dispar population success has been shown to be linked to population size Bascompte 2003, Whitmire and.…”

A review of mate‐finding Allee effects in insects: from individual behavior to population management

“…Four studies focused solely on the relationship between density and mating success in this species (Sharov et al, 1995;Tcheslavskaia et al, 2002;Contarini et al, 2009;Tobin et al, 2013). The preponderance of studies on Lepidoptera can be accounted for in part by the extensive research carried out on gypsy moth.…”

“…The detection of a mate-finding Allee effect requires independent estimates of male density and of the proportion of females mating (equation 1). An intriguing observation from studies on L. dispar and other species is that male density is often assessed by determining the rate of male capture on traps baited with synthetic sexual pheromone (Sharov et al, 1995;Tcheslavskaia et al, 2002;Contarini et al, 2009;Régnières et al, 2013;Tobin et al, 2013). However, many alternative methods are listed in Appendix 1.…”