The flexible lek:Phymatopus hectathe gold swift demonstrates the evolution of leking and male swarming via a hotspot (Lepidoptera: Hepialidae)

Abstract

Leking moths present an evolutionary problem in their apparently simultaneous reversal of male-female attraction. The mating system of Phymatopus (or Hepialus) hecta embraces an unusually wide range of procedures. Both males and females use medium-range olfactory attractants (also probably visual signals), and both sexes will lure, and both will approach, the other, either when flying or perched. This produces an 'infinite variety' which includes the classic moth mating procedure (males fly to sessile female); a typical lek procedure (female flies to sessile male); a mating swarm (hovering male follows passing female); and intermediates such as a mutual courtship dance. Male behaviour includes a flying display, two sessile displays, and an escalating war of attrition. The system is versatile, persistent, and probably evolutionarily stable. The lek site has a high density of perches suitable for copulation which facilitate predator-escape by means of a dead drop. The whole supports a model for the evolution of resource-based leks which commence with a concentration of females on a hotspot, leading to a concentration of males; and then an escalating process of sexual selection as males become increasingly attractive over a distance to females, and females use the males as a way of locating the resource. The main stabilizing pressure may be selection for efficient mate acquisition, and as with grouse leking systems, the precondition for evolution was probably having travelling females that actively sought a reproductive resource or a predator free space.

The mating system of the true fruit flyBactrocera tryoniand its sister species,Bactrocera neohumeralis

“…Modern definitions of “lek mating systems” have become very broad (see, for example, Kotrschal & Taborsky, ; Wegge et al ., ; Turner, ). In their seminal review of lek behavior in insects, Shelly and Whittier () admit “ these discrepancies [in lek definitions] render any operational definition imprecise and idiosyncratic .” Nevertheless, there are some requirements we consider necessary if the “spirit” (sensu Shelly & Whittier, ) of lek behavior is to be satisfied.…”

“…Modern definitions of "lek mating systems" have become very broad (see, for example, Kotrschal & Taborsky, 2010;Wegge et al, 2013;Turner, 2015). In their seminal review of lek behavior in insects, Shelly and Whittier (1997) admit "these discrepancies [in lek definitions] render any operational definition imprecise and idiosyncratic."…”

A molecular phylogeny for the oldest (nonditrysian) lineages of extant Lepidoptera, with implications for classification, comparative morphology and life‐history evolution

“…Males in many species initially attract females visually, sometimes lekking at dusk low over the vegetation in flocks ranging from a few individuals to several hundreds or even thousands of males (Mallet, ; Grehan, ; Davis et al , ; Kaaber et al , ; Turner, ). As recently reported by Turner () in a study of lekking behaviour in the European Gold Swift, Phymatopus hecta (Linnaeus), this behaviour can be highly plastic even within a single species depending on the conditions. Once females have approached a lek, males may employ short‐range pheromones to further attract them.…”

Large male bias in collection of Micropterix facetella Zeller, 1851 (Lepidoptera, Micropterigidae)

“…These males preferred to visit flowers that were already occupied by other M. maschukella males, resulting in an observably biased sex ratio not dissimilar to the one encountered at the Croatian oaks. This sort of mating strategy, analogous to lekking, is rare in Lepidoptera, though it has been observed in some species from the families Nymphalidae (Srygley and Penz 1999), Pyralidae (Alem et al 2011) and Hepialidae (Turner 2015). Similar male aggregations have been observed in other attempts to collect micropterigids (Zeller and Huemer 2015;D.…”