The lock-and-key mechanisms of the internal genitalia of the Noctuidae (Lepidoptera): How are they selected for?

Evolution of genitalia: theories, evidence, and new directions

“…There also other serious problems, including an almost complete lack of the predicted pattern of character displacement in males in zones of sympatry of closely related species (McAlpine 1988;Ware and Opell 1989), and clear evidence of genital species-specificity in species (such as those of species endemic to caves and oceanic islands, and of parasites isolated from all close relatives in their different hosts) that have probably evolved in complete or nearly complete physical isolation from all close relatives, and should thus not have evolved species-specific genitalia (Eberhard 1985(Eberhard , 1996Hedin 1997;Shapiro and Porter 1989). While lock and key is very probably not a general explanation for genital evolution, and the evidence that has been adduced in its favor in particular studies (Mikkola 2008) has other possible interpretations (Eberhard 2009), the possibility that it applies in any particular cases cannot be discarded without careful study.…”

On the function of cornuti, sclerotized structures of the endophallus of Lepidoptera

“…First, dissect, photograph and measure the inflated endophalli and the genital tract of females, followed by careful comparison of the superimposed preparations or images of the male and female structures (e.g. Mikkola 1992Mikkola , 1993Mikkola , 2008. This type of preliminary assessment is possible for some taxa because there are published studies that provide excellent drawings and photographs of inflated endophalli and of the corpus bursae of females.…”

Sexual Selection Within the Female Genitalia in Lepidoptera

“…In a recent review, Simmons (2014) concludes that although sexual selection is nowadays considered the main driver of genital evolution, the relative importance of the different types of sexual selection (Hosken and Stockley 2004;Eberhard 2010;Simmons 2014) and the possible role of the "lock-and-key" hypothesis (Eberhard 1985;Mikkola 2008) are still open questions whose solutions will require cost-benefit studies of mating interactions in a variety of conditions and species, as well as estimates of the tempo and mode of genital evolution in different taxa. These studies need a detailed understanding of the functional morphology of female genital traits, as well as of the patterns of variation and covariation with male genitalia.…”

“…As explained in the following section, although there are hundreds of detailed descriptions of the genitalia of female Lepidoptera, knowledge about the functions of its different structures is rather poor. Such knowledge is fundamental, not only to explain the copulatory mechanisms (which also appears to be rather variable ;Bayard 1944;Callahan 1958Callahan , 1960Ferro and Akre 1975;Naumann 1987;Miller 1988;Fänger and Naumann 1998;Justus and Mitchell 1999;Sihvonen 2007;Mikkola 2008), but to understand the selective pressures responsible for the evolutionary origin and diversification of female genital structures and of the male genital traits interacting (and possibly coevolving) with them. : an anal cone; co coecum penis; cr cornuti; cu cucullus; di diaphragma; du ductus ejaculatorius; gn gnathos; ju juxta; ph phallus; sa sacculus; sc scaphium; so socii; su subscaphyum; te tegumen; tr transtilla; un uncus; va valva; ve vesica; vi vinculum.…”

“…Intermediate possibilities are endless. Mechanical interactions of phallus-bursa copulatrix in noctuids inspired the "lock-and-key" hypothesis (Callaghan and Chapin 1960), and this interaction has been well documented (Mikkola 1992(Mikkola , 2008Mutanen et al 2006). Technical difficulties for vesica eversion in small moths have been a limiting factor to extend these studies to other groups of Lepidoptera, but technical progress in dissection promises some improvement in this area (Dang 1993;Matthews 1998;Zlatkov 2011).…”