In the four newly described species belonging to the Genus Neotrogla, living in caves in Brazil, the females have a penis. In addition, copulation can last for up to 70 hours.
A non-technical account can be read here:
A more detailed account is provided here.A team of entomologists from Japan and abroad won the 27th Ig Nobel Prize in biology for studying female insect genitalia that they say changes the definition of the word “penis.”
This year’s Ig Nobel prizes, awarded for research that “makes people laugh and think,” were announced at Harvard University on Sept. 14.
The research team includes Kazunori Yoshizawa, associate professor of systematic entomology at Hokkaido University, Yoshitaka Kamimura, associate professor of evolutionary biology at Keio University, and a number of international scholars.
The team found that female cave insects of the Neotrogla genus that were recently discovered in Brazilian caves have a penis-like organ that is inserted into the male bug during copulation.
Meanwhile, the scientific paper describing this find, is this one:
Female Penis, Male Vagina, And Their Correlated Evolution In A Cave Insect by Kazunori Yoshizawa, Kazunori Yoshizawa, Rodrigo L. Ferreira, Yoshitaka Kamimura &Charles Lienhard, Current Biology, 24(9): 1006-1010 (5th May 2014) DOI: 10.1016/j.cub.2014.03.022 [Full paper downloadable from here]
Later on in the paper, the authors reveal the following:Yoshizawa et al, 2014 wrote:Highlights
•Females of the cave insect genus Neotrogla have an elaborate penis-like organ
•The female penis acts as an intromittent organ and anchors the female to the male
•Correlated evolution is detected between the female penis and male genitalia
Sex-specific elaborations are common in animals and have attracted the attention of many biologists, including Darwin . It is accepted that sexual selection promotes the evolution of sex-specific elaborations. Due to the faster replenishment rate of gametes, males generally have higher potential reproductive and optimal mating rates than females. Therefore, sexual selection acts strongly on males , leading to the rapid evolution and diversification of male genitalia . Male genitalia are sometimes used as devices for coercive holding of females as a result of sexual conflict over mating [4, 5]. In contrast, female genitalia are usually simple. Here we report the reversal of intromittent organs in the insect genus Neotrogla (Psocodea: Prionoglarididae) from Brazilian caves. Females have a highly elaborate, penis-like structure, the gynosome, while males lack an intromittent organ. The gynosome has species-specific elaborations, such as numerous spines that fit species-specific pouches in the simple male genital chamber. During prolonged copulation (∼40–70 hr), a large and potentially nutritious ejaculate is transferred from the male via the gynosome. The correlated genital evolution in Neotrogla is probably driven by reversed sexual selection with females competing for seminal gifts. Nothing similar is known among sex-role reversed animals.
Results and Discussion
The genus Neotrogla (Figure 1A) contains four named species (adult body length 2.7–3.7 mm) [6, 7]. Its most striking feature is the presence of a large penis-like structure in the female, termed a gynosome (Figures 1, 2, and 3; Figures S1, S2, and S3 available online). We show here that the gynosome is erectile, basally membranous, and apically sclerotized. Its sclerotized part consists of a proximal rod-like extension and a penis-like distal prominence. The latter encloses a duct leading to the sperm storage organ (spermatheca), and is interpreted as a novel structure differentiated from the opening region of the spermathecal duct (Figure 1, light blue) . In contrast, the male genitalia (phallosome) consist of a simple, thin arc lacking an intromittent organ (Figures 1G and 3E). In related insects, the spermathecal duct has a simple opening and the phallosome is well developed (Figure 1).
We observed coupling in all Neotrogla species and found that the gynosome acts as an intromittent organ to receive voluminous spermatophores from the male. As in most related taxa, including those having well-developed male genitalia (Figure 1C) , the male is positioned under the female during copulation (Figure 1A). The apical sclerotized part of the gynosome, bearing the opening of the spermathecal duct, deeply penetrates the male (Figures 2, 3, S2, and S3), and its tip fits the opening of the seminal duct (Figures 2D and 3C). The membranous part inflates within the male genital chamber, and numerous spines on the membrane internally anchor the female to the male (Figures 2B, 2E, 3A, 3D, and S2). In this position, the male sternum is gripped between the female paraprocts and inflated gynosome (Figures 2B and 2C). Only the connection of the abdominal tips holds pairs fixed in copula together. Furthermore, pulling apart coupled specimens (N. curvata: n = 1) led to separation of the male abdomen from the thorax without breaking the genital coupling, showing that the female can hold the male tightly using the gynosome and paraprocts.
The gynosomal structures are species specific. The distal sclerotized part is strongly curved in N. curvata (Figures 2A–2D), but is straight or only slightly curved in other species (Figures 3 and S2). The membranous region of N. curvata has a smooth dorsal lobe (yellow) and five areas bearing sclerotized spines: a dorsal (red), a pair of lateral (green), and a pair of ventrolateral (purple) spiny areas (Figure 2). In N. aurora and N. brasiliensis, the dorsal and lateral spiny areas are present (Figure S2), but the dorsal lobe and ventrolateral spiny areas are absent. The gynosome of N. truncata lacks all elaborations, but its membranous part is densely covered by tiny bristled spines (Figure 3).
Male genitalia are simple, but also species specific, corresponding to the gynosomal structures (Table S1). In N. curvata, the seminal duct is strongly curved, as is the gynosomal apical sclerite (Figures 2B–2D), whereas these are straight or only slightly curved in the others (Figure 3 and S2). The male genital chamber of N. aurora, N. brasiliensis, and N. curvata has lateral pouches corresponding to the lateral spiny areas of the gynosome (Figures 1G, 2, S1B, and S2, green arrowheads), while ventrolateral spiny areas and corresponding male pouches are only present in N. curvata (Figures 2B, 2E, and S1B, purple arrowheads). During copulation, the spiny areas fit into the corresponding pouches and anchor the female (Figures 2 and S2). The gynosome of N. truncata lacks strong spines (Figure 3A and 3D), and the female of this species anchors itself using the entire surface of the bristled gynosomal membrane (Figure 3A and 3D). The male genital chamber of this species lacks any pouches (Figure 3E, open green arrowheads).
So, females of the insect Genus Neotrogla not only have a penis, but have secondary copulatory structures allowing them to mate coercively with the males - in short, these females are not only equipped with a penis, but with additional equipment allowing them to commit, what is in effect, rape. Furthermore, females will not only mate with multiple males in order to hoover up as much sperm as possible (a significant fraction of which is then consumed as food by the females), but each act of copulation can last up to 70 hours or more.Yoshizawa et al, 2014 wrote:Insects related to Neotrogla suggest the potential of nuptial gifts favoring the evolution and diversification of the gynosome. In Lepinotus patruelis (Trogiidae), the direction of sexual selection is reversed (without reversal of the intromittent organ). Males of this species transmit specialized spermatophores (seminal capsules formed during copulation within the female’s spermatheca), which are produced by the enlarged seminal duct . Males are choosier about mates than females, indicating the costs of spermatophore production, while females compete for the nutritious seminal gift [19, 20]. In Neotrogla, similarly shaped spermatophores (Figures 3F, S3C, and S3D) and an enlarged seminal duct producing voluminous spermatophore material (Figures 2B, S3A, and S3B) are present, suggesting that Neotrogla males also donate a nutritious seminal gift to females. All known Neotrogla species inhabit extremely dry oligotrophic caves and feed on bat guano and bat carcasses, which are relatively scarce resources [6, 7]. Under such circumstances, nutritious seminal gifts cause a strong selection pressure for increased female mating rate . During their life, Neotrogla females may acquire several spermatophores (up to 11 have been observed in N. brasiliensis) (Figures 3F and S3C) ; they are evidently polyandrous. We also observed that females consumed the contents of the spermatophores after their first mating before producing mature eggs (n = 5; Figure S3D), suggesting that the contents of the spermatophores are probably used for nutrition as well as fertilization.
This interpretation may explain the following unique characteristics of the female internal genitalia and of the coupling behavior of Neotrogla. The spermathecal duct of Neotrogla is divided by a spermathecal plate, such that the female can simultaneously maintain two filled spermatophores (Figures 3F and S3C), something unknown in related taxa [19, 22]. The duration of copulation in N. curvata is exceptionally long (52.5 ± 11.2 hr, mean ± SD, range 41–73 hr, n = 12; Table S2) in comparison with related taxa: approximately 40 min in Prionoglaris stygia , approximately 2 hr in Trogium pulsatorium , and a maximum of 4 hr in the genus Lepinotus [8, 19]. In Neotrogla, females have structures that can coercively hold males. The very long copulation, as well as polyandry, is probably controlled by females to obtain more seminal gifts from males.
Sexual conflict over the donation of a nutritious seminal gift is thus the most likely factor favoring the evolution of the gynosome. This organ may have a premating function grasping reluctant mates or a postmating function holding mates to ensure prolonged copulation, although these functions are not mutually exclusive. Because other paternal investments, such as parental care, are not observed in Neotrogla, the correlated evolution of morphologically and functionally novel genital organs has probably been driven by reversed sexual selection on copulatory function. Sex-role-reversed animals are valuable for testing the generality of theories of sexual selection . Because sex-role-reversed females usually cannot coercively hold males, they may be constrained in terms of evolving adaptations that relate to sexual conflict. The female genital anchoring mechanism of Neotrogla, correlating morphologically with specialized reduced male genitalia, is unique, and nothing similar is known among other sex-role-reversed animals. However, in addition to anchoring, the gynosomal spines may have other functions, such as genital stimulation or inflicting harm. The evidence for reversed sexual selection and sexual conflict provided here is mostly circumstantial, but further controlled studies of the mating system of Neotrogla species, together with an exploration of their phylogeny, would provide an extremely rare opportunity to test the generality and relative importance of some hypotheses about sexual selection [1, 2, 3, 4, 5, 9, 10, 11, 12, 13]. Neotrogla also offers a significant opportunity to study evolutionary novelty, an area of central interest in contemporary evolutionary biology [17, 24].
Just when you thought biology couldn't deliver any more weirdness, along comes something like this.