Nuptial feeding and genital coupling of Neopanorpa scorpionflies (Insecta: Mecoptera: Panorpidae) with notal organs of various lengths

Neopanorpa, the second largest genus in Panorpidae, is mainly characterized by the well-developed notal organ on male tergum III. However, it remains largely unknown how the length of the notal organ influences the nuptial feeding behaviour of Neopanorpa. Here, we investigated the nuptial feeding by comparing the morphology of mating-related structures and the genital coupling of a) Neopanorpa lui Chou & Ran, 1981 with a weakly-developed notal organ, b) N. carpenteri Cheng, 1957 with a medium-sized notal organ, and c) N. longiprocessa Hua & Chou, 1997 with an extremely elongated notal organ. The couples of N. lui and N. carpenteri maintain an intermittent mouth-to-mouth mode but do not exchange any edible food. After that the males secrete a salivary mass onto the surface as a nuptial gift, which is distinctly larger in N. carpenteri than in N. lui. Correspondingly, the male salivary glands are more developed in N. carpenteri than in N. lui. Males of N. longiprocessa bear very short salivary glands corresponding to a coercive mating tactic. The genital couplings are similar among the three species of Neopanorpa. The paired hypovalves of males are used to control the cerci of females. The prominent basal processes of male gonostyli grasp the posterior portion of the female medigynium across the intersegmental membrane. The male aedeagus physically couples with the female medigynium to ensure the male phallotreme to connect to the female copulatory pore. The influence of the notal organ length on the nuptial feeding behaviour of Neopanorpa is briefly discussed.

Who uses Tinder?: The Dark Triad traits, attachment, and mate value

Modern dating life has been changed with the advent of smartphone-based applications like Tinder. One way to identify who uses these applications is to compare the personality traits of users to non-users. In two brief studies (N = 581) we compared Tinder-users to non-users in individual differences associated with short-term mating (i.e., psychopathy, Machiavellianism, narcissism [the Dark Triad traits], and anxious attachment) and mate value. We revealed that the men who were Tinder users were especially high in psychopathy and narcissism and women who were Tinder users were especially high in anxious attachment and rated themselves as unsuccessful in finding relationship partners. While exploratory in nature, we suggest that men who are characterized by antisocial traits may use Tinder for opportunistic mating goals whereas women who have struggled to find relationships may use Tinder as a compensatory mating tactic.

Copulation with immature females increases male fitness in cannibalistic widow spiders

Copulatory cannibalism of male ‘widow’ spiders (genus Latrodectus ) is a model example of the extreme effects of sexual selection, particularly in L. hasselti and L. geometricus where males typically facilitate cannibalism by females and mate only once. We show that these males can increase their reproductive success by copulating with final-instar, immature females after piercing the female's exoskeleton to access her newly developed sperm storage organs. Females retain sperm through their final moult and have similar fecundity to adult-mated females. This is an adaptive male tactic because immature mating increases insemination success relative to adult mating (which predicts higher paternity) and moreover, rarely ends in cannibalism, so males can mate again. Although successful only during a brief period before the female's final moult, males may employ this tactic when they associate with final-instar females in nature. Consistent with this, one-third of L. hasselti females collected as immatures in nature were already mated. Immature mating alters sexual selection on these otherwise monogynous males, and may explain male traits allowing facultative polygyny in Latrodectus . Since male cohabitation with immature females is common among invertebrates, immature mating may be a widespread, previously unrecognized mating tactic, particularly when unmated females are of high reproductive value.