Female preferences for discrete and continuous male colour expression may help reinforce colour polymorphism in a desert lizard

Despite recognition that colour can vary continuously, colour expression in colour polymorphic species is usually treated as discrete. We conducted three experiments to evaluate the extent that discrete and continuous male coloration influenced female mating preferences in long-tailed brush lizards (Urosaurus graciosus). Each experiment provided females with a different social context: a dimorphic choice between a yellow and an orange male (coloration treated as discrete), and a choice between either two orange males or two yellow males (coloration treated as continuous variation). Females preferred orange males over yellow males in the first experiment, and the findings of our second experiment suggested that males with moderate orange coloration were most preferred. In contrast, females behaved randomly with respect to two yellow males. Our findings show that females in colour polymorphic species can evaluate both discrete and continuous aspects of morph coloration during mate assessment, which may help maintain their polymorphism.

Love is Not Colorblind: An Investigation of the Racial Hierarchy of Mate Preferences

Not my type is the usual invocation when rejecting potential lovers who don’t align with the racial hierarchy of mating preferences. The largely unchallenged norm of interracial intimacy aversion, particularly how the desire for some racial groups and rejection of others reinforces existing racial inequities, is inconsistent with the blanket notion of greater interracial acceptance. We contend that this acceptance is unequally divided along the same racial hierarchy that exists in the broader public sphere. Our investigation assessed the openness of monoracial and biracial individuals to form interracial romantic relationships. In addition, we partially replicated an interracial mate preference known as the Multiracial Dividend Effect: a pattern whereby monoracial individuals prefer to date multiracial individuals as these interracial relationships may be less likely to carry the perceived disadvantages of interracially dating someone from another monoracial group. Most monoracial groups equally preferred same-race lovers and interracially dating biracials, and they preferred interracially dating someone biracial over any monoracial group. Lastly, biracials were more open to interracially dating any monoracial group than monoracials were to interracially dating each other.

Does Asymmetrical Gonopodium Morphology Predict Lateralized Behavior in the Fish Xenophallus umbratilis?

Why bilaterally symmetrical organisms express handedness remains an important question in evolutionary biology. In some species, anatomical asymmetries have evolved that accompany behavioral handedness, yet we know remarkably little about causal links between asymmetric morphological traits and behavior. Here, we explore if a dextral or sinistral orientation of the male intromittent organ predicts side preferences in male behaviors. Our study addresses this question in the Costa Rican livebearing fish, Xenophallus umbratilis. This fish has a bilaterally symmetrical body plan, with one exception—the male anal fin (gonopodium), used to inseminate females, terminates with a distinct left- or right-handed corkscrew morphology. We used a detour assay to test males for side biases in approach behavior when exposed to four different stimuli (predator, potential mate, novel object, empty tank control). We found that left morph males preferred using their right eye to view potential mates, predators, and the control, and that right morph males preferred to use their left eye to view potential mates and predators, and their right eye to view the control. Males of both morphs displayed no eye bias when approaching the novel object. Our results suggest that there is a strong link between behavior and gonopodium orientation, with right and left morph males responding with opposite directional behaviors when presented with the same stimuli. This presents the intriguing possibility that mating preferences—in this case constrained by gonopodial morphology—could be driving lateralized decision making in a variety of non-mating behaviors.

Предпочтения в выборе брачного партнера у мужчин и женщин в индийской диаспоре Танзании

The article presents the results of a study conducted among the Indian diaspora in Tanzania. The data obtained confirm the existence of universal gender differences in the mating preferences and are consistent with the predictions of the theory of sexual strategies. Indian men tend to pay more attention to a woman's reproductive abilities, thus evaluating physical indicators of fertility, health and age, as well as the potential to be a caring mother. Women appreciate those male qualities that reflect his ability to provide for a family (and therefore joint children), such as intelligence, good education, social status, diligence, financial security, etc. At the same time, cultural components typical for Indian society influence the mating preferences. Caste and the role of parents’ opinion regarding the future marriage partner remain important criteria. Instead of a one-way movement towards Western marriage practices, as suggested by family change theories and as can be seen in other Asian contexts (such as China), trends in Indian society point to a combination of traditional Indian and Western practices.

Post-copulatory genetic matchmaking: HLA-dependent effects of cervical mucus on human sperm function

Several studies have demonstrated that women show pre-copulatory mating preferences for human leucocyte antigen (HLA)-dissimilar men. A fascinating, yet unexplored, possibility is that the ultimate mating bias towards HLA-dissimilar partners could occur after copulation, at the gamete level. Here, we explored this possibility by investigating whether the selection towards HLA-dissimilar partners occurs in the cervical mucus. After combining sperm and cervical mucus from multiple males and females (full factorial design), we found that sperm performance (swimming velocity, hyperactivation, and viability) was strongly influenced by the male–female combination. This indicates that sperm fertilization capability may be dependent on the compatibility between cervical mucus (female) and sperm (male). We also found that sperm viability was associated with partners' HLA dissimilarity, indicating that cervical mucus may selectively facilitate later gamete fusion between immunogenetically compatible partners. Together, these results provide novel insights into the female-mediated sperm selection (cryptic female choice) in humans and indicate that processes occurring after copulation may contribute to the mating bias towards HLA-dissimilar partners. Finally, by showing that sperm performance in cervical mucus is influenced by partners' genetic compatibility, the present findings may promote a deeper understanding of infertility.