Sexual selection drives the evolution of diverse traits that can prove advantageous in reproduction. Because females often mate with multiple males, traditional premating processes such as female ...choice and male-male competition have counterparts both during and after mating in the form of cryptic female choice and sperm competition. Therefore, it is critical to expand our view of sexual selection. The goal of this research was to investigate how nuptial gifts in the form of spermatophores operate in sequential episodes of sexual selection in several species of beetle. Examining how nuptial gifts affect male and female fitness components can provide insight into male trait evolution, patterns of female choice and potential sexual conflict. The impact of receiving relatively different quantities of genital nuptial gifts on female fitness parameters across many arthropod taxa was examined using a meta-analysis. In response to greater amounts of nuptial gifts, females demonstrate enhanced fecundity but reduced longevity. In two studies, spermatophore size in Photinus fireflies is manipulated to evaluate the effect of variation in nuptial gift size on female fitness parameters and male reproductive success. One of these studies documents a significant effect on female post-mating lifespan of receiving a single large spermatophore relative to a single small spermatophore, but no significant effect on female reproductive output. In the other study, firefly males with larger spermatophores experienced dual benefits in terms of both higher mate acceptance and increased paternity share. Additionally, rigourous phylogenetic methods are utilized to demonstrate a link between female flight and male spermatophore production in worldwide firefly species, with loss of female flight leading to a loss of male spermatophore production. An evaluation of the use of close chemical contact cues, cuticular hydrocarbons, to mediate communication in diurnal and nocturnal fireflies was done with gas chromatography. This analysis revealed undetectable levels of these cues in nocturnal species. Finally, proteomics and mass spectrometry were used to identify the seminal fluid proteome of male spermatophores in Tribolium castanuem. The results of these studies contribute a number of novel and broadly applicable insights into the nature and evolution of nuptial gifts in animal species.
The availability of genome sequences from 16 anopheline species provides unprecedented opportunities to study the evolution of reproductive traits relevant for malaria transmission. In Anopheles ...gambiae, a likely candidate for sexual selection is male 20-hydroxyecdysone (20E). Sexual transfer of this steroid hormone as part of a mating plug dramatically changes female physiological processes intimately tied to vectorial capacity. By combining phenotypic studies with ancestral state reconstructions and phylogenetic analyses, we show that mating plug transfer and male 20E synthesis are both derived characters that have coevolved in anophelines, driving the adaptation of a female 20E-interacting protein that promotes oogenesis via mechanisms also favoring Plasmodium survival. Our data reveal coevolutionary dynamics of reproductive traits between the sexes likely to have shaped the ability of anophelines to transmit malaria.
During animal courtship, multiple signals transmitted in different sensory modalities may be used to recognize potential mates. In fireflies (Coleoptera: Lampyridae), nocturnally active species rely ...on long-range bioluminescent signals for species, sex, and mate recognition, while several diurnally active species rely on pheromonal signals. Although in many insects non-volatile cuticular hydrocarbons (CHC) also function in species and sex discrimination, little is known about the potential role of CHC in fireflies. Here, we used gas chromatography to characterize species and sex differences in the CHC profiles of several North American fireflies, including three nocturnal and two diurnal species. Additionally, we conducted behavioral bioassays to determine whether firefly males (the searching sex) were differentially attracted to extracts from conspecific vs. heterospecific females. Gas chromatography revealed that nocturnal Photinus fireflies had low or undetectable CHC levels in both sexes, while diurnal fireflies showed higher CHC levels. No major sex differences in CHC profiles were observed for any firefly species. Behavioral bioassays demonstrated that males of the diurnal firefly Ellychnia corrusca were preferentially attracted to chemical extracts from conspecific vs. heterospecific females, while males of the remaining species showed no discrimination. These results suggest that while CHC may function as species recognition signals for some diurnal fireflies, these compounds are unlikely to be important contact signals in nocturnal Photinus fireflies.
During mating, many male insects transfer sperm packaged within a spermatophore that is produced by reproductive accessory glands. While spermatophores have been documented in some North American ...fireflies (Coleoptera: Lampyridae), little is known concerning either production or transfer of spermatophores in the aquatic Luciola fireflies widespread throughout Asia. We investigated this process in Japanese Luciola lateralis and L. cruciata by feeding males rhodamine B, a fluorescent dye known to stain spermatophore precursors. We then mated males with virgin females, and dissected pairs at various timepoints after mating. In both of these Luciola species, spermatophores were produced by three pairs of male accessory glands and were transferred to females during the second stage of copulation. Male spermatophores were highly fluorescent, and were covered by a thin outer sheath; a narrow tube leading from an internal sperm-containing sac fit precisely into the female spermathecal duct, presumably for sperm delivery. Both L. lateralis and L. cruciata females have a spherical spermatheca as well as a highly extensible gland where spermatophore breakdown commences by 24h post-mating. Similar reproductive anatomy was observed for both sexes in Luciola ficta from Taiwan. These results suggest that nuptial gifts may play an important role in many firefly-mating systems.
Females often show a preference for exaggerated male sexual traits or courtship behaviors. Such preferences can benefit females if trait expression is correlated with male genetic quality or ...phenotypic condition. Previous studies of several Photinus fireflies have revealed considerable intraspecific variation in the bioluminescent courtship signals emitted by males, and have also demonstrated that females prefer more conspicuous male signals. Thus, females might gain information about male phenotypic quality if courtship signals reflect male condition. We examined possible condition-dependence of Photinus male courtship signals using two complementary approaches. First we experimentally manipulated male mating status, which is expected to affect male condition by depleting resources required for nuptial gift formation, and looked at how individual male flash signals changed with mating status and over time. We used an additional approach to assess condition-dependence by examining whether a relationship exists between flash signal parameters and measures of male condition and body shape. We found that the pulse rate of P. greeni courtship signals was not altered by male mating status or age, and that the pulse duration of P. ignitus signals was also not affected by male mating status. In P. pyralis fireflies, males showed a non-significant trend toward reduced signal pulse duration with age. When we examined the relationship between male flash signals and condition measures, we found no effect of male condition or body shape on courtship signals in P. greeni or P. ignitus; in P. pyralis, males with wider body shapes produced longer duration flash signals. On the other hand, we found no evidence in P. pyralis that condition predicted flash duration. Taken together, these results indicate that Photinus males' flash signals do not reflect adult male condition, and suggest that females are unlikely to use courtship signals as an indicator of male phenotypic quality.
The black-winged firefly, Luciola cerata Olivier, is endemic to Taiwan and is the most common firefly on the island. Males flash spontaneously and females respond with bioluminescent flashes at fixed ...response delays. In order to explore the potential for sexual selection in L. cerata, we surveyed males at 12 sites in Taiwan. We measured variation in male morphological characteristics and mated males to females. Male flash behavior and mating success was quantified under a variety of experimental sex ratios in the lab. We found there are two male morphs of this species, which are distinguishable only by the morphology of the lantern. One morph has a pentagonal second light segment, while the other has a semi-oval second light segment and only produces a flash with the first lantern segment. Besides this difference in morphology, the flash patterns and mating behavior also differ between these two morphs. Males with a pentagonal segment have a faster flashing rate than those with a semi-oval segment and are considered more attractive to females in groups with male-biased sex ratios. Furthermore, females that mate with the pentagonal-segment morph demonstrate greater fecundity than those that mate with the semi-oval-segment morph.
Wnt5a Regulates Melanoma Antigen Recognized by T Cells 1 (MART-1), a Predominant Antigen in Melanoma Cells Dissanayake, Samudra, Post doctoral Fellow, National Institute on Aging, National Institute of Health, Baltimore, MD; Rosenthal, Devin, Student, Laboratory of Immunology, National Institute on Aging, National Institute of Health, Baltimore, MD; Hewitt, Kyle, Student, Laboratory of Immunology, National Institute on Aging, National Institute of Health, Baltimore, MD ...
Clinical immunology (Orlando, Fla.),
01/2007, Volume:
123
Journal Article
Therapy using anti‐PD‐1 immune checkpoint inhibitors (ICI) has revolutionized the treatment of many cancers including head and neck squamous cell carcinomas (HNSCC), but only a fraction of patients ...respond. To better understand the molecular mechanisms driving resistance, we performed extensive analysis of plasma and tumor tissues before and after a 4‐week neoadjuvant trial in which HNSCC patients were treated with the anti‐PD‐1 inhibitor, nivolumab. Luminex cytokine analysis of patient plasma demonstrated that HPVpos nonresponders displayed high levels of the proinflammatory chemokine, interleukin‐8 (IL‐8), which decreased after ICI treatment, but remained higher than responders. miRNAseq analysis of tetraspanin‐enriched small extracellular vesicles (sEV) purified from plasma of HPVpos nonresponders demonstrated significantly lower levels of seven miRNAs that target IL‐8 including miR‐146a. Levels of the pro‐survival oncoprotein Dsg2, which has been to down‐regulate miR‐146a, are elevated with HPVpos tumors displaying higher levels than HPVneg tumors. Dsg2 levels decrease significantly following ICI in responders but not in nonresponders. In cultured HPVpos cells, restoration of miR‐146a by forced expression or treatment with miR‐146a‐loaded sEV, reduced IL‐8 level, blocked cell cycle progression, and promoted cell death. These findings identify Dsg2, miR‐146a, and IL‐8 as potential biomarkers for ICI response and suggest that the Dsg2/miR‐146a/IL‐8 signaling axis negatively impacts ICI treatment outcomes and could be targeted to improve ICI responsiveness in HPVpos HNSCC patients.
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