Finding Sperm in the English Countryside—The 14th Biology of Spermatozoa Meeting
Most people wouldn't look to the rolling green hills of central England as the place to get a crash course on the latest in sperm biology. Yet, for the past quarter of a century, sperm biologists from around the world have congregated in the picturesque Peak District (near Sheffield) for Biology of Spermatozoa (BoS) Meetings - the most recent of which representing the 14th such gathering. BoS meetings are relatively small, typically consisting of 60-80 delegates, and attract a cadre of sperm enthusiasts who return year after year. As with previous meetings (e.g. Wolfner and Montgomerie 2016), the size and atmosphere of the event gives BoS meetings a special feel - part 'family' reunion, part meeting new colleagues, part solidifying and developing collaborations, and all cutting-edge science.
Spermatozoa in the Peak District
Conferences can be amixed bag. On the one hand, they are often invaluable for networking; for getting to, or staying at, the cutting edge; for getting helpful input from colleagues; for seeing friends and collaborators, old and new; and (occasionally) for getting to visit a new and exciting part of the world. Sometimes, unfortunately, scientific conferences are just too big; too expensive; too boring; too lonely, exhausting, and time consuming. Too often, delegates present old work that you already knew about, venues are hot and stuffy, and the chance of meeting old friends and making new ones is slim indeed. In September 2015, we attended a conference that epitomized all the positives (with none of the negatives) the biennialBiologyofSpermatozoa (BoS)meeting (http://www. bos.group.shef.ac.uk) in thegorgeousPeakDistrictofnorthern England. This small scientific meeting, run for the past 25 years by Tim Birkhead and Harry Moore, both at the University of Sheffield, focuses on the evolutionary biology ofspermatozoa,and reproduction ingeneral.Fourprinciples have guided the organizers from the start: (i) to keep the meeting small with no concurrent sessions; (ii) to require presenters to focus on unpublished research in progress or nearly finished; (iii) to invite 2-3 speakers from outside the core group of evolutionary biologists as a way of injecting new ideas and perspectives from other disciplines, such as physiology, imaging, proteomics/genomics; and (iv) to stay flexible, trying new approaches, replacing or modifying whateverdidnotworksowell in thepast.More thananything, this conference encourages and maximizes interaction and discussion whichmakesattending itsoproductiveand fun. To that end (and because there is only one presentation at a time) post-presentation questions and discussions are allowed to continue as long as they are interesting. Consequently, there isno rigidscheduleeachday except to finish in time for a drink before the sumptuous dinner served in an elegant dining room at the conference venue.
Resolving Mechanisms of Competitive Fertilization Success in Drosophila melanogaster
Battle of the Sperm In insects, sperm from multiple matings are stored and retained, and are thought to compete for ova within a female's reproductive tract. Manier et al. (p. 354, published online 18 March) visualized sperm from fruit flies transgenically tagged with green or red fluorescent protein within the reproductive tracts of female flies. Sperm showed more mobility within the female storage organs than expected, with those from the most recent copulation displacing sperm from previous males; however, sperm viability remained consistent over long-term storage and each male's sperm was equally competitive in fertilizing the female's eggs. Fluorescently labeled sperm allow direct visualization of their activity within the female reproductive tract of flies. Our understanding of postcopulatory sexual selection has been constrained by an inability to discriminate competing sperm of different males, coupled with challenges of directly observing live sperm inside the female reproductive tract. Real-time and spatiotemporal analyses of sperm movement, storage, and use within female Drosophila melanogaster inseminated by two transgenic males with, respectively, green and red sperm heads allowed us to unambiguously discriminate among hypothesized mechanisms underlying sperm precedence, including physical displacement and incapacitation of “resident” sperm by second males, female ejection of sperm, and biased use of competing sperm for fertilization. We find that competitive male fertilization success derives from a multivariate process involving ejaculate-female and ejaculate-ejaculate interactions, as well as complex sperm behavior in vivo.