…for another year. Thanks to all of the participants for lots of fun and fascinating discussion on matters hermaphroditic at SHOW 2016 last week, and a special thank you to the ZiF for hosting us, and the team here – Bahar, Michael, Yumi & Athina – for all the hard work behind-the-scenes to make it happen. (Photo credit: Bahar)
Well done to Bahar, Michael, Athina and Lennart for their excellent talk and poster contributions at this year’s International Macrostomum Meeting in Innsbruck, and thanks to Peter Ladurner and his team for hosting the annual get-together of fellow Macrostomum researchers.
It was a great pleasure to welcome Jean-François Lemaître to Bielefeld as the guest speaker in our Behaviour & Evolution Seminar Series this week, in which he talked about “Understanding sex-differences in ageing: insights from natural populations of mammals”. Jean-François is a CNRS researcher based at the Laboratoire de Biométrie et Biologie Évolutive in Lyon, where he works on the evolutionary demography of wild mammals. Thanks for your visit, Jeff!
Welcome back to Bahar, just returned from a productive research trip to the Genetic Diversity Centre at the ETH Zürich. We’re working with the GDC to measure variation in seminal fluid gene expression in Macrostomum lignano, as part of our DFG project on seminal fluid function and evolution.
Owing to its complex composition, the mixture of sperm and seminal fluid substances that comprise an ejaculate has recently been likened to a musical symphony. In a new study I conducted with former colleagues at the University of Liverpool and published this week in BMC Biology, we used proteomics techniques to ask whether male mammals can plastically adjust ejaculate composition. We discovered that the “seminal symphony” males produce indeed depends strongly upon the prevailing “social milieu”. Under more competitive conditions, males produce more sperm and a different blend of seminal fluid proteins than they do under less competitive conditions. This is presumably because high sperm numbers and large amounts of certain seminal fluid proteins enhance male competitive fertilization success, but aren’t needed when there are no competitors around, and so plasticity in ejaculate composition is selectively favoured.
Ramm SA, Edward DA, Claydon AJ, Hammond DE, Brownridge P, Hurst JL,
Beynon RJ, Stockley P (2015)
Sperm competition risk drives plasticity in seminal fluid composition
BMC Biology 13:87. doi: 10.1186/s12915-015-0197-2
Image credit: from Beethoven’s Symphony No. 5. Licensed under Public Domain via Wikimedia Commons.
… a joke about former US President Calvin Coolidge …
The President and Mrs. Coolidge were being shown [separately] around an experimental government farm. When [Mrs. Coolidge] came to the chicken yard she noticed that a rooster was mating very frequently. She asked the attendant how often that happened and was told, “Dozens of times each day.” Mrs. Coolidge said, “Tell that to the President when he comes by.” Upon being told, the President asked, “Same hen every time?” The reply was, “Oh, no, Mr. President, a different hen every time.” President: “Tell that to Mrs. Coolidge.”
(from Wikipedia entries on Calvin Coolidge and the Coolidge Effect, citing Hatfield & Walster’s A New Look At Love)
In biology, the Coolidge Effect was a term originally coined by Frank Beach to refer to the restoration of sexual activity among males that had previously reached sexual satiety when presented with a new female. More recently, that definition has tended to be broadened to encompass all forms of differential investment that males might exhibit towards novel females, and it is increasingly recognised that such investment can take on more cryptic forms. In a new paper together with Klaus Reinhold, Leif Engqvist and Albia Consul, we report one such example of strategic male investment, presenting evidence that male birch catkin bugs mate for longer with novel females.
Reinhold K, Engqvist L, Consul A, Ramm SA (2015)
Male birch catkin bugs vary copula duration to invest
more in matings with novel females.
Animal Behaviour 109:161–166. doi:10.1016/j.anbehav.2015.08.020
Image credit: Calvin and Grace Coolidge, about 1918. Public domain image from Wikimedia Commons.
Thanks to Daniel Rozen of the University of Leiden for the nice commentary on our hypodermic self-insemination paper in the “Outside JEB” section of this month’s Journal of Experimental Biology: “A head for sex”