All a question of timing: When bushcrickets mate, the male attaches a sticky package, the so-called spermatophore, to the female’s abdomen. Alongside the sperm themselves, this ‘bridal present’ consists of a protein-rich mass that the female eats after mating.
Caught in the act: The spermatophores of male bushcrickets can attain up to 40 per cent of their bodyweight. The actual sperm transfer comes later – the Bielefeld researchers’ findings suggest that when that happens is something the male determines. Klaus Reinhold
It then takes several hours for the sperm to find their way into the female’s reproductive tract. But, who decides when that will happen? A study by the Bielefeld biologists Professor Dr. Klaus Reinhold and Dr. Steven Ramm suggests that it is the male who determines the dynamics of this process even when he has long ‘hopped off’ somewhere else. They published their results at the beginning of December in the online first version of the journal Behavioural Ecology and Sociobiology.
In contrast to direct sperm transfer, the use of a spermatophore could grant the female more influence over the fertilization or non-fertilization of her eggs. However, the results of the Bielefeld study cast doubt on this assumption. They suggest a high degree of male control over this decisive stage in reproduction. For their study, Professor Dr. Klaus Reinhold and Dr. Steven Ramm from Bielefeld University paired males and females from two subspecies of the bushcricket Poecilimon veluchianus in whom the time between pairing and sperm transfer differ. Whereas in the subspecies Poecilimon veluchianus minor, sperm are transferred within the first three hours, the transfer in Poecilimon veluchianus veluchianus starts only after four hours. If the two subspecies are interbred – the researchers thought – then the number of transferred sperm after three hours would indicate whether it is the male or the female who determines how long this transfer takes.
The researchers mated nine to twelve pairs in each of the four possible combinations of Poecilimon veluchianus minor and Poecilimon veluchianus veluchianus. Three hours after mating, they examined how many sperm they could find in the female’s reproductive tract. The result: the sperm from the males of the ‘faster’ subspecies Poecilimon veluchianus minor could be found in the females of both subspecies. In contrast, the males in the ‘slower’ sub-species Poecilimon veluchianus veluchianus had transferred almost no sperm at all to either type of female.
The researchers conclude from this experiment that the males control the speed of transfer over the sperm package. However, this does not automatically lead to the conclusion that the female is powerless. Females can also influence whether sperms are transferred by how quickly they eat the spermatophore. In addition, the larger the male, the larger the size of the sperm package, and this influences how long the females need to consume the protein. As a result, the sperm have more time to transfer to the female – and the female’s eggs have a greater chance of being fertilized by a ‘high-quality’ male. Professor Reinhold stresses, ‘Our findings show that the females do not determine the transfer – not that they could not do so.’For further information in the Internet, go to:
Ingo Lohuis | idw
Atomic Design by Water
23.02.2018 | Max-Planck-Institut für Eisenforschung GmbH
22.02.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
22.02.2018 | Life Sciences
22.02.2018 | Physics and Astronomy
22.02.2018 | Earth Sciences