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. 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 have now published their results 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.'
University of Bielefeld: http://www.uni-bielefeld.de/
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Bumblebees can recall which flowers yield nectar, but like people they can get mixed up – leading them to home in on flowers they have no experience of
Brain cells that help us predict the intentions of others before they've actively made a decision have been discovered in monkeys
Experiments in mice suggest that treatment of haemophilia could be more successful if the baby's immune system is primed while in the womb
Scientists have recovered cultivated wheat DNA from an 8,000-year-old submerged site off the British coast. The finding suggests hunter-gatherers were trading for the grain long before they grew it.
An exciting fossil find in China points to a 525-million year old sea-dweller who used its new backbone to swim nimbly away from predators
Birds are dinosaurs. That’s a fact underscored by dozens upon dozens of discoveries in the last 30 years.
Eyelashes keep dust out and fend off drying breezes, a study finds. To do that they need to be a very precise length. Extra-long fake eyelashes hurt more than they help.
New research from UCL brings us closer to finding out what’s behind one of our biggest killers
The UK has now become the first country to approve laws to allow the creation of babies from three people.
Three people with paralysed arms had their hands amputated and replaced by prosthetic ones that they control with their mind