Meal beetle males inherit immunity

Fathers pass on information about pathogens to the offspring

Red-brown rice flour beetle (Tribolium castaneum) © Peggy Greb / ​​USDA
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Not only mothers, but also fathers can pass on information about pathogens to their offspring and thereby influence their immune response - at least for red-brown rice flour beetle. This has now been discovered by an international team of researchers studying the effects of pathogenic bacteria on beetles and their offspring.

So far, scientists have assumed that this type of information transfer, based on previously unknown molecular mechanisms, is only possible via the maternal line. The researchers from Münster and Zurich report on their findings in the journal "Journal of Animal Ecology".

Immune system gets fit

The transmission of genetic information from generation to generation is the prerequisite for evolution. However, in animals that are infested with pathogens, also a transfer of non-genetic information is observed, which makes the immune system of the next generation "fit" against these pathogens.

Transfer of immunity to the offspring

"The transfer of immunity to the offspring has so far been known mainly in vertebrates, namely mammals, fish and birds, " says Olivia Roth, who conducted the study at the Institute for Evolution and Biodiversity of the University of Münster and at the ETH Zurich. "While fish and birds deposit antibodies directly into their eggs, mammals transmit these important immune substances to their offspring via the placenta and after birth via breast milk."

It has recently been shown that even in insects, immune substances can be passed from the mother directly through the egg to the next generation. "The mechanisms of this transmission are still unknown, " says Roth. "The only thing that is clear is that they can not be based on antibodies because the invertebrates, unlike vertebrates, lack antibody production." Ad

In reproduction, mothers bear the brunt, as the production of eggs requires much more energy than the production of sperm. "Therefore, it was previously thought that the effort to invest in the immune response of the offspring, only worthwhile for the females, while the males to make it probably no contribution, " said Roth.

Fathers make beetles more resistant to bacteria

However, the research team was able to show for the first time that beetles are more resistant to bacteria even when the immune system of their fathers was stimulated by a confrontation with these bacteria.

"This Immune priming means that the optimal adaptation of the offspring to the environment, thanks to joint investments of mother and father comes about, at least with regard to the immune response, says Roth. Even if mother and father were exposed to various parasites or pathogens during their lifetime, this mechanism can enormously extend the life of an individual and thus increase the fitness and reproduction rate, thus increasing the high investment in sexual reproduction pays. This could be a possible alternative explanation of why sexual reproduction exists at all

Immune priming influences mate choice

In addition, according to Roth, paternal immune priming could influence mate choice. Females may choose partners in certain situations who have survived certain infections and give their offspring an advantage in interacting with these agents.

With which molecular mechanisms this transfer of the immune response from father to offspring is based will show the future, says Roth. While the team of Professor Joachim Kurtz in M nster continues to investigate this question at Mehlk fer, Roth is now investigating in Kiel at the Leibniz

Institute of Marine Sciences, whether farmers also invest in the immune response of their offspring in fish.

(idw - University of M nster, 28.10.2009 - DLO)