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- Mice sing with long and complex calls when they are genetically unrelated to each other and reproduce faster
Mice sing with long and complex calls when they are genetically unrelated to each other and reproduce faster
20.04.2020: Mice often vocalize in the ultrasonic range when exposed to a conspecific or their odor, and these vocalizations are often assumed to attract mating partners, enhance courtship and mating success. A recent study by researcher of the Konrad Lorenz Institute of Ethology (Vetmeduni Vienna) now found that mice vocalize differently when their mating partner is genetically unrelated, compared to related partners, and their vocalizations correlate with their subsequent reproductive success.
Similar to birdsong, mouse ultrasonic vocalizations can be used to signal a male’s territory or to attract females. In the past many studies have focused on ultrasonic vocalizations of laboratory strains of house mice. However, the behavior of laboratory mice and their wild counterparts is very different.
At the Konrad Lorenz Institute of Ethology (Vetmeduni Vienna), researchers of the Penn & Zala Lab are studying the behavior and vocalizations of wild house mice (Mus musculus musculus). In a recent study published in Frontiers in Zoology, they compared the ultrasonic vocalizations of male mice when paired with a female that was either related or unrelated to them. The pair could first interact through a perforated divider (introduction phase) and then the divider was removed (interaction phase). Afterwards mice were kept in breeding pairs and their reproductive success was documented.
All recorded vocalizations were detected with an automated software (A-MUD) and then manually classified into 15 different call types, that varied in their length and frequency modulation.
Direct interaction matters
“The results showed, that mice emit more and longer vocalizations when they can directly interact, compared to when they can only see and smell each other” said the first author of the study Doris Nicolakis. Additionally, this study found that mice differ in their vocalizations when the pair is genetically unrelated, and that unrelated mice used vocalizations, which were longer and contained more complex calls (i.e. vocalizations with frequency modulation and frequency jumps).
Unrelated pairs reproduce faster
The researchers also reported that pairs of unrelated mice reproduced faster and had more litters than genetically related pairs. Interestingly, some pairs showed a short latency until the first birth, while others took longer to reproduce. In unrelated pairs the time to reproduce was negatively correlated with the length and number of vocalizations emitted during direct contact, which indicates that emission of more and longer vocalizations might facilitate courtship and therefore can result in a faster reproduction.
New findings and more work for the future
This study provides the first evidence that mice use different vocalizations depending on their genetic relatedness, and that their vocalizations can predict their subsequent reproductive success. This gives insights into the potential functions of ultrasonic vocalizations in the wild, where mice might use vocalizations to assess kinship to avoid inbreeding.