Why are male mice afraid of bananas?
Olfactory exposure to late-pregnant and lactating mice produces analgesia in male but not female mice in the radiant heat paw-withdrawal test. (A and B) Latency to hind paw-withdrawal (s) from radiant heat of male (A) and female (B) mice before (Pre) and during (Post) exposure to stimulus mice of various reproductive conditions: naïve male, naïve female (NF), early pregnant (EP), late pregnant (LP), lactating (Lact.) [with pups present (+ pups), without pups present (− pups), and with pups removed 24 hours before (− pups 24 hours)], and after weaning. (C and D) Change (Δ) in hind paw-withdrawal latency (Post-Pre) in all stimulus conditions shown in graphs (A) and (B) in male (C) and female (D) mice. Positive values (green) represent analgesia; negative values (pink) represent hyperalgesia. In all graphs, individual data are shown (n = 10 to 12 mice per sex per condition); black bars represent means ± SEM. *P < 0.05, ***P < 0.001 compared to zero by two-tailed one-sample Student’s t test; asterisks are shown in red if the t test result is still statistically significant at P < 0.05 after correction for multiple comparisons. Credit: Science Advances (2022). DOI: 10.1126/sciadv.abi9366

Researchers from the University of Montreal have found a form of chemical signaling in mice. The researchers found that proximity to pregnant and lactating female mice increased stress hormones in males.

The findings have important implications for improving the reliability and reproducibility of experiments. Jeffrey Mogil, a Professor in the Department of Psychology at Montreal University and the E. P. Taylor Chair in Pain Studies, says that this is another example of a previously unknown factor in the lab environment that can affect the results of scientific studies.

Female mice are signaling to males who might be considering attacking their babies that they will defend them vigorously. The stress is caused by the threat of the fight.

Mogil says that ice have richer communication with one another than they think. The researchers were looking for a chemical. N-pentyl acetate, which is released in the urine of pregnant and lactating female mice, is an odorant that is especially effective at producing stress in male mice.

N-pentyl acetate is responsible for the unique smell of bananas. After a quick trip to the supermarket for some banana oil, we were able to confirm that the smell of banana extract stressed the male mice just as much as the pregnant females.

There are a number of examples of male-to-female olfactory signaling in rodents, but far fewer examples of female-to-male signaling, especially outside of the realm of sexual behavior.

Olfactory exposure to late-pregnant and lactating mice causes stress-induced analgesia in male mice.

More information: Sarah F. Rosen et al, Olfactory exposure to late-pregnant and lactating mice causes stress-induced analgesia in male mice, Science Advances (2022). DOI: 10.1126/sciadv.abi9366 Journal information: Science Advances Citation: Why are male mice afraid of bananas? (2022, May 24) retrieved 24 May 2022 from https://phys.org/news/2022-05-male-mice-bananas.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.