A new study, led by Dr. Kirsty Macleod of Bangor University’s School of Environmental and Natural Sciences, has just revealed some groundbreaking insights. It sheds light on the underlying maternal stress mechanism that impacts the growth and behavioral development of hatchling lizards. The study investigated a distinct form of the Australian lizard Liopholis whitii. It’s about how these lizards are unique in the animal kingdom by raising their young in complex family groups. Conducted with meticulous attention to detail, the study examined the impact of stress hormones transferred to mothers during pregnancy on their offspring.
The researchers injected stress hormones into the pregnant females, and then waited to see how this affected their hatchlings. The results showed that offspring lizards born to stressed mothers had slower growth rates. In stark contrast, those whose mothers had lower stress during pregnancy flourished. The experiments found very pronounced behavioral variations in the second generation of mother rats who had been stressed during pregnancy. This discovery indicates that maternal stress greatly shapes social experiences starting at birth.
Behavioral Changes in Offspring
The researchers discovered that the lizards whose mothers were stressed out had a range of behavioral changes in the early parts of their social lives. While one might expect that maternal stress would lead to increased withdrawal or aggression in offspring, the results showed a surprising trend: stressed baby lizards were more social than their counterparts. This leads to the conclusion that maternal stress could trigger a counteractive response in the juvenile lizards, even potentially as an adaptive survival tactic.
Dr. Macleod made the case for understanding these behavioral shifts. They are essential for understanding how more macroscopic environmental gradients drive the social complexity we observe within and among lizard populations. “Stress during pregnancy can affect how offspring grow and behave, including how they interact with others,” she noted. This key insight could have wider applications for understanding social behavior in other species too.
The Role of Environment and Maternal Influence
Beyond simply identifying the impact of maternal stress, the research went further to explore how maternal stress interacted with several environmental factors. The study’s unusual design featured raising some baby lizards with their mothers for weeks at a stretch, while others were raised in isolation. This combined approach sought to establish if maternal presence was enough to reverse the harmful effects of prenatal stress on fetal development. Interestingly, the results indicated that maternal stress appears to override the positive influences of the social environment during the critical early periods after birth.
A fundamental understanding from this research goes beyond Liopholis whitii. By examining how maternal stress impacts social behavior, scientists can better understand the complexities of animal behavior in various ecological contexts. Dr. Macleod’s conclusions underlie the growing hypothesis that maternal experiences have a profound impact on how offspring develop and adapt to their environments.
Publication and Significance
The results of this landmark study have been released in the Journal of Animal Ecology. You can read them in full with this DOI 10.1111/1365-2656.70121. The study adds to an increasing pile of interesting evidence. It illustrates how important prenatal environments are for understanding animal behavioral ecology.