Biology subjects

Lahdenpera, M.

Publications and source records attributed to Lahdenpera, M..

3 recordsLinked to original sources

bioRxiv2026

Megaherbivore mortality risk from temperature extremes is buffered by vegetation productivity but amplified by rainfall

Demographic risks from climate change remain poorly understood for megaherbivore species which face unique challenges because their large food requirements impose strong bottom-up limitation while their small surface-area-to-volume ratio limits heat dissipation. Here, we test how megaherbivore mortality is shaped by the concurrent effects of temperature and rainfall along with vegetation productivity, a potentially critical modifier of climate effects. By analysing four decades of monthly mortality records from 4,457 semi-captive Asian elephants across Myanmar, we identify multiple environmental pathways regulating megaherbivore mortality. Elephant mortality increased at extreme hot and cold temperatures in regions with low annual vegetation productivity, whereas high vegetation productivity buffered against such U-shaped effects of temperature. Furthermore, high rainfall amplified the negative impacts of extreme heat, underlining risks arising from the joint effects of heat and humidity. Seasonal declines in vegetation productivity did not explain the elevated mortality at temperature extremes. Together, our findings show that megaherbivores face elevated risks from global warming, but such risks strongly depend on vegetation productivity and humidity, highlighting multiple pathways through which climate change can shape the dynamics of megaherbivore populations.

ecology↗

bioRxiv2026

Mothers face immediate, but family-size dependent, costs of sons in preindustrial Finland

The expensive son hypothesis posits that mothers incur higher fitness costs when caring for sons versus daughters in species with male-biased size dimorphism. Evidence for maternal survival costs of sons in humans is limited to shortened overall lifespans; whether having more sons reduces short-term survival during reproductive years is unknown. Here, we utilised life-history data from 5,456 mothers from preindustrial Finland to examine whether mothers with more sons had reduced survival within one year of their last birth. While mothers with few children but more sons showed no differences in survival, at higher family sizes, mothers with more sons had increasingly lower survival. These differences peaked at [~]0.4% lower survival per son among mothers with five children, suggesting accumulated physiological costs of sons. These differences then declined and reversed among mothers with more children, potentially due to selective disappearance of frailer mothers. Our results suggest that studies focusing on post-menopausal mothers may bias estimates of the fitness costs of sons and reproductive costs more broadly. We recommend future research further examines the overlooked short-term fitness costs of sons during reproductive years, which is vital for understanding how life-history trade-offs, sexual dimorphism, and their interaction have shaped human evolution.

evolutionary biology↗

bioRxiv2024

Menopause has not evolved as a general trait in mammals: A response to "Do mammals have menopause?"

Reproductive senescence is widespread across mammals, but only a small number of species have physiological reproductive cessation and an extended post-reproductive lifespan. A recent commentary in Cell by Winkler & Goncalves (2023) suggests that menopause is actually a widespread trait of mammals, which would change our understanding of senescence and have implications for the study of menopause in humans. Here, we identify three main issues with the methodology of this commentary: the use of captive populations, the use of maximal lifespan, and misinterpretations of the data sources. We show that this methodology does not support the conclusions at the species-level, and conclude that, in line with the predictions of classic life-history theory, menopause is indeed a rare trait.

evolutionary biology↗