Kris Sales

Forest Research - Forestry Commission UK

The niches of epiphytes are widely studied and have been shown to be complex involving interspecific competition, succession and predation. This study is unique in that it applies the niche concept to moss and lichen distributions within Killarney National Park, Kerry, Ireland. We studied 75 trees between three pristine ancient woodlands and measur...

The existence of widespread male same-sex sexual behaviour (SSB) is puzzling: why does evolution allow costly homosexual activity to exist, when reproductive fitness is primarily achieved through heterosexual matings? Here, we used experimental evolution to understand why SSB occurs in the flour beetle Tribolium castaneum. By varying the adult oper...

Triploidy could prevent escaped farm salmon breeding in the wild, while also improving nutrient quality within farmed fillets. Despite these potential advantages, triploid Atlantic salmon have not been widely used in aquaculture, and their reproductive function has yet to be fully evaluated. Here, we compare reproductive function and fillet composi...

Climate change is affecting biodiversity, but proximate drivers remain poorly understood. Here, we examine how experimental heatwaves impact on reproduction in an insect system. Male sensitivity to heat is recognised in endotherms, but ectotherms have received limited attention, despite comprising most of biodiversity and being more influenced by t...

Rising and more variable global temperatures pose a challenge for biodiversity, with reproduction and fertility being especially sensitive to heat. Here, we assessed the potential for thermal adaptation in sperm and egg function using Tribolium flour beetles, a warm-temperate-tropical insect model. Following temperature increases through adult deve...

Climate change is increasing mean temperatures, and intensifying heatwaves. Natural populations may respond to stress through shorter-term acclimation via plasticity and/or longer-term inter-generational evolution. However, if the pace and/or extent of thermal change is too great, local extinctions occur; one potential cause in ectotherms is identi...

Globally, heatwaves have become more common with hazardous consequences on biological processes. Research using a model insect (Tribolium castaneum) found that 5-day experimental heatwave conditions damaged several aspects of male reproductive biology, while females remained unaffected. However, females’ reproductive fitness may still be impacted,...

Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studi...

Urban trees and other green infrastructure are advocated as a cost-effective sustainable solution to ameliorate the socio-economic and environmental challenges of urbanisation. UK research has only recently started to quantify urban trees. Tree canopy cover percentage (TCC) is a useful indicator of tree presence. Its estimation can be reproducible,...

Climate change is gripping our planet. News headlines proclaim warmer winters and hotter summers, and these changes are impacting Earth’s biodiversity. Have you ever wondered how climate change causes extinctions? This is an important, ongoing research question because understanding how heat impacts living organisms could help us predict how specie...

Urban trees form a resource that has a range of positive effects on human populations living in and around them. Termed ecosystem services, the benefits provided by urban trees help to offset many of the problems associated with increased urban development. Trees remove certain air pollutants, capture and store carbon, control water runoff and floo...

Forest Research has made the first estimate of the monetary value of non-woodland trees in the UK. This helps us understand the overall value of our treescape, in which non-woodland trees play a critical role. Non-woodland trees are (i) single trees; (ii) groups of trees covering less than 0.1 hectares; and (iii) small woods covering less than 0.5...

Adulthood‐only downregulation of insulin/IGF‐1 signalling (IIS), an evolutionarily conserved pathway regulating resource allocation between somatic maintenance and reproduction, increases lifespan without fecundity cost in the nematode, Caenorhabditis elegans. However, long‐term multigenerational effects of reduced IIS remain unexplored and are pro...

Urban trees form a resource that provides a range of benefits to human populations living in and around cities. Termed ecosystem services, the benefits provided by urban trees help to offset many of the problems associated with increased urban development. Trees remove certain air pollutants, capture and store carbon, reduce water runoff and floodi...

The theory that ageing evolves because of competitive resource allocation between the soma and the germline has been challenged by studies showing that somatic maintenance can be improved without impairing reproduction. However, it has been suggested that cost-free improvement in somatic maintenance is possible only under a narrow range of benign c...

Why is polyandry such a common mating behaviour when it exposes females to a range of significant fitness costs? Here, we investigated whether polyandry protects females against reduced male fertility caused by thermal stress from heatwave conditions. Sperm production and function are vulnerable to heat, and heatwave conditions are forecast to incr...

Dietary restriction (DR) increases lifespan in a broad variety of organisms and improves health in humans. However, long-term transgenerational consequences of dietary interventions are poorly understood. Here, we investigated the effect of DR by temporary fasting (TF) on mortality risk, age-specific reproduction and fitness across three generation...

With climate change creating a more volatile atmosphere, heatwaves that create thermal stress for living systems will become stronger and more frequent. Using the flour beetle Tribolium castaneum, we measure the impacts of thermal stress from experimental heatwaves in the laboratory on reproduction and survival across different insect life stages,...

Dominant theory maintains that organisms age due to resource allocation trade-offs between the immortal germline and the disposable soma. Strikingly, adulthood-only downregulation of insulin signalling, an evolutionarily conserved pathway regulating resource allocation between reproduction and soma, increases lifespan and offspring fitness without...

Dietary restriction increases lifespan in a broad variety of organisms and improves health in humans. However, long-term transgenerational consequences of dietary interventions are poorly understood. Here we investigated the effect of dietary restriction by temporary fasting (TF) on mortality risk, age-specific reproduction and fitness across three...

Evidence shows that natural populations are shifting their ranges and becoming locally extinct at warm margins because of climate change. However, the proximate mechanisms behind these responses are poorly understood. This PhD thesis explores one potential driver within insect systems: the impact of heatwave conditions and thermal variation on repr...

INTRODUCTION  Female and Male gametes represent good examples of common sexual traits under divergent selection and optima 1,2,3,4.  Using a poikilothermic insect model, I examine how gamete sizes develop following controlled variation in the thermal environment.  Resulting plasticity could inform on 1) adaptive significance of gamete size, and...