Y (Yuting) Dong

Y (Yuting) Dong

Promovendus

Research:

Reproduction is vital for the persistence of a species. Reproductive success is influenced by biotic and abiotic factors. In sexually reproducing organisms, mating strategy and behaviour are important biotic factors affecting reproduction by optimizing fitness through mechanisms that bias mate choice. Spiders are ectotherms and their body temperature and physiology is largely determined by ambient temperature. Temperature extremes due to anthropogenic climate change are predicted to increase in severity, duration and frequency. Extreme temperature events exert levels of stress to reproduction, in particular, because the upper thermal threshold for reproduction is often lower than for survival of a species Moreover, the negative effects of exposure to extreme heat are predicted to be stronger for higher trophic level ectotherms, such as spiders. Spiders have fascinating sexual selection strategies, however how these strategies and exposure to heat influence fertility is largely unknown. I will first study mating strategy and behaviour in the synanthropic spider, Steotoda grossa, under conditions of male-male competition and simulated mating disturbance to reveal the details of courtship behaviour and how this affect female reproductive success. Second, I will investigate how exposure to heat of adults at mating will affect reproduction. In an additional experiment I will study the effect of heat exposure on egg sac development. As the most abundant natural predator of insects, spiders are integral to the biological control of pests. This study will help to understand the reproduction success of a sedentary, web-building spider species under mating disruption and heat stress.

 

Climate change is perhaps the defining environmental and societal issue of our time. Climatic extremes, such as heat waves, generate physiological stress in organisms and can strongly affect their survival. Arthropods are ectotherms and are particularly susceptible to heat because they must regulate their body temperature in response to external temperature. Previous research has shown that the upper threshold for survival in arthropods exposed to high temperatures is often higher than for reproduction. Exposure to high temperatures may not kill an organism, but it can render is sterile by destroying eggs and/or sperm. Thus, many ectotherms exposed to heat may constitute ‘the living dead’ in nature. Spiders are vitally important components are food webs and ecological communities but thus far the effects of heat on reproduction in spiders has been little studied. Most related research has been done with ‘model’ species like fruit flies and flour beetles (i.e. herbivores) while higher trophic levels (i.e. predators) have been ignored. With an increase in extreme heat events being recorded in many temperate biomes, the sub-lethal effects of exposure to high temperatures could reduce or even decimate populations of important natural enemies, and especially those with limited motility like web-building spiders. The current research thus aims to help better understand how factors like heat stress and mating disruption affect reproductive success in a sedentary, web-building spider.