Blood parasites are often considered as indicators of immunity in birds, and data on parasite prevalence and intensity of infections are essential to reveal information about the condition of both individuals and populations. We prevented parasite vectors from biting and infecting nestling great tit Parus major by using insect repellent inside nest boxes. We found that in the absence of blood parasites, great tit nestlings had higher concentrations of haemoglobin, and they survived at significantly higher rates through the nestling phase and also during the first weeks of their fledgling period. This is the first demonstration so far of the impact these parasites have on haemoglobin levels of the hosts, which reveals one mechanism of adverse impact by blood parasites. This study shows that the effects of blood parasites can be assessed without using anti‐malaria drugs, which can cause additional risk of oxidative stress.
Terminal investment hypothesis is a longstanding theoretical idea that organisms should increase their reproductive effort as their prospects for survival and reproduction decline. However, numerous attempts to test the terminal investment in reproduction have yielded contradictory results. This study reports an experimental confirmation of the terminal investment hypothesis. It was predicted that immune-challenged yellow mealworm beetles (Tenebrio molitor) are more likely to follow terminal investment strategy when their food resources are limited. Our results suggest the key role of food resources while making decisions to follow a terminal investment strategy. We found that male individuals invested in their sexual attractiveness at the expense of immune response and survival when food was not available. In contrast, the beetles did not decrease their lifespan and did not invest in the attractiveness of their sex odours under conditions of food ad libitum. Our results show the importance of food availability and quality in understanding the evolution of reproductive strategies.
The aim of this work is to study Lithuanian stakeholders' perceptions of fire impacts in protected areas. For this study, the stakeholders consisted of foresters, ecologists and farmers. A clear understanding of the opinions of stakeholders about fire effects on environmental, social and economic aspects of Lithuanian protected areas will allow an assessment of the stakeholders' reaction to fire policy, including government measures towards fire prevention, suppression and application of prescribed fire to landscape management. The results showed that stakeholders in general think that fire is not a threat to Lithuania and to the ecological processes in the protected areas. However, they agree that fires have negative impacts on soil properties and fertility but are not to an irremediable or irrecoverable extent. Stakeholders disagree that fire has positive consequences for agricultural and cattle activities but agreed that vegetation recovers quickly. They do not see fire as a social and economic problem, do not agree that prescribed fire could be used to landscape management, and believe that mechanical thinning is a better management tool than prescribed fire. Stakeholders agree that fire does not have negative impacts on the biodiversity. These opinions depended on the age group of the respondent but especially on the respondent's professional occupation.
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