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Global warming has the potential to affect many animal species, in particular temperature-dependent insects with their short generation times and high reproductive rates which facilitate adaptations to long-term climatic fluctuations. Aphids are the model species in studying the association of insect biology with large-scale climate fluctuations because they multiply only within a certain range of temperatures and their rate of development directly depends on temperature. Here, we investigate the effect of climate warming on phenology and voltinism of the juniper aphid (Cinara juniperi De Geer 1773), a native species of a temperate climate zone in Poland. We also experimentally test for the temperature optimum of the study species. Our study demonstrated that environmental conditions significantly affected phenology of juniper aphid. The timing of larval emergence depended on mean temperatures in March, and in warmer years larvae appeared earlier. The emergence of the sexual generation was related to mean...

Ant-aphid mutualism has been investigated by many authors but it is unknown if anti-predator protection provided by ants is the main benefit for aphids. The aim of our paper is to analyse the ant-aphid interactions in the absence of predators. Based on video recordings we distinguish ant behaviours in interactions with attended aphids and we present ant time-budget at different times of the day. We also test if an aphid colony can survive without ant attendance in an environment free from predators and we inquire how much ant attendance is needed to maintain an aphid colony in good condition. Our study shows that, despite the lack of predation pressure, aphids of the species Cinara tujafilina were not able to survive without ant attendance and the extinction was caused by the excessive honeydew that covered aphids and their surroundings. We also found that ants cleaning aphids was the most frequent and time-consuming activity in ant-aphid interactions. However, in general, ants interacted with aphids only...

We studied the effect of ectoparasitism by hematophagous larvae of the blow fly of the genus Protocalliphora on nestling blackcaps Sylvia atricapilla in southeast Poland. Approximately 81% of blackcap nests left by nestlings contained Protocalliphora larvae; however, mean parasite load was only 1.8 larvae per nestling. Nestling mass and tarsus length measured just before fledging did not differ significantly with parasite load. This finding might have resulted from several factors. First, the number of larvae per nestling was very low, which may be connected with the structure of blackcap nests. Second, the time of exposure of nestlings to parasitic larvae in the studied species is relatively short as fledglings are able to leave a nest when they are 9 days old. The combination of the open lacework structure of blackcap nest and a very short nestling period may constitute an evolutionary adaptation that enables blackcap nestlings to escape the cost of Protocalliphora parasitism.

In the present study we test the ability of insight (solving novel problems) in a small passerine. Our paper reports on the predation of Blackcap Sylvia atricapilla nestlings by the Spanish Slug Arion lusitanicus and the reaction of bird parents to a novel predator. The Spanish slug is an invasive pest species, first documented in the study area in recent years. We examine whether parents are able to recognise a new species as a danger to their young and counteract to nest failure by removing a slug. We also inquire whether parents can instantly recognise that a chick is dead from watching its injuries and a slug feeding on it. Finally, we analyse if the recognition that nestlings are dead comes along with parent's understanding of losing a brood. The most striking result of our study is that none of Blackcap parents reacted aggressively against a predator that was absolutely harmless to adults and small enough to be removed from a nest. We also describe other irrational behaviours like incubating dead ch...

We analysed the eggs of the European starling Sturnus vulgaris for variability of UV and blue-green colouration. We noted the calcium deposition in eggshells, egg measurements, light conditions in nests and starling eye properties. Egg colouration shows high within-clutch similarity. Intensity of the blue-green egg colour neither depends on Ca deposition in the eggshell nor correlates with egg measurements, clutch size and laying date. This suggests that the intensity of the blue-green colour of starling eggs does not reflect female condition, which is reported to affect egg and clutch parameters. Low light intensity in cavities enables only mesopic vision, which is characterised by degraded visual acuity and colour sense, as well as Purkinje shift. As a consequence, the probability of precise assessment of the differences in eggs colour by starling males, crucial for the signalling hypothesis (Moreno & Osorno 2003), is not high. On the other hand, irrespective of its intensity, blue-green is the last col...