Carbon dioxide and methane have led midges and biting midges to the hollows of blue tit

Elevated concentrations of carbon dioxide and methane in the nests of blue Tits attract biting midges, black flies and ticks. This is the conclusion reached by the team of researchers, counting the parasites in hollows and comparing their abundance with the concentration of gases. Scientists have long known that the composition of the air inside the socket is different from the environment, but to prove that blood-sucking arthropods use these differences when searching for food, was only right now. Article with results of a study published in the journal Frontiers in Ecology and Evolution.

Bird’s nest with hatched Chicks — a real smorgasbord for mosquitoes and ticks. However, as they find the road to it, is not yet clear. According to the most popular assumption, arthropods focus on the difference in concentration of gases between the nest and the environment. This is consistent with what we know about mosquitoes: they find the man on the concentration of carbon dioxide and some volatile molecules. Unfortunately, the available data is still insufficient to confirm this hypothesis.

A team of specialists headed by Santiago Merino (Merino Santiago) from the National Museum of natural Sciences in Madrid, decided to investigate the relationship between the concentration of gases in the bird nest and the number of parasites in it. As the object of study they chose a common blue tit (Cyanistes caeruleus) — widespread bird from the family of Tits. Like most cousins, the blue Tits nest in cavities and readily take artificial bird houses.

From may to June 2016, the scientists monitored the concentration of carbon dioxide and methane in 44 populated by the blue tit nest boxes. All of them were located in one of the forests of Central Spain. Samples were taken after three, eight, thirteen and twenty days after hatching of the nestlings (at the age of 20-21 days they have already left the nest). The researchers also measured the concentration of two gases in the environment and empty nest boxes.

In addition, the authors of the study counted the arthropods, annoying blue tit Chicks. Among them was a flying bloodsuckers, such as biting midges (Culicoides) and gnats (Simuliidae) (the main carriers of dangerous for birds blood parasites of the genera Haemoproteus and Leucocytozoon , respectively), as well as the larvae of flies, fleas and ticks. They were collected with the help of special traps and searched for during the breeding litter after fledging.

To check nest boxes of the concentration of carbon dioxide in them did not differ from the environment, while methane in them was considerably less. However, with the advent of the Chicks in the nest began to accumulate carbon dioxide. Its concentration was higher than in the environment throughout the propagation cycle (p <0.0001), and the maximum value it reached on the eighth and twentieth day after hatching. In the first case it most likely was due to the intensive growth of the nestlings, while the second — with their increased activity before departure.

On the contrary, the concentration of methane in the nest during each measurement was lower than in the air outside (p<0.0001) probably due to the activity of methane-oxidizing bacteria. The minimum value of this indicator was observed on the twentieth day.

The researchers found that the number of biting midges nest on the twentieth day after hatching is positively correlated with the concentration of carbon dioxide in it (p = 0,031). While the number of midges were positively correlated with methane concentration: it is possible that these insects do not like nests with high numbers of methane-oxidizing bacteria. As for mites, they were more in the nest boxes where there was higher concentration of carbon dioxide. The number one parasites, blowflies, did not depend on the indicators of CO2 and CH4. Probably in the search and selection of the nests of these insects are guided by other signals.

The study confirmed that the concentration of carbon dioxide and methane inside the occupied nest boxes are not only markedly different from the environment, but also varies throughout the breeding cycle. At least part of the blood-sucking arthropods is focused on these indicators in search of nests.

Parasites are not the only problem faced Chicks. Just hatched from eggs, they have to compete with brothers and sisters, to attract the attention of parents and to escape from predators. Imagine yourself in the place of chick you can use our test home Alone.

Sergey Knee High

Leave a Reply

Your email address will not be published.