Mosquitoes analyse flower chemistry, according to reports in ScienceDaily 22 January 2020 and The Daily University of Washington 6 February 2020 and PNAS 7 January 2020, doi:10.1073/pnas.1910589117.
Although mosquitoes have a well-earned reputation for biting people and sucking blood, their main food source is flower nectar. As explained by Jeffrey Riffell, a professor of biology at the University of Washington, “For male mosquitoes, nectar is their only food source, and female mosquitoes feed on nectar for all but a few days of their lives.”
Like other nectar feeding insects mosquitoes pollinate the flowers they feed from, so it is important that flowers are able to attract them. Scientists at University of Washington who were studying Aedes mosquitoes noted the mosquitoes were attracted to the flowers of the blunt leafed orchid Platanthera obtusata but ignored flowers of closely related plants growing in the same area of the Okanogan-Wenatchee National Forest. They confirmed that the mosquitoes were attracted by the scent of the flowers, by covering flowers with cloth bags that hid the flowers but let the scent escape. The mosquitoes landed on the bags and tried to feed through the cloth.
Flower scents are complex combinations of chemicals and it is the ratio of different chemicals that produce particular scents. Researchers analysed the scent of the attractive and non-attractive flowers, and also studied electrical activity in the mosquitoes’ antennae and their brains when exposed to the scents. They found the Aedes mosquitoes could discern the relative amounts of different chemicals produced by the flowers and that determined whether they were attracted to a particular flower. The research team particularly studied the mosquitoes’ response to two chemicals, nonanal and lilac aldehyde, which are produced by both the attractive and non-attractive flowers, but in different proportions. They reported the mosquitoes were attracted to nonanal and lilac aldehyde mixed in the same ratio found in the attractive flowers, but were indifferent or even repelled when the proportion of lilac aldehyde was increased, as it is in the non-attractive flowers.
This research could have useful applications is preventing mosquito-borne diseases. Jeffrey Riffell explained: “Mosquitoes are processing the ratio of chemicals, not just the presence or absence of them. This isn’t just important for flower discrimination – it’s also important for how mosquitoes discern between you and I. Human scent is very complex, and what is probably important for attracting or repelling mosquitoes is the ratio of particular chemicals. We know that some people get bit more than others, and maybe a difference in ratio explains why.”
Riffel also commented that using lilac aldehyde in a mosquito repellent has an added bonus. Unlike many insect repellents this chemical “smells wonderful”.
ScienceDaily, University of Washington
Editorial Comment: This study is further confirmation that mosquitoes were really designed to pollinate flowers, and this only works because the plants produce the right combinations of chemicals and mosquito brains are able to analyse the percentage chemical composition. It is amazing that mosquito brains can ‘with a sniff’ carry out chemical analysis which requires people to use complex technology such as gas chromatography and mass spectrometry.
If you believe this mosquito and flower relationship could have evolved by chance, we would remind you that they only have one generation to get it right – that is both the plants’ complex chemistry and mosquitoes’ brain circuits. Its extinction if they don’t. For this mutually beneficial system to continue working, the mosquitoes have to reproduce, and for that the female mosquitoes need iron and protein for their eggs. In the original very good world full of lush vegetation, they could get this from plants. But since the environment degenerated after the Fall of Man and Noah’s flood, female mosquitoes have hard time finding iron and protein from plants so they seek it from easier sources, such as human blood.
Once again, the study of the living world confirms that design followed by degeneration is a better explanation for the way living things work in the world today.
News vol. 20, No. 2
12 February 2020
Creation Research Australia