Mosquito bites may induce skin colour change

Mosquito bites may induce skin colour change

by Alex Laube Tiermedizin Science

Sometimes science starts small: last year, someone posted a photo of a Calumma globifer with a mosquito sitting on it on the online platform iNaturalist. Right there you could see a black discoloration of the scales. I wonder if there was a connection?

A handful of curious people searched for more photos of mosquitoes on chameleons and found what they were looking for: On Facebook there were some of Veiled chameleons, on iNaturalist more of Furcifer minor and Furcifer nicosiai. However, there were also six observations of mosquitoes on chameleons that did not appear to have black spots.

To test the connection, scientists in Madagascar placed two Furcifer oustaleti and four carpet chameleons alone in an enclosure with 25 female Asian tiger mosquitoes (Aedes albopictus), which had not been fed for 24 hours beforehand. At the same time, all six chameleons were pricked in the skin with a needle to test whether this “trauma” would also trigger a color change in the skin. The results were surprising: in the four Furcifer lateralis, numerous black skin discolorations developed after mosquito bites, in the two Furcifer outaleti not a single one. The punctures with the needle remained without consequences in all six.

The authors of the recently published article propose three possible theories as to how the color change in the chameleon’s skin could come about: The mosquito saliva could contain a type of local anesthetic, nitric oxide or other proteins that cause the skin’s melanophores to become exclusively visible. Further research in this field would certainly be exciting!

Mosqito bite-induced color change in chameleon skin
Pablo Garcia, Raul E. Diaz Junior, Christopher V. Anderson, Tovo M. Andrianjafy, Len de Beer, Devin A. Edmonds, Ryan M. Carney
Herpetological Review 54(3), 2023, pp.353-358

Influence of UV-B on growth

Influence of UV-B on growth

by Alex Laube Short messages Science

An interesting husbandry experience from the USA was presented in a short note in the Herpetological Review. Twelve carpet chameleon hatchlings (Furcifer lateralis) from the same clutch were divided into four groups of three animals each. During the first ten weeks after hatching, two groups were provided with a daily UV index of up to 3 for 12 h, the other two groups with a UV index of up to 7. Reptisun 5.0 was used to achieve the different UV indices. Measurements were taken with the Solarmeter 6.5. The chameleons were allowed to avoid UVI up to 0. After six, eight and ten weeks, the carpet chameleons were measured and weighed. It was noticed that in weeks 6 and 10, the groups with the lower UV index were up to 25% heavier than the comparison groups.

The two authors conclude that higher UV indices during rearing in the first weeks could lead to slower growth rates in carpet chameleons. This would correspond to the observation in nature that young animals “sunbathe” rather rarely and stay more hidden in the bushes. Due to the small group of test subjects and mixed groups instead of individual keeping, you must still be cautious with conclusions here. In addition, it is unfortunately still largely unexplored whether and how chameleons can regulate their vitamin D3 regulation in artificial light compared to natural sunlight. Nevertheless, it is a very interesting approach that is certainly worth pursuing.

Furcifer lateralis (carpet chameleon): Impact of Ultraviolet Light on growth
Michael J. Nash, Christopher V. Anderson
Herpetological Review 52 (2), 2022