Animal of the Week, February 20, 2019 — When is a sea slug like a leaf?

Karen N. Pelletreau et al

This week's animal of the week Elysia chlorotica is a peculiar sea slug. First off it's not a nudibranch like the other familiar sea slugs. Instead it is a member of a different branch of the gastropod class.

The main thing about this particular marine mollusc is that it can photosynthesise for long periods of time. Various animals, notably corals, form symbiotic relationships with algae in which the the animal provides a home and protection for algae and the algae provide food for the animal. But this curious sea slug goes a step further—it eats a particular type of algae, Vaucheria litorea, and actually assimilates chloroplasts, tiny light absorbing subcellular units that make energy from sunlight.

Other relatives of E chlorotica do the same, but usually, the choloroplasts, lacking the supportive environment of the algae die in a few days. Somehow, E chlorotica keeps the algae alive for months, sometimes until the sea slug itself reaches old age and dies. The thing I find most pleasing about this whole arrangement is how much like a leaf this sea slug looks.

E chlorotica lives in a vanishingly small range on the eastern seaboard of the USA, and it's poorly studied. How it keeps the chloroplasts functioning for so long might be because the slug itself has integrated some of the algal genes that support the chloroplasts, although the science on this is out. And the rareness of the animal and the difficulties with studying it in the lab mean answers might not be forthcoming any time soon.


Picture source: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0097477

Animal of the Week, February 5, 2019 — one of our pandas is missing

A little bit belatedly to this week's animal, for it is the red panda (Ailurus fulgens), one of which had a brief excursion in the Northern Irish city of Belfast. This particular fluffball escaped from Belfast Zoo on Sunday January 27 had a merry stroll around the area of Glengormley before being captured on Monday an returned to its enclosure.

Poor panda must have been pretty confused, because Belfast (although I have never been) can't be much like the temperate montane forests of the Himalayas (Nepal, Tibet, and India) and Burma and China whence the red panda originates. Although their ranges and food sources overlap, red pandas aren't that closely related to giant pandas. In a family of their own (Ailuridae), red pandas are more closely related to raccoons, skunks, and weasels than to bears, the family to which giant pandas belong.

Nonetheless, both species of pandas have endearing facial markings and a penchant for bamboo. Another quirk possessed by both species is the so-called panda's thumb. Not a thumb at all, but a projection of a wrist bone, the appendage helps both species grasp onto and manipulate bamboo while feeding.

Both species of panda are also endangered, with wild individuals threatened by habitat loss and poaching. But fortunately for both species, their attractiveness makes them popular zoo animals and captive breeding programmes can help to conserve red panda, which is somewhat more reliable as a breeding animal in captivity than it's black and white namesake.

The Latin name, Ailurus fulgens, means "shining cat".


The zoo escape gave a brief foray into the urban environment for the panda and a tiny bit of a break from Northern Ireland only ever being mentioned in conjunction with the word "backstop". Still, the pandas home now and normal service has resumed.