Another manuscript out in the open:
“Desiccation plasticity and diapause in the Argentinian pearlfish Austrolebias bellottii”
We (Irma Varela Lasheras and myself) did detailed demographic work on A. bellottii embryos and found that these respond relatively little to being incubated in either water or air with high humidity. The eggs were incubated in multiwell plates, and this allows a very easy follow-up of the embryos, and a good yield of developed embryos. I am happy with the results and they take me all the way back to the start of my PhD thesis, when I read Prof. Michio Hori‘s thesis on Cicindela japonica, in which he did a demographic study of three stages of tiger beetle larvae with graphs similar to the one I show in this post.
This afternoon I wanted to capture some Chaoborus to feed my adults. DIfficult… The amount of rain has been so much the pumps aren’t draining the area enough.
It’s almost February, time to start raising this year’s new breeders. I’ve started at home, with bags from Uruguay and Argentina that I stored for four months (Thanks Heber Salvia, thanks Ricardo Rojas, thanks Rafael Mitre Muñoz!). The photo is the moment where I put the peat+eggs in small containers with some extra peat. I add half a cm or one cm of 15C rain water. All containers then go inside a small incubator at about 22 degrees C. Result: 23 cheradophilus “la Paloma”, some 15 vandenbergi Talon Cansado, melanoorus Tranqueras, arachan Bañado del Chuy, duraznensis Paso de san Borja, alexandri San Javier, El Bulin and El Pingo. Not bad to start the year with! Some other fish here at home will have to move soon!
I just started a trial for another heating method to store my Austrolebias eggs through winter. I tacked IR heating foil to the ceiling, right above the cupboard on which I store my eggs. Contrary to heating cables I tried before, the foil doesn’t become very hot. The heat radiates well. Previous years, I used to put heated aquaria in between my peat boxes but the warmth never distributed well. My first impression is that this new thing will work better. Soon more on this with the data from the logger I put with the eggs.
There’s a lot of snow, but temperatures aren’t that low. I did overlook some blackworm (Lumbriculus variegatus) cultures that were standing outdoors. After few days of frost, there was little water left unfrozen, but the worms in there were doing fine. I’ve moved them to a warmer spot.
The culture works like this: small 1 liter container, two strips of filter sponge, aged and rain water. The worms settle on the sponges. They eat (vegetarian) fish food. Multiplication rates are not high now, as it is cold, but the blackworms doubled in number in a bit over a month. After winter, I’ll try this on a larger scale, maybe with an airstone or some Daphnids added.
Monday staff from the ECOTRON fixed a small Herp Nursery Peltier-incubator for me, which took them about half an hour.
Apparently, the poor thing had been standing in very low temperatures for too long, and the continuous heating had destroyed the Peltier element which heats and cools the incubator. That turned out to be a small 4 x 4 centimeter plate. Impressive that this is the core of the machine.
I’ve borrowed this photograph from an online shop.
Peat is what we need, as substrate for the Austrolebias parents to lay their eggs. Instead of boiling it (which I sometimes do in a rice cooker), I just heat it for a few days in a tank in full sun. The peat sinks after warming up sufficiently, and I use it straight away.
Some species that are dead easy to raise on Artemia in a fish room, are a bit more trouble in “greened” conditions. Suddenly, I find Austrolebias nigripinnis difficult. The alevins are small, and when the temperatures are a bit low they grow relatively slowly. Meanwhile, the small pond food which I have carefully sieved out for them, has increased a lot in size. Nigripinnis gets eaten, can’t pick the food, end of story. So I definitely need to add Artemia the first week so that they don’t starve, and I will postpone hatching them to later dates, so that cold nights are not occurring anymore.