Searching for Relative Intestinal Lengths of Xenotilapia

[Gerd]

Hello,
Reflecting questions about the right diet for Xenotilapia from the rocky habitats,
(e.g. X. spiloptera, X. papilio, X. leptura)
I’m searching for informations about their “Relative Intestinal Lengths”, a parameter, that tells a lot about nutrition.
I found parameters about some other Xenotilapia, from the sandy habitats, ranging from 0,8:1 to 1,2:1. (Thank you, Estelle and Benoit for publishing the original descriptions of M. Poll on your extraordinary site!) But unfortunately I can’t find informations about the species listet above and I presume, they are far longer! (from 2:1 to about 3,5:1 ??)
Does somebody know?
Or can give me a link, where to search for information?

Thank you!
Regards
Gerd

[Thomas Andersen]

Hi Gerd,

I should be able to find the intestinal lengths in my notes somewhere, just give me a day or two.

Until then, here is the result of Büscher's examination of the gut-content of Xenotilapia papilio:

90 % Ostracods
10 % Copepods, insect larvae, algae, sand.

Thomas

[Gerd]

Hello Thomas!

I should be able to find the intestinal lengths in my notes somewhere

FINE !!
I knew, I could reckon on you!
THANKS FOR YOUR EFFORT !

just give me a day or two.

I'll even give you three!

90 % Ostracods

That's astonishing. I would have supposed more unidentified organic material, detritus. But Ostracods, living on and from detritus, sure correspond to a more or less detritivorous nutrition.
Would "selective detritivorous" be an appropriate definition?

Regards
Gerd

[Thomas Andersen]

Actually Büscher label X. papilio as a zoo-benthivore, apparently sifting the layers of detritus, eating anything ediable, and then expelling the non-editable parts (in this case detritus), just like the species found on the pure sandfloor would do with sandgrains.

Thomas

[Gerd]

Hello!
Thats interesting! So I was probably wrong, supposing a longer RIL.
Now I eagerly wait for data. Those for X. leptura too.
Thank you!
Gerd

[Thomas Andersen]

Well Gerd, I have checked my notes and several papers, and I can't find any data on the gut-length of A. leptura and X. spiloptera - I was quite certain I had the data somewhere, sorry.

But, I did find some references for the diet of A. leptura - 220 specimens were examined and the gut-content were:

48 % filamentous algae

52 % unicellar algae

0 % (!!) crustaceans, insect larvae, debris, sand.

The original description of X. spiloptera mentions nothing on external morphological features, so there's no data on gut-length, but I think it's similar to many other species of Xenotilapia, that are predominately carnivorous micro-predators of small crustaceans and insect-larvae.

Thomas

[sidguppy]

wow

that means that Asprotilapia is fairly unique in Ectodines as being a true herbivore....it really IS a grazing fish, even more so than the well known Tropheus and Petrochromis


no wonder then that most people that bought the Aspro's here a few years ago, lost them. it had been a long time since Verdyuij had them, more than 10 years.
then they suddenly had a shipment wich sold really well. but a while after that none of the hobbyists I spoke still had live ones.

most lost them to bloat.....probably didn't expect a 'sandcichlid' to be even more suspectible to it than Tropheus.

[EC]

But, I did find some references for the diet of A. leptura - 220 specimens were examined and the gut-content were:
48 % filamentous algae
52 % unicellar algae
0 % (!!) crustaceans, insect larvae, debris, sand.

X. leptura live on algal carpet and in adult stage feed only in algae. Only juveniles have algae/small crustaceans diet.
X. spiloptera have a more complete diet and feed like juvenile leptura with small crustaceans, algae and all they can eat.

Ciao Enrico

[Thomas Andersen]

Yes, it is remarkable, and indeed a great hint at their needs in the aquarium.

Gut content of some other Ectodines:

Ophthalmotilapia nasuta:

62 % unicellar algae
24 % debris
6 % insect larvae
4 % agar-like substance
2 % crustaceans
2 % sand

Ophthalmotilapia ventralis:

42 % debris
39 % filamentous algae
15 % insect larvae
2 % unicellar algae
2 % sand

[Gerd]

Hello to all!
Thank you Thomas, for your efforts, and thank you Enrico, for the additional informations about X. spiloptera!

48 % filamentous algae
52 % unicellar algae
0 % (!!) crustaceans, insect larvae, debris, sand.

100% herbivorous! Though I would have expected a diet, like the one of Tropheus or Eretmodus, I am surprised about 100%. I read about Petrochromis orthognatus (RIL 6,4 !)that even his diet has a rate of 3,4% crustaceans and larvae.
But I admit, I'm even more astonished about the diet of X. papilio

90 % Ostracods
10 % Copepods, insect larvae, algae, sand.

I would have expected X. papilio beeing by a higher rate herbivorous.

X. leptura live on algal carpet and in adult stage feed only in algae. Only juveniles have algae/small crustaceans diet.

That is corresponding with what is reported from other Aufwuchs-eating species. Juveniles need higher percentage of easily digestible proteins. And Sturmbauer e.a. report, that juveniles have a shorter RIL, compared to adults of the same species.
An highly interesting article about trophic specialization can be found here, if you download the pdf.
http://www.springerlink.com/content/b17253888v1t1130/

that means that Asprotilapia is fairly unique in Ectodines as being a true herbivore

I'm concerned with questions like this since fairly long time. And may I offer you another result, that astonished ME,!(Maybe not you)
The RIL for Ectodus is 1,0 - No surprise!
But would you have expected 3,5 for Lestradea? And 4,0 for Cardiopharynx?
For comparison: Eretmodus 2,5 Tropheus moorii 4,8
So I learned, never feed Lestradea, like you feed Ectodus!
Regards
Gerd

[EC]

That is corresponding with what is reported from other Aufwuchs-eating species. Juveniles need higher percentage of easily digestible proteins. And Sturmbauer e.a. report, that juveniles have a shorter RIL, compared to adults of the same species.
An highly interesting article about trophic specialization can be found here, if you download the pdf.
http://www.springerlink.com/content/b17253888v1t1130/

Thank you! First time I saw X. leptura in Kambwimba was a big surprise. Not only for diet but for very long parental care (3cm. fry) and because they chase competitive feeders like red rainbow, eretmodus and petro from his territory (usually a big plate rock full of filamentous algae) or A. fasciatus and telmato when they want to prey leptura fry.

Ciao Enrico