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I was wondering if anyone here has tried growing locusta migratoria only on wheat bran (+water), without additional food like cabbage or grass. Is it possible? Do they finish the whole cycle? Do they develop at a similar speed?
Locusta migratoria can not digest cellulose well & wheat bran is 19% cellulose. The L. migratoria in the wild is called a "grass specialist". I see no logic trying to rear them on a bran diet.
@gringojay Thank you for your reply.
I noticed while breeding them that if provided wheat bran, they do eat it even when grass is provided ad-libitum. Was wondering if they could be kept just on the bran, since it is cheap, easy to store and widely available for purchase.
I know that it is not recommended to give large amounts of bran to horses for example, because of its unsuitable Ca x P ratio, don't know if something like that is at play with locusts as well.
As far as I know, grass contains somewhere around 30% cellulose, eg. https://www.hindawi.com/journals/bmri/2012/303748/ , so that shouldn't be a problem?
There are several studies of how L. migratoria adjusts feed intake based on protein & carbohydrate levels it can get from a meal; they basically self-select for themselves with input from chemo-receptors in mouths. Apparently, in the wild they can find the right balance based on how much of any one type of grass it eats at one meal among all the different grasses there are in the habitat. Their meal frequency (interval between eating) & feeding duration for any one meal have been found to vary with high protein or low protein intake.
Your bran samplers may be using it for the available carbohydrates required for specific growth stages. The bran's ~56% available carbohydrates has been shown to be a dietary selection to ingest lots of carbohydrates without also ingesting a lot of water in the process (ie: it avoids loading locust with excess water to cope with as it self-selects for it's temporary adjustment of available nurient intake ratio of carbohydrates to protein). As the (1970) study "The utilization of food by the adult female desert locust" team fount during their locust's period of somatic growth (but not when ovaryies growing) bran was preferred over lettuce (35% available carbohydrates).
Thank you for the info and the reference to the study. I will probably conduct an experiment, seems like while bran might not be ideal for all stages, it might provide nutrition for the whole cycle - will see if there is some slowdown or other problems.
A.T.Minks at Netherland's Wageningen university back in 1967 reared L. migratoria on "... compact bundles of food ... mainly grasses & young plants of several species of cereal, small leaves of lettuce, endive, cauliflower & curled kale ...."
Although the room itself was kept ar 30-32°C (relative humudity = 35-40%) red incandescent bulbs were arrayed to produce local temperature gradients from 30 to 45°C; which allowed the locust to "... select their favorite temperature." See free full text pdf available on-line (the English text begins after an introductory section) titled: "Biochemical aspects of juvenile hormone action in the adult Locusta migratoria."
Grass is high in potassium; the level goes down with grass' age & number of cuttings. Orchard grass for example is originally well over 4% to almost 5% potassium: while wheat bran is almost 1.2% potassium.
You may find this useful for elaborating their diet since " ... hoppers of any instar will march under ... same conditions ...." The point here to consider is that ample potassium (such as when grass fed) reduces hoppers' "... random movements...." I assume lots of marching episodes wastes their internal resources impacting the financial return of weight gain (market price) per unit of food cost.
Marching is apparently the migratory hoppers' natural response to seek more nutritious pasture &, at least in some respect, it is the potassium content of what they were eating which seems to give them a clue whether their feed nutrition is still suitable. Previous link above specified using a diet of "young plants"; which likely have higher % potassium than when same plants get older (plus less cellulose is in the young vs. older plants)
Observe your colony because when the locusta migratoria march it is with "... abdomen raised well off the ground, antennae erect & the frons perpendicular to the long axis of the thorax ...." In captivity if their enclosure has a light over it's center section then the marchers will "circumambulate" their container. See free full (1953) pdf available on-line: "A physiological interpretation of the marching of hoppers of the African migratory locust."