Diapause

Sunday, January 10th, 2010 7 10 /01 / Jan /2010 16:28

Larvas
:

The embryonic diapause at Camponotus ligniperdus is inevitable for larvas stemming from last eggs laid by the queen in the beginning of summer. It is an indispensable condition which is going to allow them to resist at best low temperatures wintry. She(it) also takes place in captivity even if the temperatures are more clement. This diapause is thus essential for this sort(species). She(it) is conditioned(packaged) by an internal clock.

On our colonies(summer camps) of breedings, this diapause begins earlier in the year (July / August), when in natural environment. She(it) is always connected to the constraints which we impose them in captivity. Colonies(summer camps) having "gone out" more prematurely than in the nature (between February and April in breeding, rather between the end of May and July in situ), they will thus begin to slow down their development earlier in these conditions (gap of the cycle of development). According to my some observations the workers will even go as far as taking away the brood, for the largest number, from the source of heat, a part(party) however Ira until the complete development.

Larvas generally stop their growth at the stage(stadium) II, but for a small percentage of them the development can continue (stage(stadium) III and IV) *, however, it does not mean that the fresh(cool) temperatures are them credibly fatal during low temperatures. During this period larvas are in priori more fed or little, by the workers. Their development stops totally, they take then a yellowish color which we do not find in summer. To note also, a little rachitic aspect of the whole brood. Larvas train(form) aggregations during the same period.


* Differences of sizes to larvas to be noted below.

Diapause larvaire chez Camponotus ligniperdus

Diapause larvaire chez Camponotus ligniperdus

Diapause larvaire chez Camponotus ligniperdus


The queen :

The queen has a seasonal cycle of heavyweight(laying,eggs) which begins several days after the rise(ascent) of the temperatures in spring. This lapse of time where she(it) begins again to lay, is short, because it will stop after less than hundred of days of activity. This cycle according to my observations is relatively regular during the years and in the term of this one the reproductive device of the queen will stop working until the next year. The ambient temperatures allow the queen to adjust the cycle of heavyweight(laying,eggs) over the year but be that as it may conditions in which the colony(summer camp) is, the colony(summer camp) will pass necessarily by a diapause. To deprive the colony(summer camp) of the real period of cold is not certainly recommended at this sort(species), the ovarian rest is indispensable for the gyne, so as to begin again again in the best conditions a new cycle of heavyweight(laying,eggs).


The workers :


The workers also undergo a diapause, a wintry dormancy. When larvas stop(arrest) their development at the end of the summer the workers are not any more requested by these last ones and begin to decrease their activities and to reduce also any outside fourragement abandoning the protein contributions (insects) but continuing to feed with sweet liquids. They train(form) then henceforth aggregates within the nest, so as to save as much as possible their energy expenditure. The workers and the queen are directly affected(allocated) by low temperatures and their movements become slow and irregular. In captivity in approximately 10 °, some workers can be observed in the area of harvest, but they are little compared with the periods of full activity. Between 0 and 5 ° the workers are globally all in the nest, motionless, immovable, lethargic and curiously can be completely scattered in these conditions!

- According to the notes that I was able to pull(fire) my some observations a small formula could be applied …


== > date of exit(release) of diapause +
±15 days + ±104 days = preparation for the piece of news(short story) diapause

Camponotus ligniperdus nature hiver forêt

By Chris. - Published in: Diapause
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