Additional generations can only be induced when diapause or hibernation is facultative rather than obligatory (i.e. complete development requires a dormant period under cold temp). In the former case, simply preventing exposure to cold temp and/or short days will enable additional generations per year, although usually only one. There are no potential long term consequences, because if you released such insects, they were revert to dormancy under natural winter conditions. There are no ethical considerations. Breaking the laws of nature ??!! This is not about enforcing rules of human behavior. But if we were, what do you think large scale agriculture does?

Yes large scale agriculture is much similar. Specially, when we are using techniques like green house, etc to change the climate conditions to obtain more and more biomass.

Dear colleague,

Can you elaborate your question a bit. It seems to me that there is a contradiction when you are willing to engage an univoltine species in more than one generation per season instead in case when your season is longer than a year.

Regards

I am trying to establish the lab scale breeding of some grasshopper species, they typical have one generation per year. But in order to have adequate amount of biomass I need to have more than one generation per year.

Dear all,

I think that the question shouln't be be what are the consequences of such thing. But it will be better to ask how it is possible to know factors inducing diapause for an univoltine species and how it is possible to break such diapause by acting on the factors. In some species there were success for this.

Question modified......

Diapause in univoltine insects depend on physiological and genetic factors unique to the species. Factors controlling diapause in those populations are temperature and photoperiod. In some cases, food quality also plays a role in diapause induction. However, the main factors are the interaction between the daily temperature and the day length.

In grasshoppers, diapause could be facultative or obligated depending on the origin of the population. In populations with obligatory diapause, the population has been genetically selected for entering diapause to avoid the winter after a short summer season. Diapause in these populations can’t be reverted. Individuals need to undergo a diapause period before resuming normal development. In populations with facultative diapause, diapause can be averted by temperature, photoperiod or a combination of both

So, if the eggs of grasshoppers are provided with good temperature and the hatchings are provided with good temperature+photoperiod, the hatching can be saved.

If there is obligatory diapause, insensitive to photoperiod, you may possibly break it by topical application of hexane or 1% juvenile hormone analogue in acetone.

I think the good temperature + photoperiod should be provided to the parents generation. Personal advice.

Thanks for your suggestions.... I will try.. Hope it turns out.......

In addition the the info already imparted, some primarily univoltine species hedge their bets and have a proportion of individuals that fail tio diapause, a trait that can persist after many generations of selection for non diapause (I am talking about a moth I keep). Some species have, however, had diapause bred out of them through selection. Coldshock often breaks diapause but also exogenous 20 hydroxyecdysone can do the trick.