Temperature influences the premating period of insects. However many studies stop short and fail to account for both post-diapause adult emergence and 1st generation adult emergence, when developing complete temperature-dependent life-cycle phenology models for bi/multivoltine species. Post-diapause adult development (spring occurrence for temperate species) and post-eclosion adult development (summer occurrence) often involves recuperating energy levels through feeding (no nutritional uptake during overwintering and pupae stages respectively) and advancing towards sexual maturity (although some species can obtain sexual maturity prior to overwintering meaning the insects can reproduce as soon as environmental conditions improve). These stages are fundamentally linked with diapause occurrence and seasonal temperature conditions differing. Obtaining post-diapause development data can be straight forward depending on species overwintering locations. However anyone that has attempted to rear insects is aware of the difficulty in rearing healthy additional generations from a parent population to allow for monitoring of pre-oviposition development (particularly for insects with long development requirements and low survival rates).
My question is as above: is there any temperature dependent temporal relationship between the sexual maturation requirements for post-diapause parent spring emerging adults and post-eclosion 1st generation summer emerging adults i.e. if pre-oviposition data for post-diapause spring adults was compared to pre-oviposition data for post-eclosion summer adults, would one see a crude ratio like 1:2 in development time required at different constant temperature (20°C ≈7days and ≈14days respectively)? Results based on published or personal communications very welcome!
Hi Ciaran, Nice question. I suppose I can try to understand this question better in terms of how reproductive traits are formed and affected in adults that are seasonal. For example, if you look at the paper by Vermeulen et al. 2009 when studying scorpionflies, they showed that seasonality/larval history influenced the expression of sperm length. Although there is no relationship given in this article (see attached), I feel that temperature has a strong influence in the sexual maturation of many poikilotherms. Look up the effects of thermal environments on the expression of traits, as this could be central to your work + some papers by Froster et al. 2011; Atkinson, D...I will see if i can get hold of it from some where and send it across..Hope this is useful..Thanks for posting the question...
Although you can presizely measure the pre-oviposition period of the new generation, which begins at the time of emergence of adult female from pupa (or last larval instar), it is difficult with post-diapause individuals. First, you must be sure that diapause is over. Often the studies on diapause termination include some time before diapause end and then the true post-diapause development of gonads and oocytes. Second, on contrary, you may not allow the individuals to start to develop before your experiment begins. There must be sharp start, from low temperature storage. If this post-diapause pre-oviposition period is measured like this, I believe the times will be 1:1. It means that the post-diapause individuals start with similar level of gonad development as new emerging individuals. Sometimes it is not the case, there might be well developed ovaries in pupa in many Lepidoptera etc.
This paper may be of interest to this topic under discussion.
Hodek, I. 2003. Role of water and moisture in diapause development (A review). European Journal of Entomology: 100 (2) 223–232.
It discussed the data supporting water or moisture as needed for post-diapause resumption of morphogenesis and moisture as diapause terminating cue.
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