Northern Drosophila montana flies show variation both within and between cline populations in the critical day length evoking reproductive diapause

作者：Lankinen Pekka; Tyukmaeva Venera I^*; Hoikkala Anneli

来源：Journal of Insect Physiology, 2013, 59(8): 745-751.

DOI：10.1016/j.jinsphys.2013.05.006

• Adaptation
• Life cycle
• Cline
• Photoperiodic response
• Variation

Reproductive diapause, and its correct timing, plays an important role in the life cycle of many insect species living in a seasonally varying environment at high latitudes. In the present paper we have documented variation in the critical day length (CDL) for adult reproductive diapause and the steepness of photoperiodic response curves (PPRCs) in seven clinal populations of Drosophila montana in Finland between the latitudes 61 and 67 degrees N, paying special attention to variation in these traits within and between dine populations. The isofemale lines representing these populations showed a sharp transition from 0% to 100% in females%26apos; diapause incidence in the shortening day lengths, indicated by steep PPRCs. The mean CDL showed a clear latitudinal dine decreasing by 1.6 h from North to South regardless of the age of the lines, variation within the populations (i.e. among lines) in this trait being up to 3 h. The steepness of the PPRCs correlated with the age of the line and this trait showed no clear latitudinal dine. Further studies on a large number of lines from one D. montana population confirmed that while maintaining the flies in diapause preventing conditions in the laboratory has no effect on CDL, older lines had steeper PPRCs. High variation in CDL within and between D. montana dine populations is likely to be heritable and provide a good potential for the evolution of photoperiodic responses. Information on genetic variation in life-history traits, such as diapause, is of utmost importance for predicting the ability of insects to survive in seasonally changing environmental conditions and to respond to long term changes in the length of the growing period e.g. by postponing the timing of diapause towards shorter day length and later calendar date.

• 出版日期2013-8