A model for the photoperiodic counter in the aphid Megoura viciae

Sex versus parthenogenesis: A transcriptomic approach of photoperiod response in the model aphid Acyrthosiphon pisum (Hemiptera: Aphididae)

“…However, when they are reared under short photoperiods (longer nights and shorter days, characteristic of autumn and winter), they switch to produce sexual females and males usually after two generations (Simon et al, 2002). It has been demonstrated that the critical light regime for production of sexual morphs (the length of the dark phase) is very precisely measured by a yet unknown internal clock and a counter to determine the number of inductive nights necessary to trigger the switch (Lees, 1973;Nunes and Hardie, 1993;Hardie and Nunes, 2001). In order to promote the switch to sexuality, changes in the photoperiod must be detected and transduced into a, not yet understood, cascade of sensory, neural, endocrine and molecular events that will result in modification of gene expression leading to the sexual phenotypes (reviewed in Tagu et al, 2005).…”

Quantitative response to photoperiod and weak coupling between seasonal morphs and diapause regulation in the Asian comma butterfly, Polygonia c-aureum (Lepidoptera: Nymphalidae)

“…If the critical photoperiod is not precise then under a near critical photoperiod, the individual may respond by perceiving the photoperiod as either a short or long photoperiod, or both. However, this does not explain the results of other studies that indicate a quantitative measurement of photoperiodic time (Kimura, 1990;Spieth & Sauer, 1991;Vaz Nunes & Hardy, 1993;Numata & Kobayashi, 1994;Nakamura & Numata, 2000;Saunders, 2002;Goto, 2009Goto, , 2013Tagaya et al, 2010). Several insects respond to photoperiod and/or thermoperiod quantitatively (Tauber & Tauber, 1972, 1973Butterfi eld, 1976;Kimura et al, 1982;Taylor & Schrader, 1984;Horwath & Duman, 1986;Kim, 1996;Fantinou et al, 2004).…”