This research investigated the temperature and light requirements for seed germination and emergence patterns of pinnate poppy, violet horned-poppy, and nodding hypecoum, three annual Papaveraceae species found in arable lands in the Mediterranean region. Two experiments performed in growth chambers (1) analyzed light (complete darkness or 12 h light) and temperature (10/5, 15/5, and 20/10 C day/night temperatures) requirements for germination, and (2) determined base temperature (Tb) for germination. An outdoor pot trial was also set up to study emergence patterns. All species showed higher germination in complete darkness than they did with a light regime, irrespective of dormancy level, time of the year, and temperature regime under which germination was tested, illustrating better germination when seeds are buried. Tb ranged from −2.6 to 0 C, depending on the species, indicating low temperature requirements for germination. Given their higher germination in daily fluctuating, rather than constant temperatures, the three Papaveraceae species should have the capacity to form persistent seed banks. These species behaved as winter annuals (from November to February) in the pot experiment and had difficulties to emerge in spring. Given that they cannot avoid autumn–winter chemical treatments, this could partially explain their regression in arable fields. These results bring new information to develop management strategies for these Papaveraceae species in agroecosystems.

To estimate the net effect of climate change on natural populations, we must take into account the positive and negative effects of temperature oscillations and climate variability. Warming because of climate change will likely exceed the physiological optima of tropical insects, which currently live very close to their thermal optima. Tropical insects will be negatively affected if their optima are exceeded otherwise warming may affect them positively. We evaluate the demographic responses of the cowpea aphid, Aphis craccivora, to summer warming in subtropical and tropical Taiwan, and examine the effects of diel temperature oscillation on these responses. Aphids were reared at four temperatures (current summer mean, +1.4, +3.9 and +6.4 °C), the latter three simulating different levels of warming. At each average temperature, aphids experienced constant or oscillating (from −2.9 to +3.6 °C of each mean temperature) regimes. As the simulated summer temperatures increased, so did the negative effects on life-history traits and demographic parameters. Compared with aphids reared in constant temperatures, aphids reared in oscillating temperatures developed more slowly and had a longer mean generation time, but their net reproductive rate was higher. These findings demonstrate that climate warming will affect demographic parameters and life-history traits differentially. Studies that use constant temperatures are unlikely to accurately predict biotic responses to climate change.