Intergenerational acclimation in aphid overwintering

Abstract

1. When first instar nymphs and adults of the grain aphid Sitobion avenae (Fabricius) (Hemiptera: Aphidiae) were maintained in long‐term cultures (>6 months) at 20 °C and 10 °C, the LT50 decreased from −8 and −8.8 °C to −16.0 and −13.5 °C, respectively. 2. When aphids from the 20 °C culture were transferred to 10 °C, there was a progressive increase in cold tolerance through three successive generations. Transfer of newly moulted pre‐reproductive adults reared at 10 °C for three generations back to 20 °C resulted in a rapid loss of cold hardiness in their nymphal offspring. 3. In all generations reared at 10 °C, first born nymphs were more cold hardy than those born later in the birth sequence. The LT50 of nymphs produced on the first day of reproduction in the first, second and third generations maintained at 10 °C were −14.8, −17.0 and −16.6 °C, respectively. Thereafter, nymphal cold hardiness decreased over the subsequent 14 days of reproduction in each generation at 10 °C with mean LT50 values of −10.3, −12.6 and −14.8 °C, respectively. By contrast, the cold tolerance of first born nymphs of aphids reared continuously at 20 °C did not differ in comparison with later born siblings. The LT50 of adult aphids was also unaffected by ageing. 4. The ecological relevance of these findings is discussed in relation to the overwintering survival of aphids such as S. avenae.

The effect of landscape complexity and microclimate on the thermal tolerance of a pest insect

“…This finding further suggests that seasonal thermal tolerance of aphids is conferred via phenotypic plasticity as opposed to genetic adaptation. Aphids, as with all organisms, can respond to variation in environmental temperature via phenotypic plasticity (Addo‐Bediako et al ., ; Ayrinhac et al ., ) and display a high degree of plasticity in their inherent thermal tolerance (Powell & Bale, ; Alford et al ., ,b). Natural selection is unlikely to favor unnecessary thermal tolerance and, as such, any acquired cold tolerance should be lost on cessation of winter temperatures.…”

Assessment of neuropeptide binding sites and the impact of biostable kinin and CAP2b analogue treatment on aphid (Myzus persicae and Macrosiphum rosae) stress tolerance

“…Survival curves were first established to determine a species‐specific discriminating temperature for subsequent neuropeptide testing. Aphids were selected at the pre‐reproductive adult stage for cold tolerance bioassays since aphid cold tolerance is known to significantly vary throughout an aphid's life cycle . Temperature ranges were selected to encompass 0–100% mortality.…”

Host range expansion of an introduced insect pest through multiple colonizations of specialized clones

“…2002). These range from lineages practicing cyclical parthenogenesis (hereafter named ‘sexual’ lineages) that yearly produce recombinant and frost resistant eggs, to fully asexual viviparous clones that do not thrive at freezing temperatures (Powell & Bale 2008). Strict parthenogenesis has accompanied the invasion of many introduced aphid species in warm regions throughout the world, leading to the spread of clonal lineages over wide areas and long timescales (Vorburger et al .…”