Aphis polaris Stekolshchikov et Khruleva, 2014

Khruleva, Olga A. & Stekolshchikov, Andrey V., 2019, Additions to the aphid fauna of Wrangel Island due to climate change with redescription of the oviparous female of Pterocomma groenlandicum Hille Ris Lambers, 1952 (Hemiptera, Aphidoidea), Zootaxa 4615 (3), pp. 511-528 : 518-519

Aphis polaris Stekolshchikov et Khruleva, 2014

Aphis polaris was described based on the material from the previous years, in which the fundatrices were more numerous than other morphs (viviparous and oviparous females). In 2014–2015, additional material of this species was obtained.

Material. The middle reaches of the Mamontovaya River: 2–12.vii.2014, pitfall trap, 6 fund. (collected by O.S. Starova); zoogenic glade with herb-grass cover above an uninhabited polar fox den (71° 10.455 N, 179° 45.255 W), 29.vi–22.vii.2015, pitfall trap, 1 apt., 1 ovip.; dry plots on sandy-pebble floodplain with willow-dryadforb cover, predominated by Astragalus alpinus L. (71° 09.523 N, 179° 45.328 W), 30.vi–23.vii.2015, pitfall trap, 2 fund., 5 apt., 1 al., 1 alatiform aptera, 4 ovip.; the same localities, 23.vii–5.viii.2015, pitfall trap, 21 ovip. Tundrovaya Mountain: southeast-facing slope of a hill with moss-herb-legume cover, predominated by Astragalus umbellatus Bunge (71° 18.468 N, 179° 49.045 W, 315 m a. s. l.), 1–19.vii.2015, pitfall trap, 2 fund. (collected by L.F. Volkova).

Biology. In the 1980s–1990s and 2006, Aphis polaris was the only aphid species found in high abundance in various parts of Wrangel Island; it has sharp year-to-year fluctuations in numbers ( Stekolshchikov & Khruleva 2014). In 2015, the distribution of A. polaris was more restricted than in 2006: almost all specimens were collected in one of the areas in the central mountainous region (the middle reaches of the Mamontovaya River) and in a more limited spectrum of biotopes than before. They were found predominantly on a high floodplain, where Astragalus alpinus , one of the main food plants of this species, was abundant (Fig. 12). Specimens of A. polaris were only col- lected in pitfall traps. In previous years, the fundatrices dominated in the samples during the entire collection period (including August), while viviparae and oviparae were collected as single specimens mainly in the first half of August. In 2015, as early as July 22–23, viviparous and oviparous females prevailed in the sample and in early August only oviparae were collected (for the first time in such a significant number). This suggests that the A. polaris life cycle is closer to that of the Low Arctic Acyrthosiphon brevicorne ( Strathdee & Bale 1996) than that of the High Arctic Acyrthosiphon svalbardicum ( Strathdee et al. 1993b, c) that retains a highly deterministic shortened life cycle despite climate warming ( Hullé et al. 2008).