Population Genetic Structure and Demography of the Critically Endangered Chequered Blue Butterfly (Scolitantides orion) in a Highly Isolated Part of Its Distribution Range

Abstract

Scolitantides orion is a butterfly species threatened in many European countries. In Poland, it survived in a single highly isolated area (Vistula River valley), which is an example of the dramatic decline in the population number. We studied the two largest remaining populations inhabiting opposite banks of the river. Mark-release-recapture studies showed that both populations were small, and they fluctuated in numbers, but adult individuals were twice as numerous on the western site. Genetic analyses were carried out using a mitochondrial (COI, ND5) and nuclear markers (Wgl, EF-1α, and microsatellite loci). We found out that genetic variation was low at both sites but higher in the smaller eastern population. This pattern is likely to be better explained by past distribution, when the butterfly, as a continental species used to be much more widespread in the east. However, the genetic differentiation between populations was low. This could suggest that the existing gene flow is facilitated by dominant regional wind direction, which may also contribute to a better genetic condition of the western population. Finally, a comparison of the obtained COI sequences with others available enabled us to reveal the phylogeographic pattern of the S. orion from different localities within its range.

Perishing rich, expanding poor: Demography and population genetic patterns in two congeneric butterflies

“…Values found for A. niobe (≈2.51/0.51/0.45), higher than for A. adippe , are within ranges reported in studies of declining nymphalid butterflies, such as Euphydryas aurinia (Rottemburg, 1775) in Britain (4.0/0.59/0.47) (Davis et al, 2021), Melitaea ambigua (Ménétriés, 1859) in Japan (3.5/0.59/0.57) (Nakahama et al, 2018), and Boloria aquilonaris (Stichel, 1908) (≈1.25/0.49/unreported) (Turlure et al, 2014) or Hipparchia semele (Linnaeus, 1758) (3.12/0.40/0.16) (De Ro et al, 2021), both in Belgium. Still higher values were reported for some endangered butterflies, such as the lycaenids Phengaris arion (Linnaeus, 1758) (5.93/0.67/0.62) (Rutkowski et al, 2009) and Scolitantides orion (Pallas, 1771) (7.83/0.55/0.50) (Czajkowska et al, 2020) both in Poland, or the papilionids Parnassius mnemosyne (Linnaeus, 1758) (6.4/0.73/unreported) in Hungary (Meglecz et al, 1998) or Parnassius apollo nevadensis Oberthür, 1891 (7.2/0.58/0.50) in southern Spain (Mira et al, 2017).…”

“…In our system, the expanding A. adippe displayed higher mobility than the threatened A. niobe. Mobility estimates increase with the area sampled (Stevens et al, 2010;Zimmermann et al, 2011), which was apparent by comparing mobility indices obtained separately for D and L with those for DL ( (5.93/0.67/0.62) (Rutkowski et al, 2009) and Scolitantides orion (Pallas, 1771) (7.83/0.55/0.50) (Czajkowska et al, 2020) both in Poland, or the papilionids Parnassius mnemosyne (Linnaeus, 1758) (6.4/0.73/unreported) in Hungary (Meglecz et al, 1998) or Parnassius apollo nevadensis Oberthür, 1891 (7.2/0.58/0.50) in southern Spain (Mira et al, 2017).…”

Incorporating genomics into insect conservation: Butterflies as a model group

“…Butterfly conservation actions have sometimes been guided by population genetics research (Czajkowska et al, 2020; Dincă et al, 2018; Joyce & Pullin, 2004; Kadlec et al, 2010; Mattila et al, 2012). The analyses of single or a few loci for estimating population genetics parameters are often limited (e.g., Ackiss et al, 2020; Dupuis et al, 2018) and neglect other important aspects in conservation biology, such as the genetic basis of adaptation in natural populations (Shafer et al, 2015).…”