Ly Lindman will defend her doctoral thesis titled "The ecology of protected butterfly species in Estonia" on 12 February 2016 at 10.15 at the Vanemuise 46, room 301.
Supervisors: professor Toomas Tammaru (TÜ ÖMI); Jaanus Remm, PhD (TÜ ÖMI)
Opponent: Josef Settele, PhD (Helmholtz Centre for Environmental Research – UFZ, Saksamaa)
Summary: Numerous European butterflies are declining. To develop successful conservation practices it is necessary to understand the basic ecological requirements of the endangered species. The presence of a suitable host species is the main criterion for herbivorous insects. The importance of the host plant is different for monophagous (feeding only on one host species), oligophagous (feeding on few related species) and polyphagous (feeding on wide range of host species) insects, as well as host plant use may vary geographically. Therefore, it is vital to know whether any endangered species has more specific food preferences locally than believed for the region as whole. I explored the importance of host plant in Estonia for endangered buttefly species Lopinga achine, Coenonympha hero, Lycaena dispar, Euphydryas aurinia and E. maturna, using different laboratory experiments, field work and analyses of distribution. We found out that L. achine and C. hero are polyphagous, so the presence of a certain plant species does not determine the habitat quality or limit the distribution of these butterflies. Still, C. hero seems to have preferences at microhabitat level. Primary host plant for L. dispar in Estonia is the broad-leaved dock (Rumex obtusifolius), which is consistent with the results contry-wide distribution analyses: this butterfly species prefers areas with ditches and human settlemen, these factors likely creating favourable conditions for the host species. E. aurinia appears to be functionally monophagous on devil's-bit scabious (Succisa pratensis), which has remained the only confirmed host plant in the country. E. maturna is related to ash (Fraxinus excelsior): caterpillars have been found only on ash trees in the wild; the butterfly species is distributed only in the areas where the host species is present. Assessment of the conservation status of the five butterfly species was not among the aims of the present study. However, there is no direct evidence of decline for any of these species in Estonia. The conservation status of all five butterfly species appears favourable. Although the the future of E. aurinia and E. maturna looks more uncertain due to changes in agriculture practice and a fungal disease which affect their main host plants. Local populations of these five butterfly species may still require attention. Also, the information gathered must be used in other regions where these species may be of higher conservation concern.