Expansion of the winter moth outbreak range : no restrictive effects of competition with the resident autumnal moth

1. Both direct and indirect competition can have profound effects on species abundance and expansion rates, especially for a species trying to strengthen a foothold in new areas, such as the winter moth (Operophtera brumata) currently in northernmost Finland. There, winter moths have overlapping outbreak ranges with autumnal moths (Epirrita autumnata), who also share the same host, the mountain birch (Betula pubescens ssp. czerepanovii). Competitive interactions are also possible, but so far unstudied, are explanations for the observed 1–3 years phase lag between the population cycles of the two moth species. 2. In two field experiments, we studied host plant-mediated indirect inter-specific competition and direct interference/exploitation competition between autumnal and winter moths. The experimental larvae were grown either with the competing species or with the same number of conspecifics until pupation. Inter-specific competition was judged from differences in pupal mass (reflecting lifespan fecundity), larval development time and larval survival. 3. Larval performance measurements suggested that neither direct nor indirect interspecific competition with the autumnal moth reduce the growth rate of winter moth populations. Winter moths even had a higher probability of survival when reared together with autumnal moths. 4. Thus, we conclude that neither direct nor indirect inter-specific competition is capable of suppressing the spread of the winter moth outbreak range and that both are also an unlikely cause for the phase lag between the phase-locked population cycles of the two moth species

Larval parasitism of the autumnal moth reduces feeding intensity on the mountain birch

Plants respond to grazing by herbivorous insects by emitting a range of volatile organic compounds, which attract parasitoids to their insect hosts. However, a positive outcome for the host plant is a necessary precondition for making the attraction beneficial or even adaptive. Parasitoids benefit plants by killing herbivorous insects, thus reducing future herbivore pressure, but also by curtailing the feeding intensity of the still living, parasitised host. In this study, the effect of parasitism on food consumption of the 5th instar larvae of the autumnal moth (Epirrita autumnata) was examined under laboratory conditions. Daily food consumption, as well as the duration of the 5th instar, was measured for both parasitised and non-parasitised larvae. The results showed that parasitism by the solitary endoparasitoid Zele deceptor not only reduced leaf consumption significantly but also hastened the onset of pupation in autumnal moth larvae. On the basis of the results, an empirical model was derived to assess the affects on the scale of the whole tree. The model suggests that parasitoids might protect the tree from total defoliation at least at intermediate larval densities. Consequently, a potential for plant–parasitoid chemical signalling appears to exist, which seems to benefit the mountain birch (Betula pubescens ssp. czerepanovii) by reducing the overall intensity of herbivore defoliation due to parasitism by this hymenopteran parasitoid

Trophic interactions and cyclic population dynamics of the autumnal moth: the importance of hymenopteran parasitoids

Siirretty Doriast

Responses of generalist invertebrate predators to pupal densities of autumnal and winter moths under field conditions

1. Generalist natural enemies are usually not considered as being capable of causing population cycles in forest insects, but they may influence the population dynamics of their prey in the low density cycle phase when specialist enemies are largely absent. 2. In the present field study, the total response of the generalist invertebrate predator community to experimentally established pupal densities of the closely related autumnal (Epirrita autumnata) and winter moths (Operophtera brumata) was analysed. 3. Due to the high amount of variation in the dataset, the exact shape of the response curve could not be convincingly estimated. Nevertheless, two important conclusions can be drawn from the analyses. 4. Firstly, the natural invertebrate predator community seems to become saturated at rather low densities of both autumnal and winter moth pupae. Secondly, the predator community seems to become saturated at much lower densities of autumnal than of winter moth pupae. 5. Furthermore, pupal mass was significantly negatively correlated with invertebrate predation probability in autumnal moth pupae. 6. These results indicate that differences in the predator assemblage being able to consume pupae of the two moth species, as well as different handling times, could be responsible for the substantially higher predation rates in winter than in autumnal moth pupae. 7. As a consequence, the population dynamics of autumnal moths might be less affected by generalist invertebrate predators than those of winter moths, as autumnal moths seem able to escape from the regulating influence of generalist predators at much lower population densities than winter moths

Reversed impacts by specialist parasitoids and generalist predators may explain a phase lag in moth cycles : a novel hypothesis and preliminary field tests

Among cyclic populations of herbivores, inter-specific temporal synchrony has been attributed to both climatic factors and trophic interactions. In northern Europe, winter and autumnal moths undergo regular 9–11 year population cycles. The winter moth cycle has typically been phase-locked with that of the autumnal moth, but with a 1–3- year phase lag. We examined potential effects of natural enemies on this phase lag using field experiments and observational data. We found that larval parasitism was significantly higher in autumnal than in winter moths. Conversely, pupal predation by generalist invertebrates was clearly greater in winter than in autumnal moths. The difference in parasitism rates may contribute to the earlier collapse of the autumnal moth cycle. In addition, the phase lag may be strengthened by higher pupal mortality in winter moths in the early increase phase of the cycles. As a consequence, we put forward a hypothesis on reversed effects of natural enemies, providing a potential explanation for phase-lagged population cycles of these moth species

Mie ite -ryhmä vanhemmuuden tukena : Vanhempien kokemuksia ryhmästä Vuoksenniskan vuoropäiväkodissa

Tämän opinnäytetyön tarkoituksena oli selvittää vanhempien kokemuksia Kaakkois-Suomen sosiaalialan osaamiskeskus Socomin Mie ite - ryhmätoimintamallista. Mie ite -ryhmä on tarkoitettu alle kolmevuotiaiden lasten vanhemmille. Ryhmän tarkoituksena oli antaa vanhemmille kasvatuksellista tukea ja samalla tarjota vertaistukea. Opinnäytetyö oli työelämälähtöinen, ja siinä kokeiltiin toimintamallia yhteistyössä varhaiskasvatuksen ja perheneuvolan kanssa. Lisäksi selvityksessä kuvataan Mie ite -ryhmätoimintamalli sekä tuotetaan kehittämisehdotuksia. Opinnäytetyön tutkimusote oli kvalitatiivinen. Ryhmään osallistuneilta vanhemmilta kerättiin tietoa kyselylomakkeilla syksyllä 2012 liittyen vanhemmuuteen ennen ja jälkeen ryhmätoiminnan. Lisäksi tietoa opinnäytetyötä varten saatiin havainnoimalla ryhmää. Vanhempien täyttämistä kyselylomakkeista saatu tieto analysoitiin aineistolähtöistä sisällönanalyysiä käyttäen. Selvityksestä ilmeni, että Mie ite -ryhmä tuki vanhemmuutta. Positiivisuus van-hemman ja lapsen vuorovaikutuksessa lisääntyi. Vertaistuki koettiin voimaan-nuttavaksi ja Socomin Mie ite -ryhmätoimintamalli toimivaksi. Tässä opinnäytetyössä selvitettiin vanhempien kokemuksia ryhmätoiminnasta ja siitä, kuinka se tuki vanhempien kasvatustyötä. Jatkotutkimuksessa voisi selvittää, millaisia toiveita vanhemmilla on päiväkodin ja vanhempien yhteiselle kasvatuskumppanuudelle tai kantoiko perheitä ryhmästä saatu tuki myöhemmin.The purpose of this study was to examine parents' experiences of group support intended for parents who have children under three years old in the Vuoksenniska Day Care Centre. The South-East Finland Social and Welfare Centre of Expertise, Socom´s, sponsored the group, and the purpose was to provide educational support for parents, and to provide peer support. This thesis was from working life which was tested as a pilot approach to early childhood education, and collaboration with family counseling. Thesis research method was qualitative. Data for this thesis was collected from parents with questionnaires before and after the group. Information which was received from the parents was analyzed using content analysis method. The final result of this thesis was that the support group helps with parenting. Having a positive attitude and interaction between the child and the parent was increased. Peer support was seen as empowering. This thesis examined parents' experiences of the group and how it will support parenting. Further study would be interesting to explore what kinds of wishes parents have for parenting support between day care center and parents, and has support received from the group continued to help families later

Appendix C. Two tables with descriptive information about the larval parasitoids reared from autumnal moths.

Two tables with descriptive information about the larval parasitoids reared from autumnal moths

Appendix A. Four color photographs of the study site showing experimental cages and supporting results of the parasitoid-exclusion experiment.

Four color photographs of the study site showing experimental cages and supporting results of the parasitoid-exclusion experiment

Appendix B. Graphs providing abundance data for each replication unit of the parasitoid-exclusion experiment.

Graphs providing abundance data for each replication unit of the parasitoid-exclusion experiment