Seed production of a masting dwarf shrub, <i>Vaccinium myrtillus</i>,  in relation to previous reproduction and weather

Selås, Vidar

doi:10.1139/b00-017

Cited by 66 publications

(70 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The cycle may recur when mast seeding is again favoured (Selås et al 2001a). Accordingly, the mast depression hypothesis states that it is the mast seeding of mountain birch that is responsible for the regular autumnal moth outbreaks in northern Fennoscandia (Selås et al 2001a; see also Selås 1997Selås , 1998Selås , 2000aSelås , 2000bSelås and Steel 1998;Selås et al 2001b).…”

Section: Introductionmentioning

confidence: 99%

Performance of the cyclic autumnal moth, Epirrita autumnata, in relation to birch mast seeding

et al. 2003

View full text Add to dashboard Cite

The mast depression hypothesis has been put forward to explain the 9- to 10-year population cycle of the autumnal moth (Epirrita autumnata; Lepidoptera: Geometridae) in northern Fennoscandia. We analysed long-term data from Finnish Lapland in order to evaluate the critical assumption of the mast depression hypothesis: that better individual performance of herbivores, followed by high annual growth rate of populations, occurs in the year following mast seeding of the host, the mountain birch ( Betula pubescens ssp. czerepanovii). Since mast seeding has been suggested to occur at the expense of chemical defence against herbivores, we bioassayed the quality of birch leaves from the same trees by means of yearly growth trials with autumnal moth larvae. We also measured the size of wild adults as a determinant of potential fecundity of the species in different years. The relative growth rate of larvae was poorer in post-mast years compared to other years, rather than better as assumed by the hypothesis. Conversely, a slight indication of the increase in potential fecundity was observed due to the somewhat larger adult size in post-mast years. Population growth rate estimates, however, showed that the increase in fecundity would have to be much higher to facilitate population increase towards a cyclic peak with outbreak density. Accordingly, our two data sets do not support the assumption of a higher annual growth rate in autumnal moth populations subsequent to mast seeding of the host, thereby contradicting the predictions of the mast depression hypothesis. Temperatures, when indexed by the North Atlantic Oscillation and accumulated thermal sums, were observed to correlate with the abundance or rate of population change of the autumnal moth. The factors underlying the regular population cycles of the autumnal moth, however, remain unidentified. Overall, we suggest that the causal agents in cyclic insect population dynamics should be clarified by field experimentation, since trophic interactions are complex and are further modified by abiotic factors such as climate.

show abstract

Section: Introductionmentioning

confidence: 99%

Performance of the cyclic autumnal moth, Epirrita autumnata, in relation to birch mast seeding

et al. 2003

View full text Add to dashboard Cite

show abstract

“…If individual plants are forced to flower in synchrony because of climatic constraints, intraspecific competition may make it advantageous to maximise seed production, at the expense of other activities, in mast years (Selås 2000a). Since vegetative growth is actually low in mast years (e.g.…”

Section: Introductionmentioning

confidence: 99%

Population cycles of autumnal moth, Epirrita autumnata, in relation to birch mast seeding

Selås¹,

Hogstad

Andersson

et al. 2001

Oecologia

Self Cite

View full text Add to dashboard Cite

We investigated the relationship between flowering peaks of the mountain birch, Betula pubescens ssp. czerepanovii, and population levels of the autumnal moth Epirrita autumnata in Ammarnäs, Swedish Lapland, during 1968-2000, and in Budal, Central Norway, during 1972-2000. There was a significant correlation between the two moth series, both of which showed three well-defined population cycles during the study period. In both areas, the population growth index of the moth was negatively related to population size, but also to the number of years since the previous flowering peak of mountain birch. In the northern study area, Ammarnäs, there was an additional positive effect of the winter temperature index, probably due to increased mortality of moth eggs during cold winters. No significant relationships were found between the number of birch female catkins and larval density in the previous 2 years. Both in Ammarnäs and in an area without moth outbreaks in south-eastern Norway, birch flowering was positively related to temperatures during flower bud formation and to the number of years since the previous flowering peak. The results support the idea of a lower content of chemical defence compounds in birch leaves after a mast reproduction, though we cannot exclude the possibility that the negative relationship between flowering and moth population levels was influenced or caused by stress associated with defoliation during moth outbreaks.

show abstract

“…Because flowering and seed production of bilberry are synchronized by physical factors (Selå s 2000), such as temperatures and precipitation, which usually operates at regional or national scales, we assume that this index will reflect much of the variation in bilberry seed crops in large parts of southern Norway, including the moth and rodent trapping areas. A significant positive correlation between the bilberry index and the bank vole index from Vang has already been demonstrated, for the period 2000(Selå s et al 2011a). …”

Section: Plant Reproduction Indicesmentioning

confidence: 74%

Population fluctuations of moths and small rodents in relation to plant reproduction indices in southern Norway

2013

Self Cite

View full text Add to dashboard Cite

Abstract. Trophic interaction hypotheses for multiannual population fluctuations of herbivores include the predation hypothesis, the induction hypothesis and the plant stress hypothesis. Spatial synchrony is best explained by plant stress, such as high reproduction, because weather may synchronize resource allocation in plants over large areas. We used a 29-yr time series on moth light trapping (6 selected species) and small rodent snap trapping (2 selected species) from southern Norway to test whether herbivore population fluctuations can be related to sexual reproduction of their host plants. The fluctuation pattern of the moths Parashwammerdamia lutarea and Yponomeuta padella, feeding on leaves of rowan (Sorbus aucuparia), could be explained by fluctuations in an annual index of rowanberry production, whereas the fluctuation pattern of Yponomeuta evonymella, feeding on leaves of bird cherry (Prunus padus), could not. The moth Eulithis populata, feeding on bilberry (Vaccinium myrtillus) leaves, fluctuated in synchrony with the bank vole (Myodes clethrionomys), which feeds on bilberry twigs in winter. E. populata and the bank vole also fluctuated in synchrony with a shorter index on bilberry seed crops. Finally, two moths feeding on mosses, Eudonia truncicolella and Catoptria falsella, fluctuated in synchrony with the moss-feeding wood lemming (Myopus schisticolor). The observed patterns could be caused by a positive effect of the supply of highly nutritious reproductive plant tissue, but the one-year delayed response by the rodents, which to a large extent feed on the plant species in question during winter, suggests that feeding deterrents are involved.

show abstract

Seed production of a masting dwarf shrub, Vaccinium myrtillus, in relation to previous reproduction and weather

Cited by 66 publications

References 24 publications

Performance of the cyclic autumnal moth, Epirrita autumnata, in relation to birch mast seeding

Performance of the cyclic autumnal moth, Epirrita autumnata, in relation to birch mast seeding

Population cycles of autumnal moth, Epirrita autumnata, in relation to birch mast seeding

Population fluctuations of moths and small rodents in relation to plant reproduction indices in southern Norway

Contact Info

Product

Resources

About